WO2023157088A1 - Pre-chamber combustion four-stroke engine - Google Patents
Pre-chamber combustion four-stroke engine Download PDFInfo
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- WO2023157088A1 WO2023157088A1 PCT/JP2022/005988 JP2022005988W WO2023157088A1 WO 2023157088 A1 WO2023157088 A1 WO 2023157088A1 JP 2022005988 W JP2022005988 W JP 2022005988W WO 2023157088 A1 WO2023157088 A1 WO 2023157088A1
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- Prior art keywords
- chamber
- combustion
- spark plug
- stroke engine
- cylinder head
- Prior art date
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- 238000002485 combustion reaction Methods 0.000 title claims abstract description 193
- 238000001816 cooling Methods 0.000 claims abstract description 119
- 239000000446 fuel Substances 0.000 claims abstract description 103
- 238000004891 communication Methods 0.000 claims abstract description 30
- 238000002347 injection Methods 0.000 claims abstract description 26
- 239000007924 injection Substances 0.000 claims abstract description 26
- 239000002826 coolant Substances 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims description 54
- 230000002093 peripheral effect Effects 0.000 claims description 30
- 239000000203 mixture Substances 0.000 claims description 21
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 6
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 239000011651 chromium Substances 0.000 claims description 6
- 230000005484 gravity Effects 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 239000010935 stainless steel Substances 0.000 claims description 6
- 229910001220 stainless steel Inorganic materials 0.000 claims description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 5
- 230000008018 melting Effects 0.000 claims description 5
- 230000004323 axial length Effects 0.000 claims description 4
- 239000003054 catalyst Substances 0.000 abstract description 11
- 239000008246 gaseous mixture Substances 0.000 abstract 2
- 238000010586 diagram Methods 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 229910000838 Al alloy Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 229910000881 Cu alloy Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- QZLJNVMRJXHARQ-UHFFFAOYSA-N [Zr].[Cr].[Cu] Chemical compound [Zr].[Cr].[Cu] QZLJNVMRJXHARQ-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- ZTXONRUJVYXVTJ-UHFFFAOYSA-N chromium copper Chemical compound [Cr][Cu][Cr] ZTXONRUJVYXVTJ-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B19/00—Engines characterised by precombustion chambers
- F02B19/12—Engines characterised by precombustion chambers with positive ignition
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P3/00—Liquid cooling
- F01P3/02—Arrangements for cooling cylinders or cylinder heads
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
- F01P3/00—Liquid cooling
- F01P3/12—Arrangements for cooling other engine or machine parts
- F01P3/16—Arrangements for cooling other engine or machine parts for cooling fuel injectors or sparking-plugs
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/02—Details
- H01T13/16—Means for dissipating heat
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/46—Sparking plugs having two or more spark gaps
- H01T13/467—Sparking plugs having two or more spark gaps in parallel connection
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/54—Sparking plugs having electrodes arranged in a partly-enclosed ignition chamber
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B19/00—Engines characterised by precombustion chambers
- F02B2019/006—Engines characterised by precombustion chambers with thermal insulation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Definitions
- This invention relates to a pre-combustion four-stroke engine having a main combustion chamber and a pre-combustion chamber.
- Patent Document 1 Conventionally, there is known a pre-combustion four-stroke engine having a main combustion chamber and a pre-combustion chamber that communicate with each other through a plurality of communication holes, as disclosed in Patent Document 1, for example.
- the air-fuel mixture inside the pre-chamber is ignited by a spark plug.
- the pre-combustion four-stroke engine of Patent Document 1 does not have a pre-chamber fuel injection valve that injects fuel into the pre-chamber, but has an intake passage injection valve that injects fuel into the intake passage.
- the intake manifold injection valve of Patent Document 1 is controlled such that a stoichiometric or richer than stoichiometric air-fuel mixture is produced in the main combustion chamber.
- the pre-combustion four-stroke engine of Patent Document 1 has a cooling jacket (cooling section) in the cylinder head. Further, the pre-combustion four-stroke engine of Patent Document 1 has an auxiliary spark plug (ignition auxiliary device) that assists the ignition of the air-fuel mixture in the main combustion chamber.
- auxiliary spark plug ignition auxiliary device
- pre-combustion four-stroke engine such as that disclosed in Patent Document 1
- the area around the plurality of communicating holes and the electrode portion of the spark plug become hot. Since these parts become particularly hot under high load, pre-ignition tends to occur in the vicinity of these parts.
- pre-ignition is a phenomenon in which an air-fuel mixture self-ignites before being ignited by a spark plug. If the volume of the cooling jacket is increased in order to suppress the occurrence of pre-ignition, the size of the cylinder head will be increased.
- An object of the present invention is to provide a pre-combustion four-stroke engine that can suppress the occurrence of pre-ignition while suppressing an increase in the size of the cylinder head.
- a pre-combustion four-stroke engine has the following configuration.
- a main combustion chamber to which an intake passage and an exhaust passage are connected, a throttle valve that adjusts the amount of air that passes through the intake passage and is sucked into the main combustion chamber, gasoline fuel, alcohol fuel, or a mixture of gasoline and alcohol.
- an intake passage injection valve for injecting liquid fuel, which is fuel, into the interior of the intake passage;
- a pre-combustion chamber having a pre-chamber communicating with an internal space of the main combustion chamber and exposing a part of the pre-chamber spark plug to the internal space, and a control device for controlling the intake passage injection valve and the pre-chamber spark plug. It is a 4 stroke engine.
- the control device provides a first air-fuel ratio or The intake manifold injection valve is controlled so that the second air-fuel ratio is richer than the first air-fuel ratio.
- the pre-combustion four-stroke engine has neither a pre-combustion fuel injection valve for injecting fuel into the pre-combustion chamber nor an ignition assist device for assisting ignition of the air-fuel mixture in the pre-combustion chamber or the main combustion chamber.
- the cylinder head has a cooling portion that accommodates a cooling medium that receives heat from the electrode portion of the pre-chamber spark plug and the sub-chamber wall portion in which the plurality of communication holes are formed.
- the electrode portion of the pre-chamber spark plug is formed so that a plurality of spark discharges are generated in the electrode portion in a circumferentially distributed manner, and the plurality of communication holes are formed in a circumferentially-distributed manner to provide the pre-chamber spark.
- the cylinder head is formed such that a plurality of heat paths from the electrode portion of the plug to the cooling portion and a plurality of heat paths from the auxiliary chamber wall portion to the cooling portion are formed separately in the circumferential direction. is formed.
- the liquid fuel which is gasoline fuel, alcohol fuel, or gasoline-alcohol mixed fuel
- the air-fuel mixture mixed in the intake passage and the main combustion chamber has the first air-fuel ratio or a second air-fuel ratio that is richer than the first air-fuel ratio. Therefore, even when the load is low, there are many positions in the interior space of the pre-chamber where the air-fuel mixture is likely to ignite.
- pre-chamber spark when using, for example, a spark plug having an electrode portion including a plurality of ground electrodes arranged in the circumferential direction or an annular ground electrode as the pre-chamber spark plug, pre-chamber spark A plurality of spark discharges can be dispersively generated in the circumferential direction at the electrode portion of the plug. A plurality of spark discharges dispersively occur in the circumferential direction, thereby dispersively generating heat in the circumferential direction at the electrode portion of the pre-chamber spark plug. Moreover, a plurality of communication holes are formed dispersedly in the circumferential direction. Therefore, heat is dispersively generated in the circumferential direction in the sub-chamber wall portion in which the plurality of communication holes are formed.
- the cylinder head is formed such that a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion and a plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed separately in the circumferential direction. is formed. Therefore, heat tends to move from the electrode portion and the wall portion of the pre-chamber spark plug, which are particularly hot, to the cooling portion. Further, if an auxiliary ignition device such as a spark plug is provided in the main combustion chamber, the temperature of the auxiliary ignition device also becomes high, so heat is less likely to move from a position of the auxiliary chamber wall portion close to the auxiliary ignition device.
- auxiliary ignition device Since no auxiliary ignition device is provided in the main combustion chamber, it is possible to increase the uniformity in the circumferential direction of the ease of heat transfer from the pre-chamber wall to the cooling part, so heat is transferred from the pre-chamber wall. It's easy to do. Further, if an auxiliary ignition device is provided in the pre-combustion chamber, the temperature of the auxiliary ignition device will also be high, so that heat will not easily move from a position close to the auxiliary ignition device in the electrode portion of the pre-combustion chamber spark plug. Since the pre-chamber spark plug is not provided with an auxiliary ignition device, it is possible to improve the uniformity in the circumferential direction of the ease of heat transfer from the electrode portion of the pre-chamber spark plug to the cooling portion.
- Heat is easily transferred from the electrodes.
- heat is easily transferred from the electrode portion and the wall portion of the pre-chamber spark plug to the cooling portion, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cooling portion.
- an ignition auxiliary device is not provided, it is possible to further suppress an increase in the size of the cylinder head. Therefore, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cylinder head.
- a pre-combustion four-stroke engine may have the following configuration.
- the base material of the auxiliary chamber wall has a melting point higher than that of the base material of the cylinder head, a value obtained by multiplying specific heat and specific gravity is higher than that of the base material of the cylinder head, and thermal conductivity is the same as that of chromium-based stainless steel. higher than that.
- the base material of the pre-chamber wall has a higher melting point than the base material of the cylinder head. Therefore, the heat resistance of the pre-chamber wall can be ensured.
- the value obtained by multiplying the specific heat and the specific gravity of the base material of the auxiliary chamber wall is higher than that of the base material of the cylinder head.
- the value obtained by multiplying the specific heat by the specific gravity represents the heat capacity per unit volume. The larger the heat capacity per unit volume, the more difficult it is for the temperature to rise.
- the base material of the pre-chamber wall By forming the base material of the pre-chamber wall from a material that has a higher heat capacity per unit volume than the base material of the cylinder head, the temperature rise of the pre-chamber wall can be suppressed and the high-temperature pre-chamber wall can be dissipated from the cylinder head. Heat is easily transferred to the cooling portion formed in the Also, the base material of the pre-chamber wall portion has a thermal conductivity equal to or higher than that of chromium-based stainless steel. Therefore, heat is more easily transferred from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration. Except for the pre-chamber spark plug, no projection is formed on the inner surface of the pre-chamber, and the axial length of the pre-chamber spark plug in the internal space of the pre-chamber extends in the axial direction of the plug in the internal space of the pre-chamber. Less than twice the maximum length in the orthogonal direction.
- the length of the internal space of the pre-chamber in the axial direction of the plug is smaller than twice the maximum length of the internal space of the pre-chamber in the direction orthogonal to the axial direction of the plug. Therefore, the peripheral length of the pre-chamber can be made longer while securing the volume of the pre-chamber. As a result, more heat paths can be secured from the auxiliary chamber wall portion to the cooling portion. Therefore, heat is more likely to move from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration.
- the pre-chamber wall portion is formed to protrude into the internal space of the main combustion chamber, and the plug shaft of the pre-chamber spark plug passes through the internal space of the pre-chamber without passing through the outer surface of the pre-chamber wall portion.
- the internal space of the pre-combustion chamber is divided into two spaces by any plane orthogonal to the direction, the volume of the space closer to the main combustion chamber out of the two spaces is
- the sub-chamber is formed so as to have a smaller volume than the space farther from the main combustion chamber.
- the auxiliary chamber wall protrudes into the internal space of the main combustion chamber, the amount of protrusion is small. Therefore, heat is less likely to accumulate in the pre-chamber wall, and heat is likely to move from the pre-chamber wall to the cooling section. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration.
- a plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug.
- the pre-chamber spark plug since the pre-chamber spark plug is close to the cooling portion, the heat of the electrode portion of the pre-chamber spark plug is easily transferred to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration. a pre-chamber member, the interior space of which is separate from both the cylinder head body and the pre-chamber spark plug, the interior space of which is partly exposed to the interior space of the main combustion chamber, and which includes the pre-chamber wall portion; It is a space surrounded by the pre-chamber spark plug.
- the pre-chamber member can be elongated in the axial direction of the pre-chamber spark plug while maintaining the shape and size of the internal space of the spark plug. Therefore, when the material of the pre-chamber member is made of a material that facilitates heat transfer, the heat is more easily transferred from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration.
- a plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber member.
- a pre-combustion four-stroke engine may have the following configuration.
- a portion of the inner surface of the cooling portion is at least a portion of the outer peripheral surface of the sub chamber member.
- the cooling medium flowing through the cooling portion contacts the outer peripheral surface of the pre-chamber member. Therefore, heat is more easily transferred from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration.
- a male thread formed on the pre-chamber spark plug engages and contacts a female thread formed on the sub-chamber member.
- the contact area between the pre-chamber spark plug and the pre-chamber member is large. Therefore, heat is easily transferred from the pre-chamber spark plug to the pre-chamber member. Therefore, heat is easily transferred from the electrode portion of the pre-chamber spark plug to the cooling portion via the pre-chamber member. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration.
- a plane passing through the cooling portion and orthogonal to the axial direction of the plug of the pre-chamber spark plug passes through a portion where the male thread formed in the pre-chamber spark plug engages and contacts the female thread formed in the pre-chamber member. .
- the pre-chamber member is close to the cooling section, heat is more easily transferred from the pre-chamber wall portion to the cooling section. Furthermore, since the threaded contact portion between the pre-chamber spark plug and the pre-chamber member is close to the cooling portion, heat is more easily transferred from the electrode portion of the pre-chamber spark plug to the cooling portion via the pre-chamber member. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration.
- An outer peripheral surface of the sub chamber member is in contact with the cylinder head body.
- a pre-combustion four-stroke engine may have the following configuration.
- a plane that passes through the internal space of the pre-chamber and is perpendicular to the plug axial direction of the pre-chamber spark plug passes through a portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body.
- the internal space of the pre-chamber is close to the portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body. Therefore, the pre-chamber wall portion is close to the portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body. Therefore, heat is likely to move from the auxiliary chamber wall portion to the cylinder head body. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration.
- a plane passing through the internal space of the pre-chamber and orthogonal to the axial direction of the plug passes through a portion where a male thread formed in the pre-chamber member meshes and contacts a female thread formed in the cylinder head body.
- the contact area between the pre-chamber member and the cylinder head body is large. Therefore, heat is more easily transferred from the pre-chamber member to the cylinder head body. As a result, the occurrence of pre-ignition can be further suppressed.
- a pre-combustion four-stroke engine may have the following configuration. There is no main combustion chamber fuel injection valve for injecting fuel into the main combustion chamber.
- the low load region is the lower region when the region from the lowest to the highest engine load is divided into two equal parts.
- the air-fuel ratio which is the mixture ratio of fuel and air, is expressed by a first air-fuel ratio, a second air-fuel ratio and a third air-fuel ratio.
- the first air-fuel ratio is an air-fuel ratio that can be processed by the three-way catalyst after combustion.
- the first air-fuel ratio may be a stoichiometric ratio or a window of air-fuel ratios that includes the stoichiometric air-fuel ratio.
- the first air-fuel ratio may be an air-fuel ratio near the stoichiometric air-fuel ratio.
- the first air-fuel ratio may be a window that includes air-fuel ratios near the stoichiometric air-fuel ratio and does not include the stoichiometric air-fuel ratio.
- the second air-fuel ratio is a richer air-fuel ratio than the first air-fuel ratio. If the first air-fuel ratio is an air-fuel ratio near the stoichiometric air-fuel ratio or in a window that does not include the stoichiometric air-fuel ratio, the second air-fuel ratio may or may not be richer than the stoichiometric air-fuel ratio. good.
- the third air-fuel ratio is an air-fuel ratio that is leaner than the first air-fuel ratio. In the present invention and embodiments, rich means that the mixture is rich in fuel.
- the air-fuel ratio that can be processed by the three-way catalyst after combustion is the air-fuel ratio of the air-fuel mixture at which the exhaust gas generated after the combustion of the mixture can be processed by the three-way catalyst.
- the control device controls the air-fuel ratio so that the air-fuel mixture mixed in the intake passage and the main combustion chamber has a stoichiometric air-fuel ratio or an air-fuel ratio richer than the stoichiometric air-fuel ratio in at least a part of the low load region.
- the intake manifold injection valve may be controlled.
- the pre-combustion four-stroke engine of the present invention has a catalyst disposed in the exhaust passage.
- the pre-combustion four-stroke engine of the present invention may have a three-way catalyst arranged in the exhaust passage.
- the pre-combustion four-stroke engine of the present invention may have a catalyst other than a three-way catalyst located in the exhaust passage.
- the pre-combustion four-stroke engine of the present invention has an oxygen sensor which is arranged between the main combustion chamber and the catalyst and which detects the oxygen concentration of the exhaust gas flowing through the exhaust passage.
- the ignition assist device that assists the ignition of the air-fuel mixture in the pre-combustion chamber or the main combustion chamber is, for example, a device that generates microwave discharge, a device that generates dielectric barrier discharge (silent discharge). , or a spark plug that ignites the mixture in the main combustion chamber.
- the fact that the pre-combustion four-stroke engine does not have an auxiliary ignition device means not only that an auxiliary ignition device separate from the pre-combustion chamber spark plug is not provided, but also that the pre-combustion chamber spark plug not have the function of an ignition assist device.
- volume of the pre-chamber is smaller than that of the main combustion chamber means that the volume of the pre-chamber is smaller than the minimum volume of the main combustion chamber.
- volume of the main combustion chamber changes as the piston moves.
- the volume of the pre-chamber is the volume of the internal space of the pre-chamber.
- the internal space of the sub chamber does not include the internal spaces of the plurality of communication holes.
- the inner surface of the pre-chamber is the surface forming the internal space of the pre-chamber.
- the pre-chamber spark plug forms part of the inner surface of the pre-chamber.
- the sub-chamber wall portion in which a plurality of communication holes are formed is a wall portion having one side exposed to the internal space of the main combustion chamber.
- the auxiliary chamber wall portion may be formed so as to protrude into the internal space of the main combustion chamber, or may be formed so as not to protrude.
- the cooling medium is liquid or gas.
- the liquid cooling medium may be, for example, water or lubricating oil.
- the gaseous cooling medium may be air, for example.
- the cooling section in which the cooling medium is accommodated is at least one chamber or at least one passageway.
- a cooling medium may flow through the cooling section.
- a passage through which the cooling medium flowing into the cooling unit flows and a passage through which the cooling medium discharged from the cooling unit flows may be connected to the cooling unit.
- the cooling section may be multiple chambers or multiple passages that are not in communication with each other.
- a heat path is a path through which heat moves.
- the plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion are not limited to independent heat paths. That is, heat may be transferable between multiple heat paths. The same applies to the definition of a plurality of heat paths from the pre-chamber wall portion to the cooling portion in the present invention and the embodiments.
- the electrode portion of the pre-chamber spark plug includes at least one center electrode and at least one ground electrode.
- the electrode section may include, for example, a single center electrode and multiple or annular ground electrodes.
- the plurality of ground electrodes may be, for example, two ground electrodes.
- the plurality of ground electrodes may be, for example, three or more ground electrodes.
- When the electrode section has a single center electrode and multiple ground electrodes multiple discharge gaps are formed.
- an annular discharge gap is formed. A spark discharge occurs in the discharge gap.
- the plug axial direction of the pre-chamber spark plug is a direction parallel to the central axis of the pre-chamber spark plug.
- the plug axial direction of the pre-combustion chamber spark plug may or may not be parallel to the central axis of the cylinder hole forming the main combustion chamber.
- a plurality of spark discharges are distributed in the circumferential direction means that the positions where the spark discharges occur are distributed in the circumferential direction.
- the phrase "a plurality of spark discharges are distributed in the circumferential direction” does not mean that a plurality of spark discharges are simultaneously generated at positions distributed in the circumferential direction.
- a plurality of spark discharges may occur simultaneously at positions dispersed in the circumferential direction. In this case, at least one spark discharge among the plurality of spark discharges generated at the same time serves as the starting point of ignition.
- the circumferential direction in the sentence "a plurality of spark discharges are dispersed in the circumferential direction" is, for example, the circumferential direction centered on a straight line parallel to the plug axial direction of the pre-chamber spark plug.
- An example of a case where a plurality of spark discharges are not dispersed in the circumferential direction is a case where the electrode section has a single center electrode and a single ground electrode.
- Another example of a case in which a plurality of spark discharges are not dispersed in the circumferential direction is that the electrode section consists of a single center electrode, a mainly used first ground electrode, and an auxiliary used second ground electrode. This is the case with the ground electrode.
- Another example of a case in which a plurality of spark discharges are not dispersed in the circumferential direction is a case in which positions where the air-fuel mixture is likely to ignite are not substantially uniform in the circumferential direction due to variations in the concentration of the air-fuel mixture inside the pre-chamber.
- Specific examples of the case where a plurality of spark discharges are not distributed in the circumferential direction are not limited to these.
- a plurality of communication holes are formed dispersedly in the circumferential direction means that the plurality of communication holes are formed side by side in the circumferential direction without extreme bias.
- a plurality of communication holes are formed dispersedly in the circumferential direction
- the plurality of communication holes are formed side by side in the circumferential direction.
- a plurality of communication holes are formed dispersedly in the circumferential direction does not necessarily mean that the plurality of communication holes are formed at equal intervals in the circumferential direction.
- the circumferential direction in the sentence "a plurality of communication holes are formed dispersedly in the circumferential direction” is, for example, the circumferential direction centered on a straight line parallel to the plug axial direction of the pre-chamber spark plug.
- a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion are formed in a circumferentially distributed manner
- the heat path from the electrode portion of the pre-chamber spark plug to the cooling portion It means that the amount of heat that moves is distributed in the circumferential direction. In other words, it means that the degree of easiness of heat transfer from the electrode portion of the pre-chamber spark plug to the cooling portion is substantially uniform in the circumferential direction.
- the circumferential direction in the sentence "a plurality of heat paths from the electrode part of the pre-chamber spark plug to the cooling part are formed in a circumferentially distributed manner" means, for example, a straight line parallel to the plug axial direction of the pre-chamber spark plug. is the circumferential direction centered on .
- "a plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed in a circumferentially distributed manner" means that the amount of heat transferred from the pre-chamber wall portion to the cooling portion is distributed in the circumferential direction.
- the circumferential direction in the sentence “a plurality of heat paths from the pre-chamber wall portion to the cooling portion are dispersed in the circumferential direction” means, for example, a straight line parallel to the axial direction of the pre-chamber spark plug. in the circumferential direction. This may be the same as the circumferential direction in which the plurality of communication holes are arranged.
- the electrode portion is formed so that a plurality of spark discharges generated in the electrode portion are dispersed in the circumferential direction. That is, the heat generated in the electrode portion is distributed in the circumferential direction.
- the cooling portion and the portion between the pre-chamber wall portion and the cooling portion in the cylinder head are important. becomes.
- the cooling portion when the cooling portion is formed in an annular shape, a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion and a plurality of heat paths from the sub-chamber wall portion to the cooling portion are arranged in the circumferential direction. It tends to be dispersed and formed. For example, if the structure (shape and material) of the portion between the pre-chamber spark plug and the cooling section in the cylinder head is substantially uniform in the circumferential direction, multiple heat paths from the electrode section of the pre-chamber spark plug to the cooling section are generated. It tends to be dispersed in the circumferential direction.
- a plurality of heat sources from the electrode portion of the pre-chamber spark plug to the cooling portion may be generated. Paths are likely to be formed dispersed in the circumferential direction.
- An example of a case where a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion is not formed in a circumferentially distributed manner is when the cooling portion is formed only in an area of about half of the circumference. This example may be an example in which a plurality of heat paths from the pre-chamber wall portion to the cooling portion are not formed dispersedly in the circumferential direction.
- Another example of a case in which a plurality of heat paths from the pre-chamber wall to the cooling section is not formed in a distributed manner in the circumferential direction is that the pre-chamber wall to the cooling section is formed in one half area and the other half area of the circumference. This is the case where the materials between are different.
- a specific example in which the plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion is not formed in the circumferential direction, and the case where the plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed in the circumferential direction.
- Specific examples of the case where the particles are not formed dispersedly are not limited to these.
- the base material of the pre-chamber wall portion is the material of the portion occupying the largest volume among the plurality of portions.
- the auxiliary chamber wall portion does not have to be composed of a plurality of portions made of different materials.
- the base material of the cylinder head is the material of the portion occupying the largest volume among the plurality of portions.
- the portion occupying the largest volume among the plurality of portions of different materials forming the cylinder head does not include the pre-chamber wall portion.
- the cylinder head includes the auxiliary chamber wall.
- the cylinder head body partially exposed to the interior space of the main combustion chamber does not include the auxiliary chamber wall.
- the base material of the cylinder head body is the same as the base material of the cylinder head.
- the cylinder head body may or may not consist of multiple parts of different materials.
- the fact that the base material of the pre-combustion chamber wall has a thermal conductivity equal to or higher than that of chromium-based stainless steel means It means that the thermal conductivity of the base material of the pre-chamber wall is equal to or higher than that of chromium-based stainless steel under temperature conditions.
- the temperature of the main combustion chamber and the pre-combustion chamber during operation of the pre-combustion four-stroke engine is, for example, about 850 to 1000.degree.
- the axial length of the internal space of the pre-chamber is the axial length of the plug between one end and the other end of the internal space of the pre-chamber in the axial direction of the plug.
- a plane passing through one end of the internal space of the pre-chamber in the axial direction of the plug and perpendicular to the axial direction of the plug, and a plane passing through the other end of the internal space of the pre-chamber in the axial direction of the plug and perpendicular to the axial direction of the plug. is the distance between
- the definition of the length of the interior space of the pre-chamber in one direction perpendicular to the axial direction of the plug is the same as above.
- the maximum length of the interior space of the pre-chamber in the direction perpendicular to the axial direction of the plug is the maximum length among the lengths of the interior space of the pre-chamber in a plurality of directions perpendicular to the axial direction of the plug. length.
- the plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug. It does not mean that all orthogonal planes pass through the pre-chamber spark plug, but means that any plane that passes through the cooling portion and is perpendicular to the axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug. .
- the plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber member
- the plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug The plane passes through the place where the male thread formed in the pre-chamber spark plug engages and contacts the female thread formed in the pre-chamber member," and “the plane passes through the internal space of the pre-chamber and is orthogonal to the plug axial direction of the pre-chamber spark plug.
- the sentence “the plane that contacts the cylinder head body passes through the portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body” is also interpreted in the same manner as above.
- the sub-chamber member is separate from the cylinder head main body partly exposed to the internal space of the main combustion chamber
- the sub-chamber member is separated from the cylinder head main body.
- the sub-chamber member is in separable contact with the cylinder head body.
- the cylinder head main body may be composed of one inseparable member, or composed of a plurality of separable members each partially exposed to the internal space of the main combustion chamber. may be In the case where the cylinder head body is composed of a plurality of separable members, the cylinder head body does not include a member whose part is not exposed to the interior space of the main combustion chamber.
- the pre-chamber member does not include a portion of the electrode portion of the pre-chamber spark plug (for example, the ground electrode).
- the number of an element is not explicitly specified (i.e., when translated into English it appears in the singular), the number of that element is one. may be multiple.
- components whose numbers are not clearly specified include, for example, main combustion chambers, intake passages, exhaust passages, throttle valves, intake passage injection valves, pre-chambers, pre-chamber spark plugs, and the like. be.
- a pre-combustion four-stroke engine according to the present invention and embodiments may have a single main combustion chamber or may have multiple main combustion chambers. That is, the pre-combustion four-stroke engine according to the present invention and the embodiments may be a single-cylinder engine unit or a multi-cylinder engine unit.
- the number of pre-chambers and pre-chamber spark plugs are each the same as the number of main combustion chambers.
- the number of intake manifold injectors may be the same as the number of main combustion chambers or may be greater.
- the number of throttle valves may be the same as the number of main combustion chambers, or it may be less.
- the intake passage may have a shape that branches into two or more. One intake passage is connected to one main combustion chamber. A single branched intake passage may be connected to a plurality of main combustion chambers.
- the exhaust passage may have a shape that branches into two or more.
- the number of exhaust passages connected to one main combustion chamber is one.
- One branched exhaust passage may be connected to a plurality of main combustion chambers.
- the pre-combustion four-stroke engine according to the present invention and the embodiment can be mounted on a straddle-type vehicle that is lighter in weight than an automobile and requires a lighter and smaller engine.
- a straddle-type vehicle refers to a vehicle in general in which the driver straddles a saddle. Straddle-type vehicles include motorcycles, scooters, motor tricycles, ATVs (All Terrain Vehicles), snowmobiles, personal water crafts, and the like.
- the pre-combustion four-stroke engine according to the present invention and the embodiments can be mounted on a work vehicle that requires a lighter and smaller engine. Needless to say, the pre-combustion four-stroke engine according to the present invention and the embodiments can be mounted on automobiles.
- the product equipped with the pre-combustion four-stroke engine according to the present invention and the embodiments is not limited to a specific product.
- the pre-combustion four-stroke engine that is one embodiment of the present invention is mounted on a product, it may be mounted so that the central axis of the cylinder hole is 0 degrees or more and 45 degrees or less with respect to the vertical, or 45 degrees. You may mount so that it may become more than 90 degrees or less.
- the pre-combustion four-stroke engine of the present invention it is possible to suppress the occurrence of pre-ignition while suppressing the enlargement of the cylinder head.
- FIG. 1(a) to 1(f) are schematic diagrams of a pre-combustion four-stroke engine according to a first embodiment of the present invention.
- FIG. 2(a) is a schematic diagram of a pre-combustion four-stroke engine according to a third embodiment of the present invention
- FIG. 2(b) is a schematic diagram of a pre-combustion four-stroke engine according to a fourth embodiment of the present invention.
- It is a diagram.
- 3(a) to 3(c) are schematic diagrams of three examples of a pre-combustion four-stroke engine according to a fifth embodiment of the present invention.
- 4(a) to 4(e) are schematic diagrams of five examples of a pre-combustion four-stroke engine according to a fifth embodiment of the present invention.
- 5(a) and 5(b) are schematic diagrams of two examples of a pre-combustion four-stroke engine according to a fifth embodiment of the present invention.
- FIG. 1(b) shows an example of a part of the AA cross section of FIG. 1(a).
- FIGS. 1(c) and 1(d) show two examples of a portion of the BB cross-section of FIG. 1(a).
- FIGS. 1(e) and 1(f) show two examples of a portion of the CC line section of FIG. 1(a).
- the pre-combustion four-stroke engine 1 according to the first embodiment has at least one main combustion chamber 2 .
- An intake passage 5 and an exhaust passage 6 are connected to the main combustion chamber 2 .
- a main combustion chamber 2 is formed by a cylinder head 10 , a cylinder bore 11 and a piston 12 .
- the intake passage 5 includes a passage formed inside the cylinder head 10 and a passage connected to this passage.
- the exhaust passage 6 includes a passage formed inside the cylinder head 10 and a passage connected to this passage.
- the pre-combustion four-stroke engine 1 has at least one throttle valve 7 .
- the throttle valve 7 adjusts the amount of air that passes through the intake passage 5 and is drawn into the main combustion chamber 2 .
- the pre-combustion four-stroke engine 1 has at least one intake manifold injection valve 8 .
- the intake passage injection valve 8 injects liquid fuel, which is gasoline fuel, alcohol fuel, or gasoline-alcohol mixed fuel, into the intake passage 5 .
- the pre-combustion four-stroke engine 1 has at least one pre-combustion chamber 20 .
- the internal space of the auxiliary chamber 20 communicates with the internal space of the main combustion chamber 2 through a plurality of communication holes 21 .
- the auxiliary chamber 20 has a smaller volume than the main combustion chamber 2 .
- a part of the pre-chamber spark plug 23 is exposed in the internal space of the pre-chamber 20 .
- a sub chamber 20 is formed in the cylinder head 10 .
- a plurality of communication holes 21 are formed in the auxiliary chamber wall portion 22 of the cylinder head 10 .
- the auxiliary chamber wall portion 22 has one side exposed to the internal space of the main combustion chamber 2 .
- the relationship between the position of the central axis C11 of the cylinder hole 11 and the position of the central axis C23 of the pre-chamber spark plug 23 is not limited to the positional relationship shown in FIGS. 1(a) and 1(b).
- a direction parallel to the central axis C23 of the pre-chamber spark plug 23 is defined as a plug axial direction DP. 1(a) and 1(b), the plug axial direction DP is parallel to the central axis C11 of the cylinder hole 11, but the plug axial direction DP need not be parallel to the central axis C11 of the cylinder hole 11. .
- the shape of the internal space of the auxiliary chamber 20 is not limited to the shape shown in FIGS. 1(a) and 1(b).
- the pre-combustion four-stroke engine 1 has a control device 70 that controls at least one intake manifold injection valve 8 and at least one pre-chamber spark plug 23 .
- the control device 70 sets the first air-fuel ratio or
- the intake manifold injection valve 8 is controlled so that the second air-fuel ratio is richer than the first air-fuel ratio.
- the control device 70 controls the intake passage so that the air-fuel mixture mixed in the intake passage 5 and the main combustion chamber 2 becomes the first air-fuel ratio that can be processed by the three-way catalyst after combustion in at least a part of the low load region.
- Injection valve 8 may be controlled.
- the pre-combustion four-stroke engine 1 may or may not have a three-way catalyst.
- the pre-combustion four-stroke engine 1 has neither a pre-combustion fuel injection valve for injecting fuel into the pre-combustion chamber 20 nor an ignition assist device for assisting ignition of the air-fuel mixture in the pre-combustion chamber 20 or the main combustion chamber 2. .
- the cylinder head 10 accommodates a cooling medium (not shown) that receives heat from the electrode portion 24 and the sub chamber wall portion 22 of the pre chamber spark plug 23. It has a cooling part 16 that is Although the cooling portion 16 is annular in FIG. 1(b), the cooling portion 16 may not be annular.
- the electrode portion 24 of the pre-chamber spark plug 23 is formed so that a plurality of spark discharges 33 are generated in the electrode portion 24 in a circumferentially distributed manner.
- a plurality of communication holes 21 are formed dispersedly in the circumferential direction.
- the cylinder head 10 has a plurality of heat paths 14 from the electrode portion 24 of the pre-chamber spark plug 23 to the cooling portion 16 and a plurality of heat paths 15 from the pre-chamber wall portion 22 to the cooling portion 16 distributed in the circumferential direction. It is formed to be formed by For example, the plurality of spark discharges 33, the plurality of communication holes 21, the plurality of heat paths 14, and the plurality of heat paths 15 are distributed in the circumferential direction around the center axis C23 of the pre-chamber spark plug 23. may be formed.
- the heat path 14 shown in FIG. 1A is merely an example of the heat path 14 from the electrode portion 24 of the pre-chamber spark plug 23 to the cooling portion 16 .
- the configuration of the electrode section 24 is not limited to the configurations shown in FIGS. 1(c) and 1(d).
- the electrode section 24 may have a single center electrode 30 and a plurality of ground electrodes 31, for example, as shown in FIG.
- the electrode section 24 may have a single center electrode 30 and an annular ground electrode 31, for example, as shown in FIG. 1(d).
- the plurality of ground electrodes 31 are configured such that spaces are formed between the ground electrodes 31 .
- the plurality of ground electrodes 31 are separated from the center electrode 30 in a direction orthogonal to the plug axial direction DP.
- the plurality of ground electrodes 31 are not aligned with the center electrode 30 in the plug axial direction DP.
- An inner peripheral end of the ring-shaped ground electrode 31 is separated from the center electrode 30 in a direction orthogonal to the plug axial direction DP.
- the number of ground electrodes 31 may be two, for example.
- the number, positions, shapes, and sizes of the plurality of communication holes 21 are not limited to those shown in FIGS. 1(e) and 1(f).
- the number of communication holes 21 may be, for example, three or more.
- the size of the cooling portion 16 is suppressed and pre-ignition is reduced. It can suppress the occurrence. Moreover, since no auxiliary ignition device is provided, it is possible to further suppress the increase in size of the cylinder head 10 . Therefore, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cylinder head 10 .
- the pre-combustion four-stroke engine 1 in FIG. 1( a ) is formed such that any plane passing through the cooling portion 16 and perpendicular to the plug axial direction DP passes through the pre-chamber spark plug 23 .
- This plane is, for example, a plane that overlaps the AA line in FIG. 1(a).
- the pre-combustion four-stroke engine 1 is formed so that none of the planes passing through the cooling section 16 and perpendicular to the plug axial direction DP pass through the internal space of the pre-chamber 20 .
- the pre-combustion four-stroke engine 1 may be formed such that any plane passing through the cooling portion 16 and orthogonal to the plug axial direction DP passes through the interior space of the pre-chamber 20 .
- the pre-combustion four-stroke engine 1 of the first embodiment does not need to have a main combustion chamber fuel injection valve that injects fuel into the main combustion chamber 2 .
- the pre-combustion four-stroke engine 1 of the first embodiment may have neither a supercharger nor a turbocharger. That is, the pre-combustion four-stroke engine 1 may be of a naturally aspirated type.
- the auxiliary chamber combustion four-stroke engine 1 of the first embodiment need not have an external exhaust gas recirculation device including an external exhaust gas recirculation passage bypassing the main combustion chamber 2 and connecting the exhaust passage 6 and the intake passage 5. .
- a pre-combustion four-stroke engine 1 according to a second embodiment of the present invention will be described.
- the second embodiment has the configuration of the first embodiment.
- the melting point of the base material of the sub chamber wall portion 22 is higher than the melting point of the base material of the cylinder head 10 .
- the value obtained by multiplying the specific heat and specific gravity of the base material of the sub chamber wall portion 22 is higher than the value obtained by multiplying the specific heat and specific gravity of the base material of the cylinder head 10 .
- the thermal conductivity of the base material of the auxiliary chamber wall portion 22 is the same as or higher than that of chromium-based stainless steel.
- a base material of the cylinder head 10 is, for example, aluminum or an aluminum alloy.
- the base material of the cylinder head 10 is aluminum or an aluminum alloy
- materials shown in Examples 1 to 4 in Table 1 below may be used.
- the base material of the auxiliary chamber wall portion 22 may be a chromium-zirconium-copper alloy as in the first embodiment.
- the base material of the auxiliary chamber wall portion 22 may be a chromium-copper alloy.
- Comparative Examples 1 to 3 shown in Table 1 are examples of materials that are not used as the base material of the auxiliary chamber wall portion 22 when the base material of the cylinder head 10 is aluminum or an aluminum alloy.
- the auxiliary chamber wall portion 22 may be composed only of the base material.
- the auxiliary chamber wall portion 22 may be composed of a base material and a material other than the base material.
- the sub-chamber wall portion 22 may have a coating layer of a material different from the base material on at least a portion of the outer surface of the sub-chamber wall portion 22 .
- the thermal conductivity of the coating layer is preferably higher than that of the auxiliary chamber wall portion 22 .
- a pre-combustion four-stroke engine 1 according to a third embodiment of the present invention will be described with reference to FIG. 2(a).
- the pre-combustion four-stroke engine 1 of the third embodiment has the following configuration in addition to the configuration of the first or second embodiment. No projections are formed on the inner surface of the pre-chamber 20 except for the pre-chamber spark plug 23 .
- the length L1 of the internal space of the pre-chamber 20 in the axial direction DP of the plug and the maximum length L2 of the internal space of the sub-chamber 20 in the direction perpendicular to the axial direction DP of the plug, whichever is greater is the length of the smaller one. less than twice.
- the length L2 is longer than the length L1 in FIG. 2(a), the length L1 may be longer than the length L2.
- a pre-combustion four-stroke engine 1 according to a fourth embodiment of the present invention will be described with reference to FIG. 2(b).
- the fourth embodiment has at least one configuration of the first to third embodiments.
- the auxiliary chamber wall portion 22 is formed so as to protrude into the internal space of the main combustion chamber 2 .
- the auxiliary chamber 20 is formed so that the projection amount of the auxiliary chamber wall portion 22 is smaller than the volume of the auxiliary chamber 20 .
- the internal space of the pre-chamber 20 is divided into two spaces by any plane S1 that passes through the internal space of the pre-chamber 20 without passing through the outer surface of the pre-chamber wall portion 22 and perpendicular to the plug axial direction DP.
- the pre-chamber 20 is formed such that the volume of the space closer to the main combustion chamber 2 out of the two spaces is smaller than the volume of the space farther from the main combustion chamber 2 out of the two spaces.
- the plane S1 shown in FIG. 2B is merely an example of a plane S1 that does not pass through the outer surface of the pre-chamber wall portion 22 but passes through the internal space of the pre-chamber 20 and is orthogonal to the axial direction DP of the plug.
- the outer surface of the auxiliary chamber wall portion 22 is the surface exposed to the main combustion chamber 2 .
- 3(a) to 3(c), 4(a) to 4(e), 5(a) and 5 ( b) is used for explanation.
- 3(a) to 3(c) show three examples of the fifth embodiment.
- Figures 4(a) to 4(e) show five examples of the fifth embodiment.
- Figures 5(a) and 5(b) show two examples of the fifth embodiment.
- the fifth embodiment has at least one configuration of the first to fourth embodiments.
- the inner surface of the pre-chamber 20 is formed by the pre-chamber member 25 including the pre-chamber wall portion 22 and the pre-chamber spark plug 23 .
- the internal space of the pre-chamber 20 is a space surrounded by the pre-chamber member 25 and the pre-chamber spark plug 23 .
- the outer peripheral surface of the pre-chamber spark plug 23 and the inner peripheral surface of the pre-chamber member 25 are in contact with each other.
- the pre-chamber member 25 is separate from the cylinder head body 13 partially exposed to the internal space of the main combustion chamber 2 and separate from the pre-chamber spark plug 23 .
- the cylinder head body 13 may be composed of one inseparable member, or may be composed of a plurality of separable members each partly exposed to the internal space of the main combustion chamber 2 . When the cylinder head main body 13 is composed of a plurality of separable members, the cylinder head main body 13 does not include a member whose part is not exposed to the internal space of the main combustion chamber 2 .
- the outer peripheral surface of the sub chamber member 25 may be in contact with the cylinder head body 13.
- a male thread 41 formed in the pre-chamber member 25 may mesh with and be in contact with a female thread 40 formed in the cylinder head body 13.
- any of the planes S2 may pass through a portion of the outer peripheral surface of the sub chamber member 25 that contacts the cylinder head body 13 .
- a plane S2 passing through the contact portion may pass through a portion where the male thread 41 formed in the pre-chamber member 25 meshes and contacts with the female thread 40 formed in the cylinder head body 13, as shown in FIG. 3B, for example. good.
- the plane S2 passing through the contact portion may pass through portions other than the threaded portions (the male thread 41 and the female thread 40) of the pre-chamber member 25 and the cylinder head body 13, as shown in FIG. 3B, for example.
- the outer peripheral surface of the pre-chamber member 25 shown in FIG. 3(c) may be in contact with the cylinder head body 13 at a location not shown.
- the outer peripheral surface of the auxiliary chamber member 25 shown in FIG. 3(c) may be in contact with the cylinder head main body 13 so as to pass through the portion where the contact point is formed.
- the contact portion between the outer peripheral surface of the sub chamber member 25 and the cylinder head main body 13 may be a threaded portion (the male thread 41 and the female thread 40) or may not be a threaded portion.
- the outer peripheral surface of the sub chamber member 25 does not have to be in contact with the cylinder head body 13.
- the outer peripheral surface of the pre-chamber member 25 shown in FIG. 3(c) does not have to come into contact with the cylinder head body.
- the sub chamber member 25 may be connected to the cylinder head body via a member other than the cylinder head body 13 (for example, a cylinder head cover).
- the pre-chamber member 25 and the cooling chamber member 25 are arranged so that any plane S 3 passing through the cooling portion 16 and perpendicular to the axial direction DP of the plug passes through the pre-chamber member 25 .
- a portion 16 may be formed.
- the plane S3 passes through the pre-chamber member 25, for example, as shown in FIGS. There may be.
- the inner surface of the cooling part 16 does not have to include a part of the outer peripheral surface of the pre-chamber member 25, as shown in FIG. 4D, for example. Further, as shown in FIG.
- the pre-chamber member 25 and the cooling section 16 are formed so that none of the planes S3 passing through the cooling section 16 and perpendicular to the axial direction DP of the plug pass through the pre-chamber member 25.
- the relationship between the sub chamber member 25 and the cylinder head body 13 shown in FIGS. 4(a) to 4(d) is not limited to the same relationship as in FIG. 3(a), and may be any of the relationships described above. good.
- the pre-chamber member 25 protrudes into the internal space of the cooling section 16, as shown in FIG. 4B, for example. It may have at least one heat dissipation part 26 .
- the heat radiating portion 26 may or may not be annular.
- the heat radiating portion 26 may have an arc shape larger than a semicircle, or may not have an arc shape.
- the annular heat radiating section 26 may be formed so as to partition the internal space of the cooling section 16 into a plurality of spaces.
- the sub chamber member 25 may have a plurality of heat radiating portions 26 arranged in the plug axial direction DP.
- any plane S3 passing through the cooling part 16 passes through the pre-chamber member 25 (for example, FIGS. 4(a) to 4(d)), any plane S3 passing through the cooling part 16 passes through the pre-chamber member 25.
- the inner peripheral surface may pass through a portion where it contacts the outer peripheral surface of the pre-chamber spark plug 23 .
- any plane S3 passing through the cooling part 16 passes through the pre-chamber member 25, for example, as shown in FIGS.
- the female thread 42 formed on the member 25 may pass through a portion where it meshes and contacts with the male thread 43 formed on the pre-chamber spark plug 23 .
- the cooling unit 16 in FIG. 5A is the same as the cooling unit 16 in FIG. 4A, but may be the same as the cooling unit 16 in FIG. 4B.
- the cooling unit 16 in FIG. 5(b) is the same as the cooling unit 16 in FIG. 4(d), but may be the same as the cooling unit 16 in FIG. 4(c).
- the relationship between the sub chamber member 25 and the cylinder head body 13 shown in FIGS. 5(a) and 5(b) is not limited to the same relationship as that shown in FIG. good.
- the pre-combustion four-stroke engine of the present invention may have a supercharger or a turbocharger.
- a pre-combustion four-stroke engine may have a main combustion chamber fuel injector that injects fuel into the interior of the main combustion chamber.
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Abstract
A pre-chamber combustion four-stroke engine (1) does not comprise an ignition assistance device that assists in ignition of a gaseous mixture, but does comprise a pre-chamber (20) that is in communication with a main combustion chamber (2) via a plurality of communication holes (21), and that is configured so that a portion of a pre-chamber spark plug (23) is exposed to an internal space of the pre-chamber. A control device (70) controls an intake passage injection valve (8) that injects a fuel into an intake passage (5) so that, in at least a part of a low-load region, a gaseous mixture will have a first air–fuel ratio that allows treatment with a three-way catalyst after combustion or a second air–fuel ratio that is richer than the first air–fuel ratio. A cylinder head (10) comprises a cooling section (16) that accommodates a cooling medium that receives heat from an electrode section (24) of the pre-chamber spark plug and a pre-chamber wall section (22) in which the plurality of communication holes are formed. The following are each formed so as to be dispersed in a circumferential direction: a plurality of spark discharges (33) produced by the electrode section of the pre-chamber spark plug; the plurality of communication holes; a plurality of heat paths (14) from the electrode section of the pre-chamber spark plug to the cooling section; and a plurality of heat paths (15) from the pre-chamber wall section to the cooling section.
Description
この発明は、主燃焼室および副室を有する副室燃焼4ストロークエンジンに関する。
This invention relates to a pre-combustion four-stroke engine having a main combustion chamber and a pre-combustion chamber.
従来、例えば特許文献1に開示されているような、複数の連通孔を介して連通する主燃焼室および副室を有する副室燃焼4ストロークエンジンが知られている。副室の内部の混合気はスパークプラグによって点火される。特許文献1の副室燃焼4ストロークエンジンは、副室に燃料を噴射する副室燃料噴射弁を有さず、吸気通路に燃料を噴射する吸気通路噴射弁を有する。特許文献1の吸気通路噴射弁は、ストイキオメトリックまたはストイキオメトリックよりもリッチな空燃比の混合気が主燃焼室に生成されるように制御される。特許文献1の副室燃焼4ストロークエンジンは、冷却ジャケット(冷却部)をシリンダヘッドに有する。また、特許文献1の副室燃焼4ストロークエンジンは、主燃焼室における混合気の点火を補助する補助スパークプラグ(点火補助装置)を有する。
Conventionally, there is known a pre-combustion four-stroke engine having a main combustion chamber and a pre-combustion chamber that communicate with each other through a plurality of communication holes, as disclosed in Patent Document 1, for example. The air-fuel mixture inside the pre-chamber is ignited by a spark plug. The pre-combustion four-stroke engine of Patent Document 1 does not have a pre-chamber fuel injection valve that injects fuel into the pre-chamber, but has an intake passage injection valve that injects fuel into the intake passage. The intake manifold injection valve of Patent Document 1 is controlled such that a stoichiometric or richer than stoichiometric air-fuel mixture is produced in the main combustion chamber. The pre-combustion four-stroke engine of Patent Document 1 has a cooling jacket (cooling section) in the cylinder head. Further, the pre-combustion four-stroke engine of Patent Document 1 has an auxiliary spark plug (ignition auxiliary device) that assists the ignition of the air-fuel mixture in the main combustion chamber.
特許文献1のような副室燃焼4ストロークエンジンにおいては、複数の連通孔の周辺およびスパークプラグの電極部が高温となる。高負荷時にはこれらは特に高温となるため、これらの近傍でプレイグニッションが発生しやすい。なお、プレイグニッションとは、スパークプラグによる点火の前に混合気が自己着火する現象である。仮に、プレイグニッションの発生を抑制するために冷却ジャケットの容積を増大させた場合、シリンダヘッドが大型化してしまう。
In a pre-combustion four-stroke engine such as that disclosed in Patent Document 1, the area around the plurality of communicating holes and the electrode portion of the spark plug become hot. Since these parts become particularly hot under high load, pre-ignition tends to occur in the vicinity of these parts. Note that pre-ignition is a phenomenon in which an air-fuel mixture self-ignites before being ignited by a spark plug. If the volume of the cooling jacket is increased in order to suppress the occurrence of pre-ignition, the size of the cylinder head will be increased.
本発明は、シリンダヘッドの大型化を抑制しつつ、プレイグニッションの発生を抑制できる副室燃焼4ストロークエンジンを提供することを目的とする。
An object of the present invention is to provide a pre-combustion four-stroke engine that can suppress the occurrence of pre-ignition while suppressing an increase in the size of the cylinder head.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有する。
吸気通路および排気通路が接続される主燃焼室と、前記吸気通路を通過して前記主燃焼室に吸入される空気の量を調整するスロットル弁と、ガソリン燃料、アルコール燃料、またはガソリン・アルコール混合燃料である液体燃料を前記吸気通路の内部に噴射する吸気通路噴射弁と、前記主燃焼室よりも容積が小さくなるようにシリンダヘッドに形成され、その内部空間が複数の連通孔を介して前記主燃焼室の内部空間と連通し、その内部空間に副室スパークプラグの一部が露出する副室と、前記吸気通路噴射弁および前記副室スパークプラグを制御する制御装置とを有する副室燃焼4ストロークエンジンである。前記制御装置は、前記スロットル弁の開度が小さい低負荷領域の少なくとも一部において、前記吸気通路および前記主燃焼室で混合された混合気が燃焼後に三元触媒で処理できる第1空燃比または前記第1空燃比よりもリッチな第2空燃比となるように、前記吸気通路噴射弁を制御する。前記副室燃焼4ストロークエンジンは、前記副室に燃料を噴射する副室燃料噴射弁、および、前記副室または前記主燃焼室における混合気の点火を補助する点火補助装置のどちらも有さない。前記シリンダヘッドは、前記副室スパークプラグの電極部および前記複数の連通孔が形成された副室壁部からの熱を受け取る冷却媒体が収容される冷却部を有する。前記電極部に複数の火花放電が周方向に分散して生じるように前記副室スパークプラグの前記電極部が形成され、前記複数の連通孔が周方向に分散して形成され、前記副室スパークプラグの前記電極部から前記冷却部までの複数の熱経路、および、前記副室壁部から前記冷却部までの複数の熱経路が、それぞれ周方向に分散して形成されるように前記シリンダヘッドが形成される。 A pre-combustion four-stroke engine according to one embodiment of the present invention has the following configuration.
A main combustion chamber to which an intake passage and an exhaust passage are connected, a throttle valve that adjusts the amount of air that passes through the intake passage and is sucked into the main combustion chamber, gasoline fuel, alcohol fuel, or a mixture of gasoline and alcohol. an intake passage injection valve for injecting liquid fuel, which is fuel, into the interior of the intake passage; A pre-combustion chamber having a pre-chamber communicating with an internal space of the main combustion chamber and exposing a part of the pre-chamber spark plug to the internal space, and a control device for controlling the intake passage injection valve and the pre-chamber spark plug. It is a 4 stroke engine. In at least a part of a low load region in which the opening of the throttle valve is small, the control device provides a first air-fuel ratio or The intake manifold injection valve is controlled so that the second air-fuel ratio is richer than the first air-fuel ratio. The pre-combustion four-stroke engine has neither a pre-combustion fuel injection valve for injecting fuel into the pre-combustion chamber nor an ignition assist device for assisting ignition of the air-fuel mixture in the pre-combustion chamber or the main combustion chamber. . The cylinder head has a cooling portion that accommodates a cooling medium that receives heat from the electrode portion of the pre-chamber spark plug and the sub-chamber wall portion in which the plurality of communication holes are formed. The electrode portion of the pre-chamber spark plug is formed so that a plurality of spark discharges are generated in the electrode portion in a circumferentially distributed manner, and the plurality of communication holes are formed in a circumferentially-distributed manner to provide the pre-chamber spark. The cylinder head is formed such that a plurality of heat paths from the electrode portion of the plug to the cooling portion and a plurality of heat paths from the auxiliary chamber wall portion to the cooling portion are formed separately in the circumferential direction. is formed.
吸気通路および排気通路が接続される主燃焼室と、前記吸気通路を通過して前記主燃焼室に吸入される空気の量を調整するスロットル弁と、ガソリン燃料、アルコール燃料、またはガソリン・アルコール混合燃料である液体燃料を前記吸気通路の内部に噴射する吸気通路噴射弁と、前記主燃焼室よりも容積が小さくなるようにシリンダヘッドに形成され、その内部空間が複数の連通孔を介して前記主燃焼室の内部空間と連通し、その内部空間に副室スパークプラグの一部が露出する副室と、前記吸気通路噴射弁および前記副室スパークプラグを制御する制御装置とを有する副室燃焼4ストロークエンジンである。前記制御装置は、前記スロットル弁の開度が小さい低負荷領域の少なくとも一部において、前記吸気通路および前記主燃焼室で混合された混合気が燃焼後に三元触媒で処理できる第1空燃比または前記第1空燃比よりもリッチな第2空燃比となるように、前記吸気通路噴射弁を制御する。前記副室燃焼4ストロークエンジンは、前記副室に燃料を噴射する副室燃料噴射弁、および、前記副室または前記主燃焼室における混合気の点火を補助する点火補助装置のどちらも有さない。前記シリンダヘッドは、前記副室スパークプラグの電極部および前記複数の連通孔が形成された副室壁部からの熱を受け取る冷却媒体が収容される冷却部を有する。前記電極部に複数の火花放電が周方向に分散して生じるように前記副室スパークプラグの前記電極部が形成され、前記複数の連通孔が周方向に分散して形成され、前記副室スパークプラグの前記電極部から前記冷却部までの複数の熱経路、および、前記副室壁部から前記冷却部までの複数の熱経路が、それぞれ周方向に分散して形成されるように前記シリンダヘッドが形成される。 A pre-combustion four-stroke engine according to one embodiment of the present invention has the following configuration.
A main combustion chamber to which an intake passage and an exhaust passage are connected, a throttle valve that adjusts the amount of air that passes through the intake passage and is sucked into the main combustion chamber, gasoline fuel, alcohol fuel, or a mixture of gasoline and alcohol. an intake passage injection valve for injecting liquid fuel, which is fuel, into the interior of the intake passage; A pre-combustion chamber having a pre-chamber communicating with an internal space of the main combustion chamber and exposing a part of the pre-chamber spark plug to the internal space, and a control device for controlling the intake passage injection valve and the pre-chamber spark plug. It is a 4 stroke engine. In at least a part of a low load region in which the opening of the throttle valve is small, the control device provides a first air-fuel ratio or The intake manifold injection valve is controlled so that the second air-fuel ratio is richer than the first air-fuel ratio. The pre-combustion four-stroke engine has neither a pre-combustion fuel injection valve for injecting fuel into the pre-combustion chamber nor an ignition assist device for assisting ignition of the air-fuel mixture in the pre-combustion chamber or the main combustion chamber. . The cylinder head has a cooling portion that accommodates a cooling medium that receives heat from the electrode portion of the pre-chamber spark plug and the sub-chamber wall portion in which the plurality of communication holes are formed. The electrode portion of the pre-chamber spark plug is formed so that a plurality of spark discharges are generated in the electrode portion in a circumferentially distributed manner, and the plurality of communication holes are formed in a circumferentially-distributed manner to provide the pre-chamber spark. The cylinder head is formed such that a plurality of heat paths from the electrode portion of the plug to the cooling portion and a plurality of heat paths from the auxiliary chamber wall portion to the cooling portion are formed separately in the circumferential direction. is formed.
この構成によると、ガソリン燃料、アルコール燃料、またはガソリン・アルコール混合燃料である液体燃料は、吸気通路噴射弁から吸気通路に噴射される。また、低負荷領域の少なくとも一部において、吸気通路および主燃焼室で混合された混合気は第1空燃比または第1空燃比よりもリッチな第2空燃比である。そのため、低負荷時であっても、副室の内部空間において、混合気の着火しやすい位置が多い。そのため、副室スパークプラグとして、例えば、周方向に配列された複数の接地電極または環状の接地電極を含む電極部を有するスパークプラグを使用した場合に、低負荷時および高負荷時に、副室スパークプラグの電極部において複数の火花放電が周方向に分散的に生じることができる。複数の火花放電が周方向に分散して生じることによって、副室スパークプラグの電極部において周方向に分散的に熱が生じる。
また、複数の連通孔が周方向に分散して形成される。そのため、複数の連通孔が形成される副室壁部において、周方向に分散的に熱が生じる。
このように、副室スパークプラグの電極部および副室壁部において周方向に分散的に熱が生じる。さらに、副室スパークプラグの電極部から冷却部までの複数の熱経路、および、副室壁部から冷却部までの複数の熱経路が、それぞれ周方向に分散して形成されるようにシリンダヘッドが形成されている。そのため、特に高温となる副室スパークプラグの電極部および副室壁部から冷却部に熱が移動しやすい。
また、仮に主燃焼室にスパークプラグなどの点火補助装置が設けられた場合、点火補助装置も高温となるため、副室壁部のうち点火補助装置に近い位置から熱が移動しにくくなる。主燃焼室に点火補助装置が設けられないことにより、副室壁部から冷却部への熱の移動しやすさの周方向の均一性を高めることができるため、副室壁部から熱が移動しやすい。
また、仮に副室に点火補助装置が設けられた場合、点火補助装置も高温となるため、副室スパークプラグの電極部のうち点火補助装置に近い位置から熱が移動しにくくなる。副室に点火補助装置が設けられないことにより、副室スパークプラグの電極部から冷却部への熱の移動しやすさの周方向の均一性をより高めることができるため、副室スパークプラグの電極部から熱が移動しやすい。
このように、副室スパークプラグの電極部および副室壁部から冷却部に熱が移動しやすいため、冷却部の大型化を抑制しつつプレイグニッションの発生を抑制できる。しかも、点火補助装置が設けられないため、シリンダヘッドの大型化をより抑制できる。よって、シリンダヘッドの大型化を抑制しつつ、プレイグニッションの発生を抑制できる。 According to this configuration, the liquid fuel, which is gasoline fuel, alcohol fuel, or gasoline-alcohol mixed fuel, is injected into the intake passage from the intake passage injection valve. In at least part of the low load region, the air-fuel mixture mixed in the intake passage and the main combustion chamber has the first air-fuel ratio or a second air-fuel ratio that is richer than the first air-fuel ratio. Therefore, even when the load is low, there are many positions in the interior space of the pre-chamber where the air-fuel mixture is likely to ignite. Therefore, when using, for example, a spark plug having an electrode portion including a plurality of ground electrodes arranged in the circumferential direction or an annular ground electrode as the pre-chamber spark plug, pre-chamber spark A plurality of spark discharges can be dispersively generated in the circumferential direction at the electrode portion of the plug. A plurality of spark discharges dispersively occur in the circumferential direction, thereby dispersively generating heat in the circumferential direction at the electrode portion of the pre-chamber spark plug.
Moreover, a plurality of communication holes are formed dispersedly in the circumferential direction. Therefore, heat is dispersively generated in the circumferential direction in the sub-chamber wall portion in which the plurality of communication holes are formed.
Thus, heat is dispersively generated in the circumferential direction at the electrode portion and the wall portion of the pre-chamber spark plug. Further, the cylinder head is formed such that a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion and a plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed separately in the circumferential direction. is formed. Therefore, heat tends to move from the electrode portion and the wall portion of the pre-chamber spark plug, which are particularly hot, to the cooling portion.
Further, if an auxiliary ignition device such as a spark plug is provided in the main combustion chamber, the temperature of the auxiliary ignition device also becomes high, so heat is less likely to move from a position of the auxiliary chamber wall portion close to the auxiliary ignition device. Since no auxiliary ignition device is provided in the main combustion chamber, it is possible to increase the uniformity in the circumferential direction of the ease of heat transfer from the pre-chamber wall to the cooling part, so heat is transferred from the pre-chamber wall. It's easy to do.
Further, if an auxiliary ignition device is provided in the pre-combustion chamber, the temperature of the auxiliary ignition device will also be high, so that heat will not easily move from a position close to the auxiliary ignition device in the electrode portion of the pre-combustion chamber spark plug. Since the pre-chamber spark plug is not provided with an auxiliary ignition device, it is possible to improve the uniformity in the circumferential direction of the ease of heat transfer from the electrode portion of the pre-chamber spark plug to the cooling portion. Heat is easily transferred from the electrodes.
In this way, since heat is easily transferred from the electrode portion and the wall portion of the pre-chamber spark plug to the cooling portion, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cooling portion. Moreover, since an ignition auxiliary device is not provided, it is possible to further suppress an increase in the size of the cylinder head. Therefore, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cylinder head.
また、複数の連通孔が周方向に分散して形成される。そのため、複数の連通孔が形成される副室壁部において、周方向に分散的に熱が生じる。
このように、副室スパークプラグの電極部および副室壁部において周方向に分散的に熱が生じる。さらに、副室スパークプラグの電極部から冷却部までの複数の熱経路、および、副室壁部から冷却部までの複数の熱経路が、それぞれ周方向に分散して形成されるようにシリンダヘッドが形成されている。そのため、特に高温となる副室スパークプラグの電極部および副室壁部から冷却部に熱が移動しやすい。
また、仮に主燃焼室にスパークプラグなどの点火補助装置が設けられた場合、点火補助装置も高温となるため、副室壁部のうち点火補助装置に近い位置から熱が移動しにくくなる。主燃焼室に点火補助装置が設けられないことにより、副室壁部から冷却部への熱の移動しやすさの周方向の均一性を高めることができるため、副室壁部から熱が移動しやすい。
また、仮に副室に点火補助装置が設けられた場合、点火補助装置も高温となるため、副室スパークプラグの電極部のうち点火補助装置に近い位置から熱が移動しにくくなる。副室に点火補助装置が設けられないことにより、副室スパークプラグの電極部から冷却部への熱の移動しやすさの周方向の均一性をより高めることができるため、副室スパークプラグの電極部から熱が移動しやすい。
このように、副室スパークプラグの電極部および副室壁部から冷却部に熱が移動しやすいため、冷却部の大型化を抑制しつつプレイグニッションの発生を抑制できる。しかも、点火補助装置が設けられないため、シリンダヘッドの大型化をより抑制できる。よって、シリンダヘッドの大型化を抑制しつつ、プレイグニッションの発生を抑制できる。 According to this configuration, the liquid fuel, which is gasoline fuel, alcohol fuel, or gasoline-alcohol mixed fuel, is injected into the intake passage from the intake passage injection valve. In at least part of the low load region, the air-fuel mixture mixed in the intake passage and the main combustion chamber has the first air-fuel ratio or a second air-fuel ratio that is richer than the first air-fuel ratio. Therefore, even when the load is low, there are many positions in the interior space of the pre-chamber where the air-fuel mixture is likely to ignite. Therefore, when using, for example, a spark plug having an electrode portion including a plurality of ground electrodes arranged in the circumferential direction or an annular ground electrode as the pre-chamber spark plug, pre-chamber spark A plurality of spark discharges can be dispersively generated in the circumferential direction at the electrode portion of the plug. A plurality of spark discharges dispersively occur in the circumferential direction, thereby dispersively generating heat in the circumferential direction at the electrode portion of the pre-chamber spark plug.
Moreover, a plurality of communication holes are formed dispersedly in the circumferential direction. Therefore, heat is dispersively generated in the circumferential direction in the sub-chamber wall portion in which the plurality of communication holes are formed.
Thus, heat is dispersively generated in the circumferential direction at the electrode portion and the wall portion of the pre-chamber spark plug. Further, the cylinder head is formed such that a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion and a plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed separately in the circumferential direction. is formed. Therefore, heat tends to move from the electrode portion and the wall portion of the pre-chamber spark plug, which are particularly hot, to the cooling portion.
Further, if an auxiliary ignition device such as a spark plug is provided in the main combustion chamber, the temperature of the auxiliary ignition device also becomes high, so heat is less likely to move from a position of the auxiliary chamber wall portion close to the auxiliary ignition device. Since no auxiliary ignition device is provided in the main combustion chamber, it is possible to increase the uniformity in the circumferential direction of the ease of heat transfer from the pre-chamber wall to the cooling part, so heat is transferred from the pre-chamber wall. It's easy to do.
Further, if an auxiliary ignition device is provided in the pre-combustion chamber, the temperature of the auxiliary ignition device will also be high, so that heat will not easily move from a position close to the auxiliary ignition device in the electrode portion of the pre-combustion chamber spark plug. Since the pre-chamber spark plug is not provided with an auxiliary ignition device, it is possible to improve the uniformity in the circumferential direction of the ease of heat transfer from the electrode portion of the pre-chamber spark plug to the cooling portion. Heat is easily transferred from the electrodes.
In this way, since heat is easily transferred from the electrode portion and the wall portion of the pre-chamber spark plug to the cooling portion, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cooling portion. Moreover, since an ignition auxiliary device is not provided, it is possible to further suppress an increase in the size of the cylinder head. Therefore, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cylinder head.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室壁部の母材は、融点が前記シリンダヘッドの母材よりも高く、比熱と比重を乗じた値が前記シリンダヘッドの母材よりも高く、熱伝導率がクロム系ステンレスと同じかそれよりも高い。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
The base material of the auxiliary chamber wall has a melting point higher than that of the base material of the cylinder head, a value obtained by multiplying specific heat and specific gravity is higher than that of the base material of the cylinder head, and thermal conductivity is the same as that of chromium-based stainless steel. higher than that.
前記副室壁部の母材は、融点が前記シリンダヘッドの母材よりも高く、比熱と比重を乗じた値が前記シリンダヘッドの母材よりも高く、熱伝導率がクロム系ステンレスと同じかそれよりも高い。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
The base material of the auxiliary chamber wall has a melting point higher than that of the base material of the cylinder head, a value obtained by multiplying specific heat and specific gravity is higher than that of the base material of the cylinder head, and thermal conductivity is the same as that of chromium-based stainless steel. higher than that.
この構成によると、副室壁部の母材は、融点がシリンダヘッドの母材よりも高い。そのため、副室壁部の耐熱性を確保することができる。また、副室壁部の母材は、比熱と比重を乗じた値がシリンダヘッドの母材よりも高い。ここで、比熱と比重を乗じた値は、単位体積当たりの熱容量を表す。単位体積当たりの熱容量が大きいほど温度が上がりにくい。単位体積当たりの熱容量がシリンダヘッドの母材よりも高い材料で副室壁部の母材を構成することで、副室壁部の温度の上昇を抑えると共に、高温の副室壁部からシリンダヘッドに形成された冷却部に熱が移動しやすい。また、副室壁部の母材は、熱伝導率がクロム系ステンレスと同じかそれよりも高い。そのため、副室壁部から冷却部に熱がより移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, the base material of the pre-chamber wall has a higher melting point than the base material of the cylinder head. Therefore, the heat resistance of the pre-chamber wall can be ensured. In addition, the value obtained by multiplying the specific heat and the specific gravity of the base material of the auxiliary chamber wall is higher than that of the base material of the cylinder head. Here, the value obtained by multiplying the specific heat by the specific gravity represents the heat capacity per unit volume. The larger the heat capacity per unit volume, the more difficult it is for the temperature to rise. By forming the base material of the pre-chamber wall from a material that has a higher heat capacity per unit volume than the base material of the cylinder head, the temperature rise of the pre-chamber wall can be suppressed and the high-temperature pre-chamber wall can be dissipated from the cylinder head. Heat is easily transferred to the cooling portion formed in the Also, the base material of the pre-chamber wall portion has a thermal conductivity equal to or higher than that of chromium-based stainless steel. Therefore, heat is more easily transferred from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室スパークプラグを除き前記副室の内面に突起が形成されず、前記副室の内部空間の前記副室スパークプラグのプラグ軸方向の長さが副室の内部空間の前記プラグ軸方向に直交する方向の最大長さの2倍より小さい。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
Except for the pre-chamber spark plug, no projection is formed on the inner surface of the pre-chamber, and the axial length of the pre-chamber spark plug in the internal space of the pre-chamber extends in the axial direction of the plug in the internal space of the pre-chamber. Less than twice the maximum length in the orthogonal direction.
前記副室スパークプラグを除き前記副室の内面に突起が形成されず、前記副室の内部空間の前記副室スパークプラグのプラグ軸方向の長さが副室の内部空間の前記プラグ軸方向に直交する方向の最大長さの2倍より小さい。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
Except for the pre-chamber spark plug, no projection is formed on the inner surface of the pre-chamber, and the axial length of the pre-chamber spark plug in the internal space of the pre-chamber extends in the axial direction of the plug in the internal space of the pre-chamber. Less than twice the maximum length in the orthogonal direction.
仮に副室の内面に突起が形成された場合、突起に熱が溜まりやすい。副室スパークプラグを除き副室の内面に突起が形成されないことにより、副室壁部から冷却部に熱が移動しやすい。また、副室の内部空間のプラグ軸方向の長さは、副室の内部空間のプラグ軸方向に直交する方向の最大長さの2倍より小さい。そのため、副室の容積を確保しつつ副室の周長をより長くできる。それにより、副室壁部から冷却部までの熱経路をより多く確保することができる。したがって、副室壁部から冷却部に熱がより移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
If projections were formed on the inner surface of the pre-chamber, heat would easily accumulate in the projections. Since no projections are formed on the inner surface of the pre-chamber except for the spark plug in the pre-chamber, heat is easily transferred from the wall of the pre-chamber to the cooling portion. Further, the length of the internal space of the pre-chamber in the axial direction of the plug is smaller than twice the maximum length of the internal space of the pre-chamber in the direction orthogonal to the axial direction of the plug. Therefore, the peripheral length of the pre-chamber can be made longer while securing the volume of the pre-chamber. As a result, more heat paths can be secured from the auxiliary chamber wall portion to the cooling portion. Therefore, heat is more likely to move from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室壁部が、前記主燃焼室の内部空間に突出するように形成されており、前記副室壁部の外面を通らず前記副室の内部空間を通り前記副室スパークプラグのプラグ軸方向に直交するいずれかの平面によって前記副室の内部空間を2つの空間に分けた場合に、前記2つの空間のうち前記主燃焼室に近い方の空間の体積が、前記2つの空間のうち前記主燃焼室から遠い方の空間の体積よりも小さくなるように前記副室は形成されている。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
The pre-chamber wall portion is formed to protrude into the internal space of the main combustion chamber, and the plug shaft of the pre-chamber spark plug passes through the internal space of the pre-chamber without passing through the outer surface of the pre-chamber wall portion. When the internal space of the pre-combustion chamber is divided into two spaces by any plane orthogonal to the direction, the volume of the space closer to the main combustion chamber out of the two spaces is The sub-chamber is formed so as to have a smaller volume than the space farther from the main combustion chamber.
前記副室壁部が、前記主燃焼室の内部空間に突出するように形成されており、前記副室壁部の外面を通らず前記副室の内部空間を通り前記副室スパークプラグのプラグ軸方向に直交するいずれかの平面によって前記副室の内部空間を2つの空間に分けた場合に、前記2つの空間のうち前記主燃焼室に近い方の空間の体積が、前記2つの空間のうち前記主燃焼室から遠い方の空間の体積よりも小さくなるように前記副室は形成されている。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
The pre-chamber wall portion is formed to protrude into the internal space of the main combustion chamber, and the plug shaft of the pre-chamber spark plug passes through the internal space of the pre-chamber without passing through the outer surface of the pre-chamber wall portion. When the internal space of the pre-combustion chamber is divided into two spaces by any plane orthogonal to the direction, the volume of the space closer to the main combustion chamber out of the two spaces is The sub-chamber is formed so as to have a smaller volume than the space farther from the main combustion chamber.
この構成によると、副室壁部は主燃焼室の内部空間に突出しているものの、その突出量は小さい。そのため、副室壁部に熱が溜まりにくく、副室壁部から冷却部に熱が移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, although the auxiliary chamber wall protrudes into the internal space of the main combustion chamber, the amount of protrusion is small. Therefore, heat is less likely to accumulate in the pre-chamber wall, and heat is likely to move from the pre-chamber wall to the cooling section. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室スパークプラグを通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug.
前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室スパークプラグを通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug.
この構成によると、副室スパークプラグが冷却部に近いため、副室スパークプラグの電極部の熱が冷却部に移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, since the pre-chamber spark plug is close to the cooling portion, the heat of the electrode portion of the pre-chamber spark plug is easily transferred to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室の内部空間が、前記主燃焼室の内部空間にその一部が露出するシリンダヘッド本体および前記副室スパークプラグのどちらとも別体であり前記副室壁部を含む副室部材と、前記副室スパークプラグとによって囲まれた空間である。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
a pre-chamber member, the interior space of which is separate from both the cylinder head body and the pre-chamber spark plug, the interior space of which is partly exposed to the interior space of the main combustion chamber, and which includes the pre-chamber wall portion; It is a space surrounded by the pre-chamber spark plug.
前記副室の内部空間が、前記主燃焼室の内部空間にその一部が露出するシリンダヘッド本体および前記副室スパークプラグのどちらとも別体であり前記副室壁部を含む副室部材と、前記副室スパークプラグとによって囲まれた空間である。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
a pre-chamber member, the interior space of which is separate from both the cylinder head body and the pre-chamber spark plug, the interior space of which is partly exposed to the interior space of the main combustion chamber, and which includes the pre-chamber wall portion; It is a space surrounded by the pre-chamber spark plug.
この構成によると、副室の内部空間が副室壁部を含む副室部材と副室スパークプラグと他の部材(例えばシリンダヘッド本体)とによって囲まれた空間である場合に比べて、副室の内部空間の形状およびサイズを維持しつつ、副室部材を副室スパークプラグのプラグ軸方向に長くできる。そのため、副室部材の材料を熱が移動しやすい材料にした場合に、副室壁部から冷却部に熱がより移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, compared to the case where the internal space of the pre-chamber is a space surrounded by the pre-chamber member including the pre-chamber wall portion, the pre-chamber spark plug, and other members (for example, the cylinder head body), The pre-chamber member can be elongated in the axial direction of the pre-chamber spark plug while maintaining the shape and size of the internal space of the spark plug. Therefore, when the material of the pre-chamber member is made of a material that facilitates heat transfer, the heat is more easily transferred from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室部材を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber member.
前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室部材を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber member.
この構成によると、副室部材が冷却部に近いため、副室壁部から冷却部に熱がより移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, since the pre-chamber member is close to the cooling section, heat is more easily transferred from the pre-chamber wall portion to the cooling section. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記冷却部の内面の一部が、前記副室部材の外周面の少なくとも一部である。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A portion of the inner surface of the cooling portion is at least a portion of the outer peripheral surface of the sub chamber member.
前記冷却部の内面の一部が、前記副室部材の外周面の少なくとも一部である。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A portion of the inner surface of the cooling portion is at least a portion of the outer peripheral surface of the sub chamber member.
この構成によると、冷却部を流れる冷却媒体は、副室部材の外周面に接触する。そのため、副室壁部から冷却部に熱がより移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, the cooling medium flowing through the cooling portion contacts the outer peripheral surface of the pre-chamber member. Therefore, heat is more easily transferred from the pre-chamber wall portion to the cooling portion. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室スパークプラグに形成された雄ねじが、前記副室部材に形成された雌ねじと噛み合って接触している。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A male thread formed on the pre-chamber spark plug engages and contacts a female thread formed on the sub-chamber member.
前記副室スパークプラグに形成された雄ねじが、前記副室部材に形成された雌ねじと噛み合って接触している。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A male thread formed on the pre-chamber spark plug engages and contacts a female thread formed on the sub-chamber member.
この構成によると、副室スパークプラグと副室部材との接触面積が大きい。そのため、副室スパークプラグから副室部材に熱が移動しやすい。したがって、副室スパークプラグの電極部から副室部材を介して冷却部に熱が移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, the contact area between the pre-chamber spark plug and the pre-chamber member is large. Therefore, heat is easily transferred from the pre-chamber spark plug to the pre-chamber member. Therefore, heat is easily transferred from the electrode portion of the pre-chamber spark plug to the cooling portion via the pre-chamber member. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室スパークプラグに形成された前記雄ねじが前記副室部材に形成された前記雌ねじと噛み合って接触する箇所を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the cooling portion and orthogonal to the axial direction of the plug of the pre-chamber spark plug passes through a portion where the male thread formed in the pre-chamber spark plug engages and contacts the female thread formed in the pre-chamber member. .
前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室スパークプラグに形成された前記雄ねじが前記副室部材に形成された前記雌ねじと噛み合って接触する箇所を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the cooling portion and orthogonal to the axial direction of the plug of the pre-chamber spark plug passes through a portion where the male thread formed in the pre-chamber spark plug engages and contacts the female thread formed in the pre-chamber member. .
この構成によると、副室部材が冷却部に近いため、副室壁部から冷却部に熱がより移動しやすい。さらに、副室スパークプラグと副室部材とのねじによる接触部が冷却部に近いため、副室スパークプラグの電極部から副室部材を介して冷却部に熱がより移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, since the pre-chamber member is close to the cooling section, heat is more easily transferred from the pre-chamber wall portion to the cooling section. Furthermore, since the threaded contact portion between the pre-chamber spark plug and the pre-chamber member is close to the cooling portion, heat is more easily transferred from the electrode portion of the pre-chamber spark plug to the cooling portion via the pre-chamber member. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室部材の外周面が前記シリンダヘッド本体に接触している。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
An outer peripheral surface of the sub chamber member is in contact with the cylinder head body.
前記副室部材の外周面が前記シリンダヘッド本体に接触している。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
An outer peripheral surface of the sub chamber member is in contact with the cylinder head body.
この構成によると、副室部材の外周面がシリンダヘッド本体に接触していない場合に比べて、副室壁部からからシリンダヘッド本体に熱が移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, heat is more easily transferred from the pre-chamber wall portion to the cylinder head body than when the outer peripheral surface of the pre-chamber member is not in contact with the cylinder head body. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室の内部空間を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室部材の外周面の前記シリンダヘッド本体に接触する箇所を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane that passes through the internal space of the pre-chamber and is perpendicular to the plug axial direction of the pre-chamber spark plug passes through a portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body.
前記副室の内部空間を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室部材の外周面の前記シリンダヘッド本体に接触する箇所を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane that passes through the internal space of the pre-chamber and is perpendicular to the plug axial direction of the pre-chamber spark plug passes through a portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body.
この構成によると、副室の内部空間が、副室部材の外周面のシリンダヘッド本体に接触する箇所に近い。したがって、副室壁部が、副室部材の外周面のシリンダヘッド本体に接触する箇所に近い。そのため、副室壁部からシリンダヘッド本体に熱が移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, the internal space of the pre-chamber is close to the portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body. Therefore, the pre-chamber wall portion is close to the portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body. Therefore, heat is likely to move from the auxiliary chamber wall portion to the cylinder head body. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記副室の内部空間を通り前記プラグ軸方向に直交する平面が、前記副室部材に形成された雄ねじが前記シリンダヘッド本体に形成された雌ねじと噛み合って接触する箇所を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the internal space of the pre-chamber and orthogonal to the axial direction of the plug passes through a portion where a male thread formed in the pre-chamber member meshes and contacts a female thread formed in the cylinder head body.
前記副室の内部空間を通り前記プラグ軸方向に直交する平面が、前記副室部材に形成された雄ねじが前記シリンダヘッド本体に形成された雌ねじと噛み合って接触する箇所を通る。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
A plane passing through the internal space of the pre-chamber and orthogonal to the axial direction of the plug passes through a portion where a male thread formed in the pre-chamber member meshes and contacts a female thread formed in the cylinder head body.
この構成によると、副室部材とシリンダヘッド本体との接触面積が大きい。そのため、副室部材からシリンダヘッド本体に熱がより移動しやすい。その結果、プレイグニッションの発生をより抑制できる。
According to this configuration, the contact area between the pre-chamber member and the cylinder head body is large. Therefore, heat is more easily transferred from the pre-chamber member to the cylinder head body. As a result, the occurrence of pre-ignition can be further suppressed.
本発明の一実施形態の副室燃焼4ストロークエンジンは、以下の構成を有していてもよい。
前記主燃焼室の内部に燃料を噴射する主燃焼室燃料噴射弁を有さない。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
There is no main combustion chamber fuel injection valve for injecting fuel into the main combustion chamber.
前記主燃焼室の内部に燃料を噴射する主燃焼室燃料噴射弁を有さない。 A pre-combustion four-stroke engine according to an embodiment of the present invention may have the following configuration.
There is no main combustion chamber fuel injection valve for injecting fuel into the main combustion chamber.
この構成によると、主燃焼室燃料噴射弁が設けられる場合に比べて、シリンダヘッドの大型化を抑制できる。
According to this configuration, it is possible to suppress the increase in size of the cylinder head compared to the case where the main combustion chamber fuel injection valve is provided.
本発明および実施の形態において、低負荷領域とは、エンジンの負荷の最低から最高までの領域を2等分した場合の低い方の領域である。
In the present invention and the embodiment, the low load region is the lower region when the region from the lowest to the highest engine load is divided into two equal parts.
本発明および実施の形態において、燃料と空気の混合比である空燃比は、第1空燃比、第2空燃比および第3空燃比で表現される。第1空燃比とは、燃焼後に三元触媒で処理できる空燃比である。第1空燃比は、理論空燃比(stoichiometric ratio)、または、理論空燃比を含む空燃比のウィンドウでもよい。第1空燃比は、理論空燃比の近傍の空燃比でもよい。第1空燃比は、理論空燃比の近傍の空燃比を含み理論空燃比を含まないウィンドウでもよい。第2空燃比は、第1空燃比よりもリッチな空燃比である。第1空燃比が、理論空燃比の近傍の空燃比であるか、もしくは、理論空燃比を含まないウィンドウである場合、第2空燃比は、理論空燃比よりもリッチでもあってもなくてもよい。第3空燃比とは、第1空燃比よりもリーンな空燃比である。本発明および実施の形態において、リッチとは、混合気の燃料が濃いことを意味する。リーンとは、混合気の燃料が薄いことを意味する。本発明および実施の形態において、燃焼後に三元触媒で処理できる空燃比とは、混合気の燃焼後に生じる排ガスを三元触媒で処理できるような混合気の空燃比である。本発明および実施の形態において、制御装置は、低負荷領域の少なくとも一部において、吸気通路および主燃焼室で混合された混合気が理論空燃比または理論空燃比よりもリッチな空燃比となるように、吸気通路噴射弁を制御してもよい。本発明の副室燃焼4ストロークエンジンは、排気通路に配置された触媒を有する。本発明の副室燃焼4ストロークエンジンは、排気通路に配置された三元触媒を有してもよい。本発明の副室燃焼4ストロークエンジンは、排気通路に配置された三元触媒ではない触媒を有してもよい。本発明の副室燃焼4ストロークエンジンは、主燃焼室と触媒との間に配置され、排気通路を流れる排ガスの酸素濃度を検出する酸素センサを有する。
In the present invention and the embodiment, the air-fuel ratio, which is the mixture ratio of fuel and air, is expressed by a first air-fuel ratio, a second air-fuel ratio and a third air-fuel ratio. The first air-fuel ratio is an air-fuel ratio that can be processed by the three-way catalyst after combustion. The first air-fuel ratio may be a stoichiometric ratio or a window of air-fuel ratios that includes the stoichiometric air-fuel ratio. The first air-fuel ratio may be an air-fuel ratio near the stoichiometric air-fuel ratio. The first air-fuel ratio may be a window that includes air-fuel ratios near the stoichiometric air-fuel ratio and does not include the stoichiometric air-fuel ratio. The second air-fuel ratio is a richer air-fuel ratio than the first air-fuel ratio. If the first air-fuel ratio is an air-fuel ratio near the stoichiometric air-fuel ratio or in a window that does not include the stoichiometric air-fuel ratio, the second air-fuel ratio may or may not be richer than the stoichiometric air-fuel ratio. good. The third air-fuel ratio is an air-fuel ratio that is leaner than the first air-fuel ratio. In the present invention and embodiments, rich means that the mixture is rich in fuel. Lean means that the mixture is lean on fuel. In the present invention and the embodiments, the air-fuel ratio that can be processed by the three-way catalyst after combustion is the air-fuel ratio of the air-fuel mixture at which the exhaust gas generated after the combustion of the mixture can be processed by the three-way catalyst. In the present invention and embodiments, the control device controls the air-fuel ratio so that the air-fuel mixture mixed in the intake passage and the main combustion chamber has a stoichiometric air-fuel ratio or an air-fuel ratio richer than the stoichiometric air-fuel ratio in at least a part of the low load region. Alternatively, the intake manifold injection valve may be controlled. The pre-combustion four-stroke engine of the present invention has a catalyst disposed in the exhaust passage. The pre-combustion four-stroke engine of the present invention may have a three-way catalyst arranged in the exhaust passage. The pre-combustion four-stroke engine of the present invention may have a catalyst other than a three-way catalyst located in the exhaust passage. The pre-combustion four-stroke engine of the present invention has an oxygen sensor which is arranged between the main combustion chamber and the catalyst and which detects the oxygen concentration of the exhaust gas flowing through the exhaust passage.
本発明および実施の形態において、副室または主燃焼室における混合気の点火を補助する点火補助装置とは、例えば、マイクロ波放電を発生させる装置、誘電体バリア放電(無声放電)を発生させる装置、または、主燃焼室の混合気に点火するスパークプラグなどである。本発明および実施の形態において、副室燃焼4ストロークエンジンが点火補助装置を有さないとは、副室スパークプラグとは別体の点火補助装置が設けられないことだけでなく、副室スパークプラグが点火補助装置の機能を有さないことも含む。
In the present invention and the embodiments, the ignition assist device that assists the ignition of the air-fuel mixture in the pre-combustion chamber or the main combustion chamber is, for example, a device that generates microwave discharge, a device that generates dielectric barrier discharge (silent discharge). , or a spark plug that ignites the mixture in the main combustion chamber. In the present invention and the embodiments, the fact that the pre-combustion four-stroke engine does not have an auxiliary ignition device means not only that an auxiliary ignition device separate from the pre-combustion chamber spark plug is not provided, but also that the pre-combustion chamber spark plug not have the function of an ignition assist device.
本発明および実施の形態において、副室が主燃焼室よりも容積が小さいとは、副室の容積が主燃焼室の最小の容積よりも小さいことを意味する。なお、主燃焼室の容積はピストンの移動に伴って変化する。副室の容積とは副室の内部空間の容積である。本発明および実施の形態において、副室の内部空間は、複数の連通孔の内部空間を含まない。本発明および実施の形態において、副室の内面とは、副室の内部空間を形成する面である。本発明および実施の形態において、副室スパークプラグは、副室の内面の一部を形成する。本発明および実施の形態において、副室スパークプラグを除き副室の内面に突起が形成されないとは、副室の内面に突起が形成されないか、もしくは、副室の内面に形成される突起が副室スパークプラグによる突起だけであることを意味する。本発明において、複数の連通孔が形成された副室壁部とは、主燃焼室の内部空間に晒された片面を有する壁部である。副室壁部は、主燃焼室の内部空間に突出するように形成されていてもよく、突出しないように形成されていてもよい。副室壁部が主燃焼室の内部空間に突出するように形成されている場合、副室壁部は筒状の部分を有する。
In the present invention and the embodiments, that the volume of the pre-chamber is smaller than that of the main combustion chamber means that the volume of the pre-chamber is smaller than the minimum volume of the main combustion chamber. Note that the volume of the main combustion chamber changes as the piston moves. The volume of the pre-chamber is the volume of the internal space of the pre-chamber. In the present invention and embodiments, the internal space of the sub chamber does not include the internal spaces of the plurality of communication holes. In the present invention and embodiments, the inner surface of the pre-chamber is the surface forming the internal space of the pre-chamber. In the present invention and embodiments, the pre-chamber spark plug forms part of the inner surface of the pre-chamber. In the present invention and the embodiments, "no protrusions are formed on the inner surface of the pre-chamber except for the pre-chamber spark plug" means that no protrusions are formed on the inner surface of the pre-chamber or the protrusions formed on the inner surface of the pre-chamber are not formed on the inner surface of the pre-chamber. Means only the projection by the chamber spark plug. In the present invention, the sub-chamber wall portion in which a plurality of communication holes are formed is a wall portion having one side exposed to the internal space of the main combustion chamber. The auxiliary chamber wall portion may be formed so as to protrude into the internal space of the main combustion chamber, or may be formed so as not to protrude. When the sub-chamber wall is formed to protrude into the internal space of the main combustion chamber, the sub-chamber wall has a cylindrical portion.
本発明および実施の形態において、冷却媒体は、液体または気体である。液体の冷却媒体は、例えば、水でもよく、潤滑油でもよい。気体の冷却媒体は、例えば空気でもよい。本発明および実施の形態において、冷却媒体が収容される冷却部は、少なくとも1つの室(チャンバー)または少なくとも1つの通路である。冷却媒体は冷却部を流れてもよい。冷却部に流入する冷却媒体が流れる通路、および、冷却部から排出された冷却媒体が流れる通路が、冷却部に接続されてもよい。冷却部は、互いに連通しない複数の室(チャンバー)または複数の通路でもよい。
In the present invention and embodiments, the cooling medium is liquid or gas. The liquid cooling medium may be, for example, water or lubricating oil. The gaseous cooling medium may be air, for example. In accordance with the invention and embodiments, the cooling section in which the cooling medium is accommodated is at least one chamber or at least one passageway. A cooling medium may flow through the cooling section. A passage through which the cooling medium flowing into the cooling unit flows and a passage through which the cooling medium discharged from the cooling unit flows may be connected to the cooling unit. The cooling section may be multiple chambers or multiple passages that are not in communication with each other.
本発明および実施の形態において、熱経路は、熱が移動する経路である。本発明および実施の形態において、副室スパークプラグの電極部から冷却部までの複数の熱経路は、互いに独立した熱経路に限らない。つまり、複数の熱経路の間で熱が移動可能でもよい。本発明および実施の形態における副室壁部から冷却部までの複数の熱経路の定義も同様である。
In the present invention and embodiments, a heat path is a path through which heat moves. In the present invention and the embodiments, the plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion are not limited to independent heat paths. That is, heat may be transferable between multiple heat paths. The same applies to the definition of a plurality of heat paths from the pre-chamber wall portion to the cooling portion in the present invention and the embodiments.
本発明および実施の形態において、副室スパークプラグの電極部とは、少なくとも1つの中心電極と少なくとも1つの接地電極を含む。電極部は、例えば、単一の中心電極と、複数の接地電極または環状の接地電極とを含んでもよい。複数の接地電極は、例えば、2つの接地電極でもよい。複数の接地電極は、例えば、3つ以上の接地電極でもよい。電極部が単一の中心電極と複数の接地電極とを有する場合、複数の放電ギャップが形成される。電極部が単一の中心電極と環状の接地電極とを有する場合、環状の放電ギャップが形成される。火花放電は、放電ギャップにおいて発生する。本発明および実施の形態において、副室スパークプラグのプラグ軸方向とは、副室スパークプラグの中心軸線に平行な方向である。副室スパークプラグのプラグ軸方向は、主燃焼室を形成するシリンダ孔の中心軸線と平行であってもよく平行でなくてもよい。
In the present invention and embodiments, the electrode portion of the pre-chamber spark plug includes at least one center electrode and at least one ground electrode. The electrode section may include, for example, a single center electrode and multiple or annular ground electrodes. The plurality of ground electrodes may be, for example, two ground electrodes. The plurality of ground electrodes may be, for example, three or more ground electrodes. When the electrode section has a single center electrode and multiple ground electrodes, multiple discharge gaps are formed. When the electrode section has a single center electrode and an annular ground electrode, an annular discharge gap is formed. A spark discharge occurs in the discharge gap. In the present invention and the embodiments, the plug axial direction of the pre-chamber spark plug is a direction parallel to the central axis of the pre-chamber spark plug. The plug axial direction of the pre-combustion chamber spark plug may or may not be parallel to the central axis of the cylinder hole forming the main combustion chamber.
本発明および実施の形態において、「複数の火花放電が周方向に分散して生じる」とは、火花放電が生じる位置が周方向に分散していることを意味する。「複数の火花放電が周方向に分散して生じる」とは、周方向に分散した位置において複数の火花放電が同時に生じることを限定する意味ではない。周方向に分散した位置で複数の火花放電が同時に生じてもよい。この場合、同時に発生した複数の火花放電のうちの少なくとも1つの火花放電が、点火の起点となる。「複数の火花放電が周方向に分散して生じる」という文章における周方向とは、例えば、副室スパークプラグのプラグ軸方向に平行な直線を中心とした周方向である。複数の火花放電が周方向に分散して生じない場合の一例は、電極部が単一の中心電極と単一の接地電極を有する場合である。複数の火花放電が周方向に分散して形成されない場合の他の例は、電極部が、単一の中心電極と、主に使用される第1接地電極と、補助的に使用される第2接地電極を有する場合である。複数の火花放電が周方向に分散して生じない場合の他の例は、副室の内部における混合気の濃度のばらつきによって混合気の点火しやすい位置が周方向にほぼ均等でない場合である。複数の火花放電が周方向に分散して生じない場合の具体例は、これらに限らない。
In the present invention and the embodiments, "a plurality of spark discharges are distributed in the circumferential direction" means that the positions where the spark discharges occur are distributed in the circumferential direction. The phrase "a plurality of spark discharges are distributed in the circumferential direction" does not mean that a plurality of spark discharges are simultaneously generated at positions distributed in the circumferential direction. A plurality of spark discharges may occur simultaneously at positions dispersed in the circumferential direction. In this case, at least one spark discharge among the plurality of spark discharges generated at the same time serves as the starting point of ignition. The circumferential direction in the sentence "a plurality of spark discharges are dispersed in the circumferential direction" is, for example, the circumferential direction centered on a straight line parallel to the plug axial direction of the pre-chamber spark plug. An example of a case where a plurality of spark discharges are not dispersed in the circumferential direction is a case where the electrode section has a single center electrode and a single ground electrode. Another example of a case in which a plurality of spark discharges are not dispersed in the circumferential direction is that the electrode section consists of a single center electrode, a mainly used first ground electrode, and an auxiliary used second ground electrode. This is the case with the ground electrode. Another example of a case in which a plurality of spark discharges are not dispersed in the circumferential direction is a case in which positions where the air-fuel mixture is likely to ignite are not substantially uniform in the circumferential direction due to variations in the concentration of the air-fuel mixture inside the pre-chamber. Specific examples of the case where a plurality of spark discharges are not distributed in the circumferential direction are not limited to these.
本発明および実施の形態において、「複数の連通孔が周方向に分散して形成される」とは、複数の連通孔が極端な偏りなく周方向に並んで形成されることを意味する。複数の連通孔が周方向に分散して形成される場合、複数の連通孔は周方向に並んで形成される。複数の連通孔が周方向に分散して形成される」とは、複数の連通孔が周方向に等間隔に形成されることに限らない。「複数の連通孔が周方向に分散して形成される」という文章における周方向とは、例えば、副室スパークプラグのプラグ軸方向に平行な直線を中心とした周方向である。
In the present invention and the embodiment, "a plurality of communication holes are formed dispersedly in the circumferential direction" means that the plurality of communication holes are formed side by side in the circumferential direction without extreme bias. When a plurality of communication holes are formed dispersedly in the circumferential direction, the plurality of communication holes are formed side by side in the circumferential direction. "A plurality of communication holes are formed dispersedly in the circumferential direction" does not necessarily mean that the plurality of communication holes are formed at equal intervals in the circumferential direction. The circumferential direction in the sentence "a plurality of communication holes are formed dispersedly in the circumferential direction" is, for example, the circumferential direction centered on a straight line parallel to the plug axial direction of the pre-chamber spark plug.
本発明および実施の形態において、「副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成される」とは、副室スパークプラグの電極部から冷却部まで移動する熱量が周方向に分散していることを意味する。つまり、副室スパークプラグの電極部から冷却部までの熱の移動のしやすさの程度が周方向にほぼ均等であることを意味する。「副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成される」という文章における周方向とは、例えば、副室スパークプラグのプラグ軸方向に平行な直線を中心とした周方向である。本発明および実施の形態において、「副室壁部から冷却部までの複数の熱経路が周方向に分散して形成される」とは、副室壁部から冷却部まで移動する熱量が周方向に分散していることを意味する。つまり、副室壁部から冷却部までの熱の移動のしやすさの程度が周方向にほぼ均等であることを意味する。「副室壁部から冷却部までの複数の熱経路が周方向に分散して形成される」という文章における周方向とは、例えば、副室スパークプラグのプラグ軸方向に平行な直線を中心とした周方向である。これは、複数の連通孔が配列される周方向と同じでもよい。
電極部は、電極部に生じる複数の火花放電が周方向に分散して生じるように形成されている。つまり、電極部に発生する熱は周方向に分散して発生する。そのため、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されるためには、冷却部と、シリンダヘッドにおける副室スパークプラグと冷却部との間の部分が重要となる。また、副室壁部に形成される複数の連連孔は周方向に分散して形成されている。つまり、副室壁部に発生する熱は周方向に分散して発生する。そのため、副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されるためには、冷却部と、シリンダヘッドにおける副室壁部と冷却部との間の部分が重要となる。例えば、冷却部が環状に形成される場合、副室スパークプラグの電極部から冷却部までの複数の熱経路、および、副室壁部から冷却部までの複数の熱経路は、それぞれ周方向に分散して形成されやすい。例えば、シリンダヘッドにおける副室スパークプラグと冷却部との間の部分の構造(形状および材質)が周方向にほぼ均一な場合、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されやすい。また、例えば、シリンダヘッドにおける副室壁部と冷却部との間の部分の構造(形状および材質)が周方向にほぼ均一な場合、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されやすい。副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の一例は、冷却部が円周の半分程度の領域しか形成されない場合である。この例は、副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の例でもよい。副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の他の例は、円周の半分の領域と残りの半分の領域で副室壁部から冷却部までの間の材質が異なる場合である。なお、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の具体例、および、副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の具体例は、これらに限らない。 In the present invention and the embodiments, "a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion are formed in a circumferentially distributed manner" means that the heat path from the electrode portion of the pre-chamber spark plug to the cooling portion It means that the amount of heat that moves is distributed in the circumferential direction. In other words, it means that the degree of easiness of heat transfer from the electrode portion of the pre-chamber spark plug to the cooling portion is substantially uniform in the circumferential direction. The circumferential direction in the sentence "a plurality of heat paths from the electrode part of the pre-chamber spark plug to the cooling part are formed in a circumferentially distributed manner" means, for example, a straight line parallel to the plug axial direction of the pre-chamber spark plug. is the circumferential direction centered on . In the present invention and the embodiments, "a plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed in a circumferentially distributed manner" means that the amount of heat transferred from the pre-chamber wall portion to the cooling portion is distributed in the circumferential direction. means that it is distributed over In other words, it means that the degree of easiness of heat transfer from the pre-chamber wall portion to the cooling portion is substantially uniform in the circumferential direction. The circumferential direction in the sentence “a plurality of heat paths from the pre-chamber wall portion to the cooling portion are dispersed in the circumferential direction” means, for example, a straight line parallel to the axial direction of the pre-chamber spark plug. in the circumferential direction. This may be the same as the circumferential direction in which the plurality of communication holes are arranged.
The electrode portion is formed so that a plurality of spark discharges generated in the electrode portion are dispersed in the circumferential direction. That is, the heat generated in the electrode portion is distributed in the circumferential direction. Therefore, in order for a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion to be dispersed in the circumferential direction, there must be a space between the cooling portion and the pre-chamber spark plug and the cooling portion in the cylinder head. parts are important. Also, the plurality of continuous holes formed in the auxiliary chamber wall are dispersed in the circumferential direction. That is, the heat generated in the pre-chamber wall portion is distributed in the circumferential direction. Therefore, in order to form a plurality of heat paths distributed in the circumferential direction from the pre-chamber wall portion to the cooling portion, the cooling portion and the portion between the pre-chamber wall portion and the cooling portion in the cylinder head are important. becomes. For example, when the cooling portion is formed in an annular shape, a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion and a plurality of heat paths from the sub-chamber wall portion to the cooling portion are arranged in the circumferential direction. It tends to be dispersed and formed. For example, if the structure (shape and material) of the portion between the pre-chamber spark plug and the cooling section in the cylinder head is substantially uniform in the circumferential direction, multiple heat paths from the electrode section of the pre-chamber spark plug to the cooling section are generated. It tends to be dispersed in the circumferential direction. Further, for example, if the structure (shape and material) of the portion between the pre-chamber wall portion and the cooling portion in the cylinder head is substantially uniform in the circumferential direction, a plurality of heat sources from the electrode portion of the pre-chamber spark plug to the cooling portion may be generated. Paths are likely to be formed dispersed in the circumferential direction. An example of a case where a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion is not formed in a circumferentially distributed manner is when the cooling portion is formed only in an area of about half of the circumference. This example may be an example in which a plurality of heat paths from the pre-chamber wall portion to the cooling portion are not formed dispersedly in the circumferential direction. Another example of a case in which a plurality of heat paths from the pre-chamber wall to the cooling section is not formed in a distributed manner in the circumferential direction is that the pre-chamber wall to the cooling section is formed in one half area and the other half area of the circumference. This is the case where the materials between are different. A specific example in which the plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion is not formed in the circumferential direction, and the case where the plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed in the circumferential direction. Specific examples of the case where the particles are not formed dispersedly are not limited to these.
電極部は、電極部に生じる複数の火花放電が周方向に分散して生じるように形成されている。つまり、電極部に発生する熱は周方向に分散して発生する。そのため、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されるためには、冷却部と、シリンダヘッドにおける副室スパークプラグと冷却部との間の部分が重要となる。また、副室壁部に形成される複数の連連孔は周方向に分散して形成されている。つまり、副室壁部に発生する熱は周方向に分散して発生する。そのため、副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されるためには、冷却部と、シリンダヘッドにおける副室壁部と冷却部との間の部分が重要となる。例えば、冷却部が環状に形成される場合、副室スパークプラグの電極部から冷却部までの複数の熱経路、および、副室壁部から冷却部までの複数の熱経路は、それぞれ周方向に分散して形成されやすい。例えば、シリンダヘッドにおける副室スパークプラグと冷却部との間の部分の構造(形状および材質)が周方向にほぼ均一な場合、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されやすい。また、例えば、シリンダヘッドにおける副室壁部と冷却部との間の部分の構造(形状および材質)が周方向にほぼ均一な場合、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されやすい。副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の一例は、冷却部が円周の半分程度の領域しか形成されない場合である。この例は、副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の例でもよい。副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の他の例は、円周の半分の領域と残りの半分の領域で副室壁部から冷却部までの間の材質が異なる場合である。なお、副室スパークプラグの電極部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の具体例、および、副室壁部から冷却部までの複数の熱経路が周方向に分散して形成されない場合の具体例は、これらに限らない。 In the present invention and the embodiments, "a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion are formed in a circumferentially distributed manner" means that the heat path from the electrode portion of the pre-chamber spark plug to the cooling portion It means that the amount of heat that moves is distributed in the circumferential direction. In other words, it means that the degree of easiness of heat transfer from the electrode portion of the pre-chamber spark plug to the cooling portion is substantially uniform in the circumferential direction. The circumferential direction in the sentence "a plurality of heat paths from the electrode part of the pre-chamber spark plug to the cooling part are formed in a circumferentially distributed manner" means, for example, a straight line parallel to the plug axial direction of the pre-chamber spark plug. is the circumferential direction centered on . In the present invention and the embodiments, "a plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed in a circumferentially distributed manner" means that the amount of heat transferred from the pre-chamber wall portion to the cooling portion is distributed in the circumferential direction. means that it is distributed over In other words, it means that the degree of easiness of heat transfer from the pre-chamber wall portion to the cooling portion is substantially uniform in the circumferential direction. The circumferential direction in the sentence “a plurality of heat paths from the pre-chamber wall portion to the cooling portion are dispersed in the circumferential direction” means, for example, a straight line parallel to the axial direction of the pre-chamber spark plug. in the circumferential direction. This may be the same as the circumferential direction in which the plurality of communication holes are arranged.
The electrode portion is formed so that a plurality of spark discharges generated in the electrode portion are dispersed in the circumferential direction. That is, the heat generated in the electrode portion is distributed in the circumferential direction. Therefore, in order for a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion to be dispersed in the circumferential direction, there must be a space between the cooling portion and the pre-chamber spark plug and the cooling portion in the cylinder head. parts are important. Also, the plurality of continuous holes formed in the auxiliary chamber wall are dispersed in the circumferential direction. That is, the heat generated in the pre-chamber wall portion is distributed in the circumferential direction. Therefore, in order to form a plurality of heat paths distributed in the circumferential direction from the pre-chamber wall portion to the cooling portion, the cooling portion and the portion between the pre-chamber wall portion and the cooling portion in the cylinder head are important. becomes. For example, when the cooling portion is formed in an annular shape, a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion and a plurality of heat paths from the sub-chamber wall portion to the cooling portion are arranged in the circumferential direction. It tends to be dispersed and formed. For example, if the structure (shape and material) of the portion between the pre-chamber spark plug and the cooling section in the cylinder head is substantially uniform in the circumferential direction, multiple heat paths from the electrode section of the pre-chamber spark plug to the cooling section are generated. It tends to be dispersed in the circumferential direction. Further, for example, if the structure (shape and material) of the portion between the pre-chamber wall portion and the cooling portion in the cylinder head is substantially uniform in the circumferential direction, a plurality of heat sources from the electrode portion of the pre-chamber spark plug to the cooling portion may be generated. Paths are likely to be formed dispersed in the circumferential direction. An example of a case where a plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion is not formed in a circumferentially distributed manner is when the cooling portion is formed only in an area of about half of the circumference. This example may be an example in which a plurality of heat paths from the pre-chamber wall portion to the cooling portion are not formed dispersedly in the circumferential direction. Another example of a case in which a plurality of heat paths from the pre-chamber wall to the cooling section is not formed in a distributed manner in the circumferential direction is that the pre-chamber wall to the cooling section is formed in one half area and the other half area of the circumference. This is the case where the materials between are different. A specific example in which the plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion is not formed in the circumferential direction, and the case where the plurality of heat paths from the pre-chamber wall portion to the cooling portion are formed in the circumferential direction. Specific examples of the case where the particles are not formed dispersedly are not limited to these.
本発明および実施の形態において、副室壁部が材料の異なる複数の部分から構成される場合、副室壁部の母材とは、複数の部分のうち最も大きい体積を占める部分の材料である。なお、本発明および実施の形態において、副室壁部は、材料の異なる複数の部分から構成されなくてもよい。
本発明および実施の形態において、シリンダヘッドが材料の異なる複数の部分から構成される場合、シリンダヘッドの母材とは、複数の部分のうち最も大きい体積を占める部分の材料である。副室壁部の母材とシリンダヘッドの母材が異なる場合、シリンダヘッドを構成する材料の異なる複数の部分のうち最も大きい体積を占める部分は、副室壁部を含まない。なお、本発明および実施の形態において、シリンダヘッドは副室壁部を含む。本発明および実施の形態において、主燃焼室の内部空間にその一部が露出するシリンダヘッド本体は、副室壁部を含まない。シリンダヘッド本体の母材は、シリンダヘッドの母材と同じである。シリンダヘッド本体は、材料の異なる複数の部分から構成されてもよく、材料の異なる複数の部分から構成されなくてもよい。 In the present invention and the embodiments, when the pre-chamber wall portion is composed of a plurality of portions made of different materials, the base material of the pre-chamber wall portion is the material of the portion occupying the largest volume among the plurality of portions. . In addition, in the present invention and the embodiments, the auxiliary chamber wall portion does not have to be composed of a plurality of portions made of different materials.
In the present invention and the embodiments, when the cylinder head is composed of a plurality of portions made of different materials, the base material of the cylinder head is the material of the portion occupying the largest volume among the plurality of portions. When the base material of the pre-chamber wall portion and the base material of the cylinder head are different, the portion occupying the largest volume among the plurality of portions of different materials forming the cylinder head does not include the pre-chamber wall portion. Note that, in the present invention and the embodiments, the cylinder head includes the auxiliary chamber wall. In the present invention and embodiments, the cylinder head body partially exposed to the interior space of the main combustion chamber does not include the auxiliary chamber wall. The base material of the cylinder head body is the same as the base material of the cylinder head. The cylinder head body may or may not consist of multiple parts of different materials.
本発明および実施の形態において、シリンダヘッドが材料の異なる複数の部分から構成される場合、シリンダヘッドの母材とは、複数の部分のうち最も大きい体積を占める部分の材料である。副室壁部の母材とシリンダヘッドの母材が異なる場合、シリンダヘッドを構成する材料の異なる複数の部分のうち最も大きい体積を占める部分は、副室壁部を含まない。なお、本発明および実施の形態において、シリンダヘッドは副室壁部を含む。本発明および実施の形態において、主燃焼室の内部空間にその一部が露出するシリンダヘッド本体は、副室壁部を含まない。シリンダヘッド本体の母材は、シリンダヘッドの母材と同じである。シリンダヘッド本体は、材料の異なる複数の部分から構成されてもよく、材料の異なる複数の部分から構成されなくてもよい。 In the present invention and the embodiments, when the pre-chamber wall portion is composed of a plurality of portions made of different materials, the base material of the pre-chamber wall portion is the material of the portion occupying the largest volume among the plurality of portions. . In addition, in the present invention and the embodiments, the auxiliary chamber wall portion does not have to be composed of a plurality of portions made of different materials.
In the present invention and the embodiments, when the cylinder head is composed of a plurality of portions made of different materials, the base material of the cylinder head is the material of the portion occupying the largest volume among the plurality of portions. When the base material of the pre-chamber wall portion and the base material of the cylinder head are different, the portion occupying the largest volume among the plurality of portions of different materials forming the cylinder head does not include the pre-chamber wall portion. Note that, in the present invention and the embodiments, the cylinder head includes the auxiliary chamber wall. In the present invention and embodiments, the cylinder head body partially exposed to the interior space of the main combustion chamber does not include the auxiliary chamber wall. The base material of the cylinder head body is the same as the base material of the cylinder head. The cylinder head body may or may not consist of multiple parts of different materials.
本発明および実施の形態において、副室壁部の母材は熱伝導率がクロム系ステンレスと同じかそれよりも高いとは、副室燃焼4ストロークエンジンの運転時の主燃焼室および副室の温度条件において、副室壁部の母材の熱伝導率がクロム系ステンレスの熱伝導率と同じかそれよりも高いことを意味する。副室燃焼4ストロークエンジンの運転時の主燃焼室および副室の温度は、高い場合で例えば850~1000℃程度であり、低い場合で立ち例えば500~600℃程度である。
In the present invention and the embodiments, the fact that the base material of the pre-combustion chamber wall has a thermal conductivity equal to or higher than that of chromium-based stainless steel means It means that the thermal conductivity of the base material of the pre-chamber wall is equal to or higher than that of chromium-based stainless steel under temperature conditions. The temperature of the main combustion chamber and the pre-combustion chamber during operation of the pre-combustion four-stroke engine is, for example, about 850 to 1000.degree.
本発明および実施の形態において、副室の内部空間のプラグ軸方向の長さとは、プラグ軸方向における副室の内部空間の一端と他端との間のプラグ軸方向の長さである。別の言い方をすると、副室の内部空間のプラグ軸方向の一端を通りプラグ軸方向に直交する平面と、副室の内部空間のプラグ軸方向の他端を通りプラグ軸方向に直交する平面との間の距離である。本発明および実施の形態において、副室の内部空間のプラグ軸方向に直交する1つの方向の長さの定義も上記と同様である。本発明および実施の形態において、副室の内部空間のプラグ軸方向に直交する方向の最大長さとは、プラグ軸方向に直交する複数の方向における副室の内部空間の長さのうち、最大の長さである。
In the present invention and the embodiments, the axial length of the internal space of the pre-chamber is the axial length of the plug between one end and the other end of the internal space of the pre-chamber in the axial direction of the plug. In other words, a plane passing through one end of the internal space of the pre-chamber in the axial direction of the plug and perpendicular to the axial direction of the plug, and a plane passing through the other end of the internal space of the pre-chamber in the axial direction of the plug and perpendicular to the axial direction of the plug. is the distance between In the present invention and the embodiments, the definition of the length of the interior space of the pre-chamber in one direction perpendicular to the axial direction of the plug is the same as above. In the present invention and the embodiments, the maximum length of the interior space of the pre-chamber in the direction perpendicular to the axial direction of the plug is the maximum length among the lengths of the interior space of the pre-chamber in a plurality of directions perpendicular to the axial direction of the plug. length.
本発明および実施の形態において、「冷却部を通り副室スパークプラグのプラグ軸方向に直交する平面が、副室スパークプラグを通る」とは、冷却部を通り副室スパークプラグのプラグ軸方向に直交する全ての平面が副室スパークプラグを通ることを限定する意味ではなく、冷却部を通り副室スパークプラグのプラグ軸方向に直交するいずれかの平面が副室スパークプラグを通ることを意味する。本発明および実施の形態において、「冷却部を通り副室スパークプラグのプラグ軸方向に直交する平面が、副室部材を通る」、「冷却部を通り副室スパークプラグのプラグ軸方向に直交する平面が、副室スパークプラグに形成された雄ねじが副室部材に形成された雌ねじと噛み合って接触する箇所を通る」、および「副室の内部空間を通り副室スパークプラグのプラグ軸方向に直交する平面が、副室部材の外周面のシリンダヘッド本体に接触する箇所を通る」という文章も上記と同様に解釈される。
In the present invention and the embodiments, "the plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug" It does not mean that all orthogonal planes pass through the pre-chamber spark plug, but means that any plane that passes through the cooling portion and is perpendicular to the axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug. . In the present invention and the embodiments, "the plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber member," "the plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug." The plane passes through the place where the male thread formed in the pre-chamber spark plug engages and contacts the female thread formed in the pre-chamber member," and "the plane passes through the internal space of the pre-chamber and is orthogonal to the plug axial direction of the pre-chamber spark plug. The sentence "the plane that contacts the cylinder head body passes through the portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body" is also interpreted in the same manner as above.
本発明および実施の形態において、「副室部材が、主燃焼室の内部空間にその一部が露出するシリンダヘッド本体と別体である」とは、副室部材がシリンダヘッド本体から離れているか、もしくは、副室部材がシリンダヘッド本体と分離可能に接触していることを意味する。本発明および実施の形態において、シリンダヘッド本体は、分離不能な1つの部材で構成されていてもよく、主燃焼室の内部空間にその一部がそれぞれ露出する分離可能な複数の部材で構成されていてもよい。シリンダヘッド本体が分離可能な複数の部材で構成される場合、シリンダヘッド本体は、主燃焼室の内部空間にその一部が露出しない部材は含まない。
本発明および実施の形態において、「副室部材が副室スパークプラグと別体である」とは、副室部材が副室スパークプラグから離れているか、もしくは、副室部材が副室スパークプラグと分離可能に接触していることを意味する。副室部材は、副室スパークプラグの電極部の一部(例えば接地電極)を含まない。 In the present invention and the embodiments, "the sub-chamber member is separate from the cylinder head main body partly exposed to the internal space of the main combustion chamber" means that the sub-chamber member is separated from the cylinder head main body. Alternatively, it means that the sub-chamber member is in separable contact with the cylinder head body. In the present invention and the embodiments, the cylinder head main body may be composed of one inseparable member, or composed of a plurality of separable members each partially exposed to the internal space of the main combustion chamber. may be In the case where the cylinder head body is composed of a plurality of separable members, the cylinder head body does not include a member whose part is not exposed to the interior space of the main combustion chamber.
In the present invention and the embodiments, "the pre-chamber member is separate from the pre-chamber spark plug" means that the pre-chamber member is separated from the pre-chamber spark plug, or that the pre-chamber member is separate from the pre-chamber spark plug. It means that they are in separable contact. The pre-chamber member does not include a portion of the electrode portion of the pre-chamber spark plug (for example, the ground electrode).
本発明および実施の形態において、「副室部材が副室スパークプラグと別体である」とは、副室部材が副室スパークプラグから離れているか、もしくは、副室部材が副室スパークプラグと分離可能に接触していることを意味する。副室部材は、副室スパークプラグの電極部の一部(例えば接地電極)を含まない。 In the present invention and the embodiments, "the sub-chamber member is separate from the cylinder head main body partly exposed to the internal space of the main combustion chamber" means that the sub-chamber member is separated from the cylinder head main body. Alternatively, it means that the sub-chamber member is in separable contact with the cylinder head body. In the present invention and the embodiments, the cylinder head main body may be composed of one inseparable member, or composed of a plurality of separable members each partially exposed to the internal space of the main combustion chamber. may be In the case where the cylinder head body is composed of a plurality of separable members, the cylinder head body does not include a member whose part is not exposed to the interior space of the main combustion chamber.
In the present invention and the embodiments, "the pre-chamber member is separate from the pre-chamber spark plug" means that the pre-chamber member is separated from the pre-chamber spark plug, or that the pre-chamber member is separate from the pre-chamber spark plug. It means that they are in separable contact. The pre-chamber member does not include a portion of the electrode portion of the pre-chamber spark plug (for example, the ground electrode).
本発明および実施の形態において、ある構成要素の数を明確に特定していない場合(つまり、英語に翻訳された場合に単数形で表示される場合)、この構成要素の数は1つであってもよく複数であってもよい。本発明および実施の形態において、数が明確に特定されていない構成要素とは、例えば、主燃焼室、吸気通路、排気通路、スロットル弁、吸気通路噴射弁、副室、副室スパークプラグなどである。
本発明および実施の形態における副室燃焼4ストロークエンジンは、単一の主燃焼室を有してもよく、複数の主燃焼室を有してもよい。つまり、本発明および実施の形態における副室燃焼4ストロークエンジンは、単気筒エンジンユニットであってもよく、多気筒エンジンユニットであってもよい。副室および副室スパークプラグの数は、それぞれ、主燃焼室の数と同じである。吸気通路噴射弁の数は、主燃焼室の数と同じであってもよく、それより多くてもよい。スロットル弁の数は、主燃焼室の数と同じであってもよく、それより少なくてもよい。吸気通路は、2つ以上に分岐する形状でもよい。1つの主燃焼室に接続される吸気通路の数は1つである。分岐した形状の1つの吸気通路が複数の主燃焼室に接続されてもよい。排気通路は、2つ以上に分岐する形状でもよい。1つの主燃焼室に接続される排気通路の数は1つである。分岐した形状の1つの排気通路が複数の主燃焼室に接続されてもよい。 In the present invention and embodiments, where the number of an element is not explicitly specified (i.e., when translated into English it appears in the singular), the number of that element is one. may be multiple. In the present invention and embodiments, components whose numbers are not clearly specified include, for example, main combustion chambers, intake passages, exhaust passages, throttle valves, intake passage injection valves, pre-chambers, pre-chamber spark plugs, and the like. be.
A pre-combustion four-stroke engine according to the present invention and embodiments may have a single main combustion chamber or may have multiple main combustion chambers. That is, the pre-combustion four-stroke engine according to the present invention and the embodiments may be a single-cylinder engine unit or a multi-cylinder engine unit. The number of pre-chambers and pre-chamber spark plugs are each the same as the number of main combustion chambers. The number of intake manifold injectors may be the same as the number of main combustion chambers or may be greater. The number of throttle valves may be the same as the number of main combustion chambers, or it may be less. The intake passage may have a shape that branches into two or more. One intake passage is connected to one main combustion chamber. A single branched intake passage may be connected to a plurality of main combustion chambers. The exhaust passage may have a shape that branches into two or more. The number of exhaust passages connected to one main combustion chamber is one. One branched exhaust passage may be connected to a plurality of main combustion chambers.
本発明および実施の形態における副室燃焼4ストロークエンジンは、単一の主燃焼室を有してもよく、複数の主燃焼室を有してもよい。つまり、本発明および実施の形態における副室燃焼4ストロークエンジンは、単気筒エンジンユニットであってもよく、多気筒エンジンユニットであってもよい。副室および副室スパークプラグの数は、それぞれ、主燃焼室の数と同じである。吸気通路噴射弁の数は、主燃焼室の数と同じであってもよく、それより多くてもよい。スロットル弁の数は、主燃焼室の数と同じであってもよく、それより少なくてもよい。吸気通路は、2つ以上に分岐する形状でもよい。1つの主燃焼室に接続される吸気通路の数は1つである。分岐した形状の1つの吸気通路が複数の主燃焼室に接続されてもよい。排気通路は、2つ以上に分岐する形状でもよい。1つの主燃焼室に接続される排気通路の数は1つである。分岐した形状の1つの排気通路が複数の主燃焼室に接続されてもよい。 In the present invention and embodiments, where the number of an element is not explicitly specified (i.e., when translated into English it appears in the singular), the number of that element is one. may be multiple. In the present invention and embodiments, components whose numbers are not clearly specified include, for example, main combustion chambers, intake passages, exhaust passages, throttle valves, intake passage injection valves, pre-chambers, pre-chamber spark plugs, and the like. be.
A pre-combustion four-stroke engine according to the present invention and embodiments may have a single main combustion chamber or may have multiple main combustion chambers. That is, the pre-combustion four-stroke engine according to the present invention and the embodiments may be a single-cylinder engine unit or a multi-cylinder engine unit. The number of pre-chambers and pre-chamber spark plugs are each the same as the number of main combustion chambers. The number of intake manifold injectors may be the same as the number of main combustion chambers or may be greater. The number of throttle valves may be the same as the number of main combustion chambers, or it may be less. The intake passage may have a shape that branches into two or more. One intake passage is connected to one main combustion chamber. A single branched intake passage may be connected to a plurality of main combustion chambers. The exhaust passage may have a shape that branches into two or more. The number of exhaust passages connected to one main combustion chamber is one. One branched exhaust passage may be connected to a plurality of main combustion chambers.
本発明および実施の形態における副室燃焼4ストロークエンジンは、自動車より車両重量が軽量でありエンジンの軽量化および小型化が要求される鞍乗型車両に搭載することができる。鞍乗型車両とは、運転者が鞍にまたがるような状態で乗車する車両全般を指す。鞍乗型車両は、自動二輪車、スクーター、自動三輪車(motor tricycle)、四輪バギー(ATV:All Terrain Vehicle / 全地形型車両)、スノーモービル、水上オートバイ(パーソナルウォータークラフト)などを含む。また、本発明および実施の形態における副室燃焼4ストロークエンジンは、エンジンの軽量化および小型化が要求される作業用車両に搭載することができる。なお、本発明および実施の形態における副室燃焼4ストロークエンジンンが自動車に搭載できることは言うまでもない。本発明および実施の形態における副室燃焼4ストロークエンジンを搭載する製品は、特定の製品に限定されない。本発明の一実施形態である副室燃焼4ストロークエンジンが製品に搭載された場合、シリンダ孔の中心軸線が鉛直に対して0度以上45度以下になるように搭載されてもよく、45度以上90度以下になるように搭載されてもよい。
The pre-combustion four-stroke engine according to the present invention and the embodiment can be mounted on a straddle-type vehicle that is lighter in weight than an automobile and requires a lighter and smaller engine. A straddle-type vehicle refers to a vehicle in general in which the driver straddles a saddle. Straddle-type vehicles include motorcycles, scooters, motor tricycles, ATVs (All Terrain Vehicles), snowmobiles, personal water crafts, and the like. Also, the pre-combustion four-stroke engine according to the present invention and the embodiments can be mounted on a work vehicle that requires a lighter and smaller engine. Needless to say, the pre-combustion four-stroke engine according to the present invention and the embodiments can be mounted on automobiles. The product equipped with the pre-combustion four-stroke engine according to the present invention and the embodiments is not limited to a specific product. When the pre-combustion four-stroke engine that is one embodiment of the present invention is mounted on a product, it may be mounted so that the central axis of the cylinder hole is 0 degrees or more and 45 degrees or less with respect to the vertical, or 45 degrees. You may mount so that it may become more than 90 degrees or less.
本発明および実施の形態において「含む(including)、有する(having)、構成する(comprising)およびこれらの派生語」は、列挙されたアイテム及びその等価物に加えて追加的アイテムをも包含することが意図されて用いられている。
In the present invention and embodiments, the terms "including, having, comprising and derivatives thereof" are intended to encompass the recited items and their equivalents as well as additional items. is intended and used.
他に定義されない限り、本発明および実施の形態で使用される全ての用語(技術用語および科学用語を含む)は、本発明が属する当業者によって一般的に理解されるのと同じ意味を有する。一般的に使用される辞書に定義された用語のような用語は、関連する技術および本開示の文脈における意味と一致する意味を有すると解釈されるべきであり、理想化されたまたは過度に形式的な意味で解釈されることはない。
Unless defined otherwise, all terms (including technical and scientific terms) used in the present invention and embodiments have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be construed to have a meaning consistent with their meaning in the context of the relevant technology and this disclosure, and are not idealized or overly formal. not be interpreted in any meaningful way.
本発明および実施の形態において、「してもよい」という用語は非排他的なものである。「してもよい」は、「してもよいがこれに限定されるものではない」という意味である。本発明および実施の形態において、「してもよい」と記載された構成は、少なくとも請求項1の構成により得られる上記効果を奏する。
In the present invention and embodiments, the term "may" is non-exclusive. "May be" means "may be, but is not limited to." In the present invention and the embodiments, the configuration described as "may" has at least the above effect obtained by the configuration of claim 1.
本発明の実施形態を詳細に説明する前に、本発明は、以下の説明に記載されたまたは図面に図示された構成要素の構成および配置の詳細に制限されないことが理解されるべきである。本発明は、後述する実施形態以外の実施形態でも可能である。本発明は、後述する実施形態に様々な変更を加えた実施形態でも可能である。
Before describing embodiments of the present invention in detail, it should be understood that the present invention is not limited to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The present invention is also possible in embodiments other than those described below. The present invention is also possible in embodiments in which various modifications are made to the embodiments described later.
本発明の副室燃焼4ストロークエンジンによると、シリンダヘッドの大型化を抑制しつつ、プレイグニッションの発生を抑制できる。
According to the pre-combustion four-stroke engine of the present invention, it is possible to suppress the occurrence of pre-ignition while suppressing the enlargement of the cylinder head.
以下、図面を参照しながら、本発明の一実施形態である副室燃焼4ストロークエンジンについて説明する。なお、以下に説明する実施の形態は、例示である。本発明は、以下に説明する実施の形態によって、何等、限定的に解釈されるものではない。
A pre-combustion four-stroke engine that is an embodiment of the present invention will be described below with reference to the drawings. In addition, the embodiment described below is an example. The present invention is not to be construed as being limited by the embodiments described below.
<第1実施形態>
本発明の第1実施形態の副室燃焼4ストロークエンジン1について、図1(a)~図1(f)を用いて説明する。図1(b)は、図1(a)のA-A線断面の一部分の一例を示す。図1(c)および図1(d)は、図1(a)のB-B線断面の一部分の2つの例を示す。図1(e)および図1(f)は、図1(a)のC-C線断面の一部分の2つの例を示す。第1実施形態載の副室燃焼4ストロークエンジン1は、少なくとも1つの主燃焼室2を有する。吸気通路5および排気通路6が主燃焼室2に接続される。主燃焼室2は、シリンダヘッド10と、シリンダ孔11と、ピストン12とによって形成される。吸気通路5は、シリンダヘッド10の内部に形成された通路と、この通路に接続された通路を含む。排気通路6は、シリンダヘッド10の内部に形成された通路と、この通路に接続された通路を含む。副室燃焼4ストロークエンジン1は、少なくとも1つのスロットル弁7を有する。スロットル弁7は、吸気通路5を通過して主燃焼室2に吸入される空気の量を調整する。副室燃焼4ストロークエンジン1は、少なくとも1つの吸気通路噴射弁8を有する。吸気通路噴射弁8は、ガソリン燃料、アルコール燃料、またはガソリン・アルコール混合燃料である液体燃料を吸気通路5の内部に噴射する。副室燃焼4ストロークエンジン1は、少なくとも1つの副室20を有する。副室20の内部空間は、複数の連通孔21を介して主燃焼室2の内部空間と連通する。副室20の容積は、主燃焼室2の容積よりも小さく形成される。副室20の内部空間に、副室スパークプラグ23の一部が露出する。副室20はシリンダヘッド10に形成される。複数の連通孔21は、シリンダヘッド10の副室壁部22に形成される。副室壁部22は、主燃焼室2の内部空間に晒された片面を有する。シリンダ孔11の中心軸線C11との位置と副室スパークプラグ23の中心軸線C23の位置との関係は、図1(a)および図1(b)に示す位置関係に限らない。副室スパークプラグ23の中心軸線C23と平行な方向を、プラグ軸方向DPとする。図1(a)および図1(b)において、プラグ軸方向DPはシリンダ孔11の中心軸線C11と平行であるが、プラグ軸方向DPはシリンダ孔11の中心軸線C11と平行でなくてもよい。なお、副室20の内部空間の形状は、図1(a)および図1(b)に示す形状に限定されない。副室燃焼4ストロークエンジン1は、少なくとも1つの吸気通路噴射弁8および少なくとも1つの副室スパークプラグ23を制御する制御装置70を有する。制御装置70は、スロットル弁7の開度が小さい低負荷領域の少なくとも一部において、吸気通路5および主燃焼室2で混合された混合気が燃焼後に三元触媒で処理できる第1空燃比または第1空燃比よりもリッチな第2空燃比となるように、吸気通路噴射弁8を制御する。例えば、制御装置70は、低負荷領域の少なくとも一部において、吸気通路5および主燃焼室2で混合された混合気が燃焼後に三元触媒で処理できる第1空燃比となるように、吸気通路噴射弁8を制御してもよい。副室燃焼4ストロークエンジン1は、三元触媒を有してもよく有さなくてもよい。副室燃焼4ストロークエンジン1は、副室20に燃料を噴射する副室燃料噴射弁、および、副室20または主燃焼室2における混合気の点火を補助する点火補助装置のどちらも有さない。 <First embodiment>
A pre-combustion four-stroke engine 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1(a) to 1(f). FIG. 1(b) shows an example of a part of the AA cross section of FIG. 1(a). FIGS. 1(c) and 1(d) show two examples of a portion of the BB cross-section of FIG. 1(a). FIGS. 1(e) and 1(f) show two examples of a portion of the CC line section of FIG. 1(a). The pre-combustion four-stroke engine 1 according to the first embodiment has at least one main combustion chamber 2 . An intake passage 5 and an exhaust passage 6 are connected to the main combustion chamber 2 . A main combustion chamber 2 is formed by a cylinder head 10 , a cylinder bore 11 and a piston 12 . The intake passage 5 includes a passage formed inside the cylinder head 10 and a passage connected to this passage. The exhaust passage 6 includes a passage formed inside the cylinder head 10 and a passage connected to this passage. The pre-combustion four-stroke engine 1 has at least one throttle valve 7 . The throttle valve 7 adjusts the amount of air that passes through the intake passage 5 and is drawn into the main combustion chamber 2 . The pre-combustion four-stroke engine 1 has at least one intake manifold injection valve 8 . The intake passage injection valve 8 injects liquid fuel, which is gasoline fuel, alcohol fuel, or gasoline-alcohol mixed fuel, into the intake passage 5 . The pre-combustion four-stroke engine 1 has at least one pre-combustion chamber 20 . The internal space of the auxiliary chamber 20 communicates with the internal space of the main combustion chamber 2 through a plurality of communication holes 21 . The auxiliary chamber 20 has a smaller volume than the main combustion chamber 2 . A part of the pre-chamber spark plug 23 is exposed in the internal space of the pre-chamber 20 . A sub chamber 20 is formed in the cylinder head 10 . A plurality of communication holes 21 are formed in the auxiliary chamber wall portion 22 of the cylinder head 10 . The auxiliary chamber wall portion 22 has one side exposed to the internal space of the main combustion chamber 2 . The relationship between the position of the central axis C11 of the cylinder hole 11 and the position of the central axis C23 of the pre-chamber spark plug 23 is not limited to the positional relationship shown in FIGS. 1(a) and 1(b). A direction parallel to the central axis C23 of the pre-chamber spark plug 23 is defined as a plug axial direction DP. 1(a) and 1(b), the plug axial direction DP is parallel to the central axis C11 of the cylinder hole 11, but the plug axial direction DP need not be parallel to the central axis C11 of the cylinder hole 11. . The shape of the internal space of the auxiliary chamber 20 is not limited to the shape shown in FIGS. 1(a) and 1(b). The pre-combustion four-stroke engine 1 has a control device 70 that controls at least one intake manifold injection valve 8 and at least one pre-chamber spark plug 23 . The control device 70 sets the first air-fuel ratio or The intake manifold injection valve 8 is controlled so that the second air-fuel ratio is richer than the first air-fuel ratio. For example, the control device 70 controls the intake passage so that the air-fuel mixture mixed in the intake passage 5 and the main combustion chamber 2 becomes the first air-fuel ratio that can be processed by the three-way catalyst after combustion in at least a part of the low load region. Injection valve 8 may be controlled. The pre-combustion four-stroke engine 1 may or may not have a three-way catalyst. The pre-combustion four-stroke engine 1 has neither a pre-combustion fuel injection valve for injecting fuel into the pre-combustion chamber 20 nor an ignition assist device for assisting ignition of the air-fuel mixture in the pre-combustion chamber 20 or the main combustion chamber 2. .
本発明の第1実施形態の副室燃焼4ストロークエンジン1について、図1(a)~図1(f)を用いて説明する。図1(b)は、図1(a)のA-A線断面の一部分の一例を示す。図1(c)および図1(d)は、図1(a)のB-B線断面の一部分の2つの例を示す。図1(e)および図1(f)は、図1(a)のC-C線断面の一部分の2つの例を示す。第1実施形態載の副室燃焼4ストロークエンジン1は、少なくとも1つの主燃焼室2を有する。吸気通路5および排気通路6が主燃焼室2に接続される。主燃焼室2は、シリンダヘッド10と、シリンダ孔11と、ピストン12とによって形成される。吸気通路5は、シリンダヘッド10の内部に形成された通路と、この通路に接続された通路を含む。排気通路6は、シリンダヘッド10の内部に形成された通路と、この通路に接続された通路を含む。副室燃焼4ストロークエンジン1は、少なくとも1つのスロットル弁7を有する。スロットル弁7は、吸気通路5を通過して主燃焼室2に吸入される空気の量を調整する。副室燃焼4ストロークエンジン1は、少なくとも1つの吸気通路噴射弁8を有する。吸気通路噴射弁8は、ガソリン燃料、アルコール燃料、またはガソリン・アルコール混合燃料である液体燃料を吸気通路5の内部に噴射する。副室燃焼4ストロークエンジン1は、少なくとも1つの副室20を有する。副室20の内部空間は、複数の連通孔21を介して主燃焼室2の内部空間と連通する。副室20の容積は、主燃焼室2の容積よりも小さく形成される。副室20の内部空間に、副室スパークプラグ23の一部が露出する。副室20はシリンダヘッド10に形成される。複数の連通孔21は、シリンダヘッド10の副室壁部22に形成される。副室壁部22は、主燃焼室2の内部空間に晒された片面を有する。シリンダ孔11の中心軸線C11との位置と副室スパークプラグ23の中心軸線C23の位置との関係は、図1(a)および図1(b)に示す位置関係に限らない。副室スパークプラグ23の中心軸線C23と平行な方向を、プラグ軸方向DPとする。図1(a)および図1(b)において、プラグ軸方向DPはシリンダ孔11の中心軸線C11と平行であるが、プラグ軸方向DPはシリンダ孔11の中心軸線C11と平行でなくてもよい。なお、副室20の内部空間の形状は、図1(a)および図1(b)に示す形状に限定されない。副室燃焼4ストロークエンジン1は、少なくとも1つの吸気通路噴射弁8および少なくとも1つの副室スパークプラグ23を制御する制御装置70を有する。制御装置70は、スロットル弁7の開度が小さい低負荷領域の少なくとも一部において、吸気通路5および主燃焼室2で混合された混合気が燃焼後に三元触媒で処理できる第1空燃比または第1空燃比よりもリッチな第2空燃比となるように、吸気通路噴射弁8を制御する。例えば、制御装置70は、低負荷領域の少なくとも一部において、吸気通路5および主燃焼室2で混合された混合気が燃焼後に三元触媒で処理できる第1空燃比となるように、吸気通路噴射弁8を制御してもよい。副室燃焼4ストロークエンジン1は、三元触媒を有してもよく有さなくてもよい。副室燃焼4ストロークエンジン1は、副室20に燃料を噴射する副室燃料噴射弁、および、副室20または主燃焼室2における混合気の点火を補助する点火補助装置のどちらも有さない。 <First embodiment>
A pre-combustion four-
図1(a)および図1(b)に示すように、シリンダヘッド10は、副室スパークプラグ23の電極部24および副室壁部22からの熱を受け取る冷却媒体(図示せず)が収容される冷却部16を有する。図1(b)において、冷却部16は環状であるが、冷却部16は環状でなくてもよい。副室スパークプラグ23の電極部24は、電極部24に複数の火花放電33が周方向に分散して生じるように形成されている。複数の連通孔21は周方向に分散して形成されている。シリンダヘッド10は、副室スパークプラグ23の電極部24から冷却部16までの複数の熱経路14、および、副室壁部22から冷却部16までの複数の熱経路15がそれぞれ周方向に分散して形成されるように形成されている。例えば、複数の火花放電33、複数の連通孔21、複数の熱経路14、および、複数の熱経路15は、それぞれ、副室スパークプラグ23の中心軸線C23を中心とした周方向に分散して形成されてもよい。図1(a)に示す熱経路14は、副室スパークプラグ23の電極部24から冷却部16までの熱経路14の一例にすぎない。図1(a)に示す熱経路15は、副室壁部22から冷却部16までの熱経路15の一例にすぎない。図1(c)に示す2つの火花放電33は、副室スパークプラグ23の電極部24に周方向に分散して生じる複数の火花放電33の一例にすぎない。図1(d)に示す複数の火花放電33は、副室スパークプラグ23の電極部24に周方向に分散して生じる複数の火花放電33の一例にすぎない。電極部24の構成は、図1(c)および図1(d)に示す構成に限定されない。電極部24は、例えば図1(c)に示すように、単一の中心電極30と複数の接地電極31を有してもよい。電極部24は、例えば図1(d)に示すように、単一の中心電極30と環状の接地電極31を有してもよい。複数の接地電極31は、接地電極31同士の間に空間が形成されるように構成される。複数の接地電極31は、中心電極30に対してプラグ軸方向DPに直交する方向に離れている。複数の接地電極31は、中心電極30とプラグ軸方向DPに並ばない。環状の接地電極31の内周端は、中心電極30に対してプラグ軸方向DPに直交する方向に離れている。単一の中心電極30と複数の接地電極31または環状の接地電極31との間には、プラグ軸方向DPに直交する方向の複数または環状の放電ギャップが形成される。複数の接地電極31の数は例えば2つでもよい。複数の連通孔21の数、位置、形状、およびサイズは、図1(e)および図1(f)に示すものに限らない。複数の連通孔21の数は例えば3つ以上でもよい。
As shown in FIGS. 1(a) and 1(b), the cylinder head 10 accommodates a cooling medium (not shown) that receives heat from the electrode portion 24 and the sub chamber wall portion 22 of the pre chamber spark plug 23. It has a cooling part 16 that is Although the cooling portion 16 is annular in FIG. 1(b), the cooling portion 16 may not be annular. The electrode portion 24 of the pre-chamber spark plug 23 is formed so that a plurality of spark discharges 33 are generated in the electrode portion 24 in a circumferentially distributed manner. A plurality of communication holes 21 are formed dispersedly in the circumferential direction. The cylinder head 10 has a plurality of heat paths 14 from the electrode portion 24 of the pre-chamber spark plug 23 to the cooling portion 16 and a plurality of heat paths 15 from the pre-chamber wall portion 22 to the cooling portion 16 distributed in the circumferential direction. It is formed to be formed by For example, the plurality of spark discharges 33, the plurality of communication holes 21, the plurality of heat paths 14, and the plurality of heat paths 15 are distributed in the circumferential direction around the center axis C23 of the pre-chamber spark plug 23. may be formed. The heat path 14 shown in FIG. 1A is merely an example of the heat path 14 from the electrode portion 24 of the pre-chamber spark plug 23 to the cooling portion 16 . The heat path 15 shown in FIG. 1( a ) is merely an example of the heat path 15 from the auxiliary chamber wall portion 22 to the cooling portion 16 . The two spark discharges 33 shown in FIG. 1(c) are merely an example of the plurality of spark discharges 33 distributed in the electrode portion 24 of the pre-chamber spark plug 23 in the circumferential direction. The plurality of spark discharges 33 shown in FIG. 1(d) is merely an example of the plurality of spark discharges 33 distributed in the electrode portion 24 of the pre-chamber spark plug 23 in the circumferential direction. The configuration of the electrode section 24 is not limited to the configurations shown in FIGS. 1(c) and 1(d). The electrode section 24 may have a single center electrode 30 and a plurality of ground electrodes 31, for example, as shown in FIG. 1(c). The electrode section 24 may have a single center electrode 30 and an annular ground electrode 31, for example, as shown in FIG. 1(d). The plurality of ground electrodes 31 are configured such that spaces are formed between the ground electrodes 31 . The plurality of ground electrodes 31 are separated from the center electrode 30 in a direction orthogonal to the plug axial direction DP. The plurality of ground electrodes 31 are not aligned with the center electrode 30 in the plug axial direction DP. An inner peripheral end of the ring-shaped ground electrode 31 is separated from the center electrode 30 in a direction orthogonal to the plug axial direction DP. Between the single center electrode 30 and the plurality of ground electrodes 31 or the annular ground electrode 31, multiple or annular discharge gaps are formed in a direction orthogonal to the plug axial direction DP. The number of ground electrodes 31 may be two, for example. The number, positions, shapes, and sizes of the plurality of communication holes 21 are not limited to those shown in FIGS. 1(e) and 1(f). The number of communication holes 21 may be, for example, three or more.
第1実施形態の構成成によると、副室スパークプラグ23の電極部24および副室壁部22から冷却部16に熱が移動しやすいため、冷却部16の大型化を抑制しつつプレイグニッションの発生を抑制できる。しかも、点火補助装置が設けられないため、シリンダヘッド10の大型化をより抑制できる。よって、シリンダヘッド10の大型化を抑制しつつ、プレイグニッションの発生を抑制できる。
According to the configuration of the first embodiment, since heat is easily transferred from the electrode portion 24 of the pre-chamber spark plug 23 and the pre-chamber wall portion 22 to the cooling portion 16, the size of the cooling portion 16 is suppressed and pre-ignition is reduced. It can suppress the occurrence. Moreover, since no auxiliary ignition device is provided, it is possible to further suppress the increase in size of the cylinder head 10 . Therefore, it is possible to suppress the occurrence of pre-ignition while suppressing an increase in the size of the cylinder head 10 .
なお、図1(a)における副室燃焼4ストロークエンジン1は、冷却部16を通りプラグ軸方向DPに直交するいずれかの平面が副室スパークプラグ23を通るように形成されている。この平面は、例えば図1(a)のA―A線と重なる平面である。図1(a)において、副室燃焼4ストロークエンジン1は、冷却部16を通りプラグ軸方向DPに直交するいずれの平面も副室20の内部空間を通らないように形成されている。第1実施形態において、副室燃焼4ストロークエンジン1は、冷却部16を通りプラグ軸方向DPに直交するいずかの平面が副室20の内部空間を通るように形成されていてもよい。
Note that the pre-combustion four-stroke engine 1 in FIG. 1( a ) is formed such that any plane passing through the cooling portion 16 and perpendicular to the plug axial direction DP passes through the pre-chamber spark plug 23 . This plane is, for example, a plane that overlaps the AA line in FIG. 1(a). In FIG. 1( a ), the pre-combustion four-stroke engine 1 is formed so that none of the planes passing through the cooling section 16 and perpendicular to the plug axial direction DP pass through the internal space of the pre-chamber 20 . In the first embodiment, the pre-combustion four-stroke engine 1 may be formed such that any plane passing through the cooling portion 16 and orthogonal to the plug axial direction DP passes through the interior space of the pre-chamber 20 .
第1実施形態の副室燃焼4ストロークエンジン1は、主燃焼室2の内部に燃料を噴射する主燃焼室燃料噴射弁を有さなくてよい。第1実施形態の副室燃焼4ストロークエンジン1は、スーパーチャージャーおよびターボチャージャーのどちらも有さなくてよい。つまり、副室燃焼4ストロークエンジン1は、自然吸気式でもよい。第1実施形態の副室燃焼4ストロークエンジン1は、主燃焼室2を迂回して排気通路6と吸気通路5を接続する外部排気再循環通路を含む外部排気再循環装置を有さなくてよい。
The pre-combustion four-stroke engine 1 of the first embodiment does not need to have a main combustion chamber fuel injection valve that injects fuel into the main combustion chamber 2 . The pre-combustion four-stroke engine 1 of the first embodiment may have neither a supercharger nor a turbocharger. That is, the pre-combustion four-stroke engine 1 may be of a naturally aspirated type. The auxiliary chamber combustion four-stroke engine 1 of the first embodiment need not have an external exhaust gas recirculation device including an external exhaust gas recirculation passage bypassing the main combustion chamber 2 and connecting the exhaust passage 6 and the intake passage 5. .
<第2実施形態>
本発明の第2実施形態の副室燃焼4ストロークエンジン1について説明する。第2実施形態は、第1実施形態の構成を有する。第2実施形態において、副室壁部22の母材の融点は、シリンダヘッド10の母材の融点よりも高い。副室壁部22の母材の比熱と比重を乗じた値は、シリンダヘッド10の母材の比熱と比重を乗じた値よりも高い。副室壁部22の母材の熱伝導率は、クロム系ステンレスの熱伝導率と同じかそれよりも高い。シリンダヘッド10の母材は、例えば、アルミニウムまたはアルミニウム合金である。シリンダヘッド10の母材がアルミニウムまたはアルミニウム合金の場合、副室壁部22の母材として、例えば下記の表1の実施例1~4に示す材料が用いられてもよい。副室壁部22の母材は、実施例1のようなクロムジルコニウム銅合金でもよい。副室壁部22の母材は、クロム銅合金でもよい。表1に示す比較例1~3は、シリンダヘッド10の母材がアルミニウムまたはアルミニウム合金の場合に副室壁部22の母材として使用されない材料の例である。 <Second embodiment>
A pre-combustion four-stroke engine 1 according to a second embodiment of the present invention will be described. The second embodiment has the configuration of the first embodiment. In the second embodiment, the melting point of the base material of the sub chamber wall portion 22 is higher than the melting point of the base material of the cylinder head 10 . The value obtained by multiplying the specific heat and specific gravity of the base material of the sub chamber wall portion 22 is higher than the value obtained by multiplying the specific heat and specific gravity of the base material of the cylinder head 10 . The thermal conductivity of the base material of the auxiliary chamber wall portion 22 is the same as or higher than that of chromium-based stainless steel. A base material of the cylinder head 10 is, for example, aluminum or an aluminum alloy. When the base material of the cylinder head 10 is aluminum or an aluminum alloy, as the base material of the auxiliary chamber wall portion 22, for example, materials shown in Examples 1 to 4 in Table 1 below may be used. The base material of the auxiliary chamber wall portion 22 may be a chromium-zirconium-copper alloy as in the first embodiment. The base material of the auxiliary chamber wall portion 22 may be a chromium-copper alloy. Comparative Examples 1 to 3 shown in Table 1 are examples of materials that are not used as the base material of the auxiliary chamber wall portion 22 when the base material of the cylinder head 10 is aluminum or an aluminum alloy.
本発明の第2実施形態の副室燃焼4ストロークエンジン1について説明する。第2実施形態は、第1実施形態の構成を有する。第2実施形態において、副室壁部22の母材の融点は、シリンダヘッド10の母材の融点よりも高い。副室壁部22の母材の比熱と比重を乗じた値は、シリンダヘッド10の母材の比熱と比重を乗じた値よりも高い。副室壁部22の母材の熱伝導率は、クロム系ステンレスの熱伝導率と同じかそれよりも高い。シリンダヘッド10の母材は、例えば、アルミニウムまたはアルミニウム合金である。シリンダヘッド10の母材がアルミニウムまたはアルミニウム合金の場合、副室壁部22の母材として、例えば下記の表1の実施例1~4に示す材料が用いられてもよい。副室壁部22の母材は、実施例1のようなクロムジルコニウム銅合金でもよい。副室壁部22の母材は、クロム銅合金でもよい。表1に示す比較例1~3は、シリンダヘッド10の母材がアルミニウムまたはアルミニウム合金の場合に副室壁部22の母材として使用されない材料の例である。 <Second embodiment>
A pre-combustion four-
副室壁部22は母材だけで構成されてもよい。副室壁部22は母材と母材以外の材料で構成されてもよい。例えば、副室壁部22は、副室壁部22の外面の少なくとも一部に、母材とは異なる材料のコーティング層を有してもよい。コーティング層の熱伝導率は副室壁部22の熱伝導率よりも高いことが好ましい。
The auxiliary chamber wall portion 22 may be composed only of the base material. The auxiliary chamber wall portion 22 may be composed of a base material and a material other than the base material. For example, the sub-chamber wall portion 22 may have a coating layer of a material different from the base material on at least a portion of the outer surface of the sub-chamber wall portion 22 . The thermal conductivity of the coating layer is preferably higher than that of the auxiliary chamber wall portion 22 .
<第3実施形態>
本発明の第3実施形態の副室燃焼4ストロークエンジン1について、図2(a)を用いて説明する。第3実施形態の副室燃焼4ストロークエンジン1は、第1実施形態または第2実施形態の構成に加えて以下の構成を有する。副室スパークプラグ23を除き副室20の内面に突起が形成されていない。副室20の内部空間のプラグ軸方向DPの長さL1と副室20の内部空間のプラグ軸方向DPに直交する方向の最大長さL2のうち大きい方の長さが小さい方の長さの2倍より小さい。図2(a)では長さL2が長さL1よりも大きいが、長さL1が長さL2よりも大きくてもよい。 <Third Embodiment>
A pre-combustion four-stroke engine 1 according to a third embodiment of the present invention will be described with reference to FIG. 2(a). The pre-combustion four-stroke engine 1 of the third embodiment has the following configuration in addition to the configuration of the first or second embodiment. No projections are formed on the inner surface of the pre-chamber 20 except for the pre-chamber spark plug 23 . The length L1 of the internal space of the pre-chamber 20 in the axial direction DP of the plug and the maximum length L2 of the internal space of the sub-chamber 20 in the direction perpendicular to the axial direction DP of the plug, whichever is greater is the length of the smaller one. less than twice. Although the length L2 is longer than the length L1 in FIG. 2(a), the length L1 may be longer than the length L2.
本発明の第3実施形態の副室燃焼4ストロークエンジン1について、図2(a)を用いて説明する。第3実施形態の副室燃焼4ストロークエンジン1は、第1実施形態または第2実施形態の構成に加えて以下の構成を有する。副室スパークプラグ23を除き副室20の内面に突起が形成されていない。副室20の内部空間のプラグ軸方向DPの長さL1と副室20の内部空間のプラグ軸方向DPに直交する方向の最大長さL2のうち大きい方の長さが小さい方の長さの2倍より小さい。図2(a)では長さL2が長さL1よりも大きいが、長さL1が長さL2よりも大きくてもよい。 <Third Embodiment>
A pre-combustion four-
<第4実施形態>
本発明の第4実施形態の副室燃焼4ストロークエンジン1について、図2(b)を用いて説明する。第4実施形態は、第1実施形態~第3実施形態の少なくとも1つの構成を有する。第4実施形態において、副室壁部22は、主燃焼室2の内部空間に突出するように形成されている。さらに、第4実施形態において、副室20は、副室20の容積に対して副室壁部22の突出量が小さくなるように形成されている。具体的には、副室壁部22の外面を通らず副室20の内部空間を通りプラグ軸方向DPに直交するいずれかの平面S1によって副室20の内部空間を2つの空間に分けた場合に、2つの空間のうち主燃焼室2に近い方の空間の体積が、2つの空間のうち主燃焼室2から遠い方の空間の体積よりも小さくなるように、副室20は形成されている。図2(b)に示す平面S1は、副室壁部22の外面を通らず副室20の内部空間を通りプラグ軸方向DPに直交する平面S1の一例に過ぎない。なお、副室壁部22の外面とは、主燃焼室2に露出する面である。 <Fourth Embodiment>
A pre-combustion four-stroke engine 1 according to a fourth embodiment of the present invention will be described with reference to FIG. 2(b). The fourth embodiment has at least one configuration of the first to third embodiments. In the fourth embodiment, the auxiliary chamber wall portion 22 is formed so as to protrude into the internal space of the main combustion chamber 2 . Furthermore, in the fourth embodiment, the auxiliary chamber 20 is formed so that the projection amount of the auxiliary chamber wall portion 22 is smaller than the volume of the auxiliary chamber 20 . Specifically, when the internal space of the pre-chamber 20 is divided into two spaces by any plane S1 that passes through the internal space of the pre-chamber 20 without passing through the outer surface of the pre-chamber wall portion 22 and perpendicular to the plug axial direction DP. The pre-chamber 20 is formed such that the volume of the space closer to the main combustion chamber 2 out of the two spaces is smaller than the volume of the space farther from the main combustion chamber 2 out of the two spaces. there is The plane S1 shown in FIG. 2B is merely an example of a plane S1 that does not pass through the outer surface of the pre-chamber wall portion 22 but passes through the internal space of the pre-chamber 20 and is orthogonal to the axial direction DP of the plug. The outer surface of the auxiliary chamber wall portion 22 is the surface exposed to the main combustion chamber 2 .
本発明の第4実施形態の副室燃焼4ストロークエンジン1について、図2(b)を用いて説明する。第4実施形態は、第1実施形態~第3実施形態の少なくとも1つの構成を有する。第4実施形態において、副室壁部22は、主燃焼室2の内部空間に突出するように形成されている。さらに、第4実施形態において、副室20は、副室20の容積に対して副室壁部22の突出量が小さくなるように形成されている。具体的には、副室壁部22の外面を通らず副室20の内部空間を通りプラグ軸方向DPに直交するいずれかの平面S1によって副室20の内部空間を2つの空間に分けた場合に、2つの空間のうち主燃焼室2に近い方の空間の体積が、2つの空間のうち主燃焼室2から遠い方の空間の体積よりも小さくなるように、副室20は形成されている。図2(b)に示す平面S1は、副室壁部22の外面を通らず副室20の内部空間を通りプラグ軸方向DPに直交する平面S1の一例に過ぎない。なお、副室壁部22の外面とは、主燃焼室2に露出する面である。 <Fourth Embodiment>
A pre-combustion four-
<第5実施形態>
本発明の第5実施形態の副室燃焼4ストロークエンジン1について、図3(a)~図3(c)、図4(a)~図4(e)、図5(a)および図5(b)を用いて説明する。図3(a)~図3(c)は、第5実施形態の3つの例を示す。図4(a)~図4(e)は、第5実施形態の5つの例を示す。図5(a)および図5(b)は、第5実施形態の2つの例を示す。第5実施形態は、第1実施形態~第4実施形態の少なくとも1つの構成を有する。第5実施形態において、副室20の内面は、副室壁部22を含む副室部材25と副室スパークプラグ23とによって形成されている。つまり、副室20の内部空間は、副室部材25と副室スパークプラグ23とによって囲まれた空間である。副室スパークプラグ23の外周面と副室部材25の内周面は接触する。副室部材25は、主燃焼室2の内部空間にその一部が露出するシリンダヘッド本体13と別体で、且つ、副室スパークプラグ23と別体である。シリンダヘッド本体13は、分離不能な1つの部材で構成されていてもよく、主燃焼室2の内部空間にその一部がそれぞれ露出する分離可能な複数の部材で構成されていてもよい。シリンダヘッド本体13が分離可能な複数の部材で構成される場合、シリンダヘッド本体13は、主燃焼室2の内部空間にその一部が露出しない部材は含まない。 <Fifth Embodiment>
3(a) to 3(c), 4(a) to 4(e), 5(a) and 5 ( b) is used for explanation. 3(a) to 3(c) show three examples of the fifth embodiment. Figures 4(a) to 4(e) show five examples of the fifth embodiment. Figures 5(a) and 5(b) show two examples of the fifth embodiment. The fifth embodiment has at least one configuration of the first to fourth embodiments. In the fifth embodiment, the inner surface of the pre-chamber 20 is formed by thepre-chamber member 25 including the pre-chamber wall portion 22 and the pre-chamber spark plug 23 . That is, the internal space of the pre-chamber 20 is a space surrounded by the pre-chamber member 25 and the pre-chamber spark plug 23 . The outer peripheral surface of the pre-chamber spark plug 23 and the inner peripheral surface of the pre-chamber member 25 are in contact with each other. The pre-chamber member 25 is separate from the cylinder head body 13 partially exposed to the internal space of the main combustion chamber 2 and separate from the pre-chamber spark plug 23 . The cylinder head body 13 may be composed of one inseparable member, or may be composed of a plurality of separable members each partly exposed to the internal space of the main combustion chamber 2 . When the cylinder head main body 13 is composed of a plurality of separable members, the cylinder head main body 13 does not include a member whose part is not exposed to the internal space of the main combustion chamber 2 .
本発明の第5実施形態の副室燃焼4ストロークエンジン1について、図3(a)~図3(c)、図4(a)~図4(e)、図5(a)および図5(b)を用いて説明する。図3(a)~図3(c)は、第5実施形態の3つの例を示す。図4(a)~図4(e)は、第5実施形態の5つの例を示す。図5(a)および図5(b)は、第5実施形態の2つの例を示す。第5実施形態は、第1実施形態~第4実施形態の少なくとも1つの構成を有する。第5実施形態において、副室20の内面は、副室壁部22を含む副室部材25と副室スパークプラグ23とによって形成されている。つまり、副室20の内部空間は、副室部材25と副室スパークプラグ23とによって囲まれた空間である。副室スパークプラグ23の外周面と副室部材25の内周面は接触する。副室部材25は、主燃焼室2の内部空間にその一部が露出するシリンダヘッド本体13と別体で、且つ、副室スパークプラグ23と別体である。シリンダヘッド本体13は、分離不能な1つの部材で構成されていてもよく、主燃焼室2の内部空間にその一部がそれぞれ露出する分離可能な複数の部材で構成されていてもよい。シリンダヘッド本体13が分離可能な複数の部材で構成される場合、シリンダヘッド本体13は、主燃焼室2の内部空間にその一部が露出しない部材は含まない。 <Fifth Embodiment>
3(a) to 3(c), 4(a) to 4(e), 5(a) and 5 ( b) is used for explanation. 3(a) to 3(c) show three examples of the fifth embodiment. Figures 4(a) to 4(e) show five examples of the fifth embodiment. Figures 5(a) and 5(b) show two examples of the fifth embodiment. The fifth embodiment has at least one configuration of the first to fourth embodiments. In the fifth embodiment, the inner surface of the pre-chamber 20 is formed by the
例えば図3(a)および図3(b)に示すように、副室部材25の外周面は、シリンダヘッド本体13に接触していてもよい。例えば図3(b)に示すように、副室部材25に形成された雄ねじ41が、シリンダヘッド本体13に形成された雌ねじ40と噛み合って接触していてもよい。副室部材25の外周面がシリンダヘッド本体13に接触している場合、例えば図3(a)および図3(b)に示すように、副室20の内部空間を通りプラグ軸方向DPに直交するいずれかの平面S2が、副室部材25の外周面のシリンダヘッド本体13に接触する箇所を通ってもよい。接触箇所を通る平面S2は、例えば図3(b)に示すように、副室部材25に形成された雄ねじ41がシリンダヘッド本体13に形成された雌ねじ40と噛み合って接触する箇所を通ってもよい。接触箇所を通る平面S2は、例えば図3(b)に示すように、副室部材25およびシリンダヘッド本体13のねじ部(雄ねじ41と雌ねじ40)ではない箇所を通ってもよい。図3(c)に示す副室部材25の外周面が、図示されていない箇所で、シリンダヘッド本体13に接触していてもよい。例えば、副室スパークプラグ23を通り副室20の内部空間を通らないプラグ軸方向DPに直交するいずれかの平面(図示せず)が、副室部材25の外周面のシリンダヘッド本体13に接触する箇所を通るように、図3(c)に示す副室部材25の外周面がシリンダヘッド本体13に接触していてもよい。この場合、副室部材25の外周面とシリンダヘッド本体13との接触部は、ねじ部(雄ねじ41と雌ねじ40)であってもよく、ねじ部でなくてもよい。
For example, as shown in FIGS. 3(a) and 3(b), the outer peripheral surface of the sub chamber member 25 may be in contact with the cylinder head body 13. For example, as shown in FIG. 3(b), a male thread 41 formed in the pre-chamber member 25 may mesh with and be in contact with a female thread 40 formed in the cylinder head body 13. As shown in FIG. When the outer peripheral surface of the pre-chamber member 25 is in contact with the cylinder head body 13, for example, as shown in FIGS. Any of the planes S2 may pass through a portion of the outer peripheral surface of the sub chamber member 25 that contacts the cylinder head body 13 . A plane S2 passing through the contact portion may pass through a portion where the male thread 41 formed in the pre-chamber member 25 meshes and contacts with the female thread 40 formed in the cylinder head body 13, as shown in FIG. 3B, for example. good. The plane S2 passing through the contact portion may pass through portions other than the threaded portions (the male thread 41 and the female thread 40) of the pre-chamber member 25 and the cylinder head body 13, as shown in FIG. 3B, for example. The outer peripheral surface of the pre-chamber member 25 shown in FIG. 3(c) may be in contact with the cylinder head body 13 at a location not shown. For example, any plane (not shown) that passes through the pre-chamber spark plug 23 and does not pass through the internal space of the pre-chamber 20 and is orthogonal to the plug axial direction DP contacts the cylinder head main body 13 on the outer peripheral surface of the pre-chamber member 25 . The outer peripheral surface of the auxiliary chamber member 25 shown in FIG. 3(c) may be in contact with the cylinder head main body 13 so as to pass through the portion where the contact point is formed. In this case, the contact portion between the outer peripheral surface of the sub chamber member 25 and the cylinder head main body 13 may be a threaded portion (the male thread 41 and the female thread 40) or may not be a threaded portion.
副室部材25の外周面は、シリンダヘッド本体13に接触していなくてもよい。例えば図3(c)に示す副室部材25の外周面が、シリンダヘッド本体に接触しなくてもよい。例えば、副室部材25は、シリンダヘッド本体13ではない部材(例えばシリンダヘッドカバー)を介してシリンダヘッド本体に連結されていてもよい。
The outer peripheral surface of the sub chamber member 25 does not have to be in contact with the cylinder head body 13. For example, the outer peripheral surface of the pre-chamber member 25 shown in FIG. 3(c) does not have to come into contact with the cylinder head body. For example, the sub chamber member 25 may be connected to the cylinder head body via a member other than the cylinder head body 13 (for example, a cylinder head cover).
例えば図4(a)~図4(d)に示すように、冷却部16を通りプラグ軸方向DPに直交するいずれかの平面S3が副室部材25を通るように、副室部材25および冷却部16が形成されていてもよい。平面S3が副室部材25を通る場合、例えば図4(a)~図4(c)に示すように、冷却部16の内面の一部が、副室部材25の外周面の少なくとも一部であってもよい。平面S3が副室部材25を通る場合、例えば図4(d)に示すように、冷却部16の内面が、副室部材25の外周面の一部を含まなくてもよい。また、例えば図4(e)に示すように、冷却部16を通りプラグ軸方向DPに直交するいずれの平面S3も副室部材25を通らないように、副室部材25および冷却部16が形成されていてもよい。なお、図4(a)~図4(d)に示す副室部材25とシリンダヘッド本体13との関係は、図3(a)と同じ関係に限らず、上述したいずれの関係であってもよい。
For example, as shown in FIGS. 4( a ) to 4 ( d ), the pre-chamber member 25 and the cooling chamber member 25 are arranged so that any plane S 3 passing through the cooling portion 16 and perpendicular to the axial direction DP of the plug passes through the pre-chamber member 25 . A portion 16 may be formed. When the plane S3 passes through the pre-chamber member 25, for example, as shown in FIGS. There may be. When the plane S3 passes through the pre-chamber member 25, the inner surface of the cooling part 16 does not have to include a part of the outer peripheral surface of the pre-chamber member 25, as shown in FIG. 4D, for example. Further, as shown in FIG. 4E, for example, the pre-chamber member 25 and the cooling section 16 are formed so that none of the planes S3 passing through the cooling section 16 and perpendicular to the axial direction DP of the plug pass through the pre-chamber member 25. may have been The relationship between the sub chamber member 25 and the cylinder head body 13 shown in FIGS. 4(a) to 4(d) is not limited to the same relationship as in FIG. 3(a), and may be any of the relationships described above. good.
冷却部16の内面の一部が副室部材25の外周面の少なくとも一部である場合、例えば図4(b)に示すように、副室部材25は、冷却部16の内部空間に突出する少なくとも1つの放熱部26を有していてもよい。放熱部26は、環状であってもよく、環状でなくてもよい。例えば、放熱部26は、半円より大きい円弧状でもよく、円弧状でなくてもよい。環状の放熱部26は、冷却部16の内部空間を複数の空間に仕切るように形成されていてもよい。副室部材25は、プラグ軸方向DPに並んだ複数の放熱部26を有していてもよい。
When part of the inner surface of the cooling section 16 is at least part of the outer peripheral surface of the pre-chamber member 25, the pre-chamber member 25 protrudes into the internal space of the cooling section 16, as shown in FIG. 4B, for example. It may have at least one heat dissipation part 26 . The heat radiating portion 26 may or may not be annular. For example, the heat radiating portion 26 may have an arc shape larger than a semicircle, or may not have an arc shape. The annular heat radiating section 26 may be formed so as to partition the internal space of the cooling section 16 into a plurality of spaces. The sub chamber member 25 may have a plurality of heat radiating portions 26 arranged in the plug axial direction DP.
冷却部16を通るいずれかの平面S3が副室部材25を通る場合(例えば図4(a)~図4(d))、冷却部16を通るいずれかの平面S3が、副室部材25の内周面が副室スパークプラグ23の外周面と接触する箇所を通っていてもよい。冷却部16を通るいずれかの平面S3が副室部材25を通る場合、例えば図5(a)および図5(b)に示すように、冷却部16を通るいずれかの平面S3が、副室部材25に形成された雌ねじ42が副室スパークプラグ23に形成された雄ねじ43と噛み合って接触する箇所を通っていてもよい。なお、図5(a)の冷却部16は、図4(a)の冷却部16と同じであるが、図4(b)の冷却部16と同じでもよい。図5(b)の冷却部16は、図4(d)の冷却部16と同じであるが、図4(c)の冷却部16と同じでもよい。なお、図5(a)および図5(b)に示す副室部材25とシリンダヘッド本体13との関係は、図3(a)と同じ関係に限らず、上述したいずれの関係であってもよい。冷却部16を通るいずれかの平面S3が副室部材25を通る場合、冷却部16を通るいずれかの平面S3が、副室部材25の内周面が副室スパークプラグ23の外周面と接触する箇所を通らなくてもよい。
When any plane S3 passing through the cooling part 16 passes through the pre-chamber member 25 (for example, FIGS. 4(a) to 4(d)), any plane S3 passing through the cooling part 16 passes through the pre-chamber member 25. The inner peripheral surface may pass through a portion where it contacts the outer peripheral surface of the pre-chamber spark plug 23 . When any plane S3 passing through the cooling part 16 passes through the pre-chamber member 25, for example, as shown in FIGS. The female thread 42 formed on the member 25 may pass through a portion where it meshes and contacts with the male thread 43 formed on the pre-chamber spark plug 23 . The cooling unit 16 in FIG. 5A is the same as the cooling unit 16 in FIG. 4A, but may be the same as the cooling unit 16 in FIG. 4B. The cooling unit 16 in FIG. 5(b) is the same as the cooling unit 16 in FIG. 4(d), but may be the same as the cooling unit 16 in FIG. 4(c). The relationship between the sub chamber member 25 and the cylinder head body 13 shown in FIGS. 5(a) and 5(b) is not limited to the same relationship as that shown in FIG. good. When any plane S3 passing through the cooling part 16 passes through the pre-chamber member 25, any plane S3 passing through the cooling part 16 is such that the inner peripheral surface of the sub-chamber member 25 contacts the outer peripheral surface of the pre-chamber spark plug 23. You don't have to go through the place where you do.
本発明は、上述した実施形態に限られるものではなく、特許請求の範囲に記載した限りにおいて様々な変更が可能である。例えば、本発明の副室燃焼4ストロークエンジンは、スーパーチャージャーまたはターボチャージャーを有してもよい。副室燃焼4ストロークエンジンは、主燃焼室の内部に燃料を噴射する主燃焼室燃料噴射弁を有してもよい。
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. For example, the pre-combustion four-stroke engine of the present invention may have a supercharger or a turbocharger. A pre-combustion four-stroke engine may have a main combustion chamber fuel injector that injects fuel into the interior of the main combustion chamber.
1:副室燃焼4ストロークエンジン、2:主燃焼室、5:吸気通路、6:排気通路、7:スロットル弁、8:吸気通路噴射弁、10:シリンダヘッド、11:シリンダ孔、13:シリンダヘッド本体、14:副室スパークプラグの電極部から冷却部までの熱経路、15:副室壁部から冷却部までの複数の熱経路、16:冷却部、20:副室、21:連通孔、22:副室壁部、23:副室スパークプラグ、24:電極部、25:副室部材、33:火花放電、40:シリンダヘッド本体の雌ねじ、41:副室部材の雄ねじ、42:副室部材の雌ねじ、43:副室スパークプラグの雄ねじ、70:制御装置、DP:プラグ軸方向、L1:副室の内部空間のプラグ軸方向の長さ、L2:副室の内部空間のプラグ軸方向に直交する方向の最大長さ、S1、S2、S3:平面
1: Pre-combustion 4-stroke engine, 2: Main combustion chamber, 5: Intake passage, 6: Exhaust passage, 7: Throttle valve, 8: Intake passage injection valve, 10: Cylinder head, 11: Cylinder hole, 13: Cylinder Head main body 14: Heat path from electrode part of pre-chamber spark plug to cooling part 15: Plural heat paths from wall part of pre-chamber to cooling part 16: Cooling part 20: Pre-chamber 21: Communication hole , 22: pre-chamber wall portion, 23: pre-chamber spark plug, 24: electrode portion, 25: pre-chamber member, 33: spark discharge, 40: female thread of cylinder head body, 41: male thread of pre-chamber member, 42: sub Female thread of chamber member 43: Male thread of pre-chamber spark plug 70: Control device DP: Plug axial direction L1: Length of internal space of pre-chamber in plug axial direction L2: Plug axis of internal space of pre-chamber Maximum length in the direction orthogonal to the direction, S1, S2, S3: plane
Claims (14)
- 吸気通路および排気通路が接続される主燃焼室と、
前記吸気通路を通過して前記主燃焼室に吸入される空気の量を調整するスロットル弁と、
ガソリン燃料、アルコール燃料、またはガソリン・アルコール混合燃料である液体燃料を前記吸気通路の内部に噴射する吸気通路噴射弁と、
前記主燃焼室よりも容積が小さくなるようにシリンダヘッドに形成され、その内部空間が複数の連通孔を介して前記主燃焼室の内部空間と連通し、その内部空間に副室スパークプラグの一部が露出する副室と、
前記吸気通路噴射弁および前記副室スパークプラグを制御する制御装置とを有する副室燃焼4ストロークエンジンであって、
前記制御装置は、前記スロットル弁の開度が小さい低負荷領域の少なくとも一部において、前記吸気通路および前記主燃焼室で混合された混合気が燃焼後に三元触媒で処理できる第1空燃比または前記第1空燃比よりもリッチな第2空燃比となるように、前記吸気通路噴射弁を制御し、
前記副室燃焼4ストロークエンジンは、前記副室に燃料を噴射する副室燃料噴射弁、および、前記副室または前記主燃焼室における混合気の点火を補助する点火補助装置のどちらも有さず、
前記シリンダヘッドは、前記副室スパークプラグの電極部および前記複数の連通孔が形成された副室壁部からの熱を受け取る冷却媒体が収容される冷却部を有し、
前記電極部複数の火花放電が周方向に分散して生じるように前記副室スパークプラグの前記電極部が形成され、
前記複数の連通孔が周方向に分散して形成され、
前記副室スパークプラグの前記電極部から前記冷却部までの複数の熱経路、および、前記副室壁部から前記冷却部までの複数の熱経路が、それぞれ周方向に分散して形成されるように前記シリンダヘッドが形成されることを特徴とする副室燃焼4ストロークエンジン。 a main combustion chamber to which the intake passage and the exhaust passage are connected;
a throttle valve that adjusts the amount of air that passes through the intake passage and is sucked into the main combustion chamber;
an intake passage injection valve for injecting liquid fuel, which is gasoline fuel, alcohol fuel, or gasoline-alcohol mixed fuel, into the intake passage;
The cylinder head is formed to have a volume smaller than that of the main combustion chamber, and the internal space thereof communicates with the internal space of the main combustion chamber through a plurality of communication holes. A secondary chamber where the part is exposed,
A pre-chamber combustion four-stroke engine having a control device for controlling the intake passage injection valve and the pre-chamber spark plug,
In at least a part of a low load region in which the opening of the throttle valve is small, the control device provides a first air-fuel ratio or controlling the intake manifold injection valve so that the second air-fuel ratio is richer than the first air-fuel ratio;
The pre-combustion four-stroke engine has neither a pre-combustion fuel injection valve for injecting fuel into the pre-combustion chamber nor an ignition assist device for assisting ignition of the air-fuel mixture in the pre-combustion chamber or the main combustion chamber. ,
The cylinder head has a cooling portion that accommodates a cooling medium that receives heat from the electrode portion of the pre-chamber spark plug and the sub-chamber wall portion in which the plurality of communication holes are formed,
the electrode portions of the pre-chamber spark plug are formed so that spark discharges of the plurality of electrode portions are distributed in the circumferential direction;
The plurality of communication holes are formed dispersedly in the circumferential direction,
A plurality of heat paths from the electrode portion of the pre-chamber spark plug to the cooling portion and a plurality of heat paths from the sub-chamber wall portion to the cooling portion are formed so as to be dispersed in the circumferential direction. A pre-combustion four-stroke engine, characterized in that the cylinder head is formed in. - 前記副室壁部の母材は、融点が前記シリンダヘッドの母材よりも高く、比熱と比重を乗じた値が前記シリンダヘッドの母材よりも高く、熱伝導率がクロム系ステンレスと同じかそれよりも高いことを特徴とする請求項1に記載の副室燃焼4ストロークエンジン。 The base material of the auxiliary chamber wall has a melting point higher than that of the base material of the cylinder head, a value obtained by multiplying specific heat and specific gravity is higher than that of the base material of the cylinder head, and thermal conductivity is the same as that of chromium-based stainless steel. 2. Pre-combustion four-stroke engine according to claim 1, higher than that.
- 前記副室スパークプラグを除き前記副室の内面に突起が形成されず、前記副室の内部空間の前記副室スパークプラグのプラグ軸方向の長さが副室の内部空間の前記プラグ軸方向に直交する方向の最大長さの2倍より小さいことを特徴とする請求項1または2に記載の副室燃焼4ストロークエンジン。 Except for the pre-chamber spark plug, no projection is formed on the inner surface of the pre-chamber, and the axial length of the pre-chamber spark plug in the internal space of the pre-chamber extends in the axial direction of the plug in the internal space of the pre-chamber. 3. Pre-combustion four-stroke engine according to claim 1 or 2, characterized in that it is less than twice the maximum length in the orthogonal direction.
- 前記副室壁部が、前記主燃焼室の内部空間に突出するように形成されており、
前記副室壁部の外面を通らず前記副室の内部空間を通り前記副室スパークプラグのプラグ軸方向に直交するいずれかの平面によって前記副室の内部空間を2つの空間に分けた場合に、前記2つの空間のうち前記主燃焼室に近い方の空間の体積が、前記2つの空間のうち前記主燃焼室から遠い方の空間の体積よりも小さくなるように前記副室は形成されていることを特徴とする請求項1~3のいずれか1項に記載の副室燃焼4ストロークエンジン。 the auxiliary chamber wall portion is formed to protrude into the internal space of the main combustion chamber,
When the internal space of the pre-chamber is divided into two spaces by any plane that passes through the internal space of the pre-chamber without passing through the outer surface of the wall portion of the pre-chamber and is perpendicular to the axial direction of the spark plug of the pre-chamber. The auxiliary chamber is formed such that the volume of the space closer to the main combustion chamber out of the two spaces is smaller than the volume of the space farther from the main combustion chamber out of the two spaces. The pre-combustion four-stroke engine according to any one of claims 1 to 3, characterized in that - 前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室スパークプラグを通ることを特徴とする請求項1~4のいずれか1項に記載の副室燃焼4ストロークエンジン。 5. The pre-chamber combustion four-stroke according to any one of claims 1 to 4, wherein a plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber spark plug. engine.
- 前記副室の内部空間が、前記主燃焼室の内部空間にその一部が露出するシリンダヘッド本体および前記副室スパークプラグのどちらとも別体であり前記副室壁部を含む副室部材と、前記副室スパークプラグとによって囲まれた空間であることを特徴とする請求項1~5のいずれか1項に記載の副室燃焼4ストロークエンジン。 a pre-chamber member, the interior space of which is separate from both the cylinder head body and the pre-chamber spark plug, the interior space of which is partly exposed to the interior space of the main combustion chamber, and which includes the pre-chamber wall portion; The pre-combustion four-stroke engine according to any one of claims 1 to 5, wherein the pre-combustion four-stroke engine is a space surrounded by the pre-combustion chamber spark plug.
- 前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室部材を通ることを特徴とする請求項6に記載の副室燃焼4ストロークエンジン。 The pre-chamber combustion four-stroke engine according to claim 6, wherein a plane passing through the cooling portion and perpendicular to the plug axial direction of the pre-chamber spark plug passes through the pre-chamber member.
- 前記冷却部の内面の一部が、前記副室部材の外周面の少なくとも一部であることを特徴とする請求項7に記載の副室燃焼4ストロークエンジン。 The pre-combustion four-stroke engine according to claim 7, wherein a part of the inner surface of the cooling part is at least a part of the outer peripheral surface of the pre-combustion chamber member.
- 前記副室スパークプラグに形成された雄ねじが、前記副室部材に形成された雌ねじと噛み合って接触していることを特徴とする請求項6~8のいずれか1項に記載の副室燃焼4ストロークエンジン。 9. The pre-combustion chamber 4 according to any one of claims 6 to 8, wherein a male thread formed on the pre-chamber spark plug is in meshing contact with a female thread formed on the pre-chamber member. stroke engine.
- 前記冷却部を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室スパークプラグに形成された前記雄ねじが前記副室部材に形成された前記雌ねじと噛み合って接触する箇所を通ることを特徴とする請求項9に記載の副室燃焼4ストロークエンジン。 A plane passing through the cooling portion and orthogonal to the axial direction of the plug of the pre-chamber spark plug passes through a portion where the male thread formed in the pre-chamber spark plug engages and contacts the female thread formed in the pre-chamber member. 10. Pre-combustion four-stroke engine according to claim 9, characterized in that:
- 前記副室部材の外周面が前記シリンダヘッド本体に接触していることを特徴とする請求項6~10のいずれか1項に記載の副室燃焼4ストロークエンジン。 The pre-combustion four-stroke engine according to any one of claims 6 to 10, wherein the outer peripheral surface of the pre-combustion chamber member is in contact with the cylinder head body.
- 前記副室の内部空間を通り前記副室スパークプラグのプラグ軸方向に直交する平面が、前記副室部材の外周面の前記シリンダヘッド本体に接触する箇所を通ることを特徴とする請求項11に記載の副室燃焼4ストロークエンジン。 12. A plane of the pre-chamber spark plug passing through the internal space of the pre-chamber and perpendicular to the axial direction of the plug passes through a portion of the outer peripheral surface of the pre-chamber member that contacts the cylinder head body. A pre-combustion four-stroke engine as described.
- 前記副室の内部空間を通り前記プラグ軸方向に直交する平面が、前記副室部材に形成された雄ねじが前記シリンダヘッド本体に形成された雌ねじと噛み合って接触する箇所を通ることを特徴とする請求項12に記載の副室燃焼4ストロークエンジン。 A plane which passes through the internal space of the pre-chamber and is orthogonal to the axial direction of the plug passes through a portion where a male thread formed in the pre-chamber member meshes and contacts a female thread formed in the cylinder head body. 13. Pre-combustion four-stroke engine according to claim 12.
- 前記主燃焼室の内部に燃料を噴射する主燃焼室燃料噴射弁を有さないことを特徴とする請求項1~13のいずれか1項に記載の副室燃焼4ストロークエンジン。 The pre-combustion four-stroke engine according to any one of claims 1 to 13, characterized in that it does not have a main combustion chamber fuel injection valve for injecting fuel into the main combustion chamber.
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