JPH08288157A - Ignition coil of engine - Google Patents

Abstract

PURPOSE: To obtain an interval between electrodes with high precision, by providing a plate-like high voltage electrode on the coil unit side and a plate-like sensor electrode on the coil case side as well so that, when the coil unit is installed in the coil case, the high voltage electrode faces the sensor electrode with a specified interval in between. CONSTITUTION: In the hollow shaft of a secondary coil bobbin 2 on which a secondary coil 1 is wound, a coil unit 5 into which a primary coil bobbin 4 on which a primary coil 3 is wound is coaxially inserted is inserted from an open face 7 of a coil case 6 for installation, and then an insulation resin is injected into the case 6 for forming into a body. And a plate-like high voltage electrode 8 is provided on the coil unit 5 side, and further, a plate-like sensor electrode 9 is provided on the inside of the case 6, so that, when the unit 5 is installed in the case 6, the electrode 8 faces the electrode 9 with a specified interval for forming a capacitor 25. Thus the interval between the electrodes is kept with high precision.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine ignition coil having a function of detecting an ignition voltage state when the engine misfires.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
Coil unit 53 in which 1 and secondary coil 52 are wound
Is installed in the coil case 54, and the coil case 5
In an ignition coil of a potting type engine in which an insulative resin 55 is injected into 4 and integrally molded, a ring-shaped sensor conductor is provided around a secondary side socket terminal 56 into which an ignition plug cord is inserted. By mounting 57, a capacitor for detecting an ignition voltage is formed between them, and it is possible to detect whether or not the spark discharge is normally performed by the spark plug according to the voltage state induced in the capacitor. (Tokaihei 5-306
669).

[0003]

The problem to be solved is that when a capacitor for detecting the ignition voltage is provided inside the ignition coil, it is provided at a high voltage portion, so that the capacitor has a dielectric breakdown. It is necessary to secure a sufficient space between the electrodes so that the space factor will not occur, and the space factor becomes worse.

Further, when the capacitor is formed inside the ignition coil, it is easy to install the electrode at a predetermined position in the coil case, and it is not affected by the resin injection.
The question is whether the distance between the electrodes can be maintained with high accuracy.

[0005]

According to the present invention, when a capacitor for detecting an ignition voltage is installed inside an ignition coil of a potting type engine, each electrode forming the capacitor is easily and accurately positioned. In order to ensure that the coil unit side is provided with a plate-shaped high-voltage electrode and the coil case side is provided with a plate-shaped sensor electrode, when the coil unit is mounted in the coil case, the high-voltage electrode and the sensor electrode are It opposes with a predetermined space | interval.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as shown in FIGS. 1 to 3, a primary coil bobbin 4 having a primary coil 3 wound therein is coaxial with a hollow shaft of a secondary coil bobbin 2 having a secondary coil 1 wound therein. An engine in which the coil unit 5 fitted in the shape of a coil is inserted from the open surface 7 of the coil case 6 into the inside of the coil unit 6, and an insulative resin such as epoxy is injected into the coil case 6 for integral molding. In the ignition coil, the plate-shaped high-voltage electrode (high-voltage plate) 8 is provided on the coil unit 5 side, and the plate-shaped sensor electrode (sensor plate) 9 is provided inside the coil case 6. When the coil is mounted in the coil case 6, the high voltage plate 8 and the sensor plate 9 face each other with a predetermined gap, and the capacitor 2 for detecting the ignition voltage is placed.
5 is formed.

A boss 10 into which a core (not shown) is fitted from the outside is formed to project toward the open surface 7 at the center of the inside of the coil case 6, and the boss 10 is provided in the hollow shaft of the primary coil bobbin 4. The coil unit 5 is positioned and mounted in the coil case 6 by inserting.

When the high-voltage plate 8 is provided on the coil unit 5 side, the holder portion 11 is integrally formed on the flange portion of the secondary coil bobbin 2 and the holder portion 1 is formed.
The insertion part 81 of the high-pressure plate 8 is inserted into the first plate 1 for attachment.

Further, when the sensor plate 9 is provided on the coil case 6 side, here, the holder portion 12 is integrally formed in the inner side of the coil case 6 so that a groove is formed between the coil case 6 and the case inner wall. A part of the sensor plate 9 is inserted into and attached to the holder portion 12.

The high-voltage plate 8 is integrally formed with a lead portion 82. When the high-voltage plate 8 is inserted into the holder portion 11, the tip of the lead portion 82 is formed integrally with the secondary terminal 13. It is adapted to be connected to the lead portion 131.

Further, a lead portion 91 is integrally formed at one end of the sensor plate 9, and a hole 92 formed at the tip of the lead portion 91 is provided so as to project into the coil case 6 of the sensor output terminal. It is adapted to be fitted to the head 141 which is provided and to be electrically connected.

A holder portion 15 is integrally formed on the flange portion of the secondary coil bobbin 2, and the secondary terminal 13 is attached to the holder portion 15. And the coil case 6
When inserting the coil unit 5 into the secondary output pin 1, the groove of the secondary terminal 13 is provided in the coil case 6.
6 is engaged with the head 161 to be electrically connected.

The holder member 17 of the primary coil bobbin 4 has a lead member 18 connected to the winding start 31 of the primary coil 3.
Is mounted and fitted into a head portion 191 provided so as to project into the coil case 6 of the ignition signal input terminal so as to be electrically connected.

Similarly, in the holder part 17 of the primary coil bobbin 4, the lead member 20 connected to the winding end 32 of the primary coil 3 and the winding start 101 of the secondary coil 1 is mounted, and inside the coil case 6 of the power supply terminal. It is adapted to be fitted to a head portion 211 protrudingly provided so as to be electrically connected.

Further, a holder portion 22 is formed on the flange portion of the secondary coil bobbin 2, and a diode 23 for blocking a reverse current is mounted on the holder portion 22, and the cathode side thereof is the end of winding of the secondary coil 1. 102, the anode side of which is connected to the secondary terminal 13.

In the ignition coil of the engine according to the present invention having the above-described structure, when the coil unit 5 is mounted in the coil case 6, the high voltage plate 8 and the coil case 6 which are previously provided on the coil unit 5 side are provided. Since the capacitor 25 for detecting the ignition voltage is formed so as to face the sensor plate 9 provided on the side at a predetermined interval, the capacitor 25 can be easily installed in the coil case 6. And each plate 8,9
Since it is fixedly installed at a predetermined position, it does not move due to resin injection, and the distance between the plates 8 and 9 can be accurately maintained.

Further, in the present invention, the high voltage plate 8 and the sensor plate 9 form the parallel plate-shaped capacitor 25, and the concentric cylinders are formed even if the intervals are sufficiently set so as not to cause dielectric breakdown. The space factor is improved as compared with the case of forming a capacitor in the shape of a circle.

For example, when the secondary output voltage is 45 KV and the withstand voltage of the epoxy resin is 20 KV, the minimum distance between the high voltage plate 8 and the sensor plate 9 for preventing dielectric breakdown is 45 KV / 20 KV = 2. 25mm,
It is sufficient to set the interval to about 4 mm with a margin.

FIG. 4 shows an ignition system of an engine using the ignition coil 24 constructed as described above. The high pressure plate 8 and the sensor plate 9 are provided in the ignition circuit system.
An ignition detection circuit for detecting whether the spark discharge from the plug 26 is normal or is in a misfire state by taking out the sensor output voltage induced in the ignition voltage detecting capacitor 25 and comparing it with the reference voltage. 27 are provided. In the figure, 28 is a battery power source, and 29 is an igniter for generating an ignition signal.

In the engine constructed as described above, when the engine is ignited, the induced voltage of the capacitor 25 for detecting the ignition voltage varies depending on whether the spark plug 26 normally discharges sparks or misfires. A difference occurs, and the sensor output voltage corresponding to the difference is level-detected in the ignition detection circuit 27, and it is detected whether the engine is ignited normally or in a misfire state.

Further, at the time of misfire, the diode 23 blocks a current in the direction opposite to the discharge current caused by the residual charge between the electrodes of the spark plug 27, and the capacitor 25
The detection voltage induced by
The misfire state of the engine is reliably detected.

[0022]

As described above, the ignition coil of the engine according to the present invention is
A coil unit is mounted in a coil case, an insulating resin is injected into the case, and integrally molded, and a plate-shaped high-voltage electrode is fixedly provided on the coil unit side in advance and the coil case side is attached to the coil case side. A plate-shaped sensor electrode is fixedly provided so that when the coil unit is mounted in the coil case, the high voltage electrode and the sensor electrode face each other with a predetermined gap to form a capacitor for detecting an ignition voltage. Therefore, there is an advantage that the capacitor can be installed in the ignition coil easily and with high positional accuracy, and the capacitor can be installed in the ignition coil with a high space factor.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of an ignition coil of an engine according to the present invention.

FIG. 2 is a side view of the ignition coil of the engine as seen from the right side in the embodiment.

FIG. 3 is a side view of the engine ignition coil according to the embodiment as viewed from the left side.

FIG. 4 is an electric circuit diagram showing an ignition system of an engine using an ignition coil according to the present invention.

FIG. 5 is a partially sectional front view showing an ignition coil of a conventional engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Secondary coil 2 Secondary coil bobbin 3 Primary coil 4 Primary coil bobbin 5 Coil unit 6 Coil case 8 High voltage electrode (high voltage plate) 9 Sensor electrode (sensor plate) 23 Reverse current blocking diode 25 Ignition voltage detection capacitor

Front Page Continuation (72) Inventor Masahiro Kanehiro 1-4-1 Chuo, Wako-shi, Saitama Stock Research Institute Honda Technical Research Institute (72) Inventor Shigeru Maruyama 1-4-1 Chuo, Wako-shi, Saitama Stock Association Inside the Honda R & D Co., Ltd. (72) Inventor Takashi Hisaki Inside the Honda R & D Co., Ltd. 1-4-1 Chuo, Wako, Saitama

Claims (1)

[Claims] 1. A coil having a built-in capacitor for ignition voltage detection, comprising a high-voltage electrode connected to an output end of a secondary coil and a sensor electrode facing the high-voltage electrode, and a primary coil and a secondary coil being wound. In an engine ignition coil that is integrally molded by mounting the unit in a coil case and injecting insulating resin into the coil case, provide a plate-shaped high-voltage electrode on the coil unit side and A plate-shaped sensor electrode is provided, and when the coil unit is mounted in the coil case, the high-voltage electrode and the sensor electrode face each other with a predetermined gap to form a capacitor for detecting an ignition voltage. Ignition coil for the engine.