WO2015076062A1 - Internal combustion engine - Google Patents
Internal combustion engine Download PDFInfo
- Publication number
- WO2015076062A1 WO2015076062A1 PCT/JP2014/078427 JP2014078427W WO2015076062A1 WO 2015076062 A1 WO2015076062 A1 WO 2015076062A1 JP 2014078427 W JP2014078427 W JP 2014078427W WO 2015076062 A1 WO2015076062 A1 WO 2015076062A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- internal combustion
- combustion engine
- combustion chamber
- hole
- distal end
- Prior art date
Links
Classifications
-
- 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
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D35/00—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for
- F02D35/02—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions
- F02D35/023—Controlling engines, dependent on conditions exterior or interior to engines, not otherwise provided for on interior conditions by determining the cylinder pressure
Definitions
- the present invention relates to an internal combustion engine, and particularly relates to an internal combustion engine including a cylinder pressure sensor that also includes a function as a glow plug.
- a compression ignition type internal combustion engine in which a cylinder pressure sensor, which also functions as a glow plug, is installed in a combustion chamber, for example, in Japanese Patent Laid-Open No. 2009-222031.
- the cylinder pressure sensor is the result of integrally configuring the glow plug and the cylinder pressure sensor by configuring the pressure receiving section of the cylinder pressure sensor by a heater rod (heating tube) of the glow plug which generates heat by energization.
- PM Pularticulate Matter contained in EGR gas is mixed in the combustion chamber.
- the part of the PM If part of the PM enters the gap around the pressure receiving section of the cylinder pressure sensor, the part of the PM accumulates as a deposit, and a pressure change in the combustion chamber is unlikely to be accurately detected.
- the above described conventional art energizes the heater element in the heating tube of the glow plug when it determines that a deposit adheres and accumulates to such an extent that the accumulation of the deposit inhibits displacement of the pressure receiving section of the cylinder pressure sensor. Thereby, the deposit adhering to the pressure receiving section is heated and burnt, and as a result, the deposit is removed from the pressure receiving section.
- Patent Literature 1 Japanese Patent Laid-Open No. 2009-222031
- the whole of the heater rod of the glow plug which protrudes from the sensor main body is not uniformly increased in temperature. That is to say, in the heater rod, the temperature of the distal end portion to be an ignition point is increased to a high temperature, but the other range of the heater rod is structured so that the temperature thereof is difficult to increase from the viewpoint of power consumption and heat resistance. Therefore, in the above described conventional art which causes the heater rod to generate heat to burn the deposit adhering thereto, the deposit adhering to the pressure receiving section of the cylinder pressure sensor which is in contact with the root portion of the heater rod cannot be sufficiently burned, or a lot of electric power is assumed to be required to burn the deposit.
- the present invention is made in the light of the problem as described above, and has an object to restrain reduction in detection precision of a cylinder pressure by accumulation of a deposit while restraining power consumption in an internal combustion engine that includes a cylinder pressure sensor that also functions as a glow plug.
- an internal combustion engine including a cylinder pressure sensor composed of a cylindrical housing section, a heater rod that is provided to protrude in an axial direction from a distal end portion of the housing section and promotes ignition by generating heat by energization, and a detection section that detects a pressure that is received by the heater rod from an outside of the housing section,
- the internal combustion engine comprising a hole that opens into a combustion chamber
- cylinder pressure sensor is fixed in such a manner that the distal end portion is located in the hole and a distal end of the heater rod protrudes into the combustion chamber from the hole, and
- the internal combustion engine includes a promotion mechanism for promoting accumulation of a deposit, in a combustion chamber side region which is at the combustion chamber side from the distal end portion, and is a partial region of the hole.
- the promotion structure includes a small diameter section which is provided in the combustion chamber side region, and is configured so that a gap between the heater rod and a wall surface of the hole becomes narrower than a gap in the distal end portion.
- the internal combustion engine as described in the second aspect, wherein the promotion structure includes a cooling mechanism disposed in a wall of the small diameter section.
- the cooling mechanism is a mechanism which causes cooling water of the internal combustion engine to flow in the wall of the small diameter section.
- the internal combustion engine as described in the first aspect, wherein the promotion structure includes a cooling mechanism for cooling a wall portion of the combustion chamber side region.
- the configuration for promoting accumulation of a deposit is provided in the combustion chamber side region of the hole which is at the combustion chamber side from the position of the distal end portion of the housing section of the fixed cylinder pressure sensor. According to the configuration like this, chances are high that a part of PM in the combustion chamber will accumulate as a deposit in the outlet section before reaching the distal end portion of the housing section. Therefore, according to the present invention, the amount of PM that reaches the distal end portion of the housing section can be effectively decreased, and therefore, reduction in detection precision of the cylinder pressure caused by a deposit adhering to the distal end portion of the housing section can be restrained.
- the small diameter section in which the gap from the heater rod is made narrower than that at the distal end portion of the housing section is provided in the combustion chamber side region of the hole. According to the configuration like this, inflow of the combustion gas to the hole from the combustion chamber is restrained. Therefore, according to the present invention, increase in the temperature of the combustion chamber side region of the hole can be restrained.
- the cooling mechanism is disposed in the wall of the small diameter section. Therefore, according to the present invention, accumulation of a deposit can be further promoted in the combustion chamber side region of the hole.
- the cooling mechanism is configured as a mechanism which causes cooling water of the internal combustion engine to flow.
- the wall surface of the small diameter section can be effectively cooled with the simple configuration.
- the cooling mechanism is disposed in the wall surface of the combustion chamber side region. Therefore, according to the present invention, increase in the temperature of the combustion chamber side region can be restrained. Accordingly, accumulation of a deposit onto the combustion chamber side region can be effectively promoted.
- Fig. 1 is a schematic configuration diagram for explaining an internal combustion engine as a first embodiment of the present invention.
- Fig. 2 is a sectional view showing a periphery of a cylinder pressure sensor that is installed in the internal combustion engine.
- Fig. 3 is a diagram showing distillation characteristics of standard light oil fuel.
- Fig. 4 is a diagram showing a result of performing an engine endurance test by changing a distance between a hole and a heater rod by adjusting a diameter of a small diameter section.
- Fig. 5 is a view for explaining another example of a shape of the small diameter section.
- Fig. 6 is a sectional view showing a periphery of a cylinder pressure sensor that is installed in an internal combustion engine of a second embodiment of the present invention.
- Fig. 7 is a view showing a modification of the internal combustion engine of the second embodiment of the present invention.
- Fig. 8 is a view showing another modification of a cooling mechanism of the internal combustion engine of the second embodiment.
- Fig. 9 is a view showing another modification of the internal combustion engine of the second embodiment of the present invention.
- FIG. 1 is a schematic configuration diagram for explaining an internal combustion engine as a first embodiment of the present invention.
- an internal combustion engine 10 of the present embodiment is configured as a compression self- ignition type diesel engine which uses light oil as fuel.
- a piston 12 which reciprocally moves inside the cylinder is provided.
- the internal combustion engine 10 includes a cylinder head 14.
- a combustion chamber 16 is formed between the piston 12 and the cylinder head 14.
- One ends of an intake passage 18 and an exhaust passage 20 communicate with the combustion chamber 16.
- an intake valve 22 and an exhaust valve 24 are disposed respectively.
- An air cleaner 26 is mounted to an inlet of the intake passage 18. Further, an aftertreatment device 28 for purifying an exhaust gas is provided midway in the exhaust passage 20.
- the cylinder head 14 is provided with a fuel injection valve 30 for injecting fuel into the cylinder. Further, in the cylinder head 14, a cylinder pressure sensor 40 is mounted to protrude into the combustion chamber 16 from a top portion of the combustion chamber 16.
- the cylinder pressure sensor 40 is a cylinder pressure sensor that also includes a function as a glow plug by including a heater rod.
- a structure of the cylinder pressure sensor 40 and details of a mounting section thereof will be described with reference to Fig. 2. Note that in the following explanation, the "cylinder pressure sensor 40" will be also described simply as the "sensor 40".
- Fig. 2 is a sectional view showing a periphery of the cylinder pressure sensor which is installed in the internal combustion engine.
- the sensor 40 is a cylinder pressure sensor including a function as a glow plug, and is in a shape in which a heater rod 402 protrudes in an axial direction from a distal end of a cylindrical housing section 401.
- the heater rod 402 functions as a glow plug that is configured to generate heat by energization.
- a seal section 403 which is formed from a high polymer material and for closing the gap is provided in a gap between a distal end portion of the housing section 401 and the heater rod 402.
- the seal section 403 and the heater rod 402 function as a pressure receiving section that receives a pressure from an outside of the housing section 401.
- a pressure difference occurs between an inside and the outside of the housing section 401 , and a position in the axial direction of the heater rod 402 changes in response to the received pressure.
- a detecting element 404 as a detection section is disposed in such a manner as to contact an end portion of the heater rod 402.
- the detecting element 404 detects a displacement in the axial direction of the heater rod 402, and outputs a signal corresponding to a displacement amount, that is, a signal corresponding to the pressure received by the pressure receiving section.
- the cylinder head 14 is provided with a hole 32 which opens into the combustion chamber 16.
- the sensor 40 is fixed by being forced therein until the distal end portion of the housing section 401 closely contacts a taper section 321 of the hole 32. Thereby, the heater rod 402 of the sensor 40 is disposed to protrude to the combustion chamber 16 from the hole 32.
- the internal combustion engine 10 of the first embodiment of the present invention has a feature in the configuration of the mounting section. Namely, as shown in Fig. 2, at an outlet portion which opens to the combustion chamber 16, and is a part of a combustion chamber side region of the hole 32 which is at the combustion chamber 16 side from the distal end portion of the housing section 401 of the sensor 40, a small diameter section 34 having a hole diameter configured to be smaller by one step than a hole diameter at the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 is provided. According to the
- a distance (a gap) between the heater rod 402 and a wall surface of the hole 32 is configured to be shorter than the gap in the distal end portion of the housing section 401.
- a deposit is an oxide and a carbonous substance formed by an unburned component and an oil component of the fuel in combustion gas being liquefied and going through a subsequent reaction by ambient heat. That is to say, there is a close relation between accumulation of the deposit and the temperature.
- Fig. 3 is a diagram showing distillation characteristics of standard light oil fuel.
- the fuel is always at a temperature equal to or higher than 400°C, gaseous fuel is not liquefied, and therefore, the gaseous fuel does not become a deposit on a surface of the cylinder head and does not adhere thereto.
- the fuel is heated to a temperature equal to or higher than 800°C, the components which become a deposit can be decomposed into CO, C02, HC and the like by heating and discharged.
- a heat source becomes necessary and worsening of fuel economy is caused.
- Fig. 4 is a diagram showing a result of performing an engine endurance test by changing a distance between the hole 32 and the heater rod 402. Note that (A) in Fig. 4 shows an amount of the deposit that accumulates in the hole with respect to the distance between the hole and the heater rod, whereas (B) in Fig. 4 shows a maximum pressure achieved Pmax which is detected by the cylinder pressure sensor with respect to the same distance.
- accumulation of a deposit in the vicinity of the distal end portion of the housing section 401 can be restrained by a simple configuration which accumulates a deposit in the small diameter section 34.
- the deposit which accumulates in the small diameter section 34 can be effectively heated by the distal end portion side of the heater rod 402, and therefore, the accumulated deposit can be effectively subjected to burning treatment even with a small power consumption amount.
- the small diameter section 34 which is configured to have a diameter smaller by one step than the hole diameter of the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 is provided at the outlet portion of the hole 32, but disposition of the small diameter section is not limited thereto. That is to say, if only the small diameter section is disposed in the combustion chamber side region which is located at the combustion chamber 16 side from the distal end portion of the housing section 401 in the hole 32, the small diameter section may be provided in such a manner that a midpoint of the hole 32 has a small diameter.
- the small diameter section 34 which is configured to have a diameter smaller by one step than the hole diameter of the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 is provided in the range near the combustion chamber 16 in the hole 32 (the combustion chamber side region).
- the shape of the small diameter section is not limited thereto.
- the small diameter section may be provided so that the diameter becomes gradually smaller toward the combustion chamber side region of the hole 32 from the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 , for example.
- Fig. 5 is a view for explaining another example of the shape of the small diameter section.
- a small diameter section 341 which is configured so that the hole diameter becomes gradually smaller toward the combustion chamber side region of the hole 32 from the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section. According to the configuration like this, an effect similar to the configuration of the first embodiment described above can be provided.
- the small diameter section 34 or the small diameter section 341 corresponds to the "promotion structure" of the first invention.
- the small diameter section 34 is provided in the combustion chamber side region of the hole 32, and accumulation of a deposit onto the combustion chamber side region is promoted.
- fuel is more easily liquefied as the temperature of the fuel is lower.
- the standard light oil fuel shown in Fig. 3 is substantially liquefied when the temperature becomes equal to or lower than 180°C. Consequently, an internal combustion engine of the second embodiment includes a promotion structure for further promoting cooling of the small diameter section 34.
- Fig. 6 is a sectional view showing a periphery of a cylinder pressure sensor which is installed in the internal combustion engine of the second embodiment of the present invention.
- the internal combustion engine shown in Fig. 6 has a configuration similar to that of the internal combustion engine shown in Fig. 2, except that the internal combustion engine of the second embodiment includes a cooling mechanism 36 around the small diameter section 34.
- the cooling mechanism 36 is composed of a passage where cooling water of the internal combustion engine 10 flows, for example.
- the periphery of the small diameter section 34 can be effectively cooled, and therefore, accumulation of a deposit in the small diameter section 34 is further promoted to restrain accumulation onto the seal section 403 which is the pressure receiving section.
- the cooling mechanism 36 is preferably configured to be able to cool the periphery of the small diameter section 34 to a temperature equal to or lower than 180°C which is a liquefaction temperature of the standard light oil. Thereby, accumulation of the deposit in the small diameter section 34 can be effectively promoted.
- Fig. 7 is a view showing a modification of the internal combustion engine of the second embodiment of the present invention.
- the cooling mechanism 36 may be provided in the periphery of the small diameter section 341 of the internal combustion engine shown in Fig. 5.
- Fig. 8 is a view showing another modification of the cooling mechanism of the internal combustion engine of the second embodiment.
- a cooling mechanism 38 composed of a heat pipe is provided in the periphery of the small diameter section 34.
- the cooling mechanism 38 is composed of a heat pipe which extends toward a periphery of the distal end portion of the housing section 401 from the periphery of the small diameter section 34, and is configured so that heat moves in the heat pipe toward the periphery of the distal end portion of the housing section 401 from the periphery of the small diameter section 34.
- the periphery of the small diameter section 34 can be effectively cooled. Therefore, accumulation of the deposit in the small diameter section 34 is further promoted, and accumulation onto the seal section 403 which is the pressure receiving section can be restrained.
- the cooling mechanism 38 may be applied as the cooling mechanism of the internal combustion engine shown in Fig. 7.
- Fig. 9 is a view showing another modification of the internal combustion engine of the second embodiment of the present invention. While in the internal combustion engine shown in Fig. 6 described above, the cooling mechanism 36 is provided in the periphery of the small diameter section 34, the cooling mechanism 36 may be disposed in the combustion chamber side region of the hole 32 in an internal combustion engine which does not include a small diameter section, as shown in Fig. 9. According to the cooling mechanism 36, combustion gas in the combustion chamber side region of the hole 32 can be cooled, and therefore, at least an effect of promoting accumulation of a deposit by cooling can be obtained. Note that while the internal combustion engine in Fig. 9 includes the cooling mechanism 36, the internal combustion engine in Fig. 9 may be provided with the cooling mechanism 38 composed of a heat pipe in place of the cooling mechanism 36.
- the cooling mechanism 36 or the cooling mechanism 38 corresponds to the "cooling mechanism" of the third invention and the "cooling mechanism” of the fifth invention.
Abstract
In an internal combustion engine including a cylinder pressure sensor composed of a housing section, a heater rod that is provided to protrude in an axial direction from a distal end portion of the housing section, and a detection section that detects a pressure received by the heater rod from an outside of the housing section, the engine includes a hole that opens into a combustion chamber, and the cylinder pressure sensor is fixed in such a manner that the distal end portion of the housing section is located in the hole and a distal end of the heater rod protrudes into the combustion chamber from the hole, and the engine includes a promotion mechanism for promoting accumulation of a deposit, in a combustion chamber region which is at the combustion chamber side from the distal end portion of the housing section, and is a partial region of the hole.
Description
DESCRIPTION
Title of Invention
INTERNAL COMBUSTION ENGINE
Technical Field
[0001]
The present invention relates to an internal combustion engine, and particularly relates to an internal combustion engine including a cylinder pressure sensor that also includes a function as a glow plug.
Background Art
[0002]
Conventionally, there has been disclosed a compression ignition type internal combustion engine in which a cylinder pressure sensor, which also functions as a glow plug, is installed in a combustion chamber, for example, in Japanese Patent Laid-Open No. 2009-222031. The cylinder pressure sensor is the result of integrally configuring the glow plug and the cylinder pressure sensor by configuring the pressure receiving section of the cylinder pressure sensor by a heater rod (heating tube) of the glow plug which generates heat by energization. In a compression ignition type internal combustion engine, PM (Particulate Matter) contained in EGR gas is mixed in the combustion chamber. If part of the PM enters the gap around the pressure receiving section of the cylinder pressure sensor, the part of the PM accumulates as a deposit, and a pressure change in the combustion chamber is unlikely to be accurately detected. With
respect to the problem, the above described conventional art energizes the heater element in the heating tube of the glow plug when it determines that a deposit adheres and accumulates to such an extent that the accumulation of the deposit inhibits displacement of the pressure receiving section of the cylinder pressure sensor. Thereby, the deposit adhering to the pressure receiving section is heated and burnt, and as a result, the deposit is removed from the pressure receiving section.
Citation List
Patent Literature
[0003]
Patent Literature 1 : Japanese Patent Laid-Open No. 2009-222031
Summary of Invention
Technical Problem
[0004]
However, the whole of the heater rod of the glow plug which protrudes from the sensor main body is not uniformly increased in temperature. That is to say, in the heater rod, the temperature of the distal end portion to be an ignition point is increased to a high temperature, but the other range of the heater rod is structured so that the temperature thereof is difficult to increase from the viewpoint of power consumption and heat resistance. Therefore, in the above described conventional art which causes the heater rod to generate heat to burn the deposit adhering thereto, the deposit adhering to the pressure receiving section of the cylinder pressure sensor which is in contact with the root
portion of the heater rod cannot be sufficiently burned, or a lot of electric power is assumed to be required to burn the deposit.
[0005]
The present invention is made in the light of the problem as described above, and has an object to restrain reduction in detection precision of a cylinder pressure by accumulation of a deposit while restraining power consumption in an internal combustion engine that includes a cylinder pressure sensor that also functions as a glow plug.
Solution to Problem
[0006]
In accomplishing the above object, according to a first aspect of the present invention, there is provided an internal combustion engine including a cylinder pressure sensor composed of a cylindrical housing section, a heater rod that is provided to protrude in an axial direction from a distal end portion of the housing section and promotes ignition by generating heat by energization, and a detection section that detects a pressure that is received by the heater rod from an outside of the housing section,
the internal combustion engine comprising a hole that opens into a combustion chamber,
wherein the cylinder pressure sensor is fixed in such a manner that the distal end portion is located in the hole and a distal end of the heater rod protrudes into the combustion chamber from the hole, and
wherein the internal combustion engine includes a promotion mechanism for promoting accumulation of a deposit, in a combustion chamber side region which is at
the combustion chamber side from the distal end portion, and is a partial region of the hole.
[0007]
According to a second aspect of the present invention, there is provided the internal combustion engine as described in the first aspect, wherein the promotion structure includes a small diameter section which is provided in the combustion chamber side region, and is configured so that a gap between the heater rod and a wall surface of the hole becomes narrower than a gap in the distal end portion.
[0008]
According to a third aspect of the present invention, there is provided the internal combustion engine as described in the second aspect, wherein the promotion structure includes a cooling mechanism disposed in a wall of the small diameter section.
[0009]
According to a fourth aspect of the present invention, there is provided the internal combustion engine as described in the third aspect, wherein the cooling mechanism is a mechanism which causes cooling water of the internal combustion engine to flow in the wall of the small diameter section.
[0010]
According to a fifth aspect of the present invention, there is provided the internal combustion engine as described in the first aspect, wherein the promotion structure includes a cooling mechanism for cooling a wall portion of the combustion chamber side region.
Advantageous Effects of Invention
[0011]
According to the first invention, the configuration for promoting accumulation of a deposit is provided in the combustion chamber side region of the hole which is at the combustion chamber side from the position of the distal end portion of the housing section of the fixed cylinder pressure sensor. According to the configuration like this, chances are high that a part of PM in the combustion chamber will accumulate as a deposit in the outlet section before reaching the distal end portion of the housing section. Therefore, according to the present invention, the amount of PM that reaches the distal end portion of the housing section can be effectively decreased, and therefore, reduction in detection precision of the cylinder pressure caused by a deposit adhering to the distal end portion of the housing section can be restrained.
[0012]
According to the second invention, the small diameter section in which the gap from the heater rod is made narrower than that at the distal end portion of the housing section is provided in the combustion chamber side region of the hole. According to the configuration like this, inflow of the combustion gas to the hole from the combustion chamber is restrained. Therefore, according to the present invention, increase in the temperature of the combustion chamber side region of the hole can be restrained.
Accordingly, accumulation of a deposit onto the combustion chamber side region can be effectively promoted.
[0013]
According to the third invention, the cooling mechanism is disposed in the wall of the small diameter section. Therefore, according to the present invention, accumulation of a deposit can be further promoted in the combustion chamber side region of the hole.
[0014]
According to the fourth invention, the cooling mechanism is configured as a mechanism which causes cooling water of the internal combustion engine to flow.
Therefore, according to the present invention, the wall surface of the small diameter section can be effectively cooled with the simple configuration.
[0015]
According to the fifth invention, the cooling mechanism is disposed in the wall surface of the combustion chamber side region. Therefore, according to the present invention, increase in the temperature of the combustion chamber side region can be restrained. Accordingly, accumulation of a deposit onto the combustion chamber side region can be effectively promoted.
Brief Description of the Drawings
[0016]
Fig. 1 is a schematic configuration diagram for explaining an internal combustion engine as a first embodiment of the present invention.
Fig. 2 is a sectional view showing a periphery of a cylinder pressure sensor that is installed in the internal combustion engine.
Fig. 3 is a diagram showing distillation characteristics of standard light oil fuel.
Fig. 4 is a diagram showing a result of performing an engine endurance test by changing a distance between a hole and a heater rod by adjusting a diameter of a small diameter section.
Fig. 5 is a view for explaining another example of a shape of the small diameter section.
Fig. 6 is a sectional view showing a periphery of a cylinder pressure sensor that is installed in an internal combustion engine of a second embodiment of the present invention.
Fig. 7 is a view showing a modification of the internal combustion engine of the second embodiment of the present invention.
Fig. 8 is a view showing another modification of a cooling mechanism of the internal combustion engine of the second embodiment.
Fig. 9 is a view showing another modification of the internal combustion engine of the second embodiment of the present invention.
Description of Embodiments
[0017]
Hereinafter, embodiments of the present invention will be described based on the drawings. Note that common elements in the respective drawings are assigned with the same reference signs, and redundant explanation will be omitted. Further, the invention is not limited by the following embodiments.
[0018]
First embodiment
Fig. 1 is a schematic configuration diagram for explaining an internal combustion engine as a first embodiment of the present invention. As shown in Fig. 1 , an internal combustion engine 10 of the present embodiment is configured as a compression self- ignition type diesel engine which uses light oil as fuel. In a cylinder of the internal combustion engine 10, a piston 12 which reciprocally moves inside the cylinder is provided. Further, the internal combustion engine 10 includes a cylinder head 14. A combustion chamber 16 is formed between the piston 12 and the cylinder head 14. One ends of an intake passage 18 and an exhaust passage 20 communicate with the combustion chamber 16. In the intake passage 18 and the exhaust passage 20, an intake valve 22 and an exhaust valve 24 are disposed respectively.
[0019]
An air cleaner 26 is mounted to an inlet of the intake passage 18. Further, an aftertreatment device 28 for purifying an exhaust gas is provided midway in the exhaust passage 20.
[0020]
The cylinder head 14 is provided with a fuel injection valve 30 for injecting fuel into the cylinder. Further, in the cylinder head 14, a cylinder pressure sensor 40 is mounted to protrude into the combustion chamber 16 from a top portion of the combustion chamber 16. The cylinder pressure sensor 40 is a cylinder pressure sensor that also includes a function as a glow plug by including a heater rod. Hereinafter, a structure of the cylinder pressure sensor 40 and details of a mounting section thereof will be described with reference to Fig. 2. Note that in the following explanation, the "cylinder pressure sensor 40" will be also described simply as the "sensor 40".
[0021]
Fig. 2 is a sectional view showing a periphery of the cylinder pressure sensor which is installed in the internal combustion engine. First of all, details of a
configuration of the cylinder pressure sensor 40 will be described. As shown in the drawing, the sensor 40 is a cylinder pressure sensor including a function as a glow plug, and is in a shape in which a heater rod 402 protrudes in an axial direction from a distal end of a cylindrical housing section 401. The heater rod 402 functions as a glow plug that is configured to generate heat by energization. In a gap between a distal end portion of the housing section 401 and the heater rod 402, a seal section 403 which is formed from a high polymer material and for closing the gap is provided. The seal section 403 and the heater rod 402 function as a pressure receiving section that receives a pressure from an outside of the housing section 401. When the pressure receiving section receives a pressure, a pressure difference occurs between an inside and the outside of the housing section 401 , and a position in the axial direction of the heater rod 402 changes in response to the received pressure. Inside the housing section 401, a detecting element 404 as a detection section is disposed in such a manner as to contact an end portion of the heater rod 402. The detecting element 404 detects a displacement in the axial direction of the heater rod 402, and outputs a signal corresponding to a displacement amount, that is, a signal corresponding to the pressure received by the pressure receiving section.
[0022]
Next, details of the mounting section of the cylinder pressure sensor 40 will be described. The cylinder head 14 is provided with a hole 32 which opens into the combustion chamber 16. The sensor 40 is fixed by being forced therein until the distal end portion of the housing section 401 closely contacts a taper section 321 of the hole 32.
Thereby, the heater rod 402 of the sensor 40 is disposed to protrude to the combustion chamber 16 from the hole 32.
[0023]
The internal combustion engine 10 of the first embodiment of the present invention has a feature in the configuration of the mounting section. Namely, as shown in Fig. 2, at an outlet portion which opens to the combustion chamber 16, and is a part of a combustion chamber side region of the hole 32 which is at the combustion chamber 16 side from the distal end portion of the housing section 401 of the sensor 40, a small diameter section 34 having a hole diameter configured to be smaller by one step than a hole diameter at the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 is provided. According to the
configuration like this, in the small diameter section 34, a distance (a gap) between the heater rod 402 and a wall surface of the hole 32 is configured to be shorter than the gap in the distal end portion of the housing section 401.
[0024]
Next, an operation of the internal combustion engine 10 of the first embodiment of the present invention and an effect thereof will be described. A deposit is an oxide and a carbonous substance formed by an unburned component and an oil component of the fuel in combustion gas being liquefied and going through a subsequent reaction by ambient heat. That is to say, there is a close relation between accumulation of the deposit and the temperature.
[0025]
Fig. 3 is a diagram showing distillation characteristics of standard light oil fuel. As shown in the drawing, if the fuel is always at a temperature equal to or higher than
400°C, gaseous fuel is not liquefied, and therefore, the gaseous fuel does not become a deposit on a surface of the cylinder head and does not adhere thereto. Further, as shown in the drawing, if the fuel is heated to a temperature equal to or higher than 800°C, the components which become a deposit can be decomposed into CO, C02, HC and the like by heating and discharged. However, in order to always keep the inside of the cylinder of the internal combustion engine at a high temperature, a heat source becomes necessary and worsening of fuel economy is caused. Further, depending on the operation state of the internal combustion engine, there is, for example, a state in which the temperature in the cylinder is low immediately after cold start or the like, and the conditions which cannot avoid accumulation of a deposit are assumable. The accumulated deposit can be decomposed and removed by high-temperature heating as described above, but again, worsening of fuel efficiency becomes a problem.
[0026]
Consequently, in the internal combustion engine 10 of the first embodiment, the small diameter section 34 is provided at an outlet portion of the hole 32 to the combustion chamber 16. Fig. 4 is a diagram showing a result of performing an engine endurance test by changing a distance between the hole 32 and the heater rod 402. Note that (A) in Fig. 4 shows an amount of the deposit that accumulates in the hole with respect to the distance between the hole and the heater rod, whereas (B) in Fig. 4 shows a maximum pressure achieved Pmax which is detected by the cylinder pressure sensor with respect to the same distance.
[0027]
Referring to the result shown in Fig. 4, it is found that when the diameter of the small diameter section 34 is made small to reduce the distance from the heater rod in a
range near the combustion chamber 16, accumulation of the deposit in the hole 32 near the combustion chamber 16 is promoted. Further, it is found that as for the sensor output at this time, as the deposit amount accumulating in the hole 32 near the combustion chamber 16 is larger, the ratio of output reduction is lower.
[0028]
From the above described test result, a phenomenon as follows is estimated.
That is to say, when the diameter of the small diameter section 34 is made small to reduce the distance from the heater rod in the range near the combustion chamber 16, the combustion gas coming in and going out from the hole 32 is decreased. As a result, rise in the temperature of the hole 32 is restrained, and an environment where a deposit easily accumulates is brought about. Further, once accumulation of the deposit in the hole 32 starts, heat exchange on the deposit is also performed, and therefore, an environment in which unburned components are further easily liquefied is brought about. As a result, a deposit accumulates in the range near the combustion chamber 16 in the hole 32, and the unburned components hardly reaches a deep space in the hole 32. Thereby,
accumulation of the deposit in the vicinity of the distal end portion of the housing section 401 is avoided, and therefore, reduction in the sensor output by accumulation of the deposit onto the seal section 403 which is the pressure receiving section is effectively restrained. Note that near the distal end portion of the housing section 401 in the hole 32, a sufficient space is preferably ensured without providing the small diameter section 34. This is because if the space near the distal end portion of the housing section 401 is made narrow, reduction in detection precision of the cylinder pressure due to
accumulation of a deposit easily occurs.
[0029]
As above, according to the internal combustion engine 10 of the first embodiment of the present invention, accumulation of a deposit in the vicinity of the distal end portion of the housing section 401 can be restrained by a simple configuration which accumulates a deposit in the small diameter section 34. Thereby, it is not necessary to heat the heater rod 402 and burn the deposit in the vicinity of the distal end portion of the housing section 401 , and therefore, it becomes possible to restrain reduction in detection precision of the cylinder pressure due to accumulation of the deposit while restraining power consumption. Further, the deposit which accumulates in the small diameter section 34 can be effectively heated by the distal end portion side of the heater rod 402, and therefore, the accumulated deposit can be effectively subjected to burning treatment even with a small power consumption amount.
[0030]
Incidentally, in the internal combustion engine of the first embodiment described above, the small diameter section 34 which is configured to have a diameter smaller by one step than the hole diameter of the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 is provided at the outlet portion of the hole 32, but disposition of the small diameter section is not limited thereto. That is to say, if only the small diameter section is disposed in the combustion chamber side region which is located at the combustion chamber 16 side from the distal end portion of the housing section 401 in the hole 32, the small diameter section may be provided in such a manner that a midpoint of the hole 32 has a small diameter.
[0031]
Further, in the internal combustion engine of the first embodiment described above, the small diameter section 34 which is configured to have a diameter smaller by
one step than the hole diameter of the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 is provided in the range near the combustion chamber 16 in the hole 32 (the combustion chamber side region). However, the shape of the small diameter section is not limited thereto. That is to say, if only the diameter of the combustion chamber side region is configured to be a small diameter while a space near the distal end portion of the housing section 401 in the hole 32 is ensured, the small diameter section may be provided so that the diameter becomes gradually smaller toward the combustion chamber side region of the hole 32 from the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section 401 , for example.
[0032]
Fig. 5 is a view for explaining another example of the shape of the small diameter section. In an example shown in the drawing, a small diameter section 341 which is configured so that the hole diameter becomes gradually smaller toward the combustion chamber side region of the hole 32 from the distal end portion (that is, the seal section 403 which is the pressure receiving section) of the housing section. According to the configuration like this, an effect similar to the configuration of the first embodiment described above can be provided.
[0033]
Note that in the first embodiment described above, the small diameter section 34 or the small diameter section 341 corresponds to the "promotion structure" of the first invention.
[0034]
Second embodiment
In the internal combustion engine of the first embodiment described above, the small diameter section 34 is provided in the combustion chamber side region of the hole 32, and accumulation of a deposit onto the combustion chamber side region is promoted. Here, as also shown in the distillation characteristics in Fig. 3, fuel is more easily liquefied as the temperature of the fuel is lower. In particular, the standard light oil fuel shown in Fig. 3 is substantially liquefied when the temperature becomes equal to or lower than 180°C. Consequently, an internal combustion engine of the second embodiment includes a promotion structure for further promoting cooling of the small diameter section 34.
[0035]
Fig. 6 is a sectional view showing a periphery of a cylinder pressure sensor which is installed in the internal combustion engine of the second embodiment of the present invention. Note that the internal combustion engine shown in Fig. 6 has a configuration similar to that of the internal combustion engine shown in Fig. 2, except that the internal combustion engine of the second embodiment includes a cooling mechanism 36 around the small diameter section 34. The cooling mechanism 36 is composed of a passage where cooling water of the internal combustion engine 10 flows, for example.
According to the configuration like this, the periphery of the small diameter section 34 can be effectively cooled, and therefore, accumulation of a deposit in the small diameter section 34 is further promoted to restrain accumulation onto the seal section 403 which is the pressure receiving section.
[0036]
Note that the cooling mechanism 36 is preferably configured to be able to cool the periphery of the small diameter section 34 to a temperature equal to or lower than 180°C
which is a liquefaction temperature of the standard light oil. Thereby, accumulation of the deposit in the small diameter section 34 can be effectively promoted.
[0037]
Fig. 7 is a view showing a modification of the internal combustion engine of the second embodiment of the present invention. As shown in Fig. 7, the cooling mechanism 36 may be provided in the periphery of the small diameter section 341 of the internal combustion engine shown in Fig. 5.
[0038]
Further, the configuration of the cooling mechanism is not limited to the cooling mechanism 36 in which cooling water is caused to flow. Fig. 8 is a view showing another modification of the cooling mechanism of the internal combustion engine of the second embodiment. In an internal combustion engine shown in Fig. 8, a cooling mechanism 38 composed of a heat pipe is provided in the periphery of the small diameter section 34. The cooling mechanism 38 is composed of a heat pipe which extends toward a periphery of the distal end portion of the housing section 401 from the periphery of the small diameter section 34, and is configured so that heat moves in the heat pipe toward the periphery of the distal end portion of the housing section 401 from the periphery of the small diameter section 34. According to the configuration like this, the periphery of the small diameter section 34 can be effectively cooled. Therefore, accumulation of the deposit in the small diameter section 34 is further promoted, and accumulation onto the seal section 403 which is the pressure receiving section can be restrained. Note that the cooling mechanism 38 may be applied as the cooling mechanism of the internal combustion engine shown in Fig. 7.
[0039]
Furthermore, Fig. 9 is a view showing another modification of the internal combustion engine of the second embodiment of the present invention. While in the internal combustion engine shown in Fig. 6 described above, the cooling mechanism 36 is provided in the periphery of the small diameter section 34, the cooling mechanism 36 may be disposed in the combustion chamber side region of the hole 32 in an internal combustion engine which does not include a small diameter section, as shown in Fig. 9. According to the cooling mechanism 36, combustion gas in the combustion chamber side region of the hole 32 can be cooled, and therefore, at least an effect of promoting accumulation of a deposit by cooling can be obtained. Note that while the internal combustion engine in Fig. 9 includes the cooling mechanism 36, the internal combustion engine in Fig. 9 may be provided with the cooling mechanism 38 composed of a heat pipe in place of the cooling mechanism 36.
[0040]
Note that in the second embodiment described above, the cooling mechanism 36 or the cooling mechanism 38 corresponds to the "cooling mechanism" of the third invention and the "cooling mechanism" of the fifth invention.
Reference signs List
[0041]
10: internal combustion engine
12: piston
14: cylinder head
16: combustion chamber
18 intake passage
20: exhaust passage
22: intake valve
24: exhaust valve
26: air cleaner
28: aftertreatment device
30: fuel injection valve
32: hole
34, 341 : small diameter section (promotion structure) 36, 38 : cooling mechanism (promotion structure) 40: cylinder pressure sensor (sensor)
321 : taper section
401 : housing section
402: heater rod
403 : seal section
404: detecting element
Claims
1. An internal combustion engine including a cylinder pressure sensor composed of a cylindrical housing section, a heater rod that is provided to protrude in an axial direction from a distal end portion of the housing section and promotes ignition by generating heat by energization, and a detection section that detects a pressure that is received by the heater rod from an outside of the housing section,
the internal combustion engine comprising a hole that opens into a combustion chamber,
wherein the cylinder pressure sensor is fixed in such a manner that the distal end portion is located in the hole and a distal end of the heater rod protrudes into the combustion chamber from the hole, and
wherein the internal combustion engine includes a promotion mechanism for promoting accumulation of a deposit, in a combustion chamber side region which is at the combustion chamber side from the distal end portion, and is a partial region of the hole.
2. The internal combustion engine according to claim 1,
wherein the promotion structure includes a small diameter section which is provided in the combustion chamber side region, and is configured so that a gap between the heater rod and a wall surface of the hole becomes narrower than a gap in the distal end portion.
3. The internal combustion engine according to claim 2,
wherein the promotion structure includes a cooling mechanism disposed in a wall of the small diameter section.
4. The internal combustion engine according to claim 3,
wherein the cooling mechanism is a mechanism which causes cooling water of the internal combustion engine to flow in the wall of the small diameter section.
5. The internal combustion engine according to claim 1 ,
wherein the promotion structure includes a cooling mechanism for cooling a wall portion of the combustion chamber side region.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013241779A JP2015101984A (en) | 2013-11-22 | 2013-11-22 | Internal combustion engine |
| JP2013-241779 | 2013-11-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2015076062A1 true WO2015076062A1 (en) | 2015-05-28 |
Family
ID=51871256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/JP2014/078427 WO2015076062A1 (en) | 2013-11-22 | 2014-10-21 | Internal combustion engine |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2015101984A (en) |
| WO (1) | WO2015076062A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113818970A (en) * | 2021-08-10 | 2021-12-21 | 浙江吉利控股集团有限公司 | Engine cylinder cover, engine, vehicle and sediment treatment method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010139148A (en) * | 2008-12-11 | 2010-06-24 | Ngk Spark Plug Co Ltd | Glow plug with combustion pressure sensor and internal combustion engine |
| US20130269640A1 (en) * | 2011-02-25 | 2013-10-17 | Ngk Spark Plug Co., Ltd. | Glow plug with combustion pressure sensor |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009222031A (en) * | 2008-03-18 | 2009-10-01 | Toyota Motor Corp | Recovery processing method and device for glow plug-integrated cylinder internal sensor |
| JP5246434B2 (en) * | 2009-09-30 | 2013-07-24 | 株式会社デンソー | Glow plug energization control device |
-
2013
- 2013-11-22 JP JP2013241779A patent/JP2015101984A/en active Pending
-
2014
- 2014-10-21 WO PCT/JP2014/078427 patent/WO2015076062A1/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010139148A (en) * | 2008-12-11 | 2010-06-24 | Ngk Spark Plug Co Ltd | Glow plug with combustion pressure sensor and internal combustion engine |
| US20130269640A1 (en) * | 2011-02-25 | 2013-10-17 | Ngk Spark Plug Co., Ltd. | Glow plug with combustion pressure sensor |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113818970A (en) * | 2021-08-10 | 2021-12-21 | 浙江吉利控股集团有限公司 | Engine cylinder cover, engine, vehicle and sediment treatment method |
| CN113818970B (en) * | 2021-08-10 | 2022-12-23 | 浙江吉利控股集团有限公司 | Engine cylinder cover, engine, vehicle and sediment treatment method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2015101984A (en) | 2015-06-04 |
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