WO2013099226A1 - 圧力センサ付きセラミックグロープラグ - Google Patents
圧力センサ付きセラミックグロープラグ Download PDFInfo
- Publication number
- WO2013099226A1 WO2013099226A1 PCT/JP2012/008286 JP2012008286W WO2013099226A1 WO 2013099226 A1 WO2013099226 A1 WO 2013099226A1 JP 2012008286 W JP2012008286 W JP 2012008286W WO 2013099226 A1 WO2013099226 A1 WO 2013099226A1
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- WIPO (PCT)
- Prior art keywords
- heat
- ceramic
- glow plug
- pressure sensor
- ceramic heater
- Prior art date
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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
- F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
- F02P19/00—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition
- F02P19/02—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs
- F02P19/028—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs the glow plug being combined with or used as a sensor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
- F23Q7/001—Glowing plugs for internal-combustion engines
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M15/00—Testing of engines
- G01M15/04—Testing internal-combustion engines
- G01M15/08—Testing internal-combustion engines by monitoring pressure in cylinders
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23Q—IGNITION; EXTINGUISHING-DEVICES
- F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
- F23Q7/001—Glowing plugs for internal-combustion engines
- F23Q2007/002—Glowing plugs for internal-combustion engines with sensing means
Definitions
- the present invention relates to a glow plug for use in combustion assistance or the like of a diesel engine provided with a ceramic heater, and relates to a ceramic glow plug with a pressure sensor incorporating a pressure sensor capable of measuring the combustion pressure of the engine.
- an insulating ceramic is used as a base, and a resistance heating element made of a resistor or conductive ceramic is embedded in the inside of the base, or the resistance heating element is provided on the outer surface of the base (in particular, near the tip).
- Ceramic glow plugs hereinafter also referred to as heaters. Even if the ceramic glow plug is used at a high temperature such that the surface temperature of the tip of the heater is 1350 ° C., for example, there is a low possibility of disconnection as in the case of a metal glow plug comprising a resistance wire coil. Therefore, it is assumed that heat is generated at relatively high temperature for use.
- the outer periphery of the heater is held by a cylindrical holding outer cylinder made of metal.
- the holding outer cylinder also plays a role of providing an electrical connection by holding the heater and in contact with an electrode lead-out portion for supplying power to the resistance heating element provided in the heater (for example, see Patent Document 1).
- the movable member is configured to be capable of ensuring airtightness so that the combustion gas of the combustion chamber does not enter the inside of the glow plug.
- a steel plate having a thickness of about 0.15 mm is bent so as to allow relative displacement of the heater due to fluctuation of the combustion pressure.
- the heat transfer path (heat transfer path) is from the heater to the engine head via the holding outer cylinder and the housing firmly connected to the holding outer cylinder by welding, brazing, press fitting or the like.
- the movable member having a relatively thin thickness such as the above-described bellows and diaphragm
- the heat transfer path from the heater to the housing and the engine head via the movable member becomes extremely small compared to the ceramic glow plug as disclosed in Patent Document 1.
- the joint portion between the movable member and the portion to which the movable member is attached may be affected by heat, and the joint strength of the both may be reduced.
- the present invention can be attached to the movable member and the movable member even when adopting a configuration in which the amount of heat transfer of the movable member is reduced when constructing a ceramic glow plug with a pressure sensor using a ceramic heater.
- An object of the present invention is to provide a ceramic glow plug with a pressure sensor capable of achieving good heat generation over a long period of time while avoiding a decrease in bonding strength of a joint with a portion.
- the ceramic glow plug with pressure sensor of the present invention is A columnar base made of insulating ceramic, a resistance heating element which is integral with the base and generates resistance when heated by electric current, and is electrically connected to the resistance heating element and exposed to the outer surface of the base at the rear end.
- An axially extending ceramic heater having an electrode extraction portion, A metal holding outer cylinder which holds the ceramic heater while making direct or indirect contact with the electrode lead out portion and making the tip end side of the ceramic heater project.
- a housing which has a cylindrical shape and accommodates the ceramic heater and the holding outer cylinder inside itself;
- a movable member made of a thin metal plate which is joined to the holding outer cylinder and the housing and airtightly separates the front and rear of the housing and is elastically deformable by combustion pressure;
- a pressure sensor disposed on the rear end side of the ceramic heater, the holding outer cylinder, and the movable member and inside the housing to detect a pressure applied to itself;
- a ceramic glow plug with a pressure sensor provided with When the heat-producing main portion includes the tip of the ceramic heater and occupies 75% of the resistance value in the ceramic heater, the heat-producing main portion is on the tip side of the holding outer cylinder Ceramic glow plug with pressure sensor characterized in being located in.
- directly or indirectly in contact refers to direct contact by means of press-fit or various fitting and in a conductive state, or metal thin film or brazing material. It means a state in which it can be connected via the same. Therefore, for example, it does not mean a state of being electrically connected by the conductive wire connected to each.
- the "heat generation main portion” is a portion which occupies 75% of the resistance value to the total resistance value of the conductive path in the ceramic heater.
- the resistance is brought into contact with the electrode extraction part of the ceramic heater to make the resistance value of the conductive path (that is, the conductive path in the ceramic heater Measure the total resistance value).
- the ceramic heater is cut in a direction perpendicular to the longitudinal direction, the resistor is brought into contact with the conductive path exposed on the cut surface, and the resistance value of the conductive path (hereinafter referred to as a partial resistance value) is measured. Thereafter, the ratio of the partial resistance value to the total resistance value is calculated, and the tip side of the ceramic heater is set as the main heat generation portion than the position where the calculated value is 75%.
- the joint between the holding outer cylinder and the movable member be located inside the metal shell.
- the specific resistance of the heat generating resistor of the heat generating main portion is 90% of the specific resistance of the heat generating resistor at a portion other than the heat generating main portion.
- the cross-sectional area of the heat-generating resistor in the heat-generating main portion is smaller than the cross-sectional area of the heat-generating resistor in a portion other than the heat-generating main portion.
- the cross-sectional area of the heat-generating resistor in the heat-generating main part and the cross-sectional area of the heat-generating resistor in the rear end are cut in the direction perpendicular to the longitudinal direction. It refers to the area of each exposed heating resistor.
- the specific resistance of the heat generating resistor in the heat generating main portion is a value obtained by dividing the resistance value of the heat generating resistor provided in the heat generating main portion by the volume of the heat generating resistor disposed in the heat generating main portion
- the specific resistance of the heating resistor at the portion is a value obtained by dividing the resistance value of the heating resistor provided in the rear end portion by the volume of the heating resistor disposed in the rear end portion.
- the cross-sectional area of the heat-generating resistor of the heat-generating main portion is 90% of the cross-sectional area of the heat-generating resistor other than the heat-generating main portion.
- the specific resistance of the heat generating resistor of the heat generating main portion is larger than the specific resistance of the heat generating resistor at a portion other than the heat generating main portion.
- the ceramic glow plug with a pressure sensor of the fifth aspect of the present invention is a part of the resistor extending from the rear end of the heat generating main portion to the rear end.
- a portion where the sum of the resistance value of the part and the resistance value is 80% of the total resistance value is a heat generation sub-portion
- the axial length relationship is heat main portion ⁇ heat sub-portion
- a joint between the holding outer cylinder and the movable member be positioned on the rear end side of the heat generation sub-portion.
- the “heat generation subportion” is a portion where the sum of its own resistance value and the resistance value of the heat generation main portion is 80% of the total resistance value.
- the resistance value of the conductive path is brought into contact with the electrode extraction portion of the ceramic heater at normal temperature of the ceramic heater (that is, all the conductive paths in the ceramic heater). Measure the resistance value).
- the ceramic heater is cut in a direction perpendicular to the longitudinal direction, the resistor is brought into contact with the conductive path exposed on the cut surface, and the resistance value of the conductive path (hereinafter referred to as a partial resistance value) is measured. Thereafter, the ratio of the partial resistance value to the total resistance value is calculated, and the position where the calculated value is 75% to 80% is set as the heat generation sub-portion.
- the thermal conductivity of the insulating ceramic or the resistance heating element at 1350 ° C. is 15 W / m ° C. or higher, And it is preferable that the axial direction shortest distance from the front-end
- the resistance value is 75% of the total resistance value of the conductive path in the ceramic heater
- the heat generating main portion including the tip of the ceramic heater is located on the tip side of the holding outer cylinder. That is, the heat generating main part is formed intensively at the tip of the ceramic heater, and it is possible to efficiently generate heat at a relatively high temperature.
- the heat generating main portion is disposed on the tip end side with respect to the holding outer cylinder, the heat propagating from the heat generating main portion toward the rear end is transmitted to the junction of the holding outer cylinder and the movable member The heat can be dissipated from the ceramic heater to the engine head and the plug hole.
- the heat generating main portion is disposed closer to the tip end than the holding outer cylinder, while the bonding portion is positioned inside the metal shell, so that the heat generating main portion and the bonding portion As the longitudinal distance between the heat generating main part and the joint becomes longer, the metal shell surrounds the ceramic heater and heat propagating from the heat main to the rear end is transmitted to the joint. In the meantime, heat can be dissipated more from the ceramic heater to the engine head and the plug hole. Thereby, the influence of heat at the joint portion between the holding outer cylinder and the movable member can be further reduced, and a decrease in joint strength can be further suppressed. As a result, it is possible to further suppress the loss of the function as a pressure sensor as the air tightness to the combustion gas decreases.
- the specific resistance of the heat generating resistor of the heat generating main portion and the specific resistance of the heat generating resistor at a portion other than the heat generating main portion (hereinafter referred to as a rear end portion)
- a rear end portion By making the cross-sectional area of the heat-generating resistor in the heat-generating main part smaller than the cross-sectional area of the heat-generating resistor in the rear end while making the resistance uniform, 75% of the resistance of the conductive path in the ceramic heater It is possible to position the heat generating main part that occupies the value on the tip side of the holding outer cylinder.
- the cross-sectional area of the heat-generating resistor in the heat-generating main portion and the cross-sectional area of the heat-generating resistor in a portion other than the heat-generating main portion By making the specific resistance of the heat generating resistor in the heat generating main part larger than the specific resistance of the heat generating resistor in the rear end side while making the resistance uniform, 75% of the resistance of the conductive path in the ceramic heater It is possible to position the heat generating main part that occupies the value on the tip side of the holding outer cylinder.
- the heating subportion is provided so that the resistance value of the conductive path in the ceramic heater occupies 80% of the total resistance value including the resistance value of the heating main portion.
- the heat generating sub-portion is formed to be longer in axial direction than the heat generating main portion. Therefore, the heat propagating from the heat generating main portion to the rear end can be dissipated from the heat generating portion to the engine head and the plug hole while propagating through the heat generating portion. As a result, the temperature of the rear end portion of the ceramic heater can be relatively lowered.
- the joint portion between the movable outer member and the holding outer cylinder for holding the ceramic heater in the radial direction is configured to be positioned at the rear end side of the heating subportion.
- the tip portion of the ceramic heater (details if the thermal conductivity at 1350 ° C of the insulating ceramic or resistance heating element constituting the substrate is 15 W / m ° C or higher)
- the heat easily propagates from the main heat generation part to the rear end (the part where the joint is provided), but the shortest axial distance from the tip of the main heat generation part to the joint is 24 mm or more.
- the axial length of this heating subportion can be made relatively long. Therefore, the heat propagating from the heat generating main portion to the rear end can be effectively dissipated to the engine head and the plug hole while propagating through the heat generating sub-portion.
- the temperature of the rear end portion of the ceramic heater can be further lowered than that of the heating subportion, and the reduction in bonding strength between the holding outer cylinder and the movable member can be further suppressed.
- the axial shortest distance is represented by the distance between the tip of the joint and the tip of the main heat generating portion.
- FIG. 4 An enlarged view of a tip portion of a glow plug with a pressure sensor (third embodiment) embodying the present invention
- the enlarged view of the glow plug with a pressure sensor of a comparative example (figure corresponding to FIG. 3).
- the glow plug 101 includes a substantially cylindrical housing 40 made of metal, and a ceramic heater 10 having a tip (shown, lower end) 10a projecting from the tip 53 of the tip side housing 50 on the inner side thereof. Furthermore, in the housing 40, the voltage application central shaft 30, which is disposed to extend rearward from the rear end of the ceramic heater 10, and the outer peripheral surface of the rear end of the central shaft 30 and the inner peripheral surface of the housing 40. And a distortion member 210 or the like that constitutes a combustion pressure detection sensor provided therebetween.
- the housing 40 is made of, for example, SUS303, and includes a substantially cylindrical housing main body 41 and a tip end side housing 50 and the like coaxially butt-fit on the tip end side and welded.
- the ceramic heater 10 has a cylindrical shape, and is disposed coaxially with the axis G of the distal housing 50 so that the distal end 10 a protrudes from the distal end 53 of the distal housing 50.
- the ceramic heater 10 has a resistance heating element (conductive ceramic) 12 disposed in a folded shape (U-shape) at the tip end 10a inside the ceramic base 11 (corresponding to the base in the claims).
- the respective electrode lead-out portions 16 and 17 for energization are exposed on the side surface of the rear end portion of the ceramic heater 10.
- a metal holding outer cylinder 15 such as SUS 630 is externally fitted by press-fitting in the middle portion thereof, and the grounding is relatively positioned on the tip side on the inner peripheral surface of the rear end. It is electrically connected to the electrode extraction part 16 for.
- a bellows 18 (corresponding to a movable member in the claims) made of a heat-resistant Ni alloy such as Inconel (a registered trademark of INCO) is loosely inserted in the holding outer cylinder 15.
- the bellows 18 is formed, for example, in the form of a thin film having a thickness of 0.07 mm, and its rear end is welded in a sealing manner on the inner peripheral surface of the front end portion of the front end side housing 50.
- the outer circumferential surface of the holding outer cylinder 15 is welded in a sealing manner. That is, the bellows 18 allows the tip and back movement (displacement) of the heater 10 with respect to the housing 40, and forms a relay conduction portion between the electrode extraction portion 16 for grounding the heater 10 and the housing 40. While holding the inside, it has a role of sealing the inside of the tip side.
- the ceramic heater 10 and the bellows 18 will be described in detail later.
- a central shaft 30 for voltage application is arranged coaxially with the rear end so as to maintain insulation (in this embodiment, air insulation) in the housing 40 and face the rear end. And coaxial with the housing 40.
- a metal connection pipe 19 is externally fitted to the rear end of the ceramic heater 10 and the front end of the center shaft 30 by press fitting or the like, and the electrode extraction portion (positive potential side) The conduction of the terminal 17 is held on the inner circumferential surface of the connection pipe 19 and is electrically connected to the center shaft 30. That is, the connecting pipe 19 not only integrates the ceramic heater 10 and the middle shaft 30, but also ensures the conduction thereof.
- the housing 40 comprises a housing main body 41, a front end side housing 50 and the like, and on the outer peripheral surface of the main body 41, a screw 43 for fixing the glow plug in a plug hole of an engine head (not shown).
- a screw 43 for fixing the glow plug in a plug hole of an engine head (not shown).
- the rear end portion of the housing main body 41 forms an enlarged diameter cylindrical portion 45 whose diameter is enlarged so that a predetermined range from the rear end to the front end has a relatively large diameter.
- a seal protection cylinder (cap) which is a rear end side housing 60 having a relatively small diameter at the rear end side and a different diameter cylindrical shape, has an outer peripheral portion of a sensor distortion member 210 described later. It is attached sandwiching.
- the distortion member 210 has an annular (or cylindrical) shape as a whole, and the details thereof will be described later. However, the distortion member 210 is fixed to the rear end of the center shaft 30 via the insulating ring 260 at its inner periphery. It is done.
- the center shaft 30 is formed such that the tip end portion and the rear end portion are partially thick over the entire length.
- the rear end protrudes rearward from the rear end of the housing main body 41 and is located at the tip end of the large diameter cylindrical portion 63 of the seal protection cylinder (rear end side housing) 60 at the rear end.
- the tapered reduced diameter portion 33 is coaxially reduced in diameter toward the rear end At the rear end of the tapered reduced diameter portion 33, there is provided a parallel reduced diameter shaft portion 34 which is a coaxially reduced diameter insulating ring fitting shaft portion.
- a small diameter shaft 35 concentric with and thinner than the parallel reduced diameter shaft (the insulating ring fitting shaft) 34 is provided behind the parallel reduced diameter shaft 34 (the insulating ring fitting shaft).
- a plug terminal projecting outward at the rear end via a terminal spring 71 which permits displacement in the front-rear direction in the seal protection cylinder 60 at the rear end.
- a terminal fitting 75 having 73 is welded and connected.
- a seal member 69 made of, for example, rubber is loaded in the small diameter portion 65 on the rear end side of the seal protection cylinder 60 at the rear end.
- the strain member 210 is disposed at the rear end of the housing main body 41 so as to block the annular space between the inner side thereof and the outer periphery of the rear end of the center shaft 30 first and foremost. There is no.
- the center shaft 30 is provided so as to simultaneously deform the strain member 210 itself in response to the front-rear displacement of the ceramic heater 10.
- the strain member 210 has an annular thick portion 212a on the outer periphery, and the annular thick portion 212a is formed by the rear end of the enlarged diameter cylindrical portion 45 and the seal protection cylinder at the rear (rear end).
- the housing 60 is engaged with each other in a form of sandwiching with the tip of the housing 60, and for example, at each of the butting portions, laser welding is fixed in the circumferential direction from the outer peripheral surface side.
- the strain member 210 has an outer cylindrical portion 212 extending rearward (upward in FIG. 2) inside the annular thick portion 212a on the outer periphery, and an annular film portion is formed on the inner rear end of the outer cylindrical portion 212.
- (A toroidal diaphragm portion) 215 is provided.
- the inner side (inner side portion) of the annular film portion 215 has an inner cylindrical portion 211 extending forward.
- the inner cylindrical portion 211 extends so as to be located closer to the tip than the annular thick portion 212a on the outer periphery, and of the outer peripheral surface of the inner cylindrical portion 211, the outer diameter of the tip portion 211a is relatively small.
- the tip end portion 211a is relatively thin.
- strain sensors corresponding to pressure sensors in the claims
- an appropriate number of strain sensors (corresponding to pressure sensors in the claims) 220 are attached to the surface of the strain member 210 facing, for example, the rear end of the annular film portion (annular diaphragm portion) 215.
- the amount of strain based on the deformation of the strain member 210 that is deformed upon receiving the back and forth displacement of the shaft member 30 is detected via a device including a circuit that does not It is configured to
- the strain member 210 is deformed by the heater 10 and the shaft member 30 integrally moving forward and backward in the direction of the axis G of the two due to the combustion pressure.
- the combustion pressure is detected by using the strain sensor 220.
- FIG. 3 shows an enlarged view of C in FIG. 1, the distal end side housing 50 is omitted for the sake of explanation.
- the ceramic heater 10 is disposed in a U-shape inside the ceramic base 11 made of silicon nitride, and provided with a resistance heating element 12 formed of a conductive ceramic made of tungsten carbide.
- the ceramic substrate 11 is not limited to silicon nitride, and alumina, sialon or the like may be used.
- the conductive ceramic forming the resistance heating element 12 is not limited to tungsten carbide, and molybdenum disilicide and tungsten disilicide can be used as well.
- the resistance heating element 12 has a U shape as described above, and the small diameter of which the tip including the turning back of the tip (the lower end in FIG.
- the line portion 101 is formed. Furthermore, the resistance heating element 12 is tapered on the opposite inner side so as to be connected to the small diameter wire portion 101, and is further connected to a pair of tapered portions 102 formed in a tapered shape toward the rear end A pair of large diameter wire portions 103 is provided.
- the large diameter wire portions 103 are arranged in parallel to each other, are linear, and have the same transverse cross section, for example, a circular cross section (or an elliptical cross section) with a diameter of 0.9 mm. Then, toward the outside of the large diameter wire portion 103, as shown in FIG. 1, for example, circular and columnar electrode lead-out portions 16, 17 are formed so as to protrude.
- Such a ceramic heater 10 has a configuration in which the tip end portion is disposed in the combustion chamber of the engine to heat the tip portion of the ceramic heater 10 intensively to a high temperature in consideration of heating the combustion chamber.
- the heating main portion P1 having a resistance value (for example, 300 m ⁇ ) of 75% with respect to the total resistance value (for example, 400 m ⁇ ) of the ceramic heater 10 is more than that of the ceramic heater 10
- the heat source main portion P1 is disposed at a portion on the tip side among the three portions, for example, when all the portions of the ceramic heater 10 are divided into three equal parts from the tip side. ing).
- the main heating portion P1 can be positioned on the tip side of the tip of the holding outer cylinder 15.
- the tip of the ceramic heater 10 can be efficiently heated to a high temperature in a concentrated manner.
- the resistance heating element 12 is formed only of a conductive ceramic made of tungsten carbide and the resistance heating element By providing the small diameter wire portion 101 having a smaller cross-sectional area than the large diameter wire portion 103, the resistance value on the tip side of the ceramic heater 10 is made a larger resistance value.
- a heating subportion P2 is provided to be connected to the heating main portion P1.
- the heat-generating subportion P2 is a portion including the resistance value of the heat-generating main portion P1 and having a resistance value of 80% (for example, 320 m ⁇ ) with respect to the total resistance value of the ceramic heater 10. That is, the resistance value of the heating subportion P2 is a portion having a resistance value of 5% with respect to the total resistance value of the ceramic heater 10.
- the heating sub-portion P2 is provided with the large diameter wire portion 103 provided in the resistance heating element 12 so that the resistance value of the ceramic heater 10 becomes 5% of the total resistance value. It is possible.
- the rear end side of the heating subportion P2 is disposed inside the holding outer cylinder 15.
- the axial direction length of the heat-generation subpart P2 is formed longer than the axial direction length of the heat-generation main part P1.
- the axial length of the heating main portion P1 is 7.5 mm
- the axial length of the heating sub portion P2 is 12.5 mm.
- the holding outer cylinder 15 is externally fitted by press-fitting at the middle portion thereof, and the metal bellows 18 is welded to the holding outer cylinder 15.
- the bellows 18 is formed, for example, in the form of a thin film having a thickness of 0.07 mm, the amount of heat transfer of the bellows 18 itself is relatively small. For this reason, the heat transfer path from the ceramic heater 10 to the front end side housing 50 and the engine head via the bellows 18 is extremely reduced compared to the glow plug of the conventional structure, and the bonding strength of the bonding portion 110 is affected. There is a risk.
- the joint portion 110 between the holding outer cylinder 15 and the bellows 18 is located closer to the rear end side than the heating subportion P2.
- the influence of heat at the joint portion 110 between the holding outer cylinder 15 and the bellows 18 can be reduced, and a reduction in joint strength of the joint portion 110 can be suppressed.
- the joint portion 110 is positioned inside the housing 40 (see FIG. 1). As described above, by arranging the heat generation main portion P1 closer to the tip end than the holding outer cylinder 15 and locating the bonding portion 110 inside the housing 40, the longitudinal distance between the heat generation main portion P1 and the bonding portion 110 is As it becomes longer, the metal shell surrounds the ceramic heater between the heat generating main portion and the joint, and the heat propagating from the heat generating main portion P1 toward the rear end propagates to the joint 110. Between the ceramic heater 10 and the engine head and the plug hole, heat can be more dissipated.
- the thermal conductivity at 1350 ° C. of silicon nitride forming the ceramic substrate 11 is 17 W / m ° C.
- the thermal conductivity at 1350 ° C. of tungsten carbide forming the resistance heating element 12 is It is 22.5 W / m ° C.
- the heat generating main portion P1 of the ceramic heater 10 is directed to the rear end portion where the bonding portion 110 is provided. Heat is relatively easy to propagate.
- the distance T1 from the end of the main heating portion P1 (that is, the end of the ceramic heater 10) to the bonding portion 110 is 24 mm.
- the axial distance from the tip of the heat generating main portion P1 to the joining portion 110 is 24 mm or more, the axial length of the heat generating portion P2 can be formed relatively long. Therefore, the heat propagating from the heat generating main portion P1 toward the rear end can be effectively dissipated to the engine head and the plug hole while propagating through the heat generating sub portion P2.
- the temperature of the bonding portion 110 provided on the rear end side of the heating subportion P2 of the ceramic heater 10 can be further lowered, and the reduction in bonding strength of the bonding portion 110 can be further suppressed.
- the glow plug 301 of this example has a substantially cylindrical housing 340 made of metal, and a ceramic heater 410 having a tip (shown, lower end) 410 a projecting from a tip 343 of the tip side housing 342 inside thereof. Furthermore, in the housing 340, a voltage application central shaft 330, a pressure transmission tube 360 provided around the central shaft 330, and a pressure transmission tube 360 disposed so as to extend rearward from the rear end of the ceramic heater 410. At an end portion, a distortion member 350 or the like is provided which constitutes a combustion pressure detection sensor provided between the outer peripheral surface and the inner peripheral surface of the housing 340.
- the housing 340 is made of, for example, SUS303, and a substantially cylindrical housing main body 341 and a tip end side coaxially fitted in a butt-like manner on the tip end side and welded at a tip end side housing 342 and a rear end of the housing main body 341 It is composed of an intermediate housing 344, which is externally fitted and welded to the part.
- the ceramic heater 410 has a cylindrical shape, and is disposed coaxially with the axis G of the distal housing 342 so that the distal end 410 a protrudes from the distal end 343 of the distal housing 342. As shown in FIG.
- this ceramic heater 410 is a resistance heating element (conductive) disposed in a folded shape (U-shape) at the tip end 410a inside the ceramic base 411 (corresponding to the base in the claims).
- a ceramic) 412 is provided, and on the side surface of the rear end portion of the ceramic heater 410, the respective electrode lead-out portions 416 and 417 for energization are exposed.
- a metal holding outer cylinder 315 such as SUS630 is externally fitted by press-fitting in the middle portion thereof, and the grounding is relatively positioned on the tip side on the inner peripheral surface of the rear end.
- a metal elastic film (membrane) 418 (corresponding to the movable member in the claims) externally fitted on the holding outer cylinder 315 is made of stainless steel or heat-resistant Ni alloy such as Inconel (registered trademark of INCO). It is loosely inserted in the form.
- the metal elastic film 418 is formed as a thin film having a thickness of 0.3 mm, and its rear end portion is welded in a sealing manner on the inner peripheral surface of the tip end portion of the tip end side housing 342 and holds the tip end side It is welded to the outer peripheral surface of the outer cylinder 515 in a sealing manner.
- the metal elastic film 418 allows the tip and back movement (displacement) of the heater 410 with respect to the housing 340, and forms a relay conduction portion between the electrode extraction portion 416 for grounding of the heater 410 and the housing 340. While holding in the housing 340, it has a role of sealing the inside of the tip side.
- the ceramic heater 410 and the metal elastic film 418 will be described in detail later.
- a central shaft 330 for applying a voltage is arranged coaxially with the rear end so as to maintain insulation (air insulation in the present embodiment) in the housing 340 and face the rear end. And coaxial with the housing 340.
- a metal connection pipe 319 is externally fitted to the rear end of the ceramic heater 410 and the front end of the middle shaft 330 by press fitting or the like, and the electrode extraction portion (positive potential side)
- the conduction of the terminal 417 is held on the inner circumferential surface of the connection pipe 319 and is electrically connected to the center shaft 330. That is, the connecting pipe 319 is responsible not only for the integration of the ceramic heater 410 and the inner shaft 330 but also for ensuring the conduction thereof.
- the housing 340 is composed of a housing main body 341 and a tip end side housing 342 and the like, and on the outer peripheral surface of the housing main body 341, a screw for fixing the glow plug in a plug hole of an engine head not shown 346 is formed with a predetermined length.
- a substantially cylindrical intermediate housing 344 is externally fitted to the rear end portion of the housing main body 341, and the rear end of the intermediate housing 344 has a relatively small diameter rear end side and a different diameter cylindrical shape.
- a seal protection cylinder (cap) which is the rear end side housing 345, is attached across the outer periphery of a sensor distortion member 350 described later.
- the distortion member 350 has an annular shape (or a cylindrical shape) as a whole, and the details thereof will be described later.
- the distortion member 350 is joined to the pressure transfer tube 360 at the inner peripheral portion.
- the rear end of the center shaft 330 protrudes rearward from the rear end of the housing main body 341 and is positioned at the front end of the large diameter cylindrical portion 363 of the rear end protection cylinder (rear end side housing) 345 .
- a terminal fitting 375 having a plug terminal 373 projecting outward at the rear end is welded to the rear end of the center shaft 330 via a terminal spring 371 which permits displacement in the front-rear direction in the seal protection cylinder 345 at the rear end. Being connected.
- a seal member 369 made of, for example, rubber is loaded in the small diameter portion 365 on the rear end side of the seal protection cylinder 345 on the rear end.
- the front end of the pressure transfer tube 360 is joined and fixed to the rear end portion of the holding outer cylinder 315.
- the gap between the middle shaft 330 and the housing main body 341 is provided to extend in the front-rear direction while being separated from the middle shaft 330 and the housing main body 341.
- the rear end portion of the pressure transfer tube 360 is disposed in the intermediate housing 344, and the inner peripheral surface of the strain member 350 is joined to the outer peripheral surface.
- the strain member 350 is disposed at the rear end of the intermediate housing 344 so as to close the annular space between the inside thereof and the outer periphery of the rear end of the pressure transfer tube 360, ).
- the pressure transmitting tube 360 is provided so as to simultaneously deform the strain member 350 itself in response to the front-rear displacement of the ceramic heater 410. That is, the strain member 350 has an annular thick portion 352a on the outer periphery, and the annular thick portion 352a is a rear end of the intermediate housing 344 and a protective cylinder for sealing on the rear (rear end side housing) They are fitted to each other in such a manner as to be butted in a sandwiching manner with the tip of 345. For example, at each butting portion, they are fixed by laser welding in the circumferential direction from the outer peripheral surface side.
- the strain member 350 has an outer cylindrical portion 352 extending rearward (upward in FIG. 2) inside the annular thick portion 352a of the outer periphery, and an annular film portion is formed at the rear end inside of the outer cylindrical portion 352. (An annular diaphragm portion) 355 is provided. Then, on the inner side (inner circumferential side portion) of the annular film portion 355, there is an inner cylindrical portion 351 extending forward. The inner cylindrical portion 351 extends so as to be positioned on the tip end side of the annular thick portion 352a on the outer periphery.
- an appropriate number of strain sensors (corresponding to pressure sensors in the claims) 320 are attached to the rear end facing surface side of, for example, an annular film portion (annular diaphragm portion) 355 of the strain member 350.
- the amount of strain based on the deformation of the strain member 350 that is deformed upon receiving the back and forth displacement of the pressure transfer tube 360 is detected through the device including the circuit, and the electric signal based on that is output through the output wire.
- the strain member 350 is deformed by the heater 410 and the pressure transfer tube 360 integrally moving forward and backward in the direction of the axis G of the two due to the combustion pressure, and the strain member 350 is deformed
- the combustion pressure is detected by using the strain sensor 320.
- the ceramic heater 410 and the metal elastic film (membrane) 418 which are main parts of the present invention will be described.
- 5 shows an enlarged view of the tip end side D of the glow plug 301 of FIG. 4, but the tip end side housing 342 is omitted for the sake of the following description. Further, since the ceramic heater 410 is the same ceramic heater as the ceramic heater 10 of the first embodiment, the description will be omitted or simplified.
- this ceramic heater 410 is U-shaped inside a ceramic base 411 made of silicon nitride, and has a resistance heating element 412 formed of a conductive ceramic made of tungsten carbide. It is provided.
- the resistance heating element 412 has a U-shape, a small diameter wire portion 401 having a circular cross section with a diameter of 0.5 mm from the tip, a pair of tapered portions 402, and a circular cross section (or an elliptical cross section) with a diameter of 0.9 mm.
- the pair of large diameter wire portions 403 are arranged in order. Then, toward the outside of the large diameter wire portion 403, for example, as shown in FIG.
- the tip of the ceramic heater 410 is intensively heated to a high temperature, and specifically, 75% of the total resistance value (for example, 400 m ⁇ ) of the ceramic heater 410.
- the heat-generating main portion P41 having a resistance value (for example, 300 m ⁇ ) is concentrated at the tip of the ceramic heater 410 as shown in FIG. 5 (for example, all parts of the ceramic heater 410 are viewed from the tip side) Among the three parts, the heat-generating main part P41 is disposed in the part on the tip side among the three parts in the case of being divided into three equal parts). As a result, the main heating portion P41 can be positioned on the tip side of the tip of the holding outer cylinder 315. Thus, the tip of the ceramic heater 410 can be efficiently and intensively heated to a high temperature.
- resistance heating element 412 is formed of only a conductive ceramic made of tungsten carbide and resistance heating element
- a heating subportion P42 is provided to be connected to the heating main portion P41.
- the heating subportion P42 is a portion including the resistance value of the heating main portion P41 and having a resistance value of 80% (for example, 320 m ⁇ ) with respect to the total resistance value of the ceramic heater 410. That is, the resistance value of the heating subportion P42 is a portion that has a resistance value of 5% with respect to the total resistance value of the ceramic heater 410.
- the rear end side of the heating subportion P42 is disposed inside the holding outer cylinder 315.
- the axial direction length of the heat-generation subpart P42 is formed longer than the axial direction length of the heat-generation main part P41.
- the axial length of the main heating portion P41 is 7.5 mm
- the axial length of the sub heating portion P42 is 12.5 mm.
- the holding outer cylinder 315 is externally fitted by press-fitting at the middle portion thereof, and the metal elastic film (membrane) 418 is welded to the holding outer cylinder 315.
- the metal elastic film 418 is formed in, for example, a thin film having a thickness of 0.3 mm, the amount of heat transfer of the metal elastic film 418 itself is relatively small. For this reason, the heat transfer path from the ceramic heater 410 to the housing 340 and the engine head via the metal elastic film 418 is extremely reduced compared to the glow plug of the conventional structure, and the bonding strength of the bonding portion 510 is affected. There is a risk.
- the joint portion 510 between the holding outer cylinder 315 and the metal elastic film 418 is positioned closer to the rear end side than the heating subportion P42.
- the influence of heat at the bonding portion 510 between the holding outer cylinder 315 and the metal elastic film 418 can be reduced, and a decrease in bonding strength of the bonding portion 510 can be suppressed.
- the joint portion 510 is positioned inside the housing 340 (see FIG. 1). As described above, by arranging the heat generation main portion P31 closer to the tip end than the holding outer cylinder 315, and by positioning the joint portion 510 inside the housing 340, the longitudinal distance between the heat generation main portion P41 and the joint portion 510 is As the length becomes longer, the metal shell surrounds the ceramic heater between the heat generating main portion and the bonding portion, and the heat propagating from the heat generating main portion P41 toward the rear end propagates to the bonding portion 510. Between the ceramic heater 10 and the engine head and the plug hole, heat can be more dissipated.
- the thermal conductivity of silicon nitride forming the ceramic substrate 411 at 1750 ° C. is 17 W / m ° C.
- the thermal conductivity of tungsten carbide forming the resistance heating element 412 at 1350 ° C. It is 22.5 W / m ° C.
- the heating main portion P41 of the ceramic heater 410 is directed to the rear end portion where the bonding portion 510 is provided. Heat is relatively easy to propagate.
- the distance T41 from the end of the main heating portion P41 (that is, the end of the ceramic heater 410) to the bonding portion 510 is 24 mm.
- the axial distance from the tip of the heat generating main portion P41 to the joining portion 510 is 24 mm or more, the axial length of the heat generating portion P42 can be formed relatively long. Therefore, the heat propagating from the heat generating main portion P41 toward the rear end can be effectively dissipated to the engine head and the plug hole while propagating through the heat generating sub portion P42.
- the temperature of the bonding portion 510 provided on the rear end side of the heating subportion P42 of the ceramic heater 410 can be further lowered, and the reduction in bonding strength of the bonding portion 510 can be further suppressed.
- the axial distance from the tip of the main heat generating portion P41 to the joining portion 510 exceeds 40 mm, the temperature rising performance is lowered, so this axial distance is preferably 40 mm or less.
- the glow plug 701 of the third embodiment differs from the glow plug 101 of the first embodiment only in the configuration of the ceramic heater, and in the following description, portions related to the ceramic heater will be described in detail, Other parts are simplified and omitted. In the following description, the same parts as those of the glow plug 101 of the first embodiment will be described using the same reference numerals.
- the ceramic heater 710 is disposed in a U shape inside the tip end side of the ceramic substrate 711 made of silicon nitride, and the rear end of the substrate 711 is A resistive heating element 712 extending to the side is provided.
- the resistance heating element 712 is U-shaped, and includes a leading end 701 including a turnback of the end (the lower end in FIG. 3) that is the bottom of the U and two lead portions 703 so as to be connected to the leading end. It is formed.
- the tip end portion 701 has a substantially elliptical cross section, and the cross-sectional area of the tip end portion 701 with respect to the ceramic heater 710 (total value of the tip end portion 701) is 12%.
- the cross section of the lead portion 703 is substantially circular, and the cross-sectional area of the entire lead portion 703 with respect to the ceramic heater 710 is 18%. That is, the cross-sectional area of the distal end portion 701 and the cross-sectional area of the lead portion 703 are substantially uniform.
- the lead portion 703 is formed of tungsten. That is, the specific resistance (20 ⁇ cm) of the tip end portion 701 is larger than the specific resistance (5 ⁇ cm) of the lead portion.
- the ceramic substrate 711 is not limited to silicon nitride, and alumina, sialon or the like may be used.
- the tip portion 701 is not limited to the nitride ceramic, and may be made of, for example, any of silicon nitride ceramic, sialon and aluminum nitride ceramic, and silicon nitride ceramic and sialon. And at least one of aluminum nitride ceramics can be used as the main component.
- the lead portion 703 is not limited to tungsten, and a metal (for example, tantalum or the like) can be used.
- Such a ceramic heater 710 has a configuration in which the tip end portion is disposed in the combustion chamber of the engine, and in consideration of heating the combustion chamber, the tip portion of the ceramic heater 710 generates heat intensively to a high temperature.
- the heat generating main portion P71 having a resistance value (for example, 300 m ⁇ ) of 75% with respect to the total resistance value (for example, 400 m ⁇ ) of the ceramic heater 710
- the heating main portion P71 is disposed in the tip end portion of the three portions. ing).
- the heat generating main portion P71 can be positioned on the tip side of the tip of the holding outer cylinder 15.
- the tip of the ceramic heater 710 can be efficiently and intensively heated to a high temperature.
- the areas of the tip portion 701 and the lead portion 703 are made substantially uniform, and the specific resistance of the tip portion 701 By making the specific resistance of the lead portion 703 larger than that of the above, the resistance value on the tip side of the ceramic heater 710 is made a larger resistance value.
- a heating subportion P72 is provided to be connected to the heating main portion P71.
- the heat-generating subportion P72 is a portion including the resistance value of the heat-generating main portion P71 and having a resistance value of 80% (for example, 320 m ⁇ ) with respect to the total resistance value of the ceramic heater 10. That is, the resistance value of the heating subportion P72 is a portion that has a resistance value of 5% with respect to the total resistance value of the ceramic heater 710.
- the heating sub-portion P72 is a portion that provides a resistance value of 5% with respect to the total resistance value of the ceramic heater 710 by providing the lead portion 703 provided on the resistance heating element 712. Is possible.
- the rear end side of the heating subportion P72 is disposed inside the holding outer cylinder 15.
- the axial direction length of the heat-generation subpart P72 is formed longer than the axial direction length of the heat-generation main part P71.
- the axial length of the heating main portion P71 is 7.5 mm
- the axial length of the heating sub portion P72 is 12.5 mm.
- the holding outer cylinder 15 is externally fitted by press-fitting at the middle portion thereof, and the metal bellows 18 is welded to the holding outer cylinder 15.
- the bellows 18 is formed, for example, in the form of a thin film having a thickness of 0.07 mm, the amount of heat transfer of the bellows 18 itself is relatively small. For this reason, the heat transfer path from the ceramic heater 710 to the front end side housing 50 and the engine head via the bellows 18 is extremely reduced compared to the glow plug of the conventional structure, and the bonding strength of the bonding portion 110 is affected. There is a risk.
- the joint portion 110 between the holding outer cylinder 15 and the bellows 18 is positioned on the rear end side of the ceramic heater 710.
- the influence of heat at the joint portion 110 between the holding outer cylinder 15 and the bellows 18 can be reduced, and a reduction in joint strength of the joint portion 110 can be suppressed.
- the joint portion 110 is positioned inside the housing 40 (see FIG. 1). As described above, by arranging the heat generation main portion P71 closer to the tip end side than the holding outer cylinder 15 and locating the joint portion 110 inside the housing 40, the longitudinal distance between the heat generation main portion P71 and the joint portion 110 is As it becomes longer, the metallic shell will surround the ceramic heater between the main heating portion and the joint, and the heat transmitted from the main heating portion P71 toward the rear end will be transmitted to the joint 110. In addition, heat can be more dissipated from the ceramic heater 710 to the engine head and the plug hole.
- the glow plug 101 of the embodiment having the configuration described in the first embodiment and the glow plug 101 of the first embodiment as shown in FIG. 7, the axial direction of the heat generating main portion P1a and the heat generating sub portion P2a
- the temperature of the junctions 110 and 110a was measured. 7 shows only the ceramic heater 110a, the holding outer cylinder 15, and the bellows 18 as in FIG.
- the axial length of the heat generating main portion P1 is 7.5 mm
- the axial length of the heat generating sub portion P2 is 12.5 mm.
- the axial distance from the tip to the joint 110 was 24 mm.
- the axial length of the heat generating main portion P1a is 15 mm
- the axial length of the heat generating subportion P2a is 5 mm
- the distance T1 was 24 mm. That is, the positions of the rear ends of the heat generation subportions P2 and P2a and the axial distance T1 are the same in both the embodiment and the comparative example.
- the axial length of the heating main portion P1a and the heating subportion P2a is set to an example by changing the material of the conductive ceramic or changing the cross sectional area of the conductive ceramic.
- the material change of the conductive ceramic may use a single material or may combine a plurality of materials. Furthermore, the diameter of the ceramic substrates 11 and 11a is 3.1 mm, the thickness of the holding outer cylinder 15 and 15a is 0.45 mm, and the thickness of the bellows 18 is 0.07 mm.
- the glow plugs 101 and 101a of this example and comparative example are heated by energization control to reach 1000 ° C. for 2 seconds, and then reach 1350 ° C., and the temperature of the joint portions 110 and 110 a after 2 minutes Was measured with a thermocouple.
- the temperature of the bonding portion 110 in the glow plug 101 of the example was 570 ° C.
- the temperature of the bonding portion 110 a in the glow plug 101 a of the comparative example was 690 ° C.
- the heat generating subportion P2 can dissipate heat to the engine head and the plug hole, and the joint portion
- the temperature at 110 can be reduced.
- the bellows 18 is formed of a heat-resistant Ni alloy, it is preferable to control the weld portion 110 to a temperature of 600 ° C. or less at which a decrease in weld strength with respect to the bellows 18 does not occur. It can be seen that the plug 101 is preferred.
- the joint strength of the weld 110 was evaluated in the case where the axial distance from the tip of the ceramic heater 110 to the weld 110 was made different. Specifically, four glow plugs 101 having axial distances from the tip of the ceramic heater 110 to the welding portion 110 of 20 mm, 22 mm, 24 mm, and 26 mm were prepared.
- the axial length of the main heating portion P1 in the glow plug 101 according to the embodiment is 7.5 mm
- the axial length of the sub heating portion P2 is 12.5 mm
- the ceramic base 11 is silicon nitride
- resistance heating The body 12 is formed of tungsten carbide
- the holding member 15 is formed of SUS316
- the bellows 18 is formed of a heat-resistant Ni alloy.
- the ceramic base 11 has a diameter of 3.1 mm
- the thickness of the holding outer cylinder 15 is 0.45 mm
- the thickness of the bellows 18 is 0.07 mm.
- the four glow plugs 101 are disposed in an atmosphere of 450 ° C., and the ceramic heater 110 is vibrated in the vertical direction of FIG. 3 in a state where the element tip temperature is 1350 ° C. (the maximum temperature of the main heating portion P1).
- the vibration cycle until the bellows 18 broke was measured. Note that one vibration cycle refers to a cycle from applying a pressure of 300 N (21 MPa) to the tip of the ceramic heater 110 and thereafter releasing the pressure.
- the glow plug of the present invention is not limited to the above-described examples, and can be appropriately modified and embodied.
- one side of the radial direction in the longitudinal cross section has a shape and structure that is folded back at the rear, but in the distortion member, the heater is pushed rearward from the tip by the combustion pressure So long as it can be detected by the sensor so that the combustion pressure can be detected from the deformation. Therefore, it has an appropriate shape and structure such as an annular plate-like simple diaphragm (thin film) It can be done.
- strain gauges are used as sensors.
- the strain member is disposed at the rear end of the housing body and at a portion positioned near the rear end of the center shaft. It can also be provided at an intermediate position in the front-rear direction in the center axis.
- the bellows has been described as having a configuration in which the rear end is welded in a sealing manner to the inner peripheral surface of the distal end of the distal end side housing. The rear end portion of the rear end portion is sandwiched and welded at a joint (abutment portion) between the rear end of the front end side housing and the front end of the housing main body.
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Abstract
Description
絶縁性セラミックからなり柱状をなす基体と、当該基体と一体をなし通電によって抵抗発熱する抵抗発熱体と、当該抵抗発熱体と電気的に接続され後端部において前記基体の外表面へ露出形成される電極取出部とを有する、軸方向に延びるセラミックヒータと、
前記電極取出部と直接的又は間接的に接触するとともに、前記セラミックヒータの先端側を突出させつつ、前記セラミックヒータを保持する金属製の保持外筒と、
筒状をなすとともに前記セラミックヒータ及び保持外筒を自身の内部に収容するハウジングと、
前記保持外筒と前記ハウジングに接合されて自身の先後を気密に隔て、燃焼圧により弾性変形可能に構成される金属製の薄板からなる可動部材と、
前記セラミックヒータ、前記保持外筒及び前記可動部材よりも後端側で、且つ前記ハウジングの内部に配置され、自身に加わる圧力を検出する圧力センサと、
を備えた圧力センサ付きセラミックグロープラグであって、
前記セラミックヒータの先端を含み、前記セラミックヒータ中の全抵抗値に対して75%の抵抗値を占める先端寄り部位を発熱主部としたとき、当該発熱主部は前記保持外筒よりも先端側に位置することを特徴とする圧力センサ付きセラミックグロープラグ。
且つ前記発熱主部の先端から前記保持外筒と前記可動部材との前記接合部までの軸方向最短距離が24mm以上であることが好ましい。
なお、図3は、図1のCの拡大図を示しているが、説明の関係上、先端側ハウジング50については、割愛している。
なお、図5は、図4のグロープラグ301のうち、先端側のDの拡大図を示しているが、以下の説明の関係上、先端側ハウジング342については、割愛している。
また、セラミックヒータ410については、実施形態1のセラミックヒータ10と同様のセラミックヒータであるため、説明を省略または簡略して説明する。
なお、上述したように、実施例のグロープラグ101における、発熱主部P1の軸方向長さを7.5mm、発熱副部P2の軸方向長さを12.5mmとし、さらに、セラミックヒータ10の先端から接合部110までの軸方向距離を24mmとした。一方、比較例のグロープラグ101aにおける、発熱主部P1aの軸方向長さを15mm、発熱副部P2aの軸方向長さを5mmとし、さらに、セラミックヒータ10aの先端から接合部110aまでの軸方向距離T1を24mmとした。つまり、発熱副部P2、P2aの後端の位置、及び軸方向距離T1については、実施例、比較例共に同じ位置としている。
なお、比較例のグロープラグ10aにおいては、導電性セラミックの材料を変更したり、導電性セラミックの断面積を変更することで、発熱主部P1a、発熱副部P2aの軸方向長さを実施例のグロープラグ10と変えることが可能である。なお、導電性セラミックの材料変更とは、単一材料を用いてもよいし、複数材料を組み合わせてもよい。
さらに、セラミック基体11、11aは直径3.1mmとし、更に、保持外筒15、15aの厚みを0.45mm、ベローズ18の厚みを0.07mmとしている。
具体的には、セラミックヒータ110の先端から溶接部110までの軸方向距離を20mm、22mm、24mm、26mmとした4本のグロープラグ101を準備した。なお、実施例のグロープラグ101における発熱主部P1の軸方向長さは、7.5mm、発熱副部P2の軸方向長さは12.5mmとし、さらに、セラミック基体11を窒化珪素、抵抗発熱体12をタングステンカーバイド、保持金具15をSUS316、ベローズ18を耐熱Ni合金にて形成している。
さらに、セラミック基体11は直径3.1mmとし、更に、保持外筒15の厚みを0.45mm、ベローズ18の厚みを0.07mmとしている。
10、410、710・・・セラミックヒータ
11、411、711・・・セラミック基体
12、412、712・・・抵抗発熱体
15、315・・・保持外筒
18・・・ベローズ
210、350・・・歪部材
220、320・・・歪センサ
30、330・・・中軸
40、340・・・ハウジング
418・・・金属弾性膜(メンブレン)
P1、P41、P71・・・発熱主部
P2、P42、P72・・・発熱副部
110、510・・・接合部
Claims (6)
- 絶縁性セラミックからなり柱状をなす基体と、当該基体と一体をなし通電によって抵抗発熱する抵抗発熱体と、当該抵抗発熱体と電気的に接続され後端部において前記基体の外表面へ露出形成される電極取出部とを有する、軸方向に延びるセラミックヒータと、
前記電極取出部と直接的又は間接的に接触するとともに、前記セラミックヒータの先端側を突出させつつ、前記セラミックヒータを保持する金属製の保持外筒と、
筒状をなすとともに前記セラミックヒータ及び保持外筒を自身の内部に収容するハウジングと、
前記保持外筒と前記ハウジングに接合されて自身の先後を気密に隔て、燃焼圧により弾性変形可能に構成される金属製の薄板からなる可動部材と、
前記セラミックヒータ、前記保持外筒及び前記可動部材よりも後端側で、且つ前記ハウジングの内部に配置され、自身に加わる圧力を検出する圧力センサと、
を備えた圧力センサ付きセラミックグロープラグであって、
前記セラミックヒータの先端を含み、前記セラミックヒータ中の全抵抗値に対して75%の抵抗値を占める先端寄り部位を発熱主部としたとき、当該発熱主部は前記保持外筒よりも先端側に位置することを特徴とする圧力センサ付きセラミックグロープラグ。 - 請求項1に記載の圧力センサ付きセラミックグロープラグにおいて、
前記接合部は、前記主体金具の内部に位置することを特徴とする圧力センサ付きセラミックグロープラグ。 - 請求項1又は請求項2に記載の圧力センサ付きセラミックグロープラグにおいて、
前記発熱主部の前記発熱抵抗体の比抵抗は、前記発熱主部以外の部位の発熱抵抗体の比抵抗の90%~110%であり、
前記発熱主部の前記発熱抵抗体の断面積は、前記発熱主部以外の部位の発熱抵抗体の断面積よりも小さいことを特徴とする圧力センサ付きセラミックグロープラグ。 - 請求項1又は請求項2に記載の圧力センサ付きセラミックグロープラグにおいて、
前記発熱主部の前記発熱抵抗体の断面積は、前記発熱主部以外の部位の発熱抵抗体の断面積の90%~110%であり、
前記発熱主部の前記発熱抵抗体の比抵抗は、前記発熱主部以外の部位の発熱抵抗体の比抵抗よりも大きいことを特徴とする圧力センサ付きセラミックグロープラグ。 - 請求項1乃至請求項4の何れか一項に記載の圧力センサ付きセラミックグロープラグにおいて、
前記発熱主部の後端から更に後端へ延びる前記抵抗体の一部であって、自身の抵抗値と前記発熱主部の抵抗値との合計が前記全抵抗値に対して80%の抵抗値となる部位を発熱副部としたとき、軸方向長さの関係が、発熱主部<発熱副部であるとともに、
前記発熱副部よりも後端側に前記保持外筒と前記可動部材との接合部が位置することを特徴とする圧力センサ付きセラミックグロープラグ。 - 請求項1乃至請求項5の何れか一項に記載の圧力センサ付きセラミックグロープラグにおいて、
前記絶縁性セラミックまたは前記抵抗発熱体の1350℃での熱伝導率が15W/m℃以上であり、
且つ前記発熱主部の先端から前記保持外筒と前記可動部材との前記接合部までの前記軸方向最短距離が24mm以上であることを特徴とする圧力センサ付きセラミックグロープラグ。
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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EP12863258.5A EP2799774B1 (en) | 2011-12-26 | 2012-12-25 | Ceramic glow plug equipped with pressure sensor |
KR1020147017322A KR20140094643A (ko) | 2011-12-26 | 2012-12-25 | 압력 센서 부착 세라믹 글로 플러그 |
JP2013526266A JP5934215B2 (ja) | 2011-12-26 | 2012-12-25 | 圧力センサ付きセラミックグロープラグ |
US14/368,577 US9422913B2 (en) | 2011-12-26 | 2012-12-25 | Ceramic glow plug equipped with pressure sensor |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2011282577 | 2011-12-26 | ||
JP2011-282577 | 2011-12-26 |
Publications (1)
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WO2013099226A1 true WO2013099226A1 (ja) | 2013-07-04 |
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PCT/JP2012/008286 WO2013099226A1 (ja) | 2011-12-26 | 2012-12-25 | 圧力センサ付きセラミックグロープラグ |
Country Status (5)
Country | Link |
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US (1) | US9422913B2 (ja) |
EP (1) | EP2799774B1 (ja) |
JP (1) | JP5934215B2 (ja) |
KR (1) | KR20140094643A (ja) |
WO (1) | WO2013099226A1 (ja) |
Cited By (7)
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JP2014206352A (ja) * | 2013-04-16 | 2014-10-30 | 日本特殊陶業株式会社 | 燃焼圧センサ付きグロープラグ及びその製造方法 |
EP2905537A1 (en) | 2014-02-06 | 2015-08-12 | NGK Spark Plug Co., Ltd. | Glow plug with pressure sensor |
JP2015183951A (ja) * | 2014-03-25 | 2015-10-22 | 日本特殊陶業株式会社 | グロープラグ |
EP2944878A3 (en) * | 2014-05-16 | 2016-03-09 | NGK Spark Plug Co., Ltd. | Glow plug with combustion pressure sensor |
EP3006830A1 (en) * | 2014-10-09 | 2016-04-13 | NGK Spark Plug Co., Ltd. | Glow plug |
JP2016217588A (ja) * | 2015-05-19 | 2016-12-22 | 日本特殊陶業株式会社 | グロープラグおよび加熱装置 |
US12034189B2 (en) * | 2014-04-04 | 2024-07-09 | Bloom Energy Corporation | Fuel cell system glow plug and method of forming same |
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Publication number | Priority date | Publication date | Assignee | Title |
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DE102011088468A1 (de) * | 2011-12-14 | 2013-06-20 | Robert Bosch Gmbh | Druckmessglühkerze |
JP6152469B2 (ja) * | 2014-03-27 | 2017-06-21 | ボッシュ株式会社 | セラミックスヒータ型グロープラグ |
US10253982B2 (en) * | 2014-12-22 | 2019-04-09 | Ngk Spark Plug Co., Ltd. | Glow plug with pressure sensor |
JPWO2016167066A1 (ja) * | 2015-04-15 | 2017-10-19 | ボッシュ株式会社 | グロープラグ |
JP6370754B2 (ja) * | 2015-09-10 | 2018-08-08 | 日本特殊陶業株式会社 | セラミックヒータおよびグロープラグ |
DE102016114929B4 (de) * | 2016-08-11 | 2018-05-09 | Borgwarner Ludwigsburg Gmbh | Druckmessglühkerze |
EP3584556A1 (en) * | 2018-06-20 | 2019-12-25 | NGK Spark Plug Co., Ltd. | Pressure sensor with heater |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004061041A (ja) * | 2002-07-31 | 2004-02-26 | Kyocera Corp | セラミックグロープラグ |
JP2005300046A (ja) * | 2004-04-13 | 2005-10-27 | Ngk Spark Plug Co Ltd | セラミックヒータおよびグロープラグ |
WO2005117492A1 (ja) * | 2004-05-27 | 2005-12-08 | Kyocera Corporation | セラミックヒータ及びそれを用いたグロープラグ |
JP2006337020A (ja) * | 2006-09-22 | 2006-12-14 | Ngk Spark Plug Co Ltd | セラミックヒータ及びそのセラミックヒータを用いたグロープラグ |
JP2008002809A (ja) | 2006-06-20 | 2008-01-10 | Denso Corp | 燃焼圧センサー |
JP2010073422A (ja) * | 2008-09-17 | 2010-04-02 | Ngk Spark Plug Co Ltd | セラミックヒータ及びセラミックヒータの製造方法 |
JP2011033318A (ja) | 2009-08-05 | 2011-02-17 | Ngk Spark Plug Co Ltd | セラミックグロープラグ |
JP2011089688A (ja) * | 2009-10-21 | 2011-05-06 | Ngk Spark Plug Co Ltd | 圧力センサ付きグロープラグ |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4475030A (en) * | 1981-09-25 | 1984-10-02 | Caterpillar Tractor Co. | Glow plug having resiliently mounted ceramic surface-ignition element |
JP3911930B2 (ja) * | 1999-10-28 | 2007-05-09 | 株式会社デンソー | 燃焼圧センサ付きグロープラグ |
JP4003363B2 (ja) * | 1999-12-24 | 2007-11-07 | 株式会社デンソー | 燃焼圧センサ構造体 |
DE102004044727A1 (de) | 2003-09-19 | 2006-03-16 | Beru Ag | Druckmessglühkerze für einen Dieselmotor |
DE102004012673A1 (de) * | 2004-03-16 | 2005-10-06 | Robert Bosch Gmbh | Glühstiftkerze mit elastisch gelagertem Glühstift |
EP1734304B1 (en) * | 2004-04-07 | 2016-12-14 | Ngk Spark Plug Co., Ltd. | Ceramic heater and manufacturing method thereof, and glow plug using ceramic heater |
EP1637806B1 (de) * | 2004-09-15 | 2012-02-01 | Beru AG | Druckmessglühkerze für einen Dieselmotor |
JP2007309916A (ja) * | 2006-04-20 | 2007-11-29 | Denso Corp | 燃焼圧センサ |
JP2008020176A (ja) * | 2006-06-14 | 2008-01-31 | Ngk Spark Plug Co Ltd | センサ内蔵グロープラグ |
JP4386117B2 (ja) * | 2007-08-30 | 2009-12-16 | 株式会社デンソー | 燃焼圧センサ付きグロープラグ |
DE102008043822A1 (de) * | 2007-11-19 | 2009-06-10 | Denso Corporation, Kariya | Verbrennungsdrucksensor für eine Brennkraftmaschine |
KR101375989B1 (ko) * | 2008-02-20 | 2014-03-18 | 니혼도꾸슈도교 가부시키가이샤 | 세라믹 히터 및 글로우 플러그 |
-
2012
- 2012-12-25 US US14/368,577 patent/US9422913B2/en active Active
- 2012-12-25 KR KR1020147017322A patent/KR20140094643A/ko active Search and Examination
- 2012-12-25 WO PCT/JP2012/008286 patent/WO2013099226A1/ja active Application Filing
- 2012-12-25 EP EP12863258.5A patent/EP2799774B1/en not_active Not-in-force
- 2012-12-25 JP JP2013526266A patent/JP5934215B2/ja not_active Expired - Fee Related
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004061041A (ja) * | 2002-07-31 | 2004-02-26 | Kyocera Corp | セラミックグロープラグ |
JP2005300046A (ja) * | 2004-04-13 | 2005-10-27 | Ngk Spark Plug Co Ltd | セラミックヒータおよびグロープラグ |
WO2005117492A1 (ja) * | 2004-05-27 | 2005-12-08 | Kyocera Corporation | セラミックヒータ及びそれを用いたグロープラグ |
JP2008002809A (ja) | 2006-06-20 | 2008-01-10 | Denso Corp | 燃焼圧センサー |
JP2006337020A (ja) * | 2006-09-22 | 2006-12-14 | Ngk Spark Plug Co Ltd | セラミックヒータ及びそのセラミックヒータを用いたグロープラグ |
JP2010073422A (ja) * | 2008-09-17 | 2010-04-02 | Ngk Spark Plug Co Ltd | セラミックヒータ及びセラミックヒータの製造方法 |
JP2011033318A (ja) | 2009-08-05 | 2011-02-17 | Ngk Spark Plug Co Ltd | セラミックグロープラグ |
JP2011089688A (ja) * | 2009-10-21 | 2011-05-06 | Ngk Spark Plug Co Ltd | 圧力センサ付きグロープラグ |
Non-Patent Citations (1)
Title |
---|
See also references of EP2799774A4 |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2014206352A (ja) * | 2013-04-16 | 2014-10-30 | 日本特殊陶業株式会社 | 燃焼圧センサ付きグロープラグ及びその製造方法 |
EP2905537A1 (en) | 2014-02-06 | 2015-08-12 | NGK Spark Plug Co., Ltd. | Glow plug with pressure sensor |
JP2015148386A (ja) * | 2014-02-06 | 2015-08-20 | 日本特殊陶業株式会社 | 圧力センサ付きグロープラグ |
JP2015183951A (ja) * | 2014-03-25 | 2015-10-22 | 日本特殊陶業株式会社 | グロープラグ |
US12034189B2 (en) * | 2014-04-04 | 2024-07-09 | Bloom Energy Corporation | Fuel cell system glow plug and method of forming same |
EP2944878A3 (en) * | 2014-05-16 | 2016-03-09 | NGK Spark Plug Co., Ltd. | Glow plug with combustion pressure sensor |
EP3045817A1 (en) * | 2014-05-16 | 2016-07-20 | NGK Spark Plug Co., Ltd. | Glow plug with combustion pressure sensor |
EP3006830A1 (en) * | 2014-10-09 | 2016-04-13 | NGK Spark Plug Co., Ltd. | Glow plug |
JP2016217588A (ja) * | 2015-05-19 | 2016-12-22 | 日本特殊陶業株式会社 | グロープラグおよび加熱装置 |
Also Published As
Publication number | Publication date |
---|---|
US9422913B2 (en) | 2016-08-23 |
EP2799774A4 (en) | 2015-08-12 |
EP2799774B1 (en) | 2018-10-10 |
JPWO2013099226A1 (ja) | 2015-04-30 |
US20140352640A1 (en) | 2014-12-04 |
KR20140094643A (ko) | 2014-07-30 |
EP2799774A1 (en) | 2014-11-05 |
JP5934215B2 (ja) | 2016-06-15 |
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