EP0828075A1 - Deposit reduction fuel injection valve - Google Patents
Deposit reduction fuel injection valve Download PDFInfo
- Publication number
- EP0828075A1 EP0828075A1 EP97115623A EP97115623A EP0828075A1 EP 0828075 A1 EP0828075 A1 EP 0828075A1 EP 97115623 A EP97115623 A EP 97115623A EP 97115623 A EP97115623 A EP 97115623A EP 0828075 A1 EP0828075 A1 EP 0828075A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- nozzle
- heat
- injection valve
- nozzle body
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
- F02M61/14—Arrangements of injectors with respect to engines; Mounting of injectors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M53/00—Fuel-injection apparatus characterised by having heating, cooling or thermally-insulating means
- F02M53/04—Injectors with heating, cooling, or thermally-insulating means
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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
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2200/00—Input parameters for engine control
- F02D2200/02—Input parameters for engine control the parameters being related to the engine
- F02D2200/06—Fuel or fuel supply system parameters
- F02D2200/0606—Fuel temperature
Definitions
- the present invention relates to a deposit reduction fuel injection valve comprising nozzle body which has a nozzle hole formed so as to face a combustion chamber of an internal combustion engine and which directly injects and supplies fuel to the combustion chamber, wherein temperature adjusting means for adjusting the temperature of a nozzle having the nozzle hole formed thereon adjusts the temperature of the tip portion of the nozzle body so as to maintain the temperature equal to or lower than a 90%-distillation temperature of fuel, thereby suppressing the generation and accumulation of deposits on the internal surface of the nozzle hole and hence resulting in reduced variations in a flow rate.
- Examples of a first prior art technique are an electromagnetic fuel injection valve (Japanese Patent Application Laid-open (kokai) No. 62-103456) shown in FIG. 13 and a fuel injection valve (Japanese Patent Application Laid-open (kokai) No. 63-151970) shown in FIG. 14. Both of these inventions are intended to improve the heat radiation characteristics of the tip end of the injection valve N so as to reduce the temperature of the tip end of the fuel injection valve by providing the tip end of the injection valve N with a shroud S having a high heat conductivity.
- FIG. 15 Japanese Utility Model Publication (kokoku) No. 8-5336. This structure is intended to cool a nozzle N by placing in the vicinity of the nozzle N a packing P capable of circulating a cooling fluid.
- An example of a third prior art technique is a heat radiation member of a fuel injection nozzle of an internal-combustion engine shown in FIG. 16 (Japanese Patent Publication (kokoku) No. 63-65823).
- This heat radiation member is intended to improve the heat radiation characteristics of the tip end of the nozzle N by providing an elastically deformable seal lip L at the tip end of a bush.
- An example of fourth prior art technique is a cylinder head for use in a diesel engine shown in FIG. 17 (Japanese Patent Publication (kokoku) No. 59-1103 ).
- This invention is intended to provide an engine head H which shields a nozzle from heat.
- This illustrative fourth example is directed toward improving the durability and reliability of an injection valve of a direct-injection high supercharging diesel engine, as well as to a technique for accomplishing the foregoing objects (1) through (3).
- the examples of the first prior art technique are directed toward providing the tip end of the injection valve N with the shroud S having a high heat conductivity.
- the flow of heat within the injection valve N fitted to the engine has not been elucidated.
- the invention is intended to reduce the temperature of the injection valve N by providing the injection valve N with the shroud S having a high heat conductivity, the location of the engine to which the injection valve N is fitted is not specified, so that a heat flow path is not defined. Consequently, the improvements or advantageous effects of the invention cannot be specified.
- the packing P capable of circulating a cooling fluid is placed in the vicinity of the nozzle N.
- the packing P is located away from the tip end of the nozzle N, therefore resulting in a small effect of reducing the temperature of the tip end of the nozzle N. Since forming a cooling path up to the vicinity of the injection valve involves difficulties in terms of manufacture of an engine head, it is difficult to say that the invention has a high degree of practicality.
- the thermal insulation characteristics of the tip end of the nozzle N is improved by providing the elastic deformable seal lip L at the tip end of the bush.
- the seal lip L is a simple heat insulation member and consequently has a high degree of practicality. Since the material of the seal lip L is limited to elastic metal, the heat conductivity of the heat insulation member is equal to or greater than that of the nozzle. Although the heat insulation member has a function of facilitating flow of heat, it is hard to say that the function is sufficient. The heat insulation member does not have such a heat insulating effect as to interrupt or partially suppress the flow of heat.
- the example of the third prior art technique also fails to provide a sufficient function of facilitating flow of heat from the nozzle N to the engine head.
- the most important matter to reduce the temperature of the nozzle through use of a member having a high heat conductivity is to reduce the heat resistance between the nozzle and the engine head to as low a value.
- the member is press-fitted onto the nozzle, so that the contact resistance of the heat flow path is reduced.
- there are clearances between the nozzles and the engine head, or the nozzles and the engine head are only in slight contact with each other. Since there are no active efforts for reducing the heat resistance of other areas, the temperature of the tip end of the nozzle therefore cannot be reduced effectively with such an arrangement.
- the side surface of the nozzle has a wide area, it is very important to improve the heat radiation characteristics of the nozzle by reducing the contact resistance of the side surface of the nozzle.
- the engine head H shields the nozzle N from heat.
- it is not intended to prevent the flow rate of fuel from decreasing as a result of accumulation of deposits on the internal surface of the nozzle hole of the injection valve.
- a protuberance formed at the tip end of the nozzle is exposed to the combustion chamber through a thermal insulation plate.
- the embodiment section of the patent describing the fourth example does not include any descriptions related to the position of the nozzle hole.
- the nozzle hole is formed in the protuberance at the front end of the nozzle, due to the function of the nozzle hole.
- the temperature of the tip end becomes higher than a 90%-distillation temperature of fuel. Therefore, deposits are accumulated on the internal surface of the nozzle hole, thereby resulting in a reduction in the flow rate of the injection valve.
- An objection of the present invention is to solve the problem of a reduction in the flow rate of the injection valve as previously described. More specifically, the present invention is directed toward a deposit reduction fuel injection valve comprising a fuel injection valve which has a nozzle hole formed so as to face a combustion chamber of an internal combustion engine and which directly injects and supplies fuel to the combustion chamber, wherein there is prevented a phenomenon of a flow rate of fuel being reduced by a decrease in the area of the nozzle hole as a result of accumulation of deposits on the internal surface of the nozzle hole, by a reduction in lowering the temperature of the tip portion of the nozzle body so as to be lower than the 90%-distillation temperature of fuel to be used.
- FIG. 9 shows the manner in which the flow rate of the injection valve decreases at that time. The flow rate abruptly decreases until ten hours elapse from the commencement of the test. Although there is no further reduction in the flow rate after lapse of 10 hr., the rate of reduction of the flow rate reaches 10% when the test is completed.
- deposits are acknowledged to have been accumulated as a result of carbonization. From the result of this observation, it is understood that deposits cause a reduction in the area of the nozzle hole and a reduction in the flow rate of the injection valve.
- the inventors examined the manner in which the flow rate of the injection valve was reduced by performing an engine test similar to that illustrated in FIG. 9 for 30 hr. on condition that the temperature of the tip portion of the nozzle body was decreased so as to be maintained lower than 165°C. The results of such an engine test are illustrated in FIG. 10. On condition that the temperature of the tip portion of the nozzle body is 155°C, the rate of reduction in the flow rate is about 3%. In contrast, on condition that the temperature of the tip portion of the nozzle body is reduced to 100°C, the rate of reduction in the flow rate becomes about 1%.
- FIG. 3 schematically illustrates the occurrence of the phenomenon.
- Fuel contains precursors of deposit which will serve as the nucleus of deposits during the course of generation of the deposits. At room temperature, these precursors of deposit are dispersed in the fuel.
- the fuel After having been injected, the fuel remains in trace amounts on the internal surface of the nozzle hole. If the temperature of the tip portion of the nozzle body is lower than the 90%-distillation temperature of the fuel (150°C), the fuel remaining on the internal surface of the nozzle hole is held in a liquid phase. Accordingly, the precursors of deposit contained in the fuel also remain dispersed in the fuel. The precursors of deposit remaining in the dispersed state are easily flushed away together with the fuel by the next injection, thereby suppressing the generation of deposits on the internal surface of the nozzle hole.
- the temperature of the tip portion of the nozzle body is higher than the 90%-distillation temperature (150°C)
- evaporation of the fuel remaining inside the nozzle hole is promoted. Therefore, the precursors of deposit cannot remain in the dispersed state in the fuel, so they aggregate on the internal wall surface of the nozzle hole. In such a state, it is difficult to flush the thus-aggregated precursors of deposit away at the time of the next injection, so they remain in the nozzle hole. As a result, the accumulation of deposits proceeds.
- the inventors of the present invention have learned that, in order to suppress the generation of deposits on the internal surface of the nozzle hole, it is necessary to reduce the temperature of the tip portion of the nozzle body so as to maintain the temperature lower than a 90%-distillation temperature of the fuel, to constantly hold the fuel remaining on the internal surface of the nozzle hole in a liquid phase, thereby maintaining precursors of deposit dispersed in the fuel.
- the heat flow path is formed by inserting a substance having a high heat conductivity between the side surface of the nozzle and the engine head so as to minimize the contact resistance between the side surface and the substance and between the substance and the engine head.
- the heat resistance between the side surface of the nozzle body and the engine head is reduced, and the heat supplied to the nozzle body as a result of convection or radiation of a combustion gas is easily dissipated to the engine head.
- the inventors of the present invention also learned important factors in suppressing the reduction in the flow rate of the injection valve by having performed another test from different viewpoints.
- the temperature history of the tip portion of the nozzle body was measured under the same conditions as those shown in FIG. 9. Further, the injection valve was removed from the engine head after lapse of 3, 7, 15, and 30 hours, and the thickness of soot built up on the surface of the nozzle body was determined. The result of such determination is shown in FIG. 11.
- the temperature of the tip portion of the nozzle body which is 180°C immediately after the commencement of the engine test, drops to 165°C after the lapse of 30 min. since the commencement of the test.
- the temperature of the tip portion of the nozzle body decreases with the lapse of time, and the temperature drops to about 130°C after the lapse of 15 hr.
- the thickness of the soot built up on the surface of the nozzle body increases with the lapse of time, and the thickness reaches 0.34 mm after the lapse of 15 hr.
- a phenomenon is observed in which the temperature of the tip portion of the nozzle body sharply increases immediately before the operating time of the engine reaches 30 hr.
- soot has been scraped off from the surface of the nozzle body, so that the metallic base material of the nozzle body is exposed. From the results of this test, it is understood that the reduction in the temperature of the tip portion of the nozzle body has strong relevancy to the soot accumulated on the surface of the nozzle body. In short, it is concluded that the soot forms a thermal insulation layer which suppresses the flow of heat supplied to the nozzle body from the combustion chamber.
- the soot serves as a heat insulation layer which reduces the temperature of the nozzle body. Therefore, it is understood that the soot suppresses the progress of the reduction of the flow rate of the injection valve.
- It is a still further object of the present invention to provide a deposit reduction fuel injection valve comprising a nozzle hole, formed on a tip portion of a nozzle body so as to face a combustion chamber of an internal combustion engine, for injecting directly fuel in the combustion chamber, and a temperature adjusting means for adjusting a temperature of the tip portion of the nozzle body having the nozzle hole so as to maintain the temperature equal to or lower than a 90%-distillation temperature of fuel.
- the heat flow formation means comprises a heat conduction promoting member which is formed from a material having a high heat conductivity and is interposed between an internal wall surface of the engine head and an outer side surface of the nozzle body, and the heat conduction promoting member reduces a heat resistance between the nozzle body and the engine head, so that the dissipation of the heat flow supplied to the nozzle body toward the engine head is promoted.
- a deposit reduction fuel injection valve of the present invention is directed toward a fuel injection valve comprises a nozzle body which has a nozzle hole formed thereon so as to face a combustion chamber of an internal combustion engine and which directly injects and supplies fuel to the combustion chamber.
- a heat flow path is formed by inserting a substance having a high heat conductivity between the side surface of the nozzle body and the engine head so as to minimize the contact resistance between the side surface and the substance and between the substance and the engine head.
- the heat resistance between the nozzle body and the engine head is reduced, and the heat supplied to the nozzle body as a result of convection or radiation of a combustion gas becomes easily dissipated to the engine head.
- An area of the nozzle body exposed in the combustion chamber or part of this area of the nozzle body is covered with a substance having a low heat conductivity so as to interrupt or suppress the inflow of heat supplied to the nozzle body from the combustion chamber.
- the temperature of the tip portion of the nozzle body is reduced so as to become lower than a 90%-distillation temperature of fuel, so that the fuel remaining on the internal surface of the nozzle hole after having been injected is maintained in a liquid phase.
- soot differs according to the engine specifications and driving conditions, and there is also such a case as shown in FIG. 11 where the soot is scraped off from the nozzle body. Therefore, in some cases, accumulated soot may not serve as a permanent measure to maintain the temperature of the tip portion of the nozzle body at a temperature lower than the 90%-distillation temperature. For this reason, in order to stably maintain the temperature of the tip portion of the nozzle body at a temperature lower than the 90%-distillation temperature of the fuel, it is effective to attach a heat insulation material to the tip portion of the nozzle body so as to interrupt the flow of heat into the nozzle body as a result of convection or radiation of a combustion gas.
- a nozzle hole is formed to face a combustion chamber of an internal combustion engine so as to directly inject and supply fuel to the combustion chamber.
- the temperature adjusting means having the nozzle hole formed thereon adjusts the temperature of the tip portion of the nozzle body so as to maintain the temperature equal to or lower than a 90%-distillation temperature of fuel, thereby suppressing the generation and accumulation of deposits on the internal surface of the nozzle hole and hence resulting in reduced variations in a flow rate.
- a heat conduction promoting member which is formed from a material having a high heat conductivity and is interposed between the internal wall surface of the engine head and the outer side surface of the nozzle body constituting the heat flow formation means, reduces the heat resistance between the nozzle body and the engine head, so that the dissipation of the heat supplied to the nozzle body toward the engine head is promoted.
- the heat flow path is formed by inserting a substance having a high heat conductivity between the side surface of the nozzle and the engine head, thereby reducing the heat resistance between the side surface of the nozzle and the engine head.
- the heat flowing into the nozzle can be easily dissipated to the engine head.
- the heat resulting from the convection or radiation of the combustion gas is supplied to the tip portion of the nozzle body exposed in the combustion chamber, thereby increasing the temperature of the tip portion of the nozzle body.
- Heat flows into the engine head, which has a comparatively lower temperature, via the area whose heat resistance has been reduced. If the present invention is not applied to the engine, the heat principally flows to the engine head via screws and a gasket which fit the injection valve to the engine head.
- FIG. 1 illustrates one embodiment of the present invention, wherein a copper sleeve 60 is inserted between a tip portion 8 of a nozzle body and an engine head 4.
- a copper sleeve 60 is inserted between a tip portion 8 of a nozzle body and an engine head 4.
- FIG. 12 shows an injection valve analogous to the conventional injection valve shown in FIG. 16.
- An air layer is formed in an area S indicated by a dashed line, and temperatures of the tip portions of these nozzles are compared with each other in FIG. 2.
- the temperature of the tip portion of the nozzle body of the present invention is 135°C, and there is obtained a reduction in temperature as large as 45°C relative to an injection valve (the temperature of the tip portion of the nozzle body is 180°C) which does not have the copper sleeve 10 inserted therein.
- the temperature of the tip portion of the nozzle body is 150 reduction effect as compared to that of the present invention.
- the heat insulation member which is formed from a material having a low heat conductivity and which is provided in at least part of the area of the nozzle body exposed to the combustion chamber, shields the nozzle body from the heat supplied from the combustion chamber. Accordingly, the temperature of the tip portion of the nozzle body is reduced so as to be maintained lower than the 90%-distillation temperature of fuel, thereby more effectively suppressing the generation and accumulation of deposits on the internal surface of the nozzle hole and hence resulting in further effective reduction of variations in a flow rate.
- the heat insulation member according to the fourth invention is formed from a substance having a low heat conductivity and covers the area of the nozzle body exposed to the combustion chamber or a part of that area. The operation and effects of this heat insulation member when it shields the nozzle body from the heat flowing from the combustion chamber will be described.
- the amount of heat flowing into the tip portion of the nozzle body becomes smaller, enabling reductions in the temperature of the tip portion of the nozzle body.
- the ratio of heat conductivity ⁇ (W/mm/K) of the material constituting the thermal insulation member to the thickness "t" (mm) of the thermal insulation member; i.e., ⁇ /t is set to be smaller than 8.5 x 10 -4 .
- the effect of reducing the temperature of the tip portion of the nozzle body is dependent on the heat conductivity of the area of the nozzle body exposed to the combustion chamber or of a member attached to a part of the exposed area.
- a trial calculation was made with regard to the heat conductivity of the member attached to the exposed area of the nozzle body inserted in the combustion chamber, as well as to the effect of reducing the temperature of the tip portion of the nozzle body obtained when the thickness of the member was changed.
- FIG. 8 illustrates the results of such trial calculation.
- boundary conditions are set such that the temperature of the tip portion of the nozzle body becomes 180°C when the tip portion is directly exposed to the combustion chamber.
- the temperature of the tip portion of the nozzle becomes 168°C, provided that the thickness of the member is 0.35 mm.
- the temperature is reduced to 150°C with a thickness of 1.2 mm, 140°C with a thickness of 2 mm, and to 130°C with a thickness of 4 mm. The lower the heat conductivity of the member, the thinner the thickness of the member can be made.
- the temperature of the tip portion of the nozzle body can be maintained at a temperature lower than or equal to 150°C. This temperature is lower than the 90%-distillation temperature of ordinary gasoline.
- this type of injection valve the generation and accumulation of deposits on the internal surface of the nozzle hole are suppressed, thereby enabling implementation of an injection valve which reduces variations in its flow rate.
- the thermal insulation member is annularly provided at the lowermost end of the nozzle body so as to surround the nozzle hole. Therefore, the deposit reduction fuel injection valve has an effect of effectively shielding the nozzle body from the heat supplied from the combustion chamber.
- an outlet of the nozzle hole is positioned above the lowermost end of the thermal insulation member. Therefore, the outlet of the nozzle hole does not project into the combustion chamber, and there is produced an effect of reducing the amount of deposit to be deposited because the outlet port is set back from the combustion chamber.
- a deposit reduction fuel injection valve comprises a fuel injection valve 1 which has a nozzle hole 3 formed on a lower tip end of a tip portion 8 of a nozzle body so as to face a combustion chamber 2 of an internal-combustion engine and which directly feeds fuel to the combustion chamber.
- a temperature adjusting means 5 for adjusting the temperature of the tip portion 8 of the nozzle body having the nozzle hole 3 formed thereon so as to maintain the temperature equal to or lower than a 90%-distillation temperature of fuel is formed between the tip portion 8 of the nozzle body having the nozzle hole 3 formed thereon and an engine head 4.
- the deposit reduction fuel injection valve further comprises a heat flow formation means 6 which dissipates heat supplied to the nozzle 8 to the engine head 4.
- the engine head 4 is provided with a cooling path for circulating cooling water, whereby the temperature of the engine head 4 is maintained at about 80°C.
- the injection valve 1 is fixed to the engine head 4 via an injection valve fixing jig 11.
- a plurality of holes are formed in the fixing jig 11, and bolts are screwed into these holes.
- the bolts are fitted to the engine head 4.
- forces to fasten the bolts are exerted on the engine head 4 via the fixing jig 11, the injection valve flange 12, and the gasket 13, whereby the injection valve 1 is fixed to the engine head 4.
- the combustion chamber 2 is formed from a space which is surrounded by the engine head 4, a cylinder, and a piston (not shown). A mixed gas consisting of fuel and air is combusted within the combustion chamber 2 thereby to produce a large quantity of heat.
- the heat flow formation means 6 ensures a new path over which heat flows from the tip portion 8 of the nozzle body to the engine head 4.
- the heat flowing into the tip portion 8 of the nozzle body can be easily dissipated to the engine head 4.
- a heat conduction promoting member 60 is formed from a material having a high heat conductivity and is disposed between the outer side surface of a cylindrical base portion of the tip portion 8 of the nozzle body and the inner wall surface of the engine head 4.
- the heat conduction promoting member 60 is formed from a hollow cylindrical copper sleeve 61 whose base material is copper having a high heat conductivity.
- the copper sleeve 61 is formed so as to have given inner and outer diameters and is disposed between an outer circumferential surface 81 of the tip portion 8 of the nozzle body and an inner circumferential surface of a nozzle insertion hole 41 of the engine head 4.
- the heat conduction promoting member 60 is inserted into the annular space formed between the nozzle 8 and the nozzle insertion hole 41 of the engine head 4.
- the sleeve 61 has its inner circumferential surface held in close contact with the outer circumferential surface 81 of the cylindrical base portion of the tip portion 8 so as to minimize the heat resistance of the contact surface between the inner circumferential surface 81 of the sleeve 61 and the outer circumferential surface of the nozzle 8.
- the outer circumferential surface of the copper sleeve 61 is brought into close contact with the inner circumferential surface of the engine head 4, thereby minimizing the heat resistance of the contact surface between them.
- the copper sleeve 61 which is made of a material having a high heat conductivity and constitute the heat conduction promoting member 60, is inserted between the side surface 81 of the nozzle 8 and the engine head 4, so that a heat flow path is formed while the heat resistance between the side surface 81 of the nozzle 8 and the engine head 4 is minimized. As a result, the heat flowing into the nozzle 8 is dissipated to the engine head 4.
- the deposit reduction fuel injection valve according to the first embodiment which operates in the above described manner, a new path over which heat flows from the nozzle 8 to the engine head 4 is ensured.
- the heat flowed into the nozzle 8 is effectively dissipated to the engine head 4, thereby reducing the temperature of the tip portion 8 of the nozzle body having the nozzle hole 3 formed therein.
- the fuel is in the liquefied state on the inner surface of the nozzle hole 3, thereby suppressing the generation and accumulation of deposits on the internal surface of the nozzle hole 3 and hence resulting in reduced variations in a flow rate.
- the operation and effects of the deposit reduction fuel injection valve according to the first embodiment are stably ensured even when the injection valve 1 is fitted to the engine 4 utilizing screws provided on the injection valve 1, without use of the fixing jig 11 in the first embodiment.
- a deposit reduction fuel injection valve according to a second embodiment is different from that of the first embodiment in that an outer circumferential surface 621 of the copper sleeve 62 and the inner circumferential wall of the engine head 4 are tapered in order to increase the degree of close-contact between the copper sleeve 62, which comes into contact with the Side surface 81 of the tip portion 8 of the nozzle body, and the inner circumferential wall of the engine head 4.
- the difference is principally described hereinbelow.
- the copper sleeve 62 is sandwiched between and held in close contact with the engine head 4 and the nozzle 8 in a wedge-like manner when the injection valve 1 is fitted to the engine head 4.
- the surfaces of the copper sleeve 61 and the engine head 4 which are in contact with each other are tapered, and they are brought into close contact with each other in a wedge-like manner.
- a heat flow path whose contact resistance is minimized is provided between the nozzle 8 and the engine head 4, thereby facilitating the dissipation to the engine head 4 of the heat flowing to the tip portion 8 of the nozzle body.
- the surfaces of the copper sleeve 61 and the engine head 4 which are in contact with each other are tapered, so that the close contact state is improved, and the contact area between the copper sleeve and the engine head is increased.
- the above-described effect can be obtained by tapering the surfaces of the nozzle 8 and the copper sleeve which are in contact with each other, or by tapering the surfaces of the nozzle 8, the copper sleeve 62, and the engine head 4 which are in contact with each other.
- a deposit reduction fuel injection valve according to a third embodiment is different from that in the first embodiment in the following point. Namely, as illustrated in FIG. 7, in addition to the heat conduction promoting member 60 which is made of a material having a high heat conductivity and which is interposed between the side surface of the tip portion 8 of the nozzle body and the engine head 4, the deposit reduction fuel injection valve is provided with a heat insulation member 7 which is provided on the area of the nozzle 8 exposed in the combustion chamber 2 and which shields the nozzle 8 from heat fed from the combustion chamber 2. The difference is principally described hereinbelow.
- the copper sleeve 61 which contains copper having a high heat conductivity as a base material is inserted between the nozzle 8 and the engine head 4.
- the tapered-tip portion of the nozzle 8, which is exposed to the combustion chamber 2, is covered with the annular heat insulation member 7 having a low heat conductivity.
- a circular hole is formed at the center of the heat insulation member 7 so as to constitute the nozzle hole 3 having a given axial length.
- a heat flow path is formed between the side surface of the nozzle 8 and the engine head 4 by the copper sleeve 61, which serves as the heat conduction promoting member 60 in a state in which the heat resistance between the side surface of the nozzle 8 and the engine head 4 is minimized, enabling facilitation of dissipation to the engine head 4 of the heat flowing into the nozzle.
- the exposed area of the nozzle 8 in the combustion chamber 2 is covered with the heat insulation member 7 which is made of a material having a low heat conductivity, thereby interrupting or regulating the heat flowing to the nozzle 8 from the combustion chamber 2.
- the copper sleeve 61 is brought into close contact with the nozzle 8 and the engine head 4, minimizing the heat resistance of the contact surfaces between them.
- the heat supplied to the tip portion of the nozzle 8 from the combustion chamber 2 can be substantially interrupted by the heat insulation member 7. More specifically, not only the dissipation of heat from the nozzle 8 but also interruption of entry of the heat to the nozzle 8 are effected, and the temperature of the tip portion of the nozzle 8 is therefore reduced more efficiently, thereby effectively suppressing the generation and accumulation of deposits on the internal surface of the nozzle hole 3 and hence resulting in reduced variations in a flow rate.
- a deposit reduction fuel injection valve is different from that of the first embodiment in that the tip portion 8 of the nozzle body has a two-staged structure as illustrated in FIG. 8; namely, a structure comprising a base large-diameter section 84 and a tip small-diameter section 85, and in that a thin tube-like copper sleeve 64 is brought into contact with the outer circumferential surface of the base large-diameter section 84, as well as with the overall inner circumferential wall of the nozzle insertion hole of the engine head 4.
- a heat insulation member 94 having a low heat conductivity is interposed between a tip end of the tip small-diameter section 85 and the copper sleeve 64.
- the copper sleeve 64 has its lower edge bent in a radially inward direction of the nozzle 8 at a position corresponding to the lower end of the inner circumferential wall of the nozzle insertion hole of the engine head 4.
- An annular hole is formed at the center of the copper sleeve so as to constitute the nozzle hole 3 formed on a tip taper end of the tip portion 8 of the nozzle body
- the heat insulation member 94 is provided so as to come into contact with the outer circumferential wall of the tip portion small-diameter section 85 of the nozzle 8 and its tapered lowermost end.
- a tapered circular hole is formed at the lower center of the copper sleeve in consideration of a spray pattern.
- the nozzle hole 3 of the nozzle 8 is positioned a predetermined distance above the lower end of the heat insulation member 94 (the circular hole of the copper sleeve 64).
- a heat flow path is formed between the side surface of the nozzle 8 and the engine head 4 by the copper sleeve 61, which serves as the heat conduction promoting member 60 in a state in which the heat resistance between the side surface of the nozzle 8 and the engine head 4 is minimized, enabling facilitation of dissipation to the engine head 4 of the heat flowing into the nozzle.
- the exposed area of the nozzle 8 in the combustion chamber 2 is covered with the heat insulation member 94 which is made of a material having a low heat conductivity, thereby interrupting or regulating the heat flowing to the nozzle 8 from the combustion chamber 2.
- the copper sleeve 64 is brought into close contact with the nozzle 8 and the engine head 4, minimizing the heat resistance of the contact surfaces between them.
- the heat supplied to the tip portion of the nozzle 8 from the combustion chamber 2 can be interrupted substantially by the heat insulation member 94. More specifically, not only the dissipation of heat from the nozzle 8 but also interruption of entry of the heat to the nozzle 8 are effected, and the temperature of the tip portion of the nozzle 8 is therefore reduced more efficiently, thereby effectively suppressing the generation and accumulation of deposits on the internal surface of the nozzle hole 3 and hence resulting in reduced variations in a flow rate.
- the outlet of the nozzle hole 3 is positioned above the lowermost edge of the heat insulation member 94.
- the copper sleeve 64 has its lower edge inwardly folded over in the radial direction of the nozzle 8 at the lower end of the inner circumferential wall of the nozzle insertion hole of the engine head 4 so as to cover the lowermost outer periphery of the heat insulation member 94.
- the heat flowing to the heat insulation member 94 and the nozzle 8 from the combustion chamber 2 is interrupted, and the nozzle 8 is cooled and regulated by the copper sleeve 64 cooled by the engine head 4 which is cooled by the cooling water. Therefore, there is produced an effect of more efficiently reducing the temperature of the tip portion of the nozzle 8.
- the inventors verified that the fuel injection valve of the fourth embodiment could have reduced the temperature of the tip portion of the nozzle about 60°C relative to the conventional fuel injection valve.
- the present invention is also capable of adopting an embodiment in which the copper sleeve is fitted into the nozzle insertion hole of the engine head above the lowermost end of the nozzle insertion hole without folding over the lower edge of the copper sleeve.
- This structure prevents the copper sleeve from being exposed to the combustion chamber 2, while ensuring the maximum area for dissipating heat from the nozzle 8 to the engine head.
- a deposit reduction fuel injection valve including a nozzle hole, formed on a tip portion of a nozzle body so as to face a combustion chamber of an internal combustion engine, for injecting directly fuel in said combustion chamber, and a temperature adjusting system for adjusting a temperature of said tip portion of said nozzle body having said nozzle hole so as to maintain the temperature equal to or lower than a 90%-distillation temperature of fuel.
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- General Engineering & Computer Science (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
A deposit reduction fuel injection valve (1)
including a nozzle hole (3), formed on a tip portion (8) of a
nozzle body so as to face a combustion chamber (2) of an
internal combustion engine, for injecting directly fuel
in said combustion chamber, and a temperature adjusting
system (60) for adjusting a temperature of said tip portion
of said nozzle body having said nozzle hole so as to
maintain the temperature equal to or lower than a 90%-distillation
temperature of fuel.
Description
The present invention relates to a deposit
reduction fuel injection valve comprising nozzle body
which has a nozzle hole formed so as to face a
combustion chamber of an internal combustion engine and
which directly injects and supplies fuel to the
combustion chamber, wherein temperature adjusting means
for adjusting the temperature of a nozzle having the
nozzle hole formed thereon adjusts the temperature of
the tip portion of the nozzle body so as to maintain the
temperature equal to or lower than a 90%-distillation
temperature of fuel, thereby suppressing the generation
and accumulation of deposits on the internal surface of
the nozzle hole and hence resulting in reduced
variations in a flow rate.
Accumulation of deposits on the internal surface
of a nozzle hole O in a conventional fuel injection
valve N shown in FIG. 12 results in a reduction in a
flow rate. As will be described later, the accumulation
of deposits is greatly dependent on the temperature of
the tip end T of a nozzle. For this reason, the
temperature of the tip end must be reduced when the fuel
injection valve N is fitted to an engine E.
Attempts have already been made to reduce the
temperature of the injection valve. However, these
conventional attempts are principally directed toward
Definite criteria for the extent to which the
temperature of the tip end of the nozzle should be
reduced are not disclosed. There is a generality-like
criterion that the lower the temperature of the nozzle
tip end, the higher the durability and reliability of
the injection valve.
Examples of a first prior art technique are an
electromagnetic fuel injection valve (Japanese Patent
Application Laid-open (kokai) No. 62-103456) shown in
FIG. 13 and a fuel injection valve (Japanese Patent
Application Laid-open (kokai) No. 63-151970) shown in
FIG. 14. Both of these inventions are intended to
improve the heat radiation characteristics of the tip
end of the injection valve N so as to reduce the
temperature of the tip end of the fuel injection valve
by providing the tip end of the injection valve N with a
shroud S having a high heat conductivity.
An example of a second prior technique is a
cooling structure of an injection nozzle shown in FIG.
15 (Japanese Utility Model Publication (kokoku) No. 8-5336).
This structure is intended to cool a nozzle N by
placing in the vicinity of the nozzle N a packing P
capable of circulating a cooling fluid.
An example of a third prior art technique is a
heat radiation member of a fuel injection nozzle of an
internal-combustion engine shown in FIG. 16 (Japanese
Patent Publication (kokoku) No. 63-65823). This heat
radiation member is intended to improve the heat
radiation characteristics of the tip end of the nozzle N
by providing an elastically deformable seal lip L at the
tip end of a bush.
An example of fourth prior art technique is a
cylinder head for use in a diesel engine shown in FIG.
17 (Japanese Patent Publication (kokoku) No. 59-1103 ).
This invention is intended to provide an engine head H
which shields a nozzle from heat. This illustrative
fourth example is directed toward improving the
durability and reliability of an injection valve of a
direct-injection high supercharging diesel engine, as
well as to a technique for accomplishing the foregoing
objects (1) through (3).
The examples of the first prior art technique
are directed toward providing the tip end of the
injection valve N with the shroud S having a high heat
conductivity. However, the flow of heat within the
injection valve N fitted to the engine has not been
elucidated. In spite of the fact that the invention is
intended to reduce the temperature of the injection
valve N by providing the injection valve N with the
shroud S having a high heat conductivity, the location
of the engine to which the injection valve N is fitted
is not specified, so that a heat flow path is not
defined. Consequently, the improvements or advantageous
effects of the invention cannot be specified. Depending
on conditions in which the injection valve N is fitted
to the engine, there may be no substantial effect of
reducing temperatures, or there may arise an increase in
the temperature of the injection valve.
In the example of the second prior art
technique, the packing P capable of circulating a
cooling fluid is placed in the vicinity of the nozzle N.
According to the structure shown in FIG. 15, the packing
P is located away from the tip end of the nozzle N,
therefore resulting in a small effect of reducing the
temperature of the tip end of the nozzle N. Since
forming a cooling path up to the vicinity of the
injection valve involves difficulties in terms of
manufacture of an engine head, it is difficult to say
that the invention has a high degree of practicality.
In the example of the third prior art technique,
the thermal insulation characteristics of the tip end of
the nozzle N is improved by providing the elastic
deformable seal lip L at the tip end of the bush. The
seal lip L is a simple heat insulation member and
consequently has a high degree of practicality. Since
the material of the seal lip L is limited to elastic
metal, the heat conductivity of the heat insulation
member is equal to or greater than that of the nozzle.
Although the heat insulation member has a function of
facilitating flow of heat, it is hard to say that the
function is sufficient. The heat insulation member does
not have such a heat insulating effect as to interrupt
or partially suppress the flow of heat.
The example of the third prior art technique
also fails to provide a sufficient function of
facilitating flow of heat from the nozzle N to the
engine head. The most important matter to reduce the
temperature of the nozzle through use of a member having
a high heat conductivity is to reduce the heat
resistance between the nozzle and the engine head to as
low a value. The member is press-fitted onto the
nozzle, so that the contact resistance of the heat flow
path is reduced. However, in other areas, there are
clearances between the nozzles and the engine head, or
the nozzles and the engine head are only in slight
contact with each other. Since there are no active
efforts for reducing the heat resistance of other areas,
the temperature of the tip end of the nozzle therefore
cannot be reduced effectively with such an arrangement.
Particularly, since the side surface of the nozzle has a
wide area, it is very important to improve the heat
radiation characteristics of the nozzle by reducing the
contact resistance of the side surface of the nozzle.
In the example of the fourth prior art
technique, the engine head H shields the nozzle N from
heat. However, it is not intended to prevent the flow
rate of fuel from decreasing as a result of accumulation
of deposits on the internal surface of the nozzle hole
of the injection valve. This can be seen from the fact
that a protuberance formed at the tip end of the nozzle
is exposed to the combustion chamber through a thermal
insulation plate. The embodiment section of the patent
describing the fourth example does not include any
descriptions related to the position of the nozzle hole.
However, in the case of this type of injection valve, it
is publicly known that the nozzle hole is formed in the
protuberance at the front end of the nozzle, due to the
function of the nozzle hole. If the nozzle hole is
formed in this position, the temperature of the tip end
becomes higher than a 90%-distillation temperature of
fuel. Therefore, deposits are accumulated on the
internal surface of the nozzle hole, thereby resulting
in a reduction in the flow rate of the injection valve.
It is a general object of the present invention
to provide a deposit reduction fuel injection valve
wherein the reduction of variations in a flow rate by
suppression of the generation and accumulation of
deposits on the internal surface of the nozzle hole.
It is another object of the present invention to provide
a deposit reduction fuel injection valve comprising a
fuel injection valve which has a nozzle hole formed so
as to face a combustion chamber of an internal
combustion engine and which directly injects and
supplies fuel to the combustion chamber, the temperature
of the tip portion of a nozzle body having the nozzle
hole formed thereon is adjusted by temperature adjusting
means so as to maintain the temperature equal to or
lower than a 90%-distillation temperature of fuel,
thereby holding in a liquid phase the fuel which remains
on the internal surface of the nozzle hole after having
been injected.
It is still another object of the present
invention to provide a deposit reduction fuel injection
valve wherein a heat flow path for dissipating heat from
the nozzle body to the engine head is formed by heat
flow formation means formed between the nozzle body and
the engine head.
It is a further object of the present invention
to provide a deposit reduction fuel injection valve
wherein the nozzle body is shielded from the heat
supplied from the combustion chamber, by a heat
insulation member provided at the nozzle body.
An objection of the present invention is to
solve the problem of a reduction in the flow rate of the
injection valve as previously described. More
specifically, the present invention is directed toward a
deposit reduction fuel injection valve comprising a fuel
injection valve which has a nozzle hole formed so as to
face a combustion chamber of an internal combustion
engine and which directly injects and supplies fuel to
the combustion chamber, wherein there is prevented a
phenomenon of a flow rate of fuel being reduced by a
decrease in the area of the nozzle hole as a result of
accumulation of deposits on the internal surface of the
nozzle hole, by a reduction in lowering the temperature
of the tip portion of the nozzle body so as to be lower
than the 90%-distillation temperature of fuel to be
used.
In the event that the temperature of the tip
portion of the nozzle body of the injection valve
becomes higher than the 90%-distillation temperature of
fuel, there arises a recognizable reduction in the flow
rate of the injection valve. This problem is more apt
to occur in a fuel injection valve used in a direct
gasoline injection engine which consumes gasoline having
a 90%-distillation temperature lower than that of gas
oil.
Circumstances under which the flow rate of the
injection valve is reduced will be described
hereinbelow.
Through use of fuel having a 90%-distillation
temperature of 150°C, the inventors of the present
invention performed an engine test for 30 hr. at an air-to-fuel
ratio of 12 in which the tip portion of the
nozzle body reaches 165°C after 30 min. have elapsed
since the commencement of the engine test. FIG. 9 shows
the manner in which the flow rate of the injection valve
decreases at that time. The flow rate abruptly
decreases until ten hours elapse from the commencement
of the test. Although there is no further reduction in
the flow rate after lapse of 10 hr., the rate of
reduction of the flow rate reaches 10% when the test is
completed.
After observation of the internal surface of the
nozzle hole of the injection valve nozzle, deposits are
acknowledged to have been accumulated as a result of
carbonization. From the result of this observation, it
is understood that deposits cause a reduction in the
area of the nozzle hole and a reduction in the flow rate
of the injection valve.
The inventors examined the manner in which the
flow rate of the injection valve was reduced by
performing an engine test similar to that illustrated in
FIG. 9 for 30 hr. on condition that the temperature of
the tip portion of the nozzle body was decreased so as
to be maintained lower than 165°C. The results of such
an engine test are illustrated in FIG. 10. On condition
that the temperature of the tip portion of the nozzle
body is 155°C, the rate of reduction in the flow rate is
about 3%. In contrast, on condition that the
temperature of the tip portion of the nozzle body is
reduced to 100°C, the rate of reduction in the flow rate
becomes about 1%.
The mechanism of occurrence of the phenomenon is
described below. FIG. 3 schematically illustrates the
occurrence of the phenomenon.
Fuel contains precursors of deposit which will
serve as the nucleus of deposits during the course of
generation of the deposits. At room temperature, these
precursors of deposit are dispersed in the fuel.
After having been injected, the fuel remains in
trace amounts on the internal surface of the nozzle
hole. If the temperature of the tip portion of the
nozzle body is lower than the 90%-distillation
temperature of the fuel (150°C), the fuel remaining on
the internal surface of the nozzle hole is held in a
liquid phase. Accordingly, the precursors of deposit
contained in the fuel also remain dispersed in the fuel.
The precursors of deposit remaining in the dispersed
state are easily flushed away together with the fuel by
the next injection, thereby suppressing the generation
of deposits on the internal surface of the nozzle hole.
In contrast, on condition that the temperature
of the tip portion of the nozzle body is higher than the
90%-distillation temperature (150°C), evaporation of the
fuel remaining inside the nozzle hole is promoted.
Therefore, the precursors of deposit cannot remain in
the dispersed state in the fuel, so they aggregate on
the internal wall surface of the nozzle hole. In such a
state, it is difficult to flush the thus-aggregated
precursors of deposit away at the time of the next
injection, so they remain in the nozzle hole. As a
result, the accumulation of deposits proceeds.
From these tests, the inventors of the present
invention have learned that, in order to suppress the
generation of deposits on the internal surface of the
nozzle hole, it is necessary to reduce the temperature
of the tip portion of the nozzle body so as to maintain
the temperature lower than a 90%-distillation
temperature of the fuel, to constantly hold the fuel
remaining on the internal surface of the nozzle hole in
a liquid phase, thereby maintaining precursors of
deposit dispersed in the fuel.
Further, the inventors have learned that the
formation of the following heat flow path is useful for
accomplishing the foregoing requirements. Specifically,
the heat flow path is formed by inserting a substance
having a high heat conductivity between the side surface
of the nozzle and the engine head so as to minimize the
contact resistance between the side surface and the
substance and between the substance and the engine head.
By virtue of this heat flow path, the heat resistance
between the side surface of the nozzle body and the
engine head is reduced, and the heat supplied to the
nozzle body as a result of convection or radiation of a
combustion gas is easily dissipated to the engine head.
The inventors of the present invention also
learned important factors in suppressing the reduction
in the flow rate of the injection valve by having
performed another test from different viewpoints. The
temperature history of the tip portion of the nozzle
body was measured under the same conditions as those
shown in FIG. 9. Further, the injection valve was
removed from the engine head after lapse of 3, 7, 15,
and 30 hours, and the thickness of soot built up on the
surface of the nozzle body was determined. The result
of such determination is shown in FIG. 11.
The temperature of the tip portion of the nozzle
body, which is 180°C immediately after the commencement
of the engine test, drops to 165°C after the lapse of 30
min. since the commencement of the test. The
temperature of the tip portion of the nozzle body
decreases with the lapse of time, and the temperature
drops to about 130°C after the lapse of 15 hr. In
contrast, the thickness of the soot built up on the
surface of the nozzle body increases with the lapse of
time, and the thickness reaches 0.34 mm after the lapse
of 15 hr. However, a phenomenon is observed in which
the temperature of the tip portion of the nozzle body
sharply increases immediately before the operating time
of the engine reaches 30 hr. It has been ascertained
that the soot has been scraped off from the surface of
the nozzle body, so that the metallic base material of
the nozzle body is exposed. From the results of this
test, it is understood that the reduction in the
temperature of the tip portion of the nozzle body has
strong relevancy to the soot accumulated on the surface
of the nozzle body. In short, it is concluded that the
soot forms a thermal insulation layer which suppresses
the flow of heat supplied to the nozzle body from the
combustion chamber.
After continuation of the engine test, a
reduction in the temperature of the tip portion of the
nozzle body was again ascertained.
In reference to the result of measurement of the
temperature of the nozzle tip portion, the variations in
the flow rate shown in FIG. 9 are reviewed. A lack of
progress in the reduction of the flow rate after the
lapse of 8 hr since commencement of the test is
considered to be ascribed to the fact that the
temperature of the tip portion of the nozzle body has
already been dropped as a result of accumulation of
soot.
In this way, if the soot is built up on the
surface of the nozzle body, the soot serves as a heat
insulation layer which reduces the temperature of the
nozzle body. Therefore, it is understood that the soot
suppresses the progress of the reduction of the flow
rate of the injection valve.
It is a still further object of the present
invention to provide a deposit reduction fuel injection
valve comprising a nozzle hole, formed on a tip portion
of a nozzle body so as to face a combustion chamber of
an internal combustion engine, for injecting directly
fuel in the combustion chamber, and a temperature
adjusting means for adjusting a temperature of the tip
portion of the nozzle body having the nozzle hole so as
to maintain the temperature equal to or lower than a
90%-distillation temperature of fuel.
It is a yet further object of the present
invention to provide a deposit reduction fuel injection
valve wherein the temperature adjusting means comprises
a heat flow formation means formed between the nozzle
body having the nozzle hole formed thereon and an engine
head for dissipating a heat in the nozzle body to the
engine head.
It is a yet further object of the present
invention to provide a deposit reduction fuel injection
valve wherein the heat flow formation means comprises a
heat conduction promoting member which is formed from a
material having a high heat conductivity and is
interposed between an internal wall surface of the
engine head and an outer side surface of the nozzle
body, and the heat conduction promoting member reduces a
heat resistance between the nozzle body and the engine
head, so that the dissipation of the heat flow supplied
to the nozzle body toward the engine head is promoted.
A deposit reduction fuel injection valve of the
present invention is directed toward a fuel injection
valve comprises a nozzle body which has a nozzle hole
formed thereon so as to face a combustion chamber of an
internal combustion engine and which directly injects
and supplies fuel to the combustion chamber. With
regard to a nozzle body having the nozzle hole of the
injection valve formed thereon, a heat flow path is
formed by inserting a substance having a high heat
conductivity between the side surface of the nozzle body
and the engine head so as to minimize the contact
resistance between the side surface and the substance
and between the substance and the engine head. By
virtue of this heat flow path, the heat resistance
between the nozzle body and the engine head is reduced,
and the heat supplied to the nozzle body as a result of
convection or radiation of a combustion gas becomes
easily dissipated to the engine head. An area of the
nozzle body exposed in the combustion chamber or part of
this area of the nozzle body is covered with a substance
having a low heat conductivity so as to interrupt or
suppress the inflow of heat supplied to the nozzle body
from the combustion chamber. The temperature of the tip
portion of the nozzle body is reduced so as to become
lower than a 90%-distillation temperature of fuel, so
that the fuel remaining on the internal surface of the
nozzle hole after having been injected is maintained in
a liquid phase.
It is another object of the present invention to
provide a deposit reduction fuel injection valve wherein
the temperature adjusting means comprises a heat
insulation member which is formed from a material having
a low heat conductivity and which is provided in at
least part of an area of the tip portion of the nozzle
body exposed to the combustion chamber so as to insulate
heat supplied from the combustion chamber to the nozzle
body.
The accumulation of soot differs according to
the engine specifications and driving conditions, and
there is also such a case as shown in FIG. 11 where the
soot is scraped off from the nozzle body. Therefore, in
some cases, accumulated soot may not serve as a
permanent measure to maintain the temperature of the tip
portion of the nozzle body at a temperature lower than
the 90%-distillation temperature. For this reason, in
order to stably maintain the temperature of the tip
portion of the nozzle body at a temperature lower than
the 90%-distillation temperature of the fuel, it is
effective to attach a heat insulation material to the
tip portion of the nozzle body so as to interrupt the
flow of heat into the nozzle body as a result of
convection or radiation of a combustion gas.
It is a further object of the present invention
to provide a deposit reduction fuel injection valve
wherein a ratio of heat conductivity λ(W/mm/K) to a
thickness "t" (mm) of the heat insulation member; i.e.,
λ/t, is set so as to be smaller than 8.5 x 10-4.
It is a yet further object of the present
invention to provide a deposit reduction fuel injection
valve wherein the heat insulation member is provided on
a lower edge of the tip portion of the nozzle body so as
to annularly surround the nozzle hole.
It is a yet further object of the present
invention to provide a deposit reduction fuel injection
valve wherein an outlet of the nozzle hole is positioned
above a lowermost end of the heat insulation member.
In the deposit reduction fuel injection valve
according to the present invention, a nozzle hole is
formed to face a combustion chamber of an internal
combustion engine so as to directly inject and supply
fuel to the combustion chamber. The temperature
adjusting means having the nozzle hole formed thereon
adjusts the temperature of the tip portion of the nozzle
body so as to maintain the temperature equal to or lower
than a 90%-distillation temperature of fuel, thereby
suppressing the generation and accumulation of deposits
on the internal surface of the nozzle hole and hence
resulting in reduced variations in a flow rate.
In the deposit reduction fuel injection valve
according to the present invention, which has the
foregoing structure and depends on the first invention,
the heat flow formation means formed between the engine
head and the nozzle body having the nozzle hole, which
constitutes the temperature adjusting means, dissipates
heat supplied to the nozzle body to the engine head.
Therefore, the temperature of the tip portion of the
nozzle body is reduced so as to be maintained lower than
the 90%-distillation temperature of fuel by controlling
the heat flow from the nozzle body to the engine head,
thereby suppressing the generation and accumulation of
deposits on the internal surface of the nozzle hole and
hence resulting in effective reduction of variations in
a flow rate.
In the deposit reduction fuel injection valve
according to the present invention, a heat conduction
promoting member, which is formed from a material having
a high heat conductivity and is interposed between the
internal wall surface of the engine head and the outer
side surface of the nozzle body constituting the heat
flow formation means, reduces the heat resistance
between the nozzle body and the engine head, so that the
dissipation of the heat supplied to the nozzle body
toward the engine head is promoted. As a result, the
flow of heat from the nozzle body to the engine head is
promoted, so that the temperature of the tip portion of
the nozzle body is reduced so as to be maintained lower
than or equal to the 90%-distillation temperature of the
fuel, thereby suppressing the generation and
accumulation of deposits on the internal surface of the
nozzle hole and hence resulting in effective reduction
of variations in a flow rate.
Specifically, the heat flow path is formed by
inserting a substance having a high heat conductivity
between the side surface of the nozzle and the engine
head, thereby reducing the heat resistance between the
side surface of the nozzle and the engine head. As a
result, the heat flowing into the nozzle can be easily
dissipated to the engine head. The operation and
effects of this heat flow path will be described in
detail hereinbelow.
The heat resulting from the convection or
radiation of the combustion gas is supplied to the tip
portion of the nozzle body exposed in the combustion
chamber, thereby increasing the temperature of the tip
portion of the nozzle body. Heat flows into the engine
head, which has a comparatively lower temperature, via
the area whose heat resistance has been reduced. If the
present invention is not applied to the engine, the heat
principally flows to the engine head via screws and a
gasket which fit the injection valve to the engine head.
Since these screws and gasket are usually
provided in an upper part of the nozzle body, a very
small effect of reducing the temperature of the nozzle
tip portion will be expected even if an attempt is made
to reduce the heat resistance of the screws and gasket.
For this reason, in order to efficiently reduce the
temperature of the tip portion of the nozzle body,
necessary to form a new heat flow path for guiding the
heat flow from the nozzle body to the engine head by
inserting a member having a high heat conductivity
between the side surface of the nozzle body and the
engine head in a state in which the contact resistance
becomes as small as possible. As a result, the heat
supplied to the nozzle body easily flows to the engine
head having a comparatively lower temperature, enabling
effective reduction of the temperature of the tip
portion of the nozzle body.
The inventors of the present invention have
quantitatively studied a method of effectively inserting
the member having a high heat conductivity between the
nozzle body and the engine head. FIG. 1 illustrates one
embodiment of the present invention, wherein a copper
sleeve 60 is inserted between a tip portion 8 of a
nozzle body and an engine head 4. As a result, the
thermal contact resistance between the side surface of
the tip portion 8 of the nozzle body and the copper
sleeve 60, as well as that between the copper sleeve 60
and the engine head 4, is substantially reduced to zero.
In contrast, FIG. 12 shows an injection valve
analogous to the conventional injection valve shown in
FIG. 16. An air layer is formed in an area S indicated
by a dashed line, and temperatures of the tip portions
of these nozzles are compared with each other in FIG. 2.
The temperature of the tip portion of the nozzle
body of the present invention is 135°C, and there is
obtained a reduction in temperature as large as 45°C
relative to an injection valve (the temperature of the
tip portion of the nozzle body is 180°C) which does not
have the copper sleeve 10 inserted therein. In the case
of the injection valve analogous to the conventional
injection valve, as is evident from FIG. 2, the
temperature of the tip portion of the nozzle body is 150
reduction effect as compared to that of the present
invention.
In the deposit reduction fuel injection valve
according to the present invention, the heat insulation
member, which is formed from a material having a low
heat conductivity and which is provided in at least part
of the area of the nozzle body exposed to the combustion
chamber, shields the nozzle body from the heat supplied
from the combustion chamber. Accordingly, the
temperature of the tip portion of the nozzle body is
reduced so as to be maintained lower than the 90%-distillation
temperature of fuel, thereby more
effectively suppressing the generation and accumulation
of deposits on the internal surface of the nozzle hole
and hence resulting in further effective reduction of
variations in a flow rate.
The heat insulation member according to the
fourth invention, is formed from a substance having a
low heat conductivity and covers the area of the nozzle
body exposed to the combustion chamber or a part of that
area. The operation and effects of this heat insulation
member when it shields the nozzle body from the heat
flowing from the combustion chamber will be described.
If the area of the fuel injection valve nozzle
body exposed to the combustion chamber or part of that
area is covered with a substance having a low heat
conductivity, the amount of heat flowing into the tip
portion of the nozzle body becomes smaller, enabling
reductions in the temperature of the tip portion of the
nozzle body.
In the deposit reduction fuel injection valve
according to the fifth invention, which has the
foregoing structure and depends on the fourth invention,
the ratio of heat conductivity λ(W/mm/K) of the
material constituting the thermal insulation member to
the thickness "t" (mm) of the thermal insulation member;
i.e., λ/t, is set to be smaller than 8.5 x 10-4. As a
result, there is produced an effect of adjusting the
temperature of the tip portion of the nozzle body in an
optimum way so that the temperature is maintained equal
to or lower than the 90%-distillation temperature of
fuel.
The effect of reducing the temperature of the
tip portion of the nozzle body is dependent on the heat
conductivity of the area of the nozzle body exposed to
the combustion chamber or of a member attached to a part
of the exposed area. A trial calculation was made with
regard to the heat conductivity of the member attached
to the exposed area of the nozzle body inserted in the
combustion chamber, as well as to the effect of reducing
the temperature of the tip portion of the nozzle body
obtained when the thickness of the member was changed.
FIG. 8 illustrates the results of such trial
calculation. Here, boundary conditions are set such
that the temperature of the tip portion of the nozzle
body becomes 180°C when the tip portion is directly
exposed to the combustion chamber.
If a member having a heat conductivity of 1 x
10-3 W/mm is used, the temperature of the tip portion of
the nozzle becomes 168°C, provided that the thickness of
the member is 0.35 mm. The temperature is reduced to
150°C with a thickness of 1.2 mm, 140°C with a thickness
of 2 mm, and to 130°C with a thickness of 4 mm. The
lower the heat conductivity of the member, the thinner
the thickness of the member can be made. If the ratio
of the heat conductivity λ(W/mm/K) of the member
attached to the exposed area of the nozzle body in the
combustion chamber to the thickness "t" (mm) of the
member; i.e., λ/t, is set so as to be smaller than 8.5 x
10-4, the temperature of the tip portion of the nozzle
body can be maintained at a temperature lower than or
equal to 150°C. This temperature is lower than the 90%-distillation
temperature of ordinary gasoline. In this
type of injection valve, the generation and accumulation
of deposits on the internal surface of the nozzle hole
are suppressed, thereby enabling implementation of an
injection valve which reduces variations in its flow
rate.
In the deposit reduction fuel injection valve
according to the present invention, the thermal
insulation member is annularly provided at the lowermost
end of the nozzle body so as to surround the nozzle
hole. Therefore, the deposit reduction fuel injection
valve has an effect of effectively shielding the nozzle
body from the heat supplied from the combustion chamber.
In the deposit reduction fuel injection valve
according to the present invention, an outlet of the
nozzle hole is positioned above the lowermost end of the
thermal insulation member. Therefore, the outlet of the
nozzle hole does not project into the combustion
chamber, and there is produced an effect of reducing the
amount of deposit to be deposited because the outlet
port is set back from the combustion chamber.
Attention should be also given to the positional
relationship between such a substance having a low heat
conductivity and the outlet of the nozzle hole. The
outlet of the nozzle hole does not project into the
combustion chamber and is positioned above the lowermost
end of the thermal insulation member made of the
material of low heat conductivity. With this
arrangement, the thermal insulation member is utilized
to prevent the nozzle hole from being directly exposed
to heat in the same manner as a breakwater is utilized
to protect a pier from waves, thereby suppressing
accumulation of deposits on the internal surface of the
nozzle hole.
With reference to the drawings, embodiments of
the present invention will be described.
As illustrated in FIG. 5, a deposit reduction
fuel injection valve according to a first embodiment of
the present invention comprises a fuel injection valve 1
which has a nozzle hole 3 formed on a lower tip end of a
tip portion 8 of a nozzle body so as to face a
combustion chamber 2 of an internal-combustion engine
and which directly feeds fuel to the combustion chamber.
A temperature adjusting means 5 for adjusting the
temperature of the tip portion 8 of the nozzle body
having the nozzle hole 3 formed thereon so as to
maintain the temperature equal to or lower than a 90%-distillation
temperature of fuel is formed between the
tip portion 8 of the nozzle body having the nozzle hole
3 formed thereon and an engine head 4. The deposit
reduction fuel injection valve further comprises a heat
flow formation means 6 which dissipates heat supplied to
the nozzle 8 to the engine head 4.
The engine head 4 is provided with a cooling
path for circulating cooling water, whereby the
temperature of the engine head 4 is maintained at about
80°C.
In the first embodiment, the injection valve 1
is fixed to the engine head 4 via an injection valve
fixing jig 11. A plurality of holes are formed in the
fixing jig 11, and bolts are screwed into these holes.
The bolts are fitted to the engine head 4. As a result,
forces to fasten the bolts are exerted on the engine
head 4 via the fixing jig 11, the injection valve flange
12, and the gasket 13, whereby the injection valve 1 is
fixed to the engine head 4.
The combustion chamber 2 is formed from a space
which is surrounded by the engine head 4, a cylinder,
and a piston (not shown). A mixed gas consisting of
fuel and air is combusted within the combustion chamber
2 thereby to produce a large quantity of heat.
The heat flow formation means 6 ensures a new
path over which heat flows from the tip portion 8 of the
nozzle body to the engine head 4. The heat flowing into
the tip portion 8 of the nozzle body can be easily
dissipated to the engine head 4. A heat conduction
promoting member 60 is formed from a material having a
high heat conductivity and is disposed between the outer
side surface of a cylindrical base portion of the tip
portion 8 of the nozzle body and the inner wall surface
of the engine head 4. By virtue of this heat conduction
promoting member 60, the heat resistance between the
nozzle 8 and the engine head 4 is reduced to thereby
promote dissipation of the heat flowing to the nozzle 8
to the engine head 4.
The heat conduction promoting member 60 is
formed from a hollow cylindrical copper sleeve 61 whose
base material is copper having a high heat conductivity.
The copper sleeve 61 is formed so as to have given inner
and outer diameters and is disposed between an outer
circumferential surface 81 of the tip portion 8 of the
nozzle body and an inner circumferential surface of a
nozzle insertion hole 41 of the engine head 4. The
heat conduction promoting member 60 is inserted into the
annular space formed between the nozzle 8 and the nozzle
insertion hole 41 of the engine head 4.
The sleeve 61 has its inner circumferential
surface held in close contact with the outer
circumferential surface 81 of the cylindrical base
portion of the tip portion 8 so as to minimize the heat
resistance of the contact surface between the inner
circumferential surface 81 of the sleeve 61 and the
outer circumferential surface of the nozzle 8. The
outer circumferential surface of the copper sleeve 61 is
brought into close contact with the inner
circumferential surface of the engine head 4, thereby
minimizing the heat resistance of the contact surface
between them.
In the deposit reduction fuel injection valve
according to the first embodiment having the foregoing
structure, the copper sleeve 61, which is made of a
material having a high heat conductivity and constitute
the heat conduction promoting member 60, is inserted
between the side surface 81 of the nozzle 8 and the
engine head 4, so that a heat flow path is formed while
the heat resistance between the side surface 81 of the
nozzle 8 and the engine head 4 is minimized. As a
result, the heat flowing into the nozzle 8 is dissipated
to the engine head 4.
In the deposit reduction fuel injection valve
according to the first embodiment which operates in the
above described manner, a new path over which heat flows
from the nozzle 8 to the engine head 4 is ensured. The
heat flowed into the nozzle 8 is effectively dissipated
to the engine head 4, thereby reducing the temperature
of the tip portion 8 of the nozzle body having the
nozzle hole 3 formed therein. As a result, the fuel is
in the liquefied state on the inner surface of the
nozzle hole 3, thereby suppressing the generation and
accumulation of deposits on the internal surface of the
nozzle hole 3 and hence resulting in reduced variations
in a flow rate.
The operation and effects of the deposit
reduction fuel injection valve according to the first
embodiment are stably ensured even when the injection
valve 1 is fitted to the engine 4 utilizing screws
provided on the injection valve 1, without use of the
fixing jig 11 in the first embodiment.
As shown in FIG. 6, a deposit reduction fuel
injection valve according to a second embodiment is
different from that of the first embodiment in that an
outer circumferential surface 621 of the copper sleeve
62 and the inner circumferential wall of the engine head
4 are tapered in order to increase the degree of close-contact
between the copper sleeve 62, which comes into
contact with the Side surface 81 of the tip portion 8 of
the nozzle body, and the inner circumferential wall of
the engine head 4. The difference is principally
described hereinbelow.
With regard to the copper sleeve 62 inserted
between the nozzle 8 and the engine head 4, it is
necessary to minimize thermal contact resistance between
the nozzle 8 and the copper sleeve 62, as well as
between the copper sleeve 62 and the engine head 4.
As a result of tapering the outer
circumferential wall of the copper sleeve 62 and a
nozzle insertion hole 41 of the engine head 4 for
receiving the copper sleeve 62, the copper sleeve 62 is
sandwiched between and held in close contact with the
engine head 4 and the nozzle 8 in a wedge-like manner
when the injection valve 1 is fitted to the engine head
4.
In the deposit reduction fuel injection valve of
the second embodiment having the foregoing structure,
the surfaces of the copper sleeve 61 and the engine head
4 which are in contact with each other are tapered, and
they are brought into close contact with each other in a
wedge-like manner. A heat flow path whose contact
resistance is minimized is provided between the nozzle 8
and the engine head 4, thereby facilitating the
dissipation to the engine head 4 of the heat flowing to
the tip portion 8 of the nozzle body.
In the deposit reduction fuel injection valve of
the second embodiment which operates in the foregoing
way, the surfaces of the copper sleeve 61 and the engine
head 4 which are in contact with each other are tapered,
so that the close contact state is improved, and the
contact area between the copper sleeve and the engine
head is increased. As a result, there is produced an
effect of drastically reducing the thermal contact
resistance of the contact surfaces, so that the
temperature of the tip portion of the nozzle is
efficiently reduced.
The above-described effect can be obtained by
tapering the surfaces of the nozzle 8 and the copper
sleeve which are in contact with each other, or by
tapering the surfaces of the nozzle 8, the copper sleeve
62, and the engine head 4 which are in contact with each
other.
A deposit reduction fuel injection valve
according to a third embodiment is different from that
in the first embodiment in the following point. Namely,
as illustrated in FIG. 7, in addition to the heat
conduction promoting member 60 which is made of a
material having a high heat conductivity and which is
interposed between the side surface of the tip portion 8
of the nozzle body and the engine head 4, the deposit
reduction fuel injection valve is provided with a heat
insulation member 7 which is provided on the area of the
nozzle 8 exposed in the combustion chamber 2 and which
shields the nozzle 8 from heat fed from the combustion
chamber 2. The difference is principally described
hereinbelow.
The copper sleeve 61 which contains copper
having a high heat conductivity as a base material is
inserted between the nozzle 8 and the engine head 4.
The tapered-tip portion of the nozzle 8, which is
exposed to the combustion chamber 2, is covered with the
annular heat insulation member 7 having a low heat
conductivity. A circular hole is formed at the center
of the heat insulation member 7 so as to constitute the
nozzle hole 3 having a given axial length.
In the deposit reduction fuel injection valve of
the third embodiment having the foregoing structure, a
heat flow path is formed between the side surface of the
nozzle 8 and the engine head 4 by the copper sleeve 61,
which serves as the heat conduction promoting member 60
in a state in which the heat resistance between the side
surface of the nozzle 8 and the engine head 4 is
minimized, enabling facilitation of dissipation to the
engine head 4 of the heat flowing into the nozzle. The
exposed area of the nozzle 8 in the combustion chamber 2
is covered with the heat insulation member 7 which is
made of a material having a low heat conductivity,
thereby interrupting or regulating the heat flowing to
the nozzle 8 from the combustion chamber 2.
In the deposit reduction fuel injection valve of
the third embodiment which operates in the foregoing
way, the copper sleeve 61 is brought into close contact
with the nozzle 8 and the engine head 4, minimizing the
heat resistance of the contact surfaces between them.
Further, the heat supplied to the tip portion of the
nozzle 8 from the combustion chamber 2 can be
substantially interrupted by the heat insulation member
7. More specifically, not only the dissipation of heat
from the nozzle 8 but also interruption of entry of the
heat to the nozzle 8 are effected, and the temperature
of the tip portion of the nozzle 8 is therefore reduced
more efficiently, thereby effectively suppressing the
generation and accumulation of deposits on the internal
surface of the nozzle hole 3 and hence resulting in
reduced variations in a flow rate.
A deposit reduction fuel injection valve
according to a fourth embodiment is different from that
of the first embodiment in that the tip portion 8 of the
nozzle body has a two-staged structure as illustrated in
FIG. 8; namely, a structure comprising a base large-diameter
section 84 and a tip small-diameter section 85,
and in that a thin tube-like copper sleeve 64 is brought
into contact with the outer circumferential surface of
the base large-diameter section 84, as well as with the
overall inner circumferential wall of the nozzle
insertion hole of the engine head 4. A heat insulation
member 94 having a low heat conductivity is interposed
between a tip end of the tip small-diameter section 85
and the copper sleeve 64.
The copper sleeve 64 has its lower edge bent in
a radially inward direction of the nozzle 8 at a
position corresponding to the lower end of the inner
circumferential wall of the nozzle insertion hole of the
engine head 4. An annular hole is formed at the center
of the copper sleeve so as to constitute the nozzle hole
3 formed on a tip taper end of the tip portion 8 of the
nozzle body
The heat insulation member 94 is provided so as
to come into contact with the outer circumferential wall
of the tip portion small-diameter section 85 of the
nozzle 8 and its tapered lowermost end. A tapered
circular hole is formed at the lower center of the
copper sleeve in consideration of a spray pattern. The
nozzle hole 3 of the nozzle 8 is positioned a
predetermined distance above the lower end of the heat
insulation member 94 (the circular hole of the copper
sleeve 64).
In the deposit reduction fuel injection vale of
the fourth embodiment having the foregoing structure, a
heat flow path is formed between the side surface of the
nozzle 8 and the engine head 4 by the copper sleeve 61,
which serves as the heat conduction promoting member 60
in a state in which the heat resistance between the side
surface of the nozzle 8 and the engine head 4 is
minimized, enabling facilitation of dissipation to the
engine head 4 of the heat flowing into the nozzle. The
exposed area of the nozzle 8 in the combustion chamber 2
is covered with the heat insulation member 94 which is
made of a material having a low heat conductivity,
thereby interrupting or regulating the heat flowing to
the nozzle 8 from the combustion chamber 2.
In the deposit reduction fuel injection valve of
the fourth embodiment which operates in the foregoing
way, the copper sleeve 64 is brought into close contact
with the nozzle 8 and the engine head 4, minimizing the
heat resistance of the contact surfaces between them.
Further, the heat supplied to the tip portion of the
nozzle 8 from the combustion chamber 2 can be
interrupted substantially by the heat insulation member
94. More specifically, not only the dissipation of heat
from the nozzle 8 but also interruption of entry of the
heat to the nozzle 8 are effected, and the temperature
of the tip portion of the nozzle 8 is therefore reduced
more efficiently, thereby effectively suppressing the
generation and accumulation of deposits on the internal
surface of the nozzle hole 3 and hence resulting in
reduced variations in a flow rate.
In the deposit reduction fuel injection valve of
the fourth embodiment, the outlet of the nozzle hole 3
is positioned above the lowermost edge of the heat
insulation member 94. Thus, since the outlet of the
nozzle hole 3 does not project into the combustion
chamber 2 but is set back from the same, there is
produced an effect of reducing the amount of deposits to
be accumulated.
Further, in the deposit reduction fuel injection
valve of the fourth embodiment, the copper sleeve 64 has
its lower edge inwardly folded over in the radial
direction of the nozzle 8 at the lower end of the inner
circumferential wall of the nozzle insertion hole of the
engine head 4 so as to cover the lowermost outer
periphery of the heat insulation member 94. The heat
flowing to the heat insulation member 94 and the nozzle
8 from the combustion chamber 2 is interrupted, and the
nozzle 8 is cooled and regulated by the copper sleeve 64
cooled by the engine head 4 which is cooled by the
cooling water. Therefore, there is produced an effect
of more efficiently reducing the temperature of the tip
portion of the nozzle 8.
Through the engine test, the inventors verified
that the fuel injection valve of the fourth embodiment
could have reduced the temperature of the tip portion of
the nozzle about 60°C relative to the conventional fuel
injection valve.
The preferred embodiments of the present
invention, as herein disclosed, are taken as some
embodiments for explaining the present invention. It is
to be understood that the present invention should not
be restricted by these embodiments and any modifications
and additions are possible so far as they are not beyond
the technical idea or principle based on descriptions of
the scope of the patent claims.
Although the fourth embodiment has been described with reference to the example in which the copper sleeve has its lower edge inwardly folded over so as to cover the nozzle and the heat insulation member, and in which the nozzle and the heat insulation member are cooled by utilization of the cooling water of the engine head, the present invention is not limited to this case. The present invention is also capable of adopting an embodiment in which the copper sleeve is fitted into the nozzle insertion hole of the engine head above the lowermost end of the nozzle insertion hole without folding over the lower edge of the copper sleeve. This structure prevents the copper sleeve from being exposed to thecombustion chamber 2, while ensuring the maximum
area for dissipating heat from the nozzle 8 to the
engine head.
Although the fourth embodiment has been described with reference to the example in which the copper sleeve has its lower edge inwardly folded over so as to cover the nozzle and the heat insulation member, and in which the nozzle and the heat insulation member are cooled by utilization of the cooling water of the engine head, the present invention is not limited to this case. The present invention is also capable of adopting an embodiment in which the copper sleeve is fitted into the nozzle insertion hole of the engine head above the lowermost end of the nozzle insertion hole without folding over the lower edge of the copper sleeve. This structure prevents the copper sleeve from being exposed to the
A deposit reduction fuel injection valve
including a nozzle hole, formed on a tip portion of a
nozzle body so as to face a combustion chamber of an
internal combustion engine, for injecting directly fuel
in said combustion chamber, and a temperature adjusting
system for adjusting a temperature of said tip portion
of said nozzle body having said nozzle hole so as to
maintain the temperature equal to or lower than a 90%-distillation
temperature of fuel.
Claims (7)
- A deposit reduction fuel injection valve comprisinga nozzle hole, formed on a tip portion of a nozzle body so as to face a combustion chamber of an internal combustion engine, for injecting directly fuel in said combustion chamber, anda temperature adjusting means for adjusting a temperature of said tip portion of said nozzle body having said nozzle hole so as to maintain the temperature equal to or lower than a 90%-distillation temperature of fuel.
- A deposit reduction fuel injection valve according to claim 1, wherein
said temperature adjusting means comprisesa heat flow formation means formed between said nozzle body having the nozzle hole formed thereon and an engine head for dissipating a heat in said nozzle body to said engine head. - A deposit reduction fuel injection valve according to claim 2, wherein
said heat flow formation means comprisesa heat conduction promoting member which is formed from a material having a high heat conductivity and is interposed between an internal wall surface of said engine head and an outer side surface of said nozzle body, and said heat conduction promoting member reduces a heat resistance between said nozzle body and the engine head, so that the dissipation of the heat flow supplied to said nozzle body toward said engine head is promoted. - A deposit reduction fuel injection valve according to claim 3, wherein
said temperature adjusting means comprisesa heat insulation member which is formed from a material having a low heat conductivity and which is provided in at least part of an area of said tip portion of said nozzle body exposed to said combustion chamber so as to insulate heat supplied from said combustion chamber to said nozzle body. - A deposit reduction fuel injection valve according to claim 4, wherein
a ratio of heat conductivity λ(W/mm/K) to a thickness "t" (mm) of said heat insulation member; i.e., λ/t, is set so as to be smaller than 8.5 x 10-4. - A deposit reduction fuel injection valve according to claim 5, wherein
said heat insulation member is provided on a lower edge of said tip portion of said nozzle body so as to annularly surround said nozzle hole. - A deposit reduction fuel injection valve according to claim 6, wherein
an outlet of said nozzle hole is positioned above a lowermost end of said heat insulation member.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP26256396A JPH1089192A (en) | 1996-09-10 | 1996-09-10 | Deposit reducing-type fuel injection valve |
JP262563/96 | 1996-09-10 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0828075A1 true EP0828075A1 (en) | 1998-03-11 |
Family
ID=17377551
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP97115623A Withdrawn EP0828075A1 (en) | 1996-09-10 | 1997-09-09 | Deposit reduction fuel injection valve |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0828075A1 (en) |
JP (1) | JPH1089192A (en) |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1081374A2 (en) * | 1999-09-03 | 2001-03-07 | Delphi Technologies, Inc. | Injection nozzle |
EP1455083A2 (en) * | 2003-03-07 | 2004-09-08 | Nissan Motor Company, Limited | Cooling structure for fuel injection valve |
WO2005050004A1 (en) * | 2003-11-21 | 2005-06-02 | Robert Bosch Gmbh | Fuel injection valve |
US7261089B2 (en) | 2003-08-18 | 2007-08-28 | Robert Bosch Gmbh | Fuel injector nozzle seal |
DE102006013880A1 (en) * | 2006-03-25 | 2007-11-08 | Dr.Ing.H.C. F. Porsche Ag | Fuel injection arrangement for direct injection of fuel into combustion chamber of internal combustion chamber, has fuel injecting valve with flange, which is distant in radial direction with respect to insertion direction |
US7744014B2 (en) | 2002-07-25 | 2010-06-29 | Continental Automotive Gmbh | Injection module |
CN101311516B (en) * | 2004-11-02 | 2011-09-28 | 丰田自动车株式会社 | Control apparatus for internal combustion engine |
WO2017089229A1 (en) * | 2015-11-27 | 2017-06-01 | Robert Bosch Gmbh | Injector arrangement having a thermal protection sleeve |
WO2017102216A1 (en) * | 2015-12-14 | 2017-06-22 | Robert Bosch Gmbh | Fuel injector |
WO2017102245A1 (en) * | 2015-12-15 | 2017-06-22 | Robert Bosch Gmbh | Injector having an improved thermal behavior |
FR3101920A1 (en) * | 2019-10-14 | 2021-04-16 | Renault S.A.S. | Gasoline direct injector nose protector with heat shield |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2001090630A (en) * | 1999-09-27 | 2001-04-03 | Mazda Motor Corp | Fuel supply device for cylinder injection type engine |
JP2001132582A (en) | 1999-11-10 | 2001-05-15 | Mitsubishi Electric Corp | Fuel injection valve for cylinder injection |
JP2010138778A (en) * | 2008-12-11 | 2010-06-24 | Mitsubishi Heavy Ind Ltd | Cooling structure of fuel injection valve |
KR101307080B1 (en) * | 2011-07-19 | 2013-09-11 | 현대중공업 주식회사 | Pre combustion chamber for gas engine |
JP6250366B2 (en) * | 2013-11-08 | 2017-12-20 | 三菱重工業株式会社 | Fuel injection valve temperature suppression mechanism for internal combustion engine and internal combustion engine provided with the same |
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GB719952A (en) * | 1951-04-24 | 1954-12-08 | Saurer Ag Adolph | An improved fuel injection nozzle for diesel engines |
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GB2066895A (en) * | 1980-01-03 | 1981-07-15 | Bosch Gmbh Robert | Fuel injection nozzle with a heat protecting sleeve for internal combustion engines |
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JPS62103456A (en) | 1985-10-30 | 1987-05-13 | Aisan Ind Co Ltd | Electromagnetic fuel injection valve |
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JPS6365823B2 (en) | 1978-09-15 | 1988-12-16 | Bosch Gmbh Robert | |
JPH085336Y2 (en) | 1989-09-20 | 1996-02-14 | いすゞ自動車株式会社 | Cooling structure of injection nozzle |
-
1996
- 1996-09-10 JP JP26256396A patent/JPH1089192A/en active Pending
-
1997
- 1997-09-09 EP EP97115623A patent/EP0828075A1/en not_active Withdrawn
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GB719952A (en) * | 1951-04-24 | 1954-12-08 | Saurer Ag Adolph | An improved fuel injection nozzle for diesel engines |
US2777431A (en) * | 1953-08-28 | 1957-01-15 | Maschf Augsburg Nuernberg Ag | Injection nozzle arrangement |
JPS591103B2 (en) | 1978-03-13 | 1984-01-10 | 住友金属工業株式会社 | Automatic oil application control method |
JPS6365823B2 (en) | 1978-09-15 | 1988-12-16 | Bosch Gmbh Robert | |
GB2066895A (en) * | 1980-01-03 | 1981-07-15 | Bosch Gmbh Robert | Fuel injection nozzle with a heat protecting sleeve for internal combustion engines |
JPS62103456A (en) | 1985-10-30 | 1987-05-13 | Aisan Ind Co Ltd | Electromagnetic fuel injection valve |
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Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7331535B2 (en) | 1999-09-03 | 2008-02-19 | Delphi Technologies, Inc. | Injection nozzle |
EP1081374A3 (en) * | 1999-09-03 | 2003-04-16 | Delphi Technologies, Inc. | Injection nozzle |
EP1081374A2 (en) * | 1999-09-03 | 2001-03-07 | Delphi Technologies, Inc. | Injection nozzle |
EP1553287A1 (en) * | 1999-09-03 | 2005-07-13 | Delphi Technologies, Inc. | Injection Nozzle |
US7744014B2 (en) | 2002-07-25 | 2010-06-29 | Continental Automotive Gmbh | Injection module |
EP1455083A3 (en) * | 2003-03-07 | 2005-10-19 | Nissan Motor Company, Limited | Cooling structure for fuel injection valve |
EP1455083A2 (en) * | 2003-03-07 | 2004-09-08 | Nissan Motor Company, Limited | Cooling structure for fuel injection valve |
US7261089B2 (en) | 2003-08-18 | 2007-08-28 | Robert Bosch Gmbh | Fuel injector nozzle seal |
WO2005050004A1 (en) * | 2003-11-21 | 2005-06-02 | Robert Bosch Gmbh | Fuel injection valve |
DE10354465B4 (en) * | 2003-11-21 | 2014-07-17 | Robert Bosch Gmbh | Fuel injector |
CN101311516B (en) * | 2004-11-02 | 2011-09-28 | 丰田自动车株式会社 | Control apparatus for internal combustion engine |
DE102006013880A1 (en) * | 2006-03-25 | 2007-11-08 | Dr.Ing.H.C. F. Porsche Ag | Fuel injection arrangement for direct injection of fuel into combustion chamber of internal combustion chamber, has fuel injecting valve with flange, which is distant in radial direction with respect to insertion direction |
WO2017089229A1 (en) * | 2015-11-27 | 2017-06-01 | Robert Bosch Gmbh | Injector arrangement having a thermal protection sleeve |
WO2017102216A1 (en) * | 2015-12-14 | 2017-06-22 | Robert Bosch Gmbh | Fuel injector |
WO2017102245A1 (en) * | 2015-12-15 | 2017-06-22 | Robert Bosch Gmbh | Injector having an improved thermal behavior |
FR3101920A1 (en) * | 2019-10-14 | 2021-04-16 | Renault S.A.S. | Gasoline direct injector nose protector with heat shield |
WO2021074053A1 (en) * | 2019-10-14 | 2021-04-22 | Renault S.A.S | Direct fuel injector nozzle protector with heat shield |
Also Published As
Publication number | Publication date |
---|---|
JPH1089192A (en) | 1998-04-07 |
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