JP5695363B2 - Ignition device for internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine ignition device.

Conventionally, in lean combustion and stratified combustion, in order to prevent misfire caused by variations in the air-fuel ratio and smoldering of spark plugs, multiple ignition is performed using a plurality of ignition coils. However, since a high voltage flows into the other ignition coil that is being charged when one ignition coil is discharged, the ignition coil may be damaged. In such a situation, a diode should be placed on the high output side of the ignition coil. It has been known.

When the ignition device includes an electronic component such as a diode as described above, a crack may spread due to the sharpness of a fixed portion such as a diode or a lead wire. In such a situation, for example, it is known to have a configuration as disclosed in Japanese Patent Application Laid-Open No. 08-028424 (hereinafter “Patent Document 1”).

FIG. 5 shows a perspective view of the secondary bobbin of the ignition coil described in Patent Document 1. 5, in Patent Document 1, the core 1, the primary coil 3 and the secondary coil 6 in which the magnetic flux is linked via the core 1, the primary bobbin 2 for aligning the primary coil 3 and the secondary coil 6, and The secondary bobbin 5, the intermediate conductor 12 fixed to the primary bobbin 2 or the secondary bobbin 5, and the primary bobbin 2 or the secondary bobbin 5 fixed to the winding of the primary coil 3 or the secondary coil 6 A terminal 4b, an electronic component 13 electrically connected to the intermediate conductor 12 and the terminal 4b, a case 9 for housing each member, and an insulating resin 14 filled in the case 9. In the internal combustion engine ignition coil, the lead wire 13a of the electronic component 13 is fixed to the intermediate conductor 12 and the terminal 4b by caulking or press-fitting. Further, crack propagation preventing members 71 and 81 are provided in the vicinity of at least one lead wire 13 a of the electronic component 13. Further, the case is provided with an open end for taking out a high voltage, and the open end is sealed by the intermediate conductor 12 from the inside of the case. A characteristic ignition coil for an internal combustion engine has been proposed.

Japanese Patent Application Laid-Open No. 08-028424

However, the above conventional ignition device has the following problems. That is, in the ignition coil of Patent Document 1, an intermediate conductor is provided on the secondary bobbin, a press-fitting portion for press-fitting the lead wire of the electronic component on the secondary bobbin and the intermediate conductor, and a crack spreading prevention member are provided. In the above configuration, the electronic component is arranged at a position close to the inner surface of the case, so if the adhesion between the case and the insulating resin becomes insufficient, the gap between the case and the insulating resin Leakage current is generated from the electronic component to the core via the and the output of the ignition coil is reduced.

The present invention has been made in view of the above problems, and provides a highly reliable ignition device that is not affected by a leakage current that causes output failure even when a crack occurs due to peeling of the case and the mold resin. Objective.

In order to solve the above problems, the present invention is configured as follows. That is, in the invention of claim 1, a case and an ignition coil comprising a primary coil, a secondary coil and an iron core are provided in the case, and a connector for supplying power from the outside to the case is disposed. In the ignition device in which a high voltage terminal for supplying a high voltage to the ignition plug is disposed in the case and the coil housing portion of the case is filled with a mold resin, the first ignition coil and the second ignition coil are disposed in the case. And a first diode group and a second diode group for preventing a high voltage of one of the first ignition coil and the second ignition coil from flowing to the other on the inner bottom surface of the case. A groove for embedding the first diode group and the second diode group is formed on the inner bottom surface of the case, and at least one of the outer circumferences of the groove portion is formed on the inner bottom surface of the case. And ignition device, and forming a peripheral groove or the outer peripheral protrusion on.

In the above configuration, when the first ignition coil is discharged, the second ignition coil is alternately charged, and when the first ignition coil is charged, the second ignition coil is alternately discharged. May be. Further, the peripheral groove or the outer peripheral protrusion may be formed on the a location subject to cracks due to peeling of the mold resin and the case, said peripheral groove or the outer peripheral protrusion is formed on at least the outer periphery one round of the groove May be. Furthermore, you may form combining the said outer periphery groove | channel and the said outer periphery protrusion in the said case inner bottom face.

According to the above invention , it is possible to realize a highly reliable ignition device that is not affected by a leakage current that causes output failure even if a crack is generated due to peeling of the case and the mold resin.

1 is a perspective view of an ignition device according to a first embodiment of the present invention. It is BB sectional drawing seen from the arrow (a) direction of the ignition device of FIG. It is the figure which looked at the case of the ignition device which is the 1st example of the present invention from the upper direction. It is sectional drawing of the ignition device made into the modification of the 1st Example of this invention. It is a perspective view of the secondary bobbin of the ignition coil made into patent documents 1.

An embodiment showing an embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view of an ignition device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line BB of the ignition device shown in FIG. FIG. 3 shows a view, and FIG. 4 shows a cross-sectional view of an ignition device according to a second embodiment of the present invention.

1 to 4, the case 50 forming the outer shape of the ignition device 70 is formed by integral molding in a box shape having one opening surface. Further, the case 50 is formed with two case fixing portions 52 on a plane substantially perpendicular to the opening surface of the case 50 for fixing the ignition device 70 to an engine head (not shown). Further, a high voltage tower 54 for providing a high voltage terminal 36 for supplying a secondary voltage to the ignition plug is formed on the bottom surface of the case 50 so as to protrude into a plug hole formed in the upper part of the engine. .

The coil housing portion of the case 50 includes a first ignition coil 80 and a second ignition coil 90, and each of the first ignition coil 80 and the second ignition coil 90 is individually provided with a plurality of thin plates. A primary coil 10 in which a primary winding is wound about 50 turns around the outer periphery of a primary bobbin formed of resin on the outer periphery of the iron core 30, and the primary The secondary coil 20 is formed by winding a secondary winding around 3000 turns on the outer periphery of a secondary bobbin formed of resin on the outer periphery of the coil 10. Further, a secondary high voltage terminal 24 is provided on the high voltage side of the secondary coil 20, and a secondary low voltage terminal 22 is provided on the low voltage side of the secondary coil 20.

Each of the first ignition coil 80 and the second ignition coil 90 has a case side secondary high voltage terminal 38 on the inner bottom surface of the case 50. The case side secondary high voltage terminal 38 and the respective case side secondary high voltage terminals 38 are provided. The secondary high voltage terminal 24 is electrically connected. Further, in the case 50, an igniter 34 for supplying a primary voltage and an ignition signal to the first ignition coil 80 and the second ignition coil 90 is provided in the first ignition coil 80 and the second ignition coil. The igniter 34 is electrically connected to the primary coil 10 and the secondary low voltage terminal 22.

Each of the first ignition coil 80 and the second ignition coil 90 is provided with a connector 32 for connecting a battery and an ECU on the side surface of the case 50, and one end of each connector 32 is connected to the first ignition coil 80. The primary coil 10 of the ignition coil 80 and the second ignition coil 90 is electrically connected, and the other end of each connector 32 is electrically connected to the battery and the ECU. Further, the inner bottom surface of the case 50 is provided with the first ignition coil 80 and the second ignition coil 90 in order to prevent the secondary voltage of one of the first ignition coil 80 and the second ignition coil 90 from flowing to the other ignition coil. The ignition coil 80 includes first diode groups 40a, 40b, and 40c, and the second ignition coil 90 includes second diode groups 42a, 42b, and 42c.

The first diode group 40a, 40b, 40c and the second diode group 42a, 42b, 42c are provided with a lead wire 44, and the first diode group 40a, 40b, 40c and the second diode group are provided. By connecting the lead wires 44 of the groups 42a, 42b, and 42c by soldering, the first diode groups 40a, 40b, and 40c and the second diode groups 42a, 42b, and 42c are connected in series, respectively. It is configured. Further, the lead wires 44 on the anode terminal side of the first diode 40a and the second diode 42a are coupled together and electrically connected to the high voltage terminal 36.

The lead wire 44 on the cathode terminal side of the first diode 40c is electrically connected to the case side secondary high voltage terminal 38 of the first ignition coil 80, and the cathode terminal of the second diode 42c. The side lead wire 44 is electrically connected to the case side secondary high voltage terminal 38 of the second ignition coil 90. Further, a groove 56 for forming the first diode group 40a, 40b, 40c and the second diode group 42a, 42b, 42c is formed on the bottom surface inside the case 50.

Also, a substantially U-shaped lead wire fixing for fixing the lead wire 44 of the first diode group 40a, 40b, 40c and the second diode group 42a, 42b, 42c to the groove portion 56 is provided. A total of 12 portions 59 are formed at both ends of each diode of the first diode group 40a, 40b, 40c and the second diode group 42a, 42b, 42c. The insertion opening of the lead wire 44 is chamfered. Further, the groove portion 56 is formed to such a depth that the first diode groups 40a, 40b, and 40c, the second diode groups 42a, 42b, and 42c, and the lead wire fixing portion 59 do not protrude from the bottom surface of the case 50. Yes.

An outer peripheral groove 57 is formed on the inner bottom surface of the case 50. The outer peripheral groove 57 includes the first diode groups 40a, 40b, and 40c, the second diode groups 42a, 42b, and 42c, and the lead wire fixing portion. It is formed so as to surround the outer periphery of the groove portion 56 provided with 59 and the respective case-side secondary high-voltage terminals 38, the high-voltage terminals 36, and the lead wires 44. Further, the outer peripheral groove 57 is formed with a width around one third of the width of the groove portion 56, and the outer peripheral groove 57 is formed with a depth equal to the depth of the groove portion 56.

The case 50 is filled with a thermosetting mold resin 60 so as to realize electrical insulation of the ignition device 70 and physical fixation of each member. Further, the secondary voltage output from the first ignition coil 80 and the second ignition coil 90 is supplied from the high voltage terminal 36 to the ignition plug through a conductive member accommodated in the plug hole. Yes.

As a modification of the above embodiment, the configuration and the formation position of the outer peripheral groove 57 may be arbitrarily changed as long as it is affected by cracks due to peeling of the case 50 and the mold resin 60, for example. The outer peripheral groove 57 includes the first diode group 40a, 40b, 40c, the second diode group 42a, 42b, 42c, the groove part 56 including the lead wire fixing part 59, and the case side secondary high voltage. Two or more rounds may be formed on the outer periphery of the terminal 38, the high-voltage terminal 36, and the lead wire 44. The outer peripheral groove 57 includes the first diode group 40a, 40b, 40c, the second diode group 42a, 42b, 42c, the groove part 56 including the lead wire fixing part 59, and the respective case side 2s. It may be configured to be formed on any of the next high voltage terminal 38, the high voltage terminal 36, and the lead wire 44. Furthermore, instead of the outer peripheral groove 57, an outer peripheral protrusion 58 that protrudes in the vertical direction from the inner bottom surface of the case 50 may be formed, or the outer peripheral groove 57 and the outer peripheral protrusion 58 may be combined.

10: 1 primary coil
20: Secondary coil
22: Secondary low voltage terminal
24: Secondary high-voltage terminal
30: Iron core
32: Connector
34: Igniter
36: High voltage terminal
38: Secondary high-voltage terminal on the case side
40a, 40b, 40c: first diode
42a, 42b, 42c: second diode
44: Lead wire
50: Case
52: Case fixing part
54: High pressure tower
56: Groove
57: Outer groove
58: Perimeter protrusion
59: Lead wire fixing part
60: Mold resin
70: Ignition system
80: First ignition coil
90: Second ignition coil

Claims (5)

A case, and an ignition coil including a primary coil, a secondary coil, and an iron core in the case;
A connector for supplying power from the outside to the case is disposed,
A high voltage terminal for supplying a high voltage to the spark plug is disposed in the case,
In the ignition device in which the coil housing portion of the case is filled with mold resin,
A first ignition coil and a second ignition coil in the case;
A first diode group and a second diode group for preventing a high voltage of one of the first ignition coil and the second ignition coil from flowing to the other are provided on the inner bottom surface of the case. ,
Forming a groove for embedding the first diode group and the second diode group on the inner bottom surface of the case;
An ignition device, wherein an outer peripheral groove or an outer peripheral protrusion is formed on at least a part of the outer periphery of the groove portion on the inner bottom surface of the case. The second ignition coil is alternately charged when the first ignition coil is discharged, and the second ignition coil is alternately discharged when the first ignition coil is charged. The ignition device according to claim 1. 3. The ignition device according to claim 1, wherein the outer circumferential groove or the outer circumferential protrusion is formed in a place that is affected by a crack caused by peeling of the case and the mold resin. The ignition device according to any one of claims 1 to 3, wherein the outer circumferential groove or the outer circumferential projection is formed on at least one outer circumference of the groove portion. The ignition device according to any one of claims 1 to 4 , wherein the outer peripheral groove and the outer peripheral protrusion are formed in combination on the inner bottom surface of the case .

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