JPS59145941A - Washer type cylinder internal pressure sensor - Google Patents

Abstract

PURPOSE:To simplify an installation, and to prevent an insulation failure by placing an insulating member on a circumferential part of an ignition plug connected to a washer type cylinder internal pressure sensor, and burying a signal fetch terminal integrated with the insulating member in this insulating member. CONSTITUTION:On the part clamped by an installing seat 2A and a clamping seat 3B of a cylinder internal pressure sensor 10, an annular piezoelectric elements 11A and 11B are placed in a state that a signal fetch electrode 12 used as its center electrode too is inserted and held, and extending from the upper face side of the piezoelectric element 11A to the lower face side of the piezoelectric element 11B, a ground electrode plate 13 is provided in the shape of wrapping these piezoelectric elements 11A, 11B, and a powder 14 of an insulator is packed between a turning-back part of the ground electrode plate 13 and the piezoelectric elements 11A, 11B. According to said constitution, the installation is executed easily, and possibility of the insulation failure can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a monitoring sensor that is attached to a washer of a fire hydrant or the like to detect internal pressure.

It is widely known that elements related to engine operating conditions, such as ignition timing, can be controlled by detecting the in-cylinder pressure, which directly reflects the combustion state in the cylinder. Pressure 1i at the washer position of the stopper
! A sensor incorporating the element has been developed (Tokuko Sho I
/ー． glJ da issue), and there is one commercially available from Rion Corporation under the name KR sensor.

Figure 1 shows an example of such a conventional washer-type cylinder pressure sensor, where / is the cylinder pressure sensor, and sensor / is the cylinder pressure sensor.
C has a piezoelectric element (not shown) formed in the shape of a washer, and when screwing the spark plug 3 onto the top of the cylinder head 2,
The ignition plug is installed between the two seats and the fastening seat 3B of the plug body 3A. Furthermore, l is the sensor/
This is a signal line drawn out from the signal line extraction point IN/A.

The washer type cylinder pressure sensor configured in this way is the spark plug 3.
It is maintained under a predetermined compression force by being screwed to the cylinder head with a specified torque.
Here, when the cylinder pressure is increased by combustion, the spark plug 3
The compressive force is reduced by pushing the entire body upward through the plug body 3A.

Therefore, the pressure change occurring in the cylinder pressure sensor l is directly transmitted to the piezoelectric element. Therefore, in the piezoelectric element, a charge corresponding to the pressure change is generated, and this charge is taken out via the signal line l, and the output signal taken out in this way is detected via a charge amplifier (not shown). By doing so, it can be observed as an in-cylinder pressure signal and used for monitoring and controlling the combustion state.

However, such conventional washer-type cylinder pressure sensors are configured so that the signal line is drawn out directly from the washer position, and furthermore, the signal line extraction position rotates when the ignition plug is screwed on. Not only is it difficult to draw out the lead wire in a narrow space where the ignition plug is installed, but it is also difficult to use a shielded wire, so it is easy to receive noise from the high-voltage ignition cable located nearby.

Furthermore, since it is necessary to fasten the sensor together with the spark plug, there are also problems with the mounting means, such as lead wires breaking when the spark plug is attached or removed, and the durability of the sensor itself being affected.

SUMMARY OF THE INVENTION An object of the present invention is to address these conventional problems and provide a washer-type cylinder pressure sensor that is easy to install, has no risk of insulation failure, and is robust.

In order to achieve such an object, in the present invention, an insulating member is arranged around the ignition plug connected to the washer seat internal pressure sensor, and a signal output terminal integrated with the insulating member is buried in this insulating member. Configure.

Another object of the present invention is to improve performance by making it possible to use a connector with a rubber cap that incorporates terminals for both the in-cylinder pressure signal line and the ignition high-voltage cable, and to provide a washer for easy output output. An object of the present invention is to provide a mold cylinder internal pressure sensor.

In order to achieve this object, in another form of the present invention, a signal extraction electrode buried in an insulator is exposed all around the ignition plug to form a terminal part, and a signal line is connected to the terminal part at 1. so that the connector is guided.

The present invention will be described in detail below based on the drawings. FIGS. 2 and 3 show an embodiment of the present invention, where /θ is the in-cylinder pressure sensor of the present invention. Cylinder pressure sensor
/θ is installed by inserting ring-shaped pressure m2 elements //A and //B with a signal extraction electrode /2 which also serves as the center electrode in the part where the two seats and the tightening seat 3B are pressed. As shown in the figure, a ground electrode plate 13 extends from the upper surface of piezoelectric element //A to the lower surface of piezoelectric element //A and //B. An insulating powder /I is provided between the folded part of the ground electrode plate 13 and the piezoelectric elements //A and //B.
- is filled.

/jA is a signal output terminal portion extending along the plug 3A, /S is an electrode /
2 and the terminal portion 7. This is an insulating resin layer provided to ensure insulation between the 2 people and the ground electrode/3.

Note that in forming the insulating resin layer/3 in this way, it is preferable to use molding.Since the signal output terminal portion 7.2A etc. are molded with a thin plate, when using molding, its retention is more reliable. For this reason, it is desirable to have a chrysanthemum or comb shape as in this example.

In the washer type cylinder pressure sensor /θ configured in this way, the signal output terminal part /2A can be reliably held at a position separated from the plug body 3A by the insulating resin layer 15,
Not only does insulation failure due to dirt such as soot be prevented, but the insulation between the ground electrode/3 and the cylinder head λ is maintained, and furthermore, it is easy to attach and detach, and there is no risk of damage due to attachment and detachment.

Next, how to attach a connector for drawing out a lead wire to the in-cylinder pressure sensor/θ having such a configuration will be described with reference to FIG.

Here, ``/'' is an insulating rubber cap, and in this example, the rubber cap ``/'' holds the terminal n of the high voltage cable in a state connected to the ignition plug 3, and at the same time connects the signal line as described later. This not only makes it easy to attach and detach, but also prevents damage to the signal line and has the effect of preventing noise.

That is, 2g is a signal coaxial cable passed through a rubber cap λ/, a shield 1-21/ is inserted into the cape look, a holder B is crimped to A, and a plug is further attached to holder R. It is connected to a group of contact terminals that maintain contact with the circumferential surface of the body 3A at multiple locations. Furthermore, by extending the insulating coated cord part 24ZB of the cable 2g downward and providing a caulking member 27 at the end thereof, the signal line 211O in the cord part 211B folded back at the caulking member l is Connect it to the caulking member blade.

d is the terminal part arranged around the cylinder pressure sensor/θ, 2A
These contact members I are configured to be integrated with the caulking member I.

By configuring the connector for pulling out the lead wires in this way and inserting them into the rubber cap 2/, it is not only possible to attach the signal cable 2 with ease, but also to completely connect the signal cable 2 with the shielded wire jIIA. grounding to prevent noise from entering.

As explained above, according to the present invention, the piezoelectric elements are arranged above and below the signal extraction electrode so as to sandwich it, and the piezoelectric element is arranged continuously from the outer circumference of these piezoelectric elements to the entire side circumference of the spark plug body. A stable signal output terminal is integrated with the ignition plug together with the in-cylinder pressure sensor by arranging an insulating member and exposing the signal output terminal connected to the signal output electrode described above by guiding it to the side from within this insulating member. Because of this, there is no risk of damage to the signal line due to attachment and detachment as in the conventional case, and it is easy to handle and durable.

By arranging the signal output terminal all the way around the plug body, it is possible to extract the signal output through the connector held in the insulated socket cover along with the ignition high voltage cable terminal, making it easy to attach and detach. In addition, there is no risk of contamination, and insulation can be improved to prevent noise from entering.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of the mounting state of a conventional washer type cylinder pressure booster, Fig. 2 is a sectional view showing an example of the configuration of the washer type cylinder pressure sensor of the present invention, and Fig. 3 is a sectional view of the ignition plug. FIG. 4 is a cross-sectional view showing a state in which a high-voltage cable and a signal cable are attached via a capped connector to a spark plug equipped with the present Komei washer-type internal pressure sensor. /...Cylinder pressure sensor, /A...Signal line extraction position, ! ...Cylinder head, 2A...Spark plug installation seat, 3...Spark plug, 3A...Plug body, 3B...Tightening seat, l...Signal line, /θ...Cylinder pressure Sensor, //A, //B...Pressure-6 element, /NO...Signal extraction electrode, /NOA...Signal extraction terminal section, /3...Grounding electrode plate, /II.・Powder, /j...Insulating resin layer, 2no...Cap, 〃...High voltage cable, n...Terminal, 2'l...Signal cable, 2gA...Shield wire, 2 B...Code part, 2'/G...Signal line, holder, 26...Zui f revision, sword...Caulking member, j...Contact member. Applicant: Nissan Motor Co., Ltd. Figure 1

Claims (1)

[Scope of Claims] 1) The ignition plug has the shape of a washer that fits into the ignition plug, and the ignition plug is installed in the cylinder head by detecting changes in cylinder pressure using a piezoelectric element interposed between the seat and the ignition plug, In the washer-type cylinder pressure sensor that outputs the detected electric signal, a continuous insulating member is circumferentially cut from the washer-shaped outer circumference of the piezoelectric element to the side surface of the spark plug, and connected to the piezoelectric element via the insulating member. A washer-type cylinder pressure sensor characterized in that an electric signal extraction electrode is extended and exposed on a side surface of the insulating member to serve as an electric signal extraction terminal. 2) When installing a spark plug in a cylinder head, use a washer-type cylinder pressure sensor that detects changes in cylinder pressure using a piezoelectric element held between a seat and a spark plug, and outputs an electrical signal. An insulating member is provided that extends from the part to the entire circumference of the side surface of the spark plug, and an electric signal extraction electrode connected to the piezoelectric element is extended into the insulating member, and is guided and exposed to the side surface of the insulating member to receive a plurality of electric signals. With or without extraction terminal,
It is possible to use a connector with an insulating socket cover that incorporates a high-voltage cable for ignition of the spark plug and a signal cable connected to a contact that maintains contact with the plurality of electrical outlet terminals. A washer-type cylinder pressure sensor featuring: