JPH08121308A - Cylinder internal pressure sensor integrated ignition device - Google Patents

Abstract

PURPOSE: To provide an ignition device which can be integrated by providing a coil part which serves as a direct type ignition coil, to an ignition plug provided to each air cylinder of an internal combustion engine, and by providing a cylinder internal pressure sensor to this coil part through a cylindrical body. CONSTITUTION: An ignition device 16 consists of a cylindrical support 17, a coil part 19, an ignition plug 30 and a cylinder internal pressure sensor 31. Also, a signal processing circuit 36 to process a signal from the cylinder internal pressure sensor 31, is formed on one side surface of the coil part 19 which becomes the outside of a cylinder head 11. Hereby, the distance between the coil part 19 and the ignition plug 30 can be shortened and a lowering of high voltage can be prevented. Further, heat from the cylinder head 11 can be prevented from being transmitted to the signal processing circuit 36, and the cylinder internal pressure sensor 31 can be detected with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device of the type in which a coil is provided for each cylinder, and more particularly to an in-cylinder pressure sensor integrated ignition device in which an in-cylinder pressure sensor is integrally incorporated in the coil part. .

[0002]

2. Description of the Related Art In general, an ignition device for causing a spark discharge in an ignition plug mounted on a cylinder head of an internal combustion engine uses a voltage of 12 V from a battery as a high voltage by using an ignition coil as a coil portion. There is a distributor system that is higher and supplies the spark plug for each cylinder by the distributor's power distribution unit.

However, in the distributor-type ignition device, a high voltage generated from the ignition coil is supplied to the spark plugs mounted on each cylinder by the distributor while controlling the ignition timing, so that a long high-voltage cable is required. Therefore, there is a problem that the high voltage is lowered due to the voltage drop due to this cable, and noise is generated due to the influence of the electric field generated from the high voltage cable. Further, since the distributor has a power distribution unit that distributes power to each spark plug, the power distribution unit may be worn,
There is also a problem that electric noise is generated from the power distribution unit.

As described above, in order to solve the problems of the ignition device using the distributor, the ignition device without the distributor, so-called DLI (Distributorless).
Ignition) is known. Further, in this ignition device, an ignition coil that generates a high voltage is provided for each cylinder of the cylinder head. Further, this ignition coil is generally called a direct ignition coil, and the direct ignition coil includes a core, a primary coil wound around the outer circumference of the core, and an outer circumference of the core. The primary coil and a secondary coil wound concentrically are generally configured. Further, except that a control unit is used in place of the distributor, the principle of generating a high voltage is similar to that of a distributor ignition coil, but since the ignition coil is provided as a coil portion in the cylinder head, the conventional ignition device is used. The high-voltage cable can be eliminated, and the power distribution unit can be configured by electrical switching (contactless switch).

On the other hand, as an in-cylinder pressure sensor for detecting the combustion pressure of an internal combustion engine, for example, the one described in Japanese Utility Model Laid-Open No. 61-63134 is known. This in-cylinder pressure sensor is a washer made up of an annular piezoelectric body attached to the cylinder head with an initial load applied thereto, and an electrode plate provided on the piezoelectric body for deriving a detection voltage from the piezoelectric body. Type pressure sensors are known. The in-cylinder pressure sensor receives the pressure due to the vibration of the cylinder head generated by the combustion pressure of the internal combustion engine by the piezoelectric body, detects the detection signal as a voltage by the electrode plate according to this pressure, and outputs it to the external control unit. It is designed to output.

[0006]

By the way, in the in-cylinder pressure sensor according to the prior art, a voltage corresponding to the combustion pressure is detected from the piezoelectric body, and this detection signal is transmitted by a transmission cable (harness).
To a control unit provided in the driver's cab of the vehicle, and the signal processing unit provided in the control unit removes noise and performs waveform shaping, etc., and inputs it to the control circuit of the next stage. It was

However, such a conventional in-cylinder pressure sensor has a problem that the output impedance is high and noise is likely to be superimposed because the piezoelectric body uses a piezoelectric type piezoelectric body. In order to solve this, it is possible to connect a low noise cable (Low Noise Cable) with noise countermeasures to the control unit in order to extract the detection voltage from each electrode plate, but in this case the cost is high. At the same time, there is a problem that the detection accuracy of the combustion pressure decreases due to the temperature characteristics of the low noise cable.

Therefore, after performing signal processing so that the detection voltage from the in-cylinder pressure sensor can be transmitted, a filter circuit and a preamplifier circuit are provided for outputting to the control unit via a signal cable. A signal processing circuit is provided in the vicinity of the in-cylinder pressure sensor, and the signal processing circuit removes the influence of noise in advance and reduces impedance to reduce the influence of noise on the output after amplification.

Therefore, in the direct ignition coil described above, the coil portion is provided in the cylinder head, and the in-cylinder pressure sensor is also provided in the cylinder head. These coil portion and in-cylinder pressure sensor are provided in the cylinder head. Focusing on the provision of the signal processing circuit and the signal processing circuit on the cylinder head side, it is considered.

However, when the coil portion and the in-cylinder pressure sensor are integrally provided in the cylinder head and the signal processing circuit is provided in the cylinder head, how to secure a space for accommodating the signal processing circuit, and There is an unsolved problem of how to protect a signal processing circuit composed of electronic parts and the like against high heat of the cylinder head.

The present invention has been made in view of the above-mentioned unsolved problems. In the present invention, when a coil portion which serves as an ignition coil and an in-cylinder pressure sensor for detecting combustion pressure are integrated, a signal processing portion is provided inside the coil portion. An object of the present invention is to provide an in-cylinder pressure sensor integrated ignition device that is housed.

Another object of the present invention is to provide an in-cylinder pressure sensor integrated ignition device which has improved heat resistance against high heat from the cylinder head side when the signal processing section is housed in the coil section. Is intended.

[0013]

In order to solve the above-mentioned problems, an in-cylinder pressure sensor integrated ignition device adopted by the invention of claim 1 is a plug formed in a cylinder head of an internal combustion engine toward a combustion chamber. A tubular body inserted into the insertion hole, a coil portion located on one axial side of the tubular body to close the plug insertion hole, and an axially other side of the tubular body. Is located at the bottom of the plug insertion hole and is electrically connected to the coil portion, and is located on the other side in the axial direction of the tubular body for detecting the combustion pressure in the combustion chamber. The in-cylinder pressure sensor is provided as well as the signal processing section that is provided in the coil section and has an electronic component for processing the detected voltage from the in-cylinder pressure sensor.

According to a second aspect of the present invention, the signal processing section is provided on one side surface of the coil section so as to be located outside the cylinder head.

According to a third aspect of the present invention, the in-cylinder pressure sensor is
An annular piezoelectric body located at the bottom of the plug insertion hole and attached with an initial load applied by the ignition plug, and an electrode plate provided on the piezoelectric body for deriving a detection voltage from the piezoelectric body It consists of and.

According to a fourth aspect of the present invention, the coil section is provided with a cooling means located near the signal processing section for circulating cooling water.

According to a fifth aspect of the present invention, a housing recess for housing the signal processing unit is provided on one side surface of the coil unit, and a bottom surface of the housing recess is a substrate on which electronic parts of the signal processing unit are mounted. This is because a plurality of protrusions that contact each other are formed.

According to a sixth aspect of the present invention, cooling fins are formed on the outer periphery of the coil portion.

[0019]

According to the invention of claim 1, the coil portion is provided on one side in the axial direction and the ignition plug is provided on the other side through the tubular body inserted into the plug insertion hole of the cylinder head, and the tubular body Since the cylinder pressure sensor is located on the other side in the axial direction, the distance between the coil portion and the spark plug can be shortened,
The voltage drop of the high voltage supplied from the coil to the spark plug can be reduced.

Further, by providing the signal processing section in the coil section, a space for accommodating the signal processing circuit can be secured, and the detection signal from the in-cylinder pressure sensor is pre-filtered and pre-amplified to obtain a signal. By transmitting, it is possible to prevent noise from being superimposed on the detection signal.

According to the second aspect of the present invention, by providing the signal processing section on one side surface of the coil section located outside the cylinder head, the distance between the signal processing section and the cylinder head can be secured, and the inside of the bonnet can be secured. It can be exposed to cold air, the signal processing unit can be prevented from reaching a high temperature, and electronic components can be protected.

According to the third aspect of the present invention, since the in-cylinder pressure sensor is composed of the ring-shaped piezoelectric body mounted in the state in which the initial load is applied, and the electrode plate provided on the piezoelectric body,
The pressure due to the vibration of the cylinder head generated by the combustion pressure of the internal combustion engine is received by the piezoelectric body, and this pressure can be detected from the electrode plate as a detection signal.

According to the fourth aspect of the present invention, the coil section is provided with the cooling means for circulating the cooling water in the vicinity of the signal processing section, so that the vicinity of the signal processing section is forcibly cooled and the signal processing section The temperature rise can be suppressed and electronic components can be protected.

According to the fifth aspect of the present invention, the coil portion is formed by forming a plurality of protrusions on the bottom surface of the accommodating recess for accommodating the signal processing unit and holding the substrate of the signal processing unit in the accommodating recess by point contact. It is possible to reduce conduction of heat from the substrate to the substrate.

As in the sixth aspect of the present invention, by forming the cooling fins on the outer circumference of the coil portion forming the circuit processing portion, the heat radiation area can be increased and the temperature rise can be prevented.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 8, and FIGS. 1 to 3 show a first embodiment of the present invention.

In the drawing, reference numeral 11 denotes a cylinder head of an internal combustion engine. A combustion chamber 12 is formed for each of a plurality of cylinders (only one is shown) in the cylinder head 11, and the combustion chamber is provided in the cylinder head 11. A plug insertion hole 13 extending toward 12 and a plug screw hole 14 formed in a hole bottom 13A of the plug insertion hole 13 and communicating with the combustion chamber 12 are formed. Further, a rectangular accommodating portion 15 for accommodating a coil portion 19, which will be described later, is formed at the opening of the plug insertion hole 13, and the accommodating portion 15 has screw holes 15A, 15
A is formed.

Reference numeral 16 denotes an ignition device according to this embodiment. The ignition device 16 includes a cylindrical support 17 described later, and a coil portion 19 provided on one side of the cylindrical support 17 in the axial direction.
The cylinder plug 17 is generally configured by an ignition plug 30 and an in-cylinder pressure sensor 31 which are provided on the other side in the axial direction of the cylindrical support 17.

Reference numeral 17 denotes a tubular support as a tubular body, and the tubular support 17 is made of a resin material or a metal material in a tubular shape, and is provided in the plug insertion hole 13 of the cylinder head 11. . An annular sensor mounting portion 17A is formed on one side in the axial direction of the tubular support 17 as shown in FIG. 2, and a seal member formed of a soft rubber material in a stepped cylindrical shape on the other side in the axial direction. 18 is fitted. Further, the seal member 18 is formed with an annular positioning recess 18A.

Reference numeral 19 denotes a coil portion which is provided on one axial side of the cylindrical support 17 and constitutes a direct ignition coil. The coil portion 19 is accommodated so that the other side surface closes the plug insertion hole 13. A coil case 20 which is provided in the portion 15 and is formed in a rectangular parallelepiped shape having a connector portion 20A made of an insulating resin material; a coil case 20 which is provided in the coil case 20 and has both ends projecting from the coil case 20; Core 2 with 21A
1, a primary coil 23 wound around a primary coil bobbin 22 located on the outer periphery of the core 21, and the primary coil 23.
And a secondary coil 25 wound around a secondary coil bobbin 24 located on the outer periphery of the secondary coil bobbin 24. The primary coil 23 and the secondary coil 25 are concentrically arranged with the core 21 as an axis. .

Further, a circuit accommodating portion 26 as an accommodating concave portion for accommodating a signal processing circuit 36 described later is formed on one side surface of the coil portion 19, and a positioning concave portion 18A for the sealing member 18 is formed on the other side surface. An annular positioning convex portion 19A that engages with is formed to project. Here, the circuit accommodating portion 26 is recessed in one side surface of the coil portion 19 so as to open toward the outside (inside the hood) of the cylinder head 11.

Numeral 27 is provided on the inner peripheral side of the positioning projection 19A on the other side of the coil portion 19, and is provided in the plug insertion hole 13
An insulating cylinder extending inward is shown. The insulating cylinder 27 is formed of a heat-resistant hard rubber member in a stepped cylinder shape, one side in the axial direction is fixed to the coil portion 19, and the spark plug 30 is provided on the other side.
Holding section 27A for holding the insulator 30F
Are formed. A rod-shaped metal terminal 28 is inserted and held on the inner peripheral surface of the insulating cylinder 27 in the axial direction.
One end of 8 is a secondary coil 25 provided in the coil portion 19.
And the other end is connected to a spark plug 30 via a conductive spring 29.

Reference numeral 30 denotes an ignition plug which is located on the other side in the axial direction of the cylindrical support 17 and is screwed into the plug screwing hole 14, and the ignition plug 30 is sequentially arranged from the base end to the tip. Ignition electrode part 30A, screw part 30B, gasket 3
0C, housing 30D, hexagonal nut portion 30E, insulator 30F, and input terminal 30G. Further, when mounting the spark plug 30,
When the threaded portion 30B is screwed into the plug screwing hole 14, the in-cylinder pressure sensor 31, the washer 32, and the sensor mounting portion 17A of the cylindrical support 17 are provided between the hole bottom 13A of the plug insertion hole 13 and the housing 30D. Hold it together. The ignition electrode portion 30A of the spark plug 30 is held in the combustion chamber 12 in an open state. Further, the insulating cylindrical body 27 is inserted from the tip end side of the spark plug 30, and the plug holding portion 27A
By holding the insulator 30F at, the input terminal 30G of the ignition plug 30 is electrically connected to the coil portion 19 via the spring 29 and the metal terminal 28.

Reference numeral 31 denotes an in-cylinder pressure sensor according to this embodiment. The in-cylinder pressure sensor 31 is located on the other side in the axial direction of the cylindrical support 17 and the spark plug 30 and the plug insertion hole 1 are provided.
Washer 32 and cylindrical support 1 between hole bottom 13A of 3
7 and the sensor mounting portion 17A. The in-cylinder pressure sensor 31 detects the pressure inside the combustion chamber 12, and is also called a combustion pressure sensor.

Here, as shown in FIG. 2, the in-cylinder pressure sensor 31 has a sensor mounting portion 17 of the cylindrical support 17.
Located at A, and the spark plug 30 and the plug screw hole 1
4, a ring-shaped piezoelectric body 33 attached under an initial load, and a pair of ring-shaped electrode plates 34, 34 provided on both axial side surfaces of the piezoelectric body 33.
A lead wire 35 for leading a detection signal detected from each electrode plate 34 to a signal processing circuit 36 is provided along the cylindrical support 17, and the lead wire 35 is formed of a flexible substrate.

Reference numeral 36 denotes a signal processing circuit as a signal processing unit, and the signal processing circuit 36 is connected to the lead wire 35 via a connection line 37 shown in a dotted line provided in the coil unit 19. The signal processing circuit 36 is accommodated in the circuit accommodating portion 26 formed on one side surface of the coil portion 19 and arranged so as to be located outside the cylinder head 11.

Here, the signal processing circuit 36 is a substrate 36.
A and an electronic component 36B such as a filter circuit and a preamplifier circuit mounted on the substrate 36A. The signal processing circuit 36 performs noise removal and preamplification processing of the detection voltage output from the in-cylinder pressure sensor 31. It is corrected to a detection signal that can be transmitted. In addition, the signal processing circuit 36
The electronic component 36B mounted on the substrate 36A is also provided with a power transistor or the like having a switching characteristic for interrupting the current applied to the primary coil 23 in the coil portion 19.

38 is a connector portion 20 of the coil case 20.
An output terminal embedded in A, the output terminal 38 is connected to the primary coil 23, the secondary coil 25, and the signal processing circuit 36, and extends to the connector portion 20A.

Reference numerals 39 and 39 denote screws. The ignition device 16 is fixed to the accommodating portion 15 of the cylinder head 11 by screwing each screw 39 into the screw hole 15A through the mounting hole 21A of the core 21.

Next, the assembling of the ignition device 16 according to this embodiment to the cylinder head 11 will be described.

First, the sensor mounting portion 1 of the tubular support 17
7A, the cylinder pressure sensor 31 previously attached to the cylinder head 11 is inserted into the plug insertion hole 13 of the cylinder head 11, and the cylinder pressure sensor 31 is positioned so as to come into contact with the hole bottom 13A of the plug insertion hole 13. The spark plug 30 is inserted into the support 17 using a jig (plug wrench) not shown, and rotated through the hexagonal nut portion 30E to rotate the screw portion 30.
Screw B into the plug screw hole 14. At this time, the washer 32, the in-cylinder pressure sensor 31, and the sensor mounting portion 17A of the cylindrical support 17 are sandwiched between the housing 30D and the hole bottom 13A via the gasket 30C. When the spark plug 30 is completely screwed into the plug screw hole 14, the washer 32, between the housing 30D of the spark plug 30 and the hole bottom 13A of the plug insertion hole 13,
The in-cylinder pressure sensor 31 and the sensor mounting portion 17A of the cylindrical support 17 are clamped and clamped, and in particular, the piezoelectric body 33 of the in-cylinder pressure sensor 31 is in an initial load.

Next, the insulating cylinder 27 is inserted into the cylindrical support 17 while aligning the coil portion 19 with the insulating cylinder 27 attached to the accommodating portion 15, and the plug of the insulating cylinder 27 is inserted. It is pushed in until the holding portion 27A holds the insulator 30F, and in this state, each mounting hole 21A of the core 21 is pushed.
And each screw hole 15A are aligned and fixed with screws 39, 39.

This completes the mounting of the ignition device 16 including the ignition plug 30 and the in-cylinder pressure sensor 31 in the housing portion 15 of the cylinder head 11.

In the ignition device 16 of this embodiment constructed as described above, the operation of generating a high voltage utilizes the electromagnetic induction action that occurs when the low-voltage DC current applied to the primary coil 23 is suddenly cut off. To generate a high voltage in the secondary coil 25 and supply the high voltage to the spark plug 30 via the metal terminal 28, and the ignition electrode portion 30A of the spark plug 30.
Spark discharge can be caused by.

Further, from the secondary coil 25 to the spark plug 30
The distance to which a high voltage is supplied can be shortened, and by using the metal terminal 28 for the connection, the voltage drop can be reduced, and a plug mistake (ignition failure) due to the ignition plug 30 can be prevented to improve the ignitability. it can.

Further, in the ignition device 16 of this embodiment, the in-cylinder pressure sensor 31 is provided on the other side of the cylindrical support 17 in the axial direction, and the circuit is housed in the coil case 20 constituting the coil portion 19 located on one side in the axial direction. Since the portion 26 is formed and the signal processing circuit 36 for removing the noise in the detection voltage from the in-cylinder pressure sensor 31 is provided in the circuit housing portion 26, the coil case 20 forming a part of the coil portion 19 is used. The signal processing circuit 36 can be housed in the ignition device 16
Can be made compact.

Further, since the signal processing circuit 36 is provided on one side surface of the coil portion 19, the distance between the cylinder head 11 serving as a heat source and the signal processing circuit 36 can be increased, and the cool air in the bonnet can be obtained. Can be exposed. For this reason, it is possible to suppress the temperature of the circuit housing portion 26 from becoming high, and the electronic component 36B of the signal processing circuit 36 is shielded from high heat on the cylinder head 11 side, and heat resistance is improved.
As a result, it is possible to reliably prevent the electronic component 36B from being damaged by heat and malfunctioning.

Further, the cylinder pressure sensor 31 and the signal processing circuit 3
6 is connected by a lead wire 35 and a connecting wire 37, the distance can be shortened, and fluctuations in the detection voltage from the in-cylinder pressure sensor 31 and noise superposition are reliably prevented. it can.

Therefore, in the ignition device 16 according to the present embodiment, the coil portion 19 and the in-cylinder pressure sensor 31 are integrally provided in the cylinder head 11, and noise in the detected voltage from the in-cylinder pressure sensor 31 is removed. By providing the signal processing circuit 36 in the coil case 20 of the coil unit 19, the signal processing circuit 36 can be compactly housed and highly accurate detection of the in-cylinder pressure sensor 31 can be performed.

Further, by providing the signal processing circuit 36 on one side surface of the coil portion 19 separated from the cylinder head 11, a distance between the cylinder head 11 which is a heat source and the signal processing circuit 36 can be secured, and the signal processing circuit 36 can be secured. The thermal destruction of 36 can be reliably prevented.

Further, in this embodiment, the cylinder pressure sensor 31 is used.
Without using a low noise cable that was considered to prevent noise from being superimposed on the detection signal from
Since noise can be removed, the cost can be significantly reduced compared to the low noise cable.

As a result, in the ignition device 16, the in-cylinder pressure sensor 31 capable of highly accurate detection can be integrated with the coil portion 19 which constitutes the direct ignition coil. Further, a combustion pressure detection signal from the in-cylinder pressure sensor 31 and an ignition signal to the ignition plug 30 can be transmitted by one connector portion 20A.

Next, FIG. 4 and FIG. 5 show a second embodiment of the present invention. The feature of this embodiment is that a cooling means for circulating cooling water is provided on the lower surface of the circuit accommodating portion. . In addition,
The same components as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 41 denotes a coil portion according to this embodiment, and the coil portion 41 is the coil portion 1 described in the first embodiment.
9, the coil case 20 having the connector portion 20A and the core 21 provided in the coil case 20
A primary coil 23 wound around a primary coil bobbin 22 and a secondary coil 25 wound around a secondary coil bobbin 24. However, the feature of this embodiment is that the coil portion 4
Circuit accommodating portion 4 as an accommodating recess formed on one side surface
On the lower side of 2, a water jacket 43 as a cooling means is formed by a plurality of cooling passages 43A, 43A, ....

Further, reference numerals 44 and 44 (only one is shown) in FIG. 5 are cooling water passage pipes for supplying cooling water to the water jacket 43, and the cooling water passage pipe 44 is connected to a radiator (not shown). ing.

Even in the ignition device of this embodiment having the above-described structure, the same effects as those of the first embodiment described above can be obtained. However, in the present embodiment, the cooling water passage pipe 44 is used to remove water. The circuit housing portion 42 can be forcibly cooled by the cooling water flowing through the jacket 43 to prevent the circuit housing portion 42 from reaching a high temperature, and the electronic component 36B of the signal processing circuit 36 is protected from the high heat of the cylinder head 11. It is possible to protect and effectively prevent thermal destruction of the electronic component 36B.

Next, FIG. 6 shows a third embodiment according to the present invention. The feature of this embodiment is that a plurality of protrusions 51A, 51A, ... Are formed on the bottom of the circuit housing 51 as a housing recess. There is something I did.

As a result, the substrate 36A can be supported in the circuit accommodating portion 51 by point contact, heat transfer from the coil portion 19 to the substrate 36A can be suppressed, and the same effect as that of the first embodiment can be obtained. it can.

Further, FIG. 7 shows a fourth embodiment according to the present invention, and the feature of this embodiment is that cooling fins 61, 61, ... Are formed on the outer periphery of the circuit accommodating portion 26 of the coil portion 19. .

As a result, the heat radiation area can be increased, the temperature rise can be prevented, and the same effect as that of the first embodiment can be obtained.

Next, FIG. 8 shows a fifth embodiment according to the present invention. The feature of this embodiment is that the circuit accommodating case 71, which is a separate member, is provided in the circuit accommodating portion 26 of the coil case 20,
The circuit housing case 71 is formed by a heat insulating material such as ceramics.

As a result, the signal processing circuit 36 can be adiabatically housed in the circuit housing case 71, heat from the coil portion 19 can be prevented from being transferred to the signal processing circuit 36, and an operation similar to that of the first embodiment is achieved. The effect can be obtained.

In each of the above embodiments, the coil portion 19
Primary coil 23 and secondary coil 25 provided in (41)
The relation with the primary coil 23 is set to the inner side,
The present invention is not limited to this, and the secondary coil 25 may be replaced by the primary coil 2.
Of course, it may be arranged inside 3.

Further, the in-cylinder pressure sensor 31 is not limited to the one in each of the above-mentioned embodiments, but may be one having a shape in which piezoelectric layers are laminated in two or three layers and an electrode plate is arranged between each layer. Good.

Further, the signal processing circuit 36 includes a coil section 19
Although it has been described that it is provided on one side surface so as to be distant from the cylinder head 11, it may be provided so as to be provided inside the coil case 20, and its attachment position can be appropriately selected.

[0066]

As described in detail above, according to the present invention of claim 1, the coil portion is axially on one side and the ignition plug is on the other side via the cylindrical body inserted into the plug insertion hole of the cylinder head. Since the coil portion and the ignition plug are electrically connected and the in-cylinder pressure sensor is provided on the other side in the axial direction of the cylindrical body, the distance between the coil portion and the ignition plug can be shortened, It is possible to reduce the voltage drop of the high voltage supplied from the coil portion to the spark plug. As a result, the ignition failure of the internal combustion engine can be prevented and the drivability of the internal combustion engine can be improved.

Further, by providing the coil section with the signal processing section having electronic parts for processing the detection voltage from the in-cylinder pressure sensor, a space for accommodating the signal processing circuit is secured by utilizing the inside of the coil section. Therefore, it is possible to prevent noise from being superposed on the detection voltage from the in-cylinder pressure sensor, and to detect the combustion pressure in the combustion chamber with high accuracy.

According to the second aspect of the present invention, by providing the signal processing section on one side surface of the coil section so as to be located outside the cylinder head, the distance between the signal processing section and the cylinder head serving as the heat source is increased. It is possible to secure the temperature of the signal processing unit, prevent the signal processing unit from being heated to a high temperature, expose the bonnet to the cool air, protect the electronic components forming the signal processing unit, and prevent the electronic components from being thermally destroyed. You can Thus, the in-cylinder pressure sensor that can detect the combustion pressure in the combustion chamber with high accuracy can be integrated with the ignition device.

According to a third aspect of the present invention, an in-cylinder pressure sensor is attached with an annular piezoelectric body mounted with an initial load applied between the ignition plug and the bottom of the plug insertion hole.
Since it is composed of the electrode plate provided on the piezoelectric body, the piezoelectric body receives the pressure due to the vibration of the cylinder head caused by the combustion pressure of the internal combustion engine, and this pressure can be detected as a voltage signal. Can be accurately detected.

According to the fourth aspect of the invention, the coil section is provided with the cooling means by the cooling water in the vicinity of the signal processing section.
It is possible to forcibly cool the vicinity of the signal processing unit, suppress an increase in temperature of the signal processing unit, and protect the electronic components forming the signal processing unit.

According to the invention of claim 5, a plurality of protrusions for holding the board on which the electronic parts of the signal processing unit are mounted in point contact are formed on the bottom surface of the accommodating recess for accommodating the signal processing unit. The heat from the coil portion is prevented from being conducted to the substrate.

In the sixth aspect of the present invention, the cooling fins are formed on the outer circumference of the coil portion forming the circuit processing portion, thereby increasing the heat radiation area and preventing the temperature rise.

As described above, according to the inventions of claims 4 to 6, by suppressing the temperature of the circuit processing unit from becoming high temperature by various means, thermal destruction and malfunction of the electronic parts constituting the circuit processing unit are prevented. However, the combustion pressure in the combustion chamber can be detected with high accuracy by the in-cylinder pressure sensor.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an in-cylinder pressure sensor integrated ignition device according to a first embodiment.

FIG. 2 is an enlarged vertical sectional view showing an enlarged in-cylinder pressure sensor in FIG.

FIG. 3 is an exploded perspective view showing a state before the cylinder pressure sensor integrated ignition device according to the first embodiment is mounted on the cylinder head.

FIG. 4 is a vertical sectional view showing an in-cylinder pressure sensor integrated ignition device according to a second embodiment.

FIG. 5 is an exploded perspective view showing a state before the cylinder pressure sensor integrated ignition device according to the second embodiment is mounted on the cylinder head.

FIG. 6 is a vertical sectional view showing an in-cylinder pressure sensor integrated ignition device according to a third embodiment.

FIG. 7 is an exploded perspective view showing a state before the cylinder pressure sensor integrated ignition device according to the fourth embodiment is mounted on a cylinder head.

FIG. 8 is a vertical cross-sectional view showing an in-cylinder pressure sensor integrated ignition device according to a fifth embodiment.

[Explanation of symbols]

 11 Cylinder Head 12 Combustion Chamber 13 Plug Insertion Hole 13A Hole Bottom 14 Plug Screwing Hole 16 Ignition Device 17 Cylindrical Support (Cylindrical Body) 19,41 Coil Part 20 Coil Case 21 Core 23 Primary Coil 25 Secondary Coil 26, 42, 51 Circuit accommodating part (accommodating concave part) 28 Metal terminal 30 Spark plug 31 In-cylinder pressure sensor 33 Piezoelectric body 34 Electrode plate 36 Signal processing circuit (signal processing part) 36A board 36B Electronic component 43 Water jacket (cooling means) 51A Protrusion 61 Cooling fins

Claims (6)

[Claims] 1. A cylindrical body inserted into a plug insertion hole formed in a cylinder head of an internal combustion engine toward a combustion chamber,
A coil portion located on one axial side of the tubular body and provided to close the plug insertion hole, and a coil portion located on the other axial side of the tubular body on the bottom of the plug insertion hole. Is provided,
An ignition plug electrically connected to the coil portion, an in-cylinder pressure sensor provided on the other side in the axial direction of the tubular body for detecting the combustion pressure in the combustion chamber, and the coil portion. And an in-cylinder pressure sensor integrated ignition device including a signal processing unit including an electronic component for processing a detection voltage from the in-cylinder pressure sensor. 2. The in-cylinder pressure sensor integrated ignition device according to claim 1, wherein the signal processing section is provided on one side surface of the coil section so as to be located outside the cylinder head. 3. The in-cylinder pressure sensor is located at the bottom of the plug insertion hole, is attached to the piezoelectric body with an annular piezoelectric body mounted in a state where an initial load is applied by the ignition plug, and The in-cylinder pressure sensor integrated ignition device according to claim 1, which is composed of an electrode plate for deriving a detection voltage from the piezoelectric body. 4. The coil unit is provided with cooling means located near the signal processing unit for circulating cooling water.
The in-cylinder pressure sensor integrated ignition device. 5. A housing recess for housing the signal processing unit is provided on one side surface of the coil unit, and a plurality of substrates on which electronic components of the signal processing unit are mounted are in point contact with a bottom surface of the housing recess. The in-cylinder pressure sensor integrated ignition device according to claim 1, wherein the ignition device comprises a protrusion. 6. The in-cylinder pressure sensor integrated ignition device according to claim 1, wherein cooling fins are formed on the outer periphery of the coil portion.