JPS6065281A - High-energy ignitor - Google Patents

Abstract

PURPOSE:To prevent generation of noise by covering the peripheral side surface of the iron core of a DC-DC converter by thermosetting resin, etc. and fixing the iron core previously to the assembly of a whole ignition apparatus, thus securing the sufficient insulation of a transformer and correctly maintaining the core gap. CONSTITUTION:The space 16A between the iron core 3 of an ignition coil 3 and the pouring case 10 of the transformer 8a of a DC-DC converter 8 is filled with the molding resin 16 having the superior insulation performance, thermal resistance, and mechanical strength. The ferrite core 8d of the transformer 8a of the converter 8 is pouring-fixed in the pouring case 10 by the thermosetting synthetic resin 11 such as epoxy resin, and the whole periphery of the pouring case 10 is covered by the molding resin 16. Therefore, magnetic vibration can be perfectly suppressed even in case of high-frequency oscillation, and a small-sized DC-DC converter having high efficiency and low noise can be obtained

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an ignition system for an internal combustion engine, and more particularly to the structure of a high-energy ignition system.

[Background of the invention]

An ignition device is a device that ignites the air-fuel mixture of an internal combustion engine by spark discharge, causing explosive combustion.It has an important influence on the initial combustion of an internal combustion engine, and by increasing the ignition energy, It is possible to improve combustion efficiency, reduce fuel consumption, and improve output.

Several methods have been devised to increase the ignition energy, but one relatively practical method is, for example, the method disclosed in the earlier patent application No. 58-761 filed by the same applicant.
There is No. 64, but the ignition coil as a high voltage source,
Furthermore, there is a high-energy ignition device that is equipped with a DC-DC converter, which is a medium-high voltage power supply that superimposes on the discharge current of the spark discharge from the ignition coil to increase and extend the discharge current to make it high energy.

FIG. 1 shows an example of a circuit for a high-energy ignition system.

1 is a battery, 2 is a key switch, 3 is an ignition coil, 3a is a primary coil, 3b is a secondary coil, and 3C is an iron core. 4 is an IC igniter that switches the primary current i of the primary coil 3a of the ignition coil to generate a high voltage vf of 30 to 40 kV in the secondary coil 3b. 5 is a pickup for detecting ignition timing. 6 is a power distributor, and 7 is a spark plug. 8 is a DC-DC converter which is a medium-high voltage power supply and generates a voltage of about 2 to 5 kV. 8a is a transformer, 8b is a primary coil, 8C is a secondary coil, 8d
is an iron core. 8e is a switching transistor, 8f is an oscillation circuit, 8g is a rectifier diode, and 8h is a capacitor. 9a to 9f are connected with high voltage cords.

According to the high-energy ignition device shown in Figure 1, the discharge energy of a typical ignition device is several times that of 20 to 40 mJ, and the combustion efficiency of the internal combustion engine can be greatly improved. I can do it.

However, since the transformer of this type of DC-DC converter generates a voltage of 2 to 10 kV, it is necessary to perform insulation treatment. Moreover, the ferrite core has two E-type cores.
However, there is a problem in that the output characteristics of the transformer change significantly due to fluctuations in the gap between the cores. In addition, the transformer of the DC-DC converter uses high-frequency oscillation in order to achieve miniaturization, but this oscillation causes the core to generate magnetic vibrations, which emit noise through the vehicle body, making it difficult to put it into practical use. .

[Purpose of the invention]

The present invention provides a high energy ignition device with DC-DC
The purpose is to sufficiently insulate the transformer of the converter, maintain the gears of the ferrite core accurately, and prevent noise generated by the magnetic vibration of the core itself.

[Summary of the invention]

The present invention provides that the DC-D
This is characterized in that at least the peripheral side of the core of the C converter transformer is covered and fixed with a thermosetting resin or the like.

[Embodiments of the invention]

Next, one embodiment of the present invention will be described with reference to FIGS. 2 and 3 of VC1. In the drawings, members having the same reference numerals as in FIG. 1 represent the same elements. That is, numeral 3 is an ignition coil, which is a closed magnetic circuit type ignition coil in order to reduce the size. - Next coil 3a.

The secondary coil 3b is insulated by vacuum impregnation with epoxy resin after winding and heating and curing. The iron core 3c is formed by punching and laminating silicon steel plates in a five-shape shape.

Now, 8a is a transformer of the DC-DC converter 8. 8b is a primary coil, 8C is a secondary coil, and 8d is an iron ferrite core, which is formed by combining two E-type cores. After the primary coil 8b and secondary coil 8C are set in the ferrite core 8d, the transformer 8a constituted by these is inserted and set into the casting case 10.

Therefore, a thermosetting synthetic resin 11 such as epoxy resin is vacuum impregnated into the casting case 10 and cured by heating to provide insulation. This D C-I) C converter 8 has an oscillation frequency of 10~
The frequency is 20 kHz, which is aimed at miniaturization.

The diode 8g above the transformer 8a is connected between the low voltage side of the secondary coil 3b of the ignition coil 3 and the high voltage side of the secondary coil 8C of the DC-DC converter 8. The capacitor 8h is connected between the high voltage side of the secondary coil 8C and the iron core 3C of the ignition coil 3. Further, the ground side of the secondary coil 8C is also connected to the iron core 3C of the ignition coil 3.

12 is a primary terminal connected to the primary coil 3a of the ignition coil 3. 13 is a power supply terminal, the power supply side of the primary coil 3a of the ignition coil 3,! : is connected to the power supply side of the primary coil 8b of the DC-DC converter. 14 is D
It is a control terminal of the C-DC converter 8 and is connected to one side of the secondary coil 8b. The high voltage terminal 15 is a terminal connected to the high voltage side of the secondary coil 3b of the ignition coil 3, and is the terminal to which the high voltage cord 9a shown in FIG. 1 is connected.

After making the main connections in advance in this way, the molded resin 16
integrally injection molded. At this time, the iron core 3 of the ignition coil 3
A space 16A is created between C and the casting case 10 of the transformer 8a of the DC-DC converter 8, and this space is also filled with the molding resin 16. Molding resin 16
For this purpose, a material having excellent insulation properties, heat resistance, and mechanical strength, such as glass-filled PBT, is used.

FIG. 3 is a perspective view showing the external shape common to each embodiment of the present invention. 17 is 1. This case houses the switching transistor 8e and oscillation section 8f of the DC-DCJ7 converter 8, and is made of die-cast aluminum to improve heat dissipation. In addition, this switching transistor 8
A lead wire 18 is connected between the control terminal 14 of the primary coil 8b of the DC-DC converter 8 and the control terminal 14 of the primary coil 8b of the DC-DC converter 8. The attachment band 19 is fastened to the core 3C of the in-point coil, and also serves to ground the core 3C4l.

The high energy igniter of this first embodiment of the invention is D
The ferrite core 8di of the transformer 8a of the C-DC converter 8 is fixed in a molded case 10 with a thermosetting synthetic resin 11 such as epoxy resin, and the entire circumference of the molded case 10 is further covered with a molded resin 16. Because of this, magnetic vibration can be completely suppressed even at high frequency oscillations, making it compact and compact.
A highly efficient and low noise DC-DC converter can be obtained,
It is a highly practical high-energy ignition device.

Note that the same effect can be obtained even if an elastic body such as rubber is sandwiched between the iron core 3C of the ignition coil 3 and the transformer 8a of the DC-DC converter 8 and integrally molded with the molding resin 16.

Next, another embodiment of the present invention will be described with reference to FIG. This second embodiment is different from the first embodiment shown in FIG.
, and because the width of the casting case 100 increases accordingly, the space 16A into which the molded resin 16 enters is eliminated, and the iron core 3C of the ignition coil 3 and the casting case 10 are placed in close contact with each other. be.

By doing so, the transformer 8a can be positioned more accurately within the casting case 10 than in the first embodiment.
Advantages such as magnetic vibration prevention effect, small size, and high efficiency are the same as those of the first embodiment.

Furthermore, other embodiments of the present invention will be described with reference to FIG. In this case, the aim is to achieve other objectives as well. In other words, thermosetting synthetic resins such as epoxy resins can be used to repel stains and other types of stains.
However, compressive stress is applied to the ferrite core, which is the iron core of the transformer, due to the contraction of the transformer, which deteriorates the characteristics of the core.
This prevents the step-up efficiency of the transformer from decreasing.

Therefore, in this embodiment, the casting case 101 as in the above two embodiments is not used, but the ferrite core 8d of the transformer 8a of the DC-DC converter 8 is wrapped with an elastic material 20 such as rubber, and then epoxy resin or the like is used. It is poured with thermosetting synthetic resin 11. Therefore, since the elastic material 20 completely absorbs and relieves the compressive stress caused by curing shrinkage of epoxy resin, etc., it is possible to completely prevent the deterioration of the characteristics of the ferrite core 8d, resulting in a small and highly efficient DC-
A transformer 8d of the DC converter 8 can be provided. Further, the elastic material 20 is molded in advance from rubber or the like so as to completely surround the ferrite core 8d, and the inside of this molded member contains a large number of independent microbubbles.

Of course, the effect of absorbing the magnetic vibration sound generated by the oscillation of the DC-DC converter 8 by wrapping the siferite core 8d with the elastic material 20 is the same as the soundproofing effect of the thermosetting synthetic resin 11 surrounding the outside thereof. Together, they are equivalent to or better than the two embodiments described above. In these embodiments, the entire surface of the ferrite core 8d is covered with the resin 11, etc., but the peripheral surface, that is, in FIGS. As a result of experiments, it was confirmed that the noise prevention effect of the present invention can be sufficiently obtained by simply covering only the side surfaces of the four circumferences shown in cross section in FIGS. 4 and 5.

〔Effect of the invention〕

According to the present invention, in a high-energy ignition device, the transistor of the DC-DC converter is covered with a thermosetting synthetic resin, so that the DC-DC converter nodrance is sufficiently insulated, and the gap between the ferrite cores can be accurately maintained. However, the noise generated by the magnetic vibration of the core itself can be completely prevented.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a high-energy ignition device, FIG. 2 is a sectional view showing the first embodiment of the present invention, FIG. 3 is a perspective view showing the external shape common to each embodiment of the present invention, and FIG. The figure shows the second aspect of the present invention.
Embodiment FIG. 5 is a sectional view showing a third embodiment of the present invention. 2...Key switch, 3...Ignition coil, 3a...
- Secondary coil, 3b...Secondary coil, 3c...Iron core, 4...IC igniter, 5...Pickup, 6
...Distributor, 7...Ignition flag, 8...DC-D
C converter, 8a...transformer, 8b...-secondary coil, 8c...secondary coil, 8d...ferrite core, 8e...switching transistor, 8f...
Oscillation circuit, 8g... Rectifier diode, 8h... Capacitor, 9a to 9f... High voltage cord, 10... Casting case, 10a... Protrusion, 11... Thermosetting resin,
12... - next terminal, 13... power supply terminal, 14...
Control terminal, 15... High voltage terminal, 16... Molded resin,
17... Case, 18... Lead wire, 19... Mounting band, 20... Elastic material. Agent Patent Attorney Tatsuyuki Unuma 1m

Claims (1)

[Claims] 1. An ignition coil that generates a high voltage pulse necessary to generate a spark discharge between the electrodes of a spark plug, and a medium-high voltage pulse for further sustaining the discharge after generating the spark discharge. DC-DC converter, ignition coil and DC-D
In a high-energy ignition device integrally formed with a DC-DC converter, at least the circumferential side of the core of the transformer of the DC-DC converter is covered and fixed with thermosetting synthetic resin, etc., and then parts such as the ignition coil and the DC-DC A high-energy ignition device characterized by integrally molding the converter with molded resin. 2. In Claim 1, the thermosetting synthetic resin or the like is injected and impregnated into the gap between the case and the transformer after the cast case and the transformer of the DC-DC converter are inserted and set therein. A high-energy ignition device characterized by being made of synthetic resin. 3. The high-energy ignition device according to claim 2, characterized in that a protrusion for determining and fixing the set position of the transformer of the DC-DC converter is provided inside the cast case. 4. In claim 1, the thermosetting synthetic resin is composed of an elastic material such as rubber and a thermosetting synthetic resin, and after completely covering the core of the transformer of the DC-DC converter with the elastic material, A high-energy ignition device that is completely cast and fixed using hardening synthetic resin.