JPH05149235A - Ignition voltage detecting device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an ignition voltage detecting device, for an internal combustion engine, which is excellent in detecting accuracy and durability and with no necessity of a protecting circuit for coping with a leak of high voltage and to attain lightness in weight and smallness in size. CONSTITUTION:A sensor 1 is constituted of a block unit 2 consisting of an insulating material having insertion holes 3 of water-tightly inserting high tension cords 4, electric conductors 6 arranged with a predetermined space H in the outside in a diametric direction from a peripheral edge part of the insertion hole 3 in this block unit 2 and an insulator 8 consisting of ceramic arranged to be positioned between the insertion hole 3 and the electric conductor 6 in the block unit 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition voltage detection device for an internal combustion engine which detects the ignition voltage of a spark ignition type internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a device for detecting an ignition voltage on a secondary side in an ignition system of an internal combustion engine is known. This is as disclosed in JP-A-52-118135.
By winding a band made of a conductor as a sensor on the outside of a high-voltage cord (high-tension cord) to which a spark plug or the like is connected, a minute capacitor having a covering insulator of the high-voltage cord as a dielectric is formed, and The conductor is connected in series with a measuring capacitor whose one end is grounded. Then, according to the principle of electrostatic voltage division, a predetermined signal voltage is obtained in the measuring capacitor,
It is possible to confirm that the ignition voltage is generated.

[0003]

However, when it is attempted not only to confirm that the ignition voltage is generated but also to accurately measure the waveform of the ignition voltage, in the above-mentioned conventional apparatus, the high voltage cord is used. Since it is a simple structure that only a band made of a conductor is wound around, the capacitance is likely to change due to vibration and temperature (moisture), which causes large fluctuations in the measurement voltage and causes problems in detection accuracy and durability. there were. Further, since high voltages of tens of thousands of volts are close to each other, a large-scale protection circuit is required in order to cope with a high voltage leak, which causes a problem that the configuration becomes complicated accordingly.

The present invention has been made in view of the above circumstances, and an object thereof is to provide excellent detection accuracy and durability, and to eliminate the need for a protection circuit for coping with high voltage leakage, and to make it lightweight and compact. An ignition voltage detection device for an internal combustion engine is provided.

[0005]

In order to achieve the above object, the present invention provides an internal combustion engine which detects the ignition voltage of the internal combustion engine by providing a sensor outside the secondary high voltage cord in the ignition system of the internal combustion engine. In the ignition voltage detection device, the sensor includes a block body made of an insulating material having an insertion hole through which the high-voltage cord is watertightly inserted, and a predetermined space radially outside the peripheral portion of the insertion hole in the block body. And an insulator made of ceramic and disposed between the insertion hole and the conductor in the block body.

In order to achieve the same purpose, the present invention also provides
In an ignition voltage detection device for an internal combustion engine, wherein a sensor is provided outside a secondary high pressure cord in an ignition system of an internal combustion engine having a plurality of cylinders to detect an ignition voltage of the internal combustion engine. A block body made of an insulating material having a plurality of insertion holes corresponding to the number of cylinders, and arranged in the block body at predetermined intervals radially outside of the peripheral portions of the plurality of insertion holes. It is characterized by comprising a conductor provided and an insulator made of ceramic disposed in the block body between the insertion hole and the conductor.

[0007]

In the ignition voltage detecting device for the internal combustion engine according to the first and second aspects, the high-voltage cord is watertightly inserted through the insertion hole of the block body made of an insulating material, and there is a predetermined interval radially outside the high-voltage cord. Since the conductor is disposed on the substrate, the durability and the insulation are excellent, and high detection accuracy and stable output can be secured. Further, since the insulator made of ceramic is provided between the insertion hole and the conductor, the corona discharge from the high-voltage cord can be prevented and the conductor can be brought close to the high-voltage cord. Also, deterioration of the conductor can be prevented.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a longitudinal sectional view of a sensor in an ignition voltage detecting device for an internal combustion engine according to a first embodiment of the present invention, and FIG. 2 is a partially cutaway plan view of the sensor. In the figure, reference numeral 1 denotes a sensor of an ignition voltage detecting device, which has a block body 2 made of an insulating material such as rubber (EPDM) having a high withstand voltage or silicon. The block body 2 has a substantially rectangular cross section, and a plurality of (four in this embodiment) insertion holes 3 are formed in correspondence with the number of cylinders of an internal combustion engine (not shown).
The center of each of these insertion holes 3 is located on the same straight line (center line of the block body 2) L orthogonal to its axis, and they are arranged at equal intervals in a direction orthogonal to the axis. ..

Secondary-side high-voltage cords 4 in the ignition system of the internal combustion engine are watertightly inserted in the respective insertion holes 3. These high-voltage cords 4 are obtained by coating the core wire 4a with inner and outer double coating layers 4b and 4c. The core wire 4a is
A conductive material made of nichrome wire or the like is wound around an center line made of aramid fiber or the like through an insulating material. The inner coating layer 4b is made of an insulating material such as flexible crosslinked polyethylene or rubber (EPDM) having a high withstand voltage. Further, the outer coating layer 4c is made of rubber (EPD) having high withstand voltage.
It is made of an insulating material such as M). The inner diameter of each insertion hole 3 is set to be larger than the outer diameter of the high-voltage cord 4. On both inner peripheral surfaces of both ends of each insertion hole 3, a waterproof annular lip portion 5 is integrally provided so as to project. The inner peripheral surfaces of the annular lip portions 5 are in close contact with the outer peripheral surface of the high-voltage cord 4 as shown in FIG. 3, and the annular lip portions 5 allow water to flow between the insertion hole 3 and the high-pressure cord 4. Intrusion is prevented.

In the block body 2, a conductor 6 is arranged corresponding to each insertion hole 3. These conductors 6 form an annular (cylindrical) shape that is concentric with the insertion hole 3. Each of the conductors 6 is located outside the peripheral edge of the insertion hole 3 in the radial direction by a predetermined distance H. The distance H is a value such that the conductor 6 is not affected by corona discharge from the high voltage cord 4, and is, for example, about 5 mm to 10 mm. Each conductor 6
Are integrally connected to each other at their adjacent portions.
The conductor 6 at one end (the left end in FIGS. 1 and 2) is connected to one end of a conductive wire 7 made of a shield wire. The conductive wire 7 is formed by winding a shield material made of a conductive material around a core wire made of a conductive material with an insulator interposed therebetween, and covering the outer side of the core material with an exterior material made of an insulator. The other end of the conductive wire 7 extends outward from one end face in the longitudinal direction of the block body 2. The conductive line 7 allows the signal voltage of the conductor 6 to be extracted to the outside of the block body 2. An insulator 8 made of ceramic is disposed in the annular space between the insertion hole 3 and the conductor 6.

The conductor 6 and the insulator 8 are set in a mold for the block body 2 with the conductive wire 7 connected to the conductor 6 in advance, and the block body 2 is molded to form the block body 2. It is molded by the block body 2.

The sensor 1 of the ignition voltage detecting device constructed as described above is incorporated in the ignition system of the internal combustion engine as shown in FIGS. That is, one end of the high-voltage cord 4 inserted into each insertion hole 3 of the block body 2 of the sensor 1 has an ignition plug 9
The other end is connected to the output side of the distributor 10. Further, the conductive wire 7 extending outside the block body 2 of the sensor 1 is connected to the input side of the detection unit 11. The detection unit 11 and the sensor 1 constitute an ignition voltage detection device. This detection unit 1
The output side of 1 is connected to the input side of the ECU 12. The output side of the ECU 12 is connected to the input side of the distributor 10 via an igniter 13, an ignition coil 14 and a diode 15. Note that FIG.
16 is a power supply (battery), and its positive electrode is a resistor 17
It is connected to the ignition coil 14 via.
The detection unit 11 has a determination circuit 18 that determines whether or not the ignition voltage is normal. The determination circuit 18 has an operational amplifier 19, a capacitor 21 and resistors 22 and 23.

Next, the operation will be described.

A high voltage is generated on the secondary side because the igniter 13 cuts off the primary current of the ignition coil 14 by the ignition signal from the ECU 12 which is output in synchronization with the ignition timing adjusted and set according to the number of revolutions of the internal combustion engine. Then, this high voltage is distributed to the spark plug 9 of each cylinder via the distributor 10 and the high voltage cord 4, and each cylinder is ignited.

The high voltage, that is, the ignition voltage is detected by the sensor 1, and the detected voltage signal is detected by the detection unit 11.
Is input to the ECU 12 and compared with a predetermined voltage value set in advance in the determination circuit 18 to determine whether the ignition voltage is normal. The determination signal is input to the ECU 12 as information for adjusting the ignition timing. ..

The above operation is similar to the conventional one.

In the present embodiment, the conductors 6 are arranged radially outside the peripheral edge of the insertion hole 3 of the block body 2 made of an insulating material, and the high-voltage cord 4 is inserted in the insertion hole 3. Since the connector is inserted, the conductor 6 is arranged in a state in which a predetermined distance is accurately ensured with respect to the high voltage cord 4. Therefore, the adverse effect of the conductor 6 due to the corona discharge phenomenon generated from the high-voltage cord 4 can be prevented, the durability of the conductor 6 can be improved, and high detection accuracy and stable output can be obtained.

Further, since the insulator 8 made of ceramic is provided between the insertion hole 3 and the conductor 6, corona discharge from the high voltage cord is surely prevented and the conductor 6 is brought closer to the high voltage cord 4. Therefore, it is possible to reduce the weight and size of the sensor 1 as a whole, prevent deterioration of the conductor 6, and improve its durability.

Further, since the high-voltage cord 4 is watertightly inserted into the insertion hole 3 of the block body 2, the capacitance of the conductor 6 is less likely to be affected by vibration, humidity (moisture) or the like. Also,
The diameter of the insertion hole 3 is set to be larger than the outer diameter of the high pressure cord 4, and the waterproof annular lip portion 5 provided on the inner peripheral surface of the insertion hole 3 ensures water tightness between the insertion hole 3 and the high pressure cord 4. By doing so, the high pressure cord 4 can be easily inserted into the insertion hole 3 while ensuring the watertightness between the insertion hole 3 and the high pressure cord 4.

Further, since the plurality of conductors 6 are integrally connected to each other, only one conductor wire 7 for extracting the signal voltage thereof to the outside of the block body 2 is required, and the sensor 1 as a whole can be reduced in size and weight. .. Further, since the conductive wire 7 is a shield wire, the resistance to radio interference and noise resistance are improved, and the influence of disturbance noise on the detected voltage can be prevented.

[Second Embodiment] FIG. 5 is a vertical sectional view of a sensor 1 according to a second embodiment of the present invention. In this embodiment, one flat plate-shaped conductor 6 having a length extending over each of the insertion holes 3 is arranged so as to be displaced to one side in the radial direction with respect to the center of the insertion hole 3, and one end of the conductor 6 is arranged. In addition to connecting the conductive wire 7 to, an insulator 8 made of ceramic is attached to the entire inner surface (side surface of the insertion hole 3) of the conductor 6. Other configurations are shown in FIG.
Since it is the same as the first embodiment shown in FIG. 4, the same reference numerals are given to the same portions in the drawings and the description thereof will be omitted.

[Third Embodiment] FIG. 6 is a vertical sectional view of a sensor 1 according to a third embodiment of the present invention. In this embodiment, a pair of flat plate-shaped conductors 6 having the same insulator 8 as that of the second embodiment shown in FIG. A projecting wall that is symmetrically arranged on both sides in the radial direction with respect to the center, has one conductive wire 7 connected to one end of each of the conductors 6 and 6, and integrally projects on the lower surface side of the block body 2. 2a is provided with a slit 24, and this slit 24
The mounting bracket 25 is inserted and fixed to the. The mounting bracket 25 allows the sensor 1 to be mounted at a predetermined position. Since the other structure is the same as that of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Fourth Embodiment] FIG. 7 is a vertical sectional view of a sensor 1 according to a fourth embodiment of the present invention. In this embodiment, one curved plate-shaped conductor 6 having a length extending over each of the insertion holes 3 is arranged so as to be displaced to one side in the radial direction with respect to the center of the insertion hole 3.
A conductive wire 7 is connected to one end of the conductor 6, and an insulator 8 made of ceramic is attached to the entire inner side surface (side surface of the insertion hole 3) of the conductor 6. The curved surface of the conductor 6 is concentric with the respective insertion holes 3. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Fifth Embodiment] FIG. 8 is a vertical sectional view of a sensor 1 according to a fifth embodiment of the present invention. In this embodiment, a pair of curved plate-shaped conductors 6 having the same insulator 8 as that of the fourth embodiment shown in FIG. It is arranged symmetrically on both sides in the radial direction with respect to the center of, and one conductive wire 7 is connected to one end of both conductors 6 and 6. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Sixth Embodiment] FIG. 9 is a vertical sectional view of a sensor 1 according to a sixth embodiment of the present invention. In this embodiment, the conductor 6 has a U-shape surrounding each insertion hole 3, and the conductors 6 corresponding to the insertion holes 3 are integrally connected to each other, and the entire inner surface of the conductor 6 is made of ceramic. The insulating body 8 is attached, and the mounting bracket 25 is inserted into the protruding wall 2a of the block body 2. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Seventh Embodiment] FIG. 10 is a vertical sectional view of a sensor 1 according to a seventh embodiment of the present invention. In this embodiment, the conductor 6 has a substantially square frame shape surrounding each insertion hole 3, and the conductors 6 corresponding to these insertion holes 3 are integrally connected to each other, and the entire inner surface of the conductor 6 is connected. An insulator 8 made of ceramic is attached to the mounting bracket 25, and the protruding wall 2a of the block body 2 is attached to the mounting bracket 25 as in the sixth embodiment shown in FIG.
Is inserted. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Eighth Embodiment] FIG. 11 is a vertical sectional view of a sensor 1 according to an eighth embodiment of the present invention. In this embodiment, the conductor 6 has a rectangular frame shape surrounding all the insertion holes 3, and an insulator 8 made of ceramic is formed on the entire inner surface of the conductor 6.
And the slit 2 of the protruding wall 2a of the block body 2
4, the mounting bracket 25 is inserted and fixed similarly to the third embodiment shown in FIG. 6 described above. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above,
The same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

In the above-described first to eighth embodiments, the conductor 6 is arranged so as to be displaced to the one side in the radial direction with respect to the center of the insertion hole 3, which is advantageous in that the entire sensor 1 can be made compact. Is.

The conductors 6 symmetrically arranged on both sides in the radial direction with respect to the center of the insertion hole 3 (including a ring) are
This is advantageous in improving and stabilizing the voltage detection accuracy.

Further, the larger the area of the shape of the conductor 6 facing the high-voltage cord 4 at a certain distance is, the more the detection accuracy is improved (which is advantageous in increasing the capacitance). [Ninth Embodiment] FIG. 12 is a vertical sectional view of a sensor 1 according to a ninth embodiment of the present invention. In this embodiment, a plurality of insertion holes 3
Are located on the same circular line L ₁ centered on the central portion of the block body 2 having a substantially square cross section, and are arranged at equal intervals in the circumferential direction. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Tenth Embodiment] FIG. 13 shows a tenth embodiment of the present invention.
It is a longitudinal section of sensor 1 showing an example. In this example,
A substantially square frame-shaped conductor 6 surrounding the entire plurality of insertion holes 3 arranged in the same manner as in the ninth embodiment shown in FIG. 12 is provided, and an insulation made of ceramic is formed on the entire inner surface of the conductor 6. The body 8 is attached. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Eleventh Embodiment] FIG. 14 shows the eleventh embodiment of the present invention.
It is a longitudinal section of sensor 1 showing an example. In the present embodiment, a radiation plate-shaped conductor 6 centered on the central portion is provided in the central portion of the area surrounded by a plurality of insertion holes 3 arranged similarly to the ninth embodiment shown in FIG. An insulator 8 made of ceramic is attached to the entire outer surface of the conductor 6, and one end of one conductor wire 7 is connected to one piece of the conductor 6, and each conductor 6 is inserted. The surface facing the hole 3 has an arc shape concentric with the insertion hole 3. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Twelfth Embodiment] FIG. 15 shows the twelfth embodiment of the present invention.
It is a longitudinal section of sensor 1 showing an example. This embodiment is a cross-shaped (radiating plate) conductor centered on the center of an area surrounded by a plurality of insertion holes 3 arranged similarly to the ninth embodiment shown in FIG. 6 is provided, an insulator 8 made of ceramic is attached to the entire outer surface of the conductor 6, and one end of one conductor wire 7 is connected to one piece of the conductor 6. Other configurations are shown in FIGS.
Since it is the same as the first embodiment shown in FIG. 4, the same parts in the drawings are designated by the same reference numerals and the description thereof is omitted.

[Thirteenth Embodiment] FIG. 16 shows the thirteenth embodiment of the present invention.
It is a longitudinal section of sensor 1 showing an example. In this embodiment, a rod-shaped conductor 6 having a substantially square cross section is arranged in the central portion of the area surrounded by a plurality of insertion holes 3 arranged similarly to the ninth embodiment shown in FIG. An insulator 8 made of ceramic is attached to the entire outer surface of the above, and one end of one conductive wire 7 is connected to one corner of the conductor 6. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

[Fourteenth Embodiment] FIG. 17 shows a fourteenth embodiment of the present invention.
18 is a perspective view of the sensor 1 showing an embodiment, and FIG. 18 is a vertical sectional view of the sensor 1. In this embodiment, a block body 2 is formed in the same shape as a code clamper attached to a cylinder head cover (not shown) of an internal combustion engine, and the upper surface of the block body 2 has a substantially semicircular cross section with a parallel interval therebetween. Insertion hole 3
Four conductors 6 having a substantially semicircular cross section are provided on the block body 2 along the inner peripheral surface of each insertion hole 3 and integrally connected to each other, and the entire surface of these conductors 6 is made of an insulator 8. It is molded, one end of one conductive wire 7 is connected to the conductor 6, and a mounting bracket 26 for mounting to the cylinder head cover is provided on the lower surface of the block body 2. Since other configurations are the same as those of the first embodiment shown in FIGS. 1 to 4 described above, the same reference numerals are given to the same portions in the drawings, and the description thereof will be omitted.

The ninth to the first shown in FIGS. 12 to 16 described above.
As in the third embodiment, the insertion holes 3 are located on the same circular line L ₁ whose center is the center of the block body 2 having a substantially square cross section, and are equidistant from each other in the circumferential direction. Due to the arrangement, the sensor 1 can be compared with the first to eighth embodiments described above.
This is advantageous in that the entire shape can be made compact.

In each of the above embodiments, the case where the block body 2 is provided with the four through holes 3 has been described, but the number of the through holes 3 is not limited to this, and the number of the through holes 3 may be increased. It is set according to the number of cylinders.

[0039]

As described above, according to the ignition voltage detecting apparatus for an internal combustion engine of the present invention, the sensor structure is provided with a conductor at a predetermined distance radially outside the peripheral portion of the insertion hole of the block body made of an insulating material. Since the high-voltage cord is inserted through the insertion hole and the high-voltage cord is inserted through the insertion hole, the conductor is arranged in a state in which a predetermined distance is accurately secured with respect to the high-voltage cord. Therefore, the adverse effect of the conductor due to the corona discharge phenomenon generated from the high-voltage cord can be prevented, the durability of the conductor is improved, and high detection accuracy and stable output can be obtained. Further, since an insulator made of ceramic is provided between the insertion hole and the conductor, corona discharge from the high voltage cord is reliably prevented, and
Since the conductor can be brought closer to the high-voltage cord, the overall weight and size of the sensor can be reduced and
It is possible to prevent deterioration of the conductor and improve its durability. Further, since the high-voltage cord is watertightly inserted into the insertion hole of the block body, the electrostatic capacitance of the conductor is less likely to be affected by vibration, humidity (water), or the like. Further, when the sensor having such a structure is provided, a protection circuit for coping with high voltage leakage is unnecessary.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a sensor in an ignition voltage detection device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway plan view of the sensor.

FIG. 3 is a system configuration diagram of an ignition system of an internal combustion engine equipped with the device of the present invention.

FIG. 4 is an electric circuit diagram of the system.

FIG. 5 is a vertical cross-sectional view of a sensor according to a second embodiment of the present invention.

FIG. 6 is a vertical sectional view of a sensor according to a third embodiment of the present invention.

FIG. 7 is a vertical sectional view of a sensor according to a fourth embodiment of the present invention.

FIG. 8 is a vertical sectional view of a sensor according to a fifth embodiment of the present invention.

FIG. 9 is a vertical sectional view of a sensor according to a sixth embodiment of the present invention.

FIG. 10 is a vertical sectional view of a sensor according to a seventh embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view of a sensor according to an eighth embodiment of the present invention.

FIG. 12 is a vertical cross-sectional view of a sensor according to a ninth embodiment of the present invention.

FIG. 13 is a vertical sectional view of a sensor according to a tenth embodiment of the present invention.

FIG. 14 is a vertical sectional view of a sensor according to an eleventh embodiment of the present invention.

FIG. 15 is a vertical cross-sectional view of a sensor according to a twelfth embodiment of the present invention.

FIG. 16 is a vertical sectional view of a sensor according to a thirteenth embodiment of the present invention.

FIG. 17 is a perspective view of a sensor according to a fourteenth embodiment of the present invention.

FIG. 18 is a vertical sectional view of the sensor.

[Explanation of symbols]

 1 Sensor 2 Block Body 3 Insertion Hole 4 High Voltage Cord 5 Annular Lip 6 Conductor 7 Conductive Wire 8 Insulator H Predetermined Interval

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaki Kanehiro 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor Shigeki Baba 1-4-1 Chuo, Wako-shi, Saitama No. Incorporated in Honda R & D Co., Ltd. (72) Inventor Takuji Ishioka 1-4-1 Chuo, Wako, Saitama Incorporated in Honda R & D Co., Ltd.

Claims (9)

[Claims] 1. An ignition voltage detection device for an internal combustion engine, wherein a sensor is provided outside a secondary high voltage cord in an ignition system of the internal combustion engine to detect an ignition voltage of the internal combustion engine. A block body made of an insulating material having an insertion hole that is watertightly inserted, a conductor disposed inside the block body at a predetermined distance radially outside the peripheral portion of the insertion hole, and inside the block body. An ignition voltage detection device for an internal combustion engine, comprising: an insulator made of ceramic, which is disposed between the insertion hole and the conductor. 2. An ignition voltage detection device for an internal combustion engine, wherein a sensor is provided outside a secondary high voltage cord in an ignition system of an internal combustion engine having a plurality of cylinders to detect an ignition voltage of the internal combustion engine. A block body made of an insulating material having a plurality of through holes through which the high-pressure cords are inserted in a watertight manner, and a predetermined interval radially outside the peripheral portions of the plurality of through holes in the block body. And an insulator made of ceramics disposed between the insertion hole and the conductor in the block body. Ignition voltage detection device. 3. The plurality of insertion holes are arranged such that the centers thereof are on the same straight line orthogonal to the axis and are arranged at equal intervals in the direction orthogonal to the axis. The ignition voltage detection device for an internal combustion engine according to claim 2. 4. The plurality of insertion holes are such that their centers are located on the same circle centered on the central portion of the block body and are arranged at equal intervals in the circumferential direction. The ignition voltage detecting device for an internal combustion engine according to claim 2, wherein 5. The ignition of an internal combustion engine according to claim 1, wherein the conductor is arranged so as to be displaced to one side in the radial direction with respect to the center of the insertion hole. Voltage detection device. 6. The ignition voltage detection for an internal combustion engine according to claim 1, wherein the conductors are symmetrically arranged on both sides in a radial direction with respect to a center of the insertion hole. apparatus. 7. The ignition voltage detection device for an internal combustion engine according to claim 2, wherein the conductors corresponding to the plurality of insertion holes are integrally connected to each other. 8. The inner diameter of the insertion hole is larger than the outer diameter of the high pressure cord, and water is prevented from entering between the insertion hole and the high pressure cord at least on the inner peripheral surfaces of both ends of the insertion hole. 8. An ignition voltage detection device for an internal combustion engine according to claim 1 or 6, further comprising a waterproof annular lip portion for blocking. 9. The ignition voltage detection for an internal combustion engine according to claim 1, wherein the signal voltage of the conductor is taken out of the block body through a conductor wire made of a shield wire. apparatus.