JPH02157629A - In-cylinder pressure sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) This invention relates to an improvement in a cylinder pressure sensor that detects the pressure inside a cylinder of an engine.

(Prior Art) In general, a configuration has been developed in which a cylinder pressure sensor is mounted on the engine body to detect the pressure inside the cylinder, and a knock state of the engine body is detected based on a detection signal from the cylinder pressure sensor. ing. In this case, in the conventional configuration, for example, a cylinder pressure sensor mounting part is formed by machining in the combustion chamber and its surrounding area in the cylinder head, and the cylinder pressure sensor is attached to the second sensor mounting part. That's what I was doing. However, when trying to increase the output of the engine body by making each combustion chamber in the engine body have multiple valves or by changing the valve train to a DOHC (double overhead camshaft), for example, the combustion chamber in the cylinder head and its Since the structure of the surrounding parts becomes complicated, there is a problem in that it is difficult to provide a space for mounting an in-cylinder pressure sensor in the combustion chamber of the cylinder head and its surrounding parts.

Furthermore, since a sensor mounting part is formed in the combustion chamber and its surrounding area in the cylinder head, there is a problem in that the shape of the combustion chamber is restricted in order to mount the cylinder pressure sensor. Ta. Furthermore, since the number of component parts of the engine body increases, there is also a problem in simplifying the overall structure of the engine body.

Therefore, it has been considered to attach an in-cylinder pressure sensor formed by a piezoelectric element to the washer of the spark plug installed in each combustion chamber of the engine body. There is a problem in that a space is required for mounting the in-cylinder pressure sensor and an extra space for arranging the lead wire of the in-cylinder pressure sensor.

Therefore, in this case as well, space problems may occur when each combustion chamber of the engine body is made to have multiple valves or when the valve train is changed to a DOHC type to increase the output of the engine body.

(Problems to be Solved by the Invention) In conventional configurations, each combustion chamber in the engine body has multiple valves, or the valve mechanism is changed to a DOHC (double overhead J shaft), for example. When aiming for high output, the structure of the combustion chamber and surrounding areas in the cylinder head becomes complicated, so it is difficult to provide space for installing a cylinder pressure sensor in the combustion chamber and surrounding areas of the cylinder head. In addition to this, there was also the problem that the shape of the combustion chamber was restricted in order to mount the in-cylinder pressure sensor.

This invention was made in view of the above-mentioned circumstances, and even if the structure of the combustion chamber and its surrounding parts in the cylinder head of the engine body is complicated, it can be easily installed on the engine body, and It is possible to prevent an increase in the number of component parts of the engine body and simplify the overall configuration of the engine body, and in addition, it is possible to individually and accurately detect the pressure state in a plurality of cylinders formed within the engine body. The object of the present invention is to provide an in-cylinder pressure sensor that can perform the following functions.

[Structure of the Invention] (Means for Solving the Problems) The first invention is a cylinder head gasket, in which a piezoelectric element is installed in a bore grommet portion of the cylinder head gasket, which detects pressure changes within the cylinder. A cylinder pressure sensor main body incorporating an element is provided.

Further, the second invention provides a cylinder pressure sensor main body incorporating a piezoelectric element that detects pressure changes in the cylinder axial direction in a bore grommet portion of the cylinder head gasket that is arranged at the peripheral edge of the opening for the cylinder in the engine. It is something that

Furthermore, a third invention provides an in-cylinder pressure sensor that incorporates a piezoelectric element that detects pressure changes in the radial direction of the cylinder in a bore grommet located at the peripheral edge of the cylinder opening in the engine in the cylinder head gasket. It has a main body.

(Function) In the first invention, when the engine body is operating, the piezoelectric element of the cylinder pressure sensor body incorporated in the bore grommet of the cylinder head gasket detects pressure changes in the cylinder of the engine, and combustion in the cylinder head of the engine body is detected. By omitting the special machining required for installing the cylinder pressure sensor body in the chamber and surrounding areas, it is easy to install the cylinder pressure sensor on the engine body even if the structure of the cylinder head of the engine body is complicated. In addition to simplifying the overall configuration of the engine by preventing an increase in the number of component parts in the engine, the design also allows for mounting of cylinders around the multiple cylinder openings formed in the engine. By installing the in-cylinder pressure sensor body, the pressure state within a plurality of cylinders formed within the engine body can be individually and accurately detected.

Further, in the second invention, when the engine body is operating, pressure changes in the cylinder axis direction of the engine are detected by a piezoelectric element of the cylinder pressure sensor body incorporated in the bore grommet portion of the cylinder head gasket.

Furthermore, in the third invention, when the engine body is in operation, pressure changes in the radial direction of the engine cylinder are detected by a piezoelectric element of the cylinder pressure sensor body incorporated in the bore grommet portion of the cylinder head gasket.

(Embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 4. 1 to 3 are schematic configurations of a power vest type cylinder head gasket 4 interposed between a cylinder block 2 and a cylinder head 3 of a 4' cylinder engine body 1, for example, as shown in FIG. 4. This shows that.

In FIG. 4, 5 is a cylinder formed within the cylinder block 2, 6 is a piston disposed within this cylinder 5,
7 is a combustion chamber formed within the cylinder head 3. In this case, as shown in FIG. 1, the cylinder head gasket 4 is formed with a cylinder opening 8 having approximately the same diameter as the inner diameter of the cylinder 5 at a portion corresponding to the cylinder 5. , insertion holes 9 for fixing bolts (not shown) of the cylinder head 3, and circulation holes 10 for cooling water or lubricating oil are formed, respectively.

Further, as shown in FIG. 3, a cover member 11 made of a conductor such as metal is disposed on the outer peripheral surface of the cylinder head gasket 4. As shown in FIG.

Further, inside the cylinder head gasket 4, there are a pair of piezoelectric elements 12a each formed in a substantially ring shape and arranged around each nobleman 8.

12b (cylinder 5 in the engine body 1)
. . .) cylinder pressure sensor bodies 13a.

i3b, 13c, and 13d, and a pair of gasket materials 14a and 14b made of a soft material such as low-density graphite are provided in the portions other than the mounting portions of the cylinder pressure sensor bodies 13a to 13d. Further, the core material 15 disposed inside the cylinder head gasket 4 includes each piezoelectric element 12a, 12b and the gasket material 14a.
.

14b. In this case, the core material 15 includes, for example, a conductive path 16a for positive signal output of the piezoelectric elements 12a, 12b of the cylinder pressure sensor bodies 13a to 13d on a substrate formed of an insulator.

16b, 16c, and 16d are formed, respectively. A cover member 11 disposed on the outer peripheral surface of the cylinder head gasket 4 forms a negative electrode of each piezoelectric element 12a, 12b, and each in-cylinder pressure sensor body 13a~
The piezoelectric elements 12a and 12b 13d are used to detect pressure changes in the axial direction of the cylinder 5 as indicated by arrow F in FIG.

In addition, the peripheral edge of each member 8 of the cylinder head gasket 4 is provided with a flange shape in which the edge of the cover member 11 on the inside cylinder 8 side that covers the outer circumferential surface of the lower piezoelectric element 12b is bent upward. A bent portion 17 is formed. The tip 17a of this bent portion 17 is joined in an overlapping state to the peripheral edge portion of the nobleman 8 on the cover member 11 that covers the outer peripheral surface of the upper piezoelectric element 12a. Then, each cylinder pressure sensor body 13
Inside the cylinder 8 in the piezoelectric elements 12a and 12b of a to 13d
The side edge portion is covered by a bent portion 17 formed at the edge portion on the cylinder inner 8 side of the cover member 11 that covers the outer peripheral surface of the lower piezoelectric element 12b. 12a.

A bore grommet portion is formed to prevent the end edge portion of 12b on the cylinder interior 8 side from being exposed to direct flame within the cylinder 5.

Further, a positive signal output conduction path 16a of the piezoelectric cables 12a, 12b of each cylinder pressure sensor body 13a to 13d formed on the substrate of the core material 15 of the cylinder head gasket 4,
External lead wires 18... are connected to 16b, 16c, and 16d.
is connected. Connectors 19 are connected to the tips of these lead wires 18.
9 is connected to a control unit 21 formed by, for example, a microcomputer for a knock control system and its peripheral circuits.

Next, the operation of the above configuration will be explained.

First, when assembling the engine body 1, the cylinder head 3
is fixed to the cylinder block 2 side via the cylinder head gasket 4 under a predetermined tightening pressure using a fixing bolt (not shown). In this case, each cylinder pressure sensor body 13a-l in the cylinder head gasket 4
The id piezoelectric elements 12a and 12b are held in a standard state in which they are pressed under pressure during normal tightening.

Further, during operation of the engine body 1, a pressing force is applied to the cylinder head 3 in a direction away from the cylinder block 2 side due to the explosive combustion pressure in each cylinder 5. Since the sealing surface pressure of the cylinder head gasket 4 between the cylinder head 3 and the cylinder block 2 changes due to the pressing force acting on the cylinder head 3, the cylinder Each cylinder pressure sensor body 13 inside the head gasket 4
Electric signals are output from the piezoelectric cords 12a and 12b of a to 13d. Piezoelectric elements 12a and 12 of each cylinder pressure sensor body 13a to 13d in this cylinder head gasket 4
The output signal from b is transmitted through a positive signal output conduction path 16a formed on the substrate of the core material 15 of the cylinder head gasket 4.
16d1 lead wires 18, . . . connectors 19, lead wires 20, .

Therefore, in the case of the above structure, the cylinder pressure sensor is installed in the bent part 17 for forming the bore grommet part around each node hole 8 of the cylinder head gasket 4, which is used as an essential component of the engine body 1. The piezoelectric elements 12a and 12b of the main bodies 138 to 13d are incorporated, and when the engine main body 1 is in operation, the pressure changes in the cylinder 5 of the engine main body 1 are detected by the piezoelectric elements 12a and 12b of the cylinder pressure sensor main bodies 13a to 13d. Therefore, it is possible to omit the special machining required to attach the cylinder pressure sensor body to the combustion chamber 7 and its surrounding area in the cylinder head 3 of the engine body 1 as in the conventional case. Therefore,
Even if the structure of the peripheral portion of the combustion chamber 7 in the cylinder head 3 of the engine body 1 is complicated in WL, it can be easily installed in the engine body 1. Furthermore, since an increase in the number of component parts of the engine body 1 can be prevented, the overall configuration of the engine body 1 can be simplified.

During operation of the engine body 1, the sealing surface pressure of the cylinder head gasket 4 between the cylinder head 3 and the cylinder block 2 changes due to the explosion combustion pressure in each cylinder 5 directly or by the pressing force acting on the cylinder head 3. Since the pressure can be detected by the piezoelectric elements 12a and 12b of each in-cylinder pressure sensor main body 13a to 13d in the cylinder head gasket 4 according to the pressure fluctuation, the S/N ratio of the detection data of the pressure fluctuation in each cylinder can be increased. This can improve the accuracy of knock control, etc.

Further, since the cylinder pressure sensor bodies 13a to 13d are respectively installed around the plurality of cylinders 5 formed in the engine body 1 and the corresponding node holes 8, the engine Main body 1
The pressure state inside the cylinders 5 formed within the cylinder 5 can be individually detected with high precision.

Further, inside the cover member 11 of the cylinder head gasket 4, a pair of piezoelectric elements 12a are arranged around each node hole 8.
, 12b, the cylinder pressure sensor body 13a, 13b,
13c and 13d, respectively, and a pair of gasket materials 14a and 14b made of a soft material such as low-density graphite are provided in the parts other than the mounting portions of the cylinder pressure sensor bodies 13a to 13d, so that the cylinder head 3 When the fixing bolt is tightened to a predetermined level under pressure and the bolt is tightened to the cylinder block 2 side via the cylinder head gasket 4, the maximum pressure is applied to the mounting portion of each in-cylinder pressure sensor body 13a to 13d in the cylinder head gasket 4. Surface pressure can be generated. Therefore, the detection accuracy of the pressure state inside the cylinders 5 can be further improved.

Note that this invention is not limited to the above embodiments. For example, as in the second embodiment shown in FIG. Cylinder pressure sensor body 13 that detects pressure fluctuations
It is also possible to adopt a configuration in which a to 13d are formed. in this case,
An insulator 32 is interposed between the core material 15 of the cylinder head gasket 4 and the cover member 11 disposed on the outer peripheral surface of the cylinder head gasket 4. Furthermore, core material 1
5, conductive paths 16a and 16b for positive signal outputs of the piezoelectric elements 31 of the respective cylinder pressure sensor bodies 13a to 13d on a substrate formed of an insulator, for example.

16c and 16d are formed, respectively. Then, a negative electrode of each piezoelectric cord 31 is formed by a cover member 11 disposed on the outer peripheral surface of the cylinder head gasket 4,
Changes in pressure in the axial direction of the cylinder 5 are detected by the piezoelectric elements 31 of each cylinder pressure sensor body 13a to 13d. Therefore, in this case as well, the same effects as in the first embodiment can be obtained.

Further, the present invention may be applied to a so-called steel vest type cylinder head gasket 41, as in a third embodiment shown in FIG. This steel vest type cylinder head gasket 41 has soft gasket materials 43a, 4 such as low-density graphite on both sides of the core material 42.
3b are disposed, and ring-shaped grommets 44 are respectively installed around each node hole 8 in this cylinder head gasket 41.

In this case, the grommet 44 has a substantially U-shaped cross section, and a pair of piezoelectric elements 12a and 12b are incorporated inside the grommet 44, so that each cylinder pressure sensor body 13
a to 13d are formed. Further, in the core material 42, conductive paths 16a, 16b, 16c, and 16d for positive signal outputs of the piezoelectric elements 12a and 12b of the cylinder pressure sensor bodies 13a to 13d are respectively formed on a substrate formed of an insulator, for example. There is. Then, each pressure [8 pieces 12a, 12
A negative electrode b is formed, and each cylinder pressure sensor body 13a to 1
3d piezoelectric element 12a.

12b detects pressure changes in the axial direction of the cylinder 5. Therefore, in this case as well, the same effects as in the first embodiment can be obtained.

Furthermore, as in the fourth embodiment shown in FIG. 7, pressure changes in the radial direction of the cylinder 5 (indicated by arrow F in FIG. 7) are applied around each node hole 8 in the cylinder head gasket 51. A cylinder pressure sensor main body 53 incorporating a piezoelectric cord 52 for detection may be provided.

In this case, the cylinder head gasket 51 is of the power best type, and 54 is the cylinder head gasket 5.
The core materials 55a and 55b of No. 1 are gasket materials disposed on both sides of this core material 54.

Further, 56 is an outer plate disposed on the outer surface of one gasket material 55a, 57 is an outer plate disposed on the outer surface of the other gasket material 55b, and 58 is the cylinder head gasket 5.
It is a ring-shaped grommet arranged around each knot hole 8 in 1. And outer plates 56.57 on both sides
The grommet 58 forms a cover member 59 made of a conductor such as metal for the cylinder head gasket 51, and the piezoelectric element 52 is mounted inside the grommet 58. Furthermore, the core material 54 is provided with a cylinder pressure sensor body 53 for each cylinder 5 on a substrate made of an insulator, for example.
Conduction path 16a for positive signal output of piezoelectric element 52...
, 16b, 16e, and 16d are formed, respectively.

Then, the cylinder head gas, the grommet 58 of the cylinder head 51, and the outer plates 56 and 571 on both sides form the negative electrodes of the piezoelectric elements 12a and 12b, and the piezoelectric elements 52 of the cylinder pressure sensor bodies 53... The pressure change in the radial direction of the cylinder 5 is detected by this. Therefore, in this case as well, the same effects as in the first embodiment can be obtained.

Further, as in the fifth embodiment shown in FIG. 8, each node hole 8 in the cylinder head gasket 51 of the fourth embodiment...
-A piezoelectric element 52 for detecting pressure changes in the radial direction of the cylinder 5 and a piezoelectric element 12a for detecting pressure changes in the axial direction of the cylinder 5.

12b may also be provided. In this case, an insulator 62 is disposed between the piezoelectric element 52 that detects pressure changes in the radial direction and the piezoelectric cables 12a and 12b that detect pressure changes in the axial direction, and For example, conduction paths 63 for the positive signal outputs of the piezoelectric elements 52 of the cylinder pressure sensor bodies 61 and the piezoelectric cables 12a and 12b provided for each cylinder 5 on a substrate formed of an insulator.・・・
64... are formed respectively. Therefore, in this case as well, the same effects as in the first embodiment can be obtained.

Further, bead portions protruding toward the cylinder block 2 side and the cylinder head 3 side are formed at the peripheral edge portions of both holes 8 in the cover member 11 on the outer peripheral surface of the cylinder head gasket 4 of the first embodiment. , by locally increasing the surface pressure at the peripheral portions of both holes 8 between the cylinder head gasket 4 and the cylinder block 2 side and cylinder head 3 side using these bead portions, the seal quality can be improved. good.

Alternatively, the outer circumferential surface of the cover member 11 of the cylinder head gasket 4 may be coated with, for example, fluororubber to improve the seal quality. In this case, a conductive portion not coated with a coating layer is formed on a part of the outer peripheral surface of the cover member 11, and the piezoelectric element 12a
, 12b are connected to the engine body 1 via this conductive part.
It is connected to the side.

Furthermore, it goes without saying that various other modifications can be made without departing from the gist of the invention.

Effects of the Invention According to the present invention, the cylinder pressure sensor body incorporates a piezoelectric element for detecting pressure changes in the cylinder in the bore grommet portion of the cylinder head gasket, which is disposed at the peripheral edge of the opening for the cylinder in the engine. Even if the structure of the combustion chamber and its surrounding parts in the cylinder head of the engine body becomes complicated, it can be easily installed on the engine body, and it also prevents an increase in the number of component parts of the engine body. Thus, the configuration of the entire engine body can be simplified, and in addition, the pressure state within the plurality of cylinders formed within the engine body can be individually detected with high precision.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view showing the arrangement of the piezoelectric element in the cylinder head gasket, and FIG. FIG. 3 is a sectional view taken along the line ■-m in FIG. FIG. 6 is a longitudinal cross-sectional view of the main part showing the third embodiment of the present invention, and FIG. 7 is a longitudinal cross-sectional view of the main part showing the fourth embodiment of the invention. The plan view and FIG. 8 are longitudinal sectional views of essential parts showing a fifth embodiment of the present invention. l... Engine body, 4, 41.51... Cylinder head gasket, 5... Cylinder, 8... Both holes (
Cylinder opening), 12 a = 12 b, 31
+52...Piezoelectric element, 13a, 13b, 13c. 13d... Cylinder pressure sensor main body, 17... Bent part (bore grommet part). Applicant's agent Patent attorney Takehiko Suzue Figure 2 Figure 4

Claims (3)

[Claims] (1) A cylinder pressure sensor body incorporating a piezoelectric element for detecting pressure changes in the cylinder is provided in the bore grommet portion of the cylinder head gasket, which is located at the peripheral edge of the opening for the cylinder in the engine. Cylinder pressure sensor. (2) A cylinder pressure sensor body incorporating a piezoelectric element for detecting pressure changes in the cylinder axis direction is provided in the bore grommet portion of the cylinder head gasket, which is located at the peripheral edge of the cylinder opening in the engine. Characteristic cylinder pressure sensor. (3) A cylinder pressure sensor body incorporating a piezoelectric element for detecting pressure changes in the radial direction of the cylinder is provided in the bore grommet portion of the cylinder head gasket located at the peripheral edge of the cylinder opening in the engine. A cylinder pressure sensor featuring: