JPS63120863A - Ignition coil for internal combution engine - Google Patents

Abstract

PURPOSE:To enable the feed of a signal generated to an igniter to an ignition coil without damping it, by a method wherein an ignition plug connecting means, connecting the one end of the winding of the secondary coil of a transformer to a heat terminal, is formed integrally with a primary coil signal generating circuit. CONSTITUTION:An ignition coil 400, mounted to an ignition plug 200 attached to a cylinder head 170 so as to front on the interior of a combution chamber 150, is contained in a plug hole 180 of an engine 100. The ignition coil 400 is formed such that an ignition plug connection metal 410, interconnecting a secondary coil 312 of a transformer 310 and a head terminal 210 of the ignition plug 200, is formed integrally with a transistor case 362 containing a power transistor with which to form a primary coil signal generating circuit 360. This constitution enables the feed of a signal from the ignal generating circuit 360 to a primary coil 311 not through a long lead plug, and permits application of a high voltage, generated at a secondary coil 312, on the ignition plug 200 without damping.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition coil that applies a high voltage directly to the ignition plug of an internal combustion engine.

[Prior Art] Conventionally, the ignition coil, which generates high voltage in response to an ignition signal from the igniter, has been installed at a distance from the ignition plug installed in the engine. was connected through.

This high-voltage cable has the problem that high voltage flows intermittently in response to engine rotation, which generates radiant noise from the high-voltage cable and attenuates the high voltage as it flows through the long high-voltage cable.

Therefore, a transformer part is attached to the plug cap connected to the ignition plug, and an ignition signal is supplied from the igniter to the primary coil of the transformer part, a high voltage is generated in the secondary coil, and the generated high voltage is transferred to the ignition plug. An ignition coil has been devised that applies direct voltage to the ignition coil.

[Problems to be Solved by the Invention] Igniters include semi-transistor type, full transistor type, capacitor discharge type, etc. Among these, for example, the transistor type includes a power transistor at the final stage of the control circuit.

This power transistor is not only large in size but also
Since more spark plugs are required, the overall shape of the igniter becomes larger. For this reason, when mounting the igniter in a car, for example, it is necessary to find a space to mount the igniter in a narrow vehicle space, which has the problem of making the igniter very difficult to mount.

Further, since the igniter and the ignition coil are provided at separate positions, the igniter and the ignition coil are connected via a lead wire. Therefore, there is a problem in that the voltage generated by the igniter is attenuated while being supplied to the ignition coil.

Furthermore, at the time of ignition, a momentary high voltage is generated in the primary coil of the ignition coil. This generated high voltage is also generated in the lead wires connected to the primary coil, so if multiple lead wires connected to each ignition coil are bundled together, erroneous signals may be induced in other lead wires. It had sexuality.

The present invention has been made in view of the above circumstances, and its object is to provide an ignition coil for an internal combustion engine that is easy to mount and is capable of supplying a signal generated by an igniter to the ignition coil without attenuation. .

Means for Solving the Problems] In order to achieve the above objects, the present invention provides a transformer including a primary coil and a secondary coil, and a transformer that connects one end of the winding of the secondary coil to the head of a spark plug. a spark plug connection means connected to the terminal;
The technical means is that the present invention is integrated with a primary coil signal generation circuit that generates a signal to the primary coil so that a high voltage is generated in the secondary coil depending on the operating state of the internal combustion engine.

[Operation] The primary coil signal generation circuit generates an ignition signal according to the operating state of the internal combustion engine.

Since the primary coil signal generating circuit and the transformer are integrated, the signal generated by the primary coil signal generating circuit is supplied to the primary coil of the transformer without passing through a long lead wire.

When an ignition signal is generated from the primary coil signal generation circuit to the primary coil, a high voltage is generated in the secondary coil.

Since the transformer and spark plug connection means are integrated, 2
The high voltage generated in the next coil is applied to the ignition plug without going through the high voltage cable.

[Effects of the Invention] According to the present invention, the signal generated by the primary coil signal generation circuit can be applied to the primary coil of the transformer without passing through a long lead wire. The generated output can be supplied to the primary coil without attenuation. Thereby, the secondary coil can stably generate a designed high voltage when the primary coil receives the ignition signal.

Furthermore, since the primary coil signal generation circuit is divided according to the number of spark plugs, each of which is miniaturized, the mountability is excellent.

On the other hand, since the high voltage generated in the transformer can be applied to the ignition plug without going through a high-voltage cable, the generated high voltage can be supplied to the ignition plug without attenuation.

Furthermore, since the high voltage generated in the transformer can be applied to the spark plug without going through the high voltage cable, it is possible to eliminate the radiation noise that was conventionally generated by the high voltage cable.

[Example] Next, an ignition coil for an internal combustion engine according to the present invention will be described based on an example shown in the drawings.

FIG. 1 shows a sectional view of a gasoline engine (internal combustion engine) for an automobile.

The engine 100 of this embodiment includes an intake camshaft 120 that directly drives the intake valve 110, and an exhaust valve 13.
The spark plug 200 is connected to the cylinder head through a cylindrical plug hole 180 provided in the cam cover 160 and the cylinder head 170 above the combustion chamber 150. 170 mM.

In this embodiment, a current interrupt type is used as the i voltage generation means for supplying a high voltage to the spark plug 200 at the ignition timing of the engine 100.

The current interrupting type high voltage generating means applied to this embodiment is a transistor ignition type, as shown in the electric circuit of FIG.
It consists of a transformer 310 including a primary coil 311 and a secondary coil 312, and an igniter 320.

' One end of the primary coil 311 and the secondary coil 312 are connected to the vehicle battery 340 via the key switch 330.
It is connected to the. Further, the other end of the primary coil 311 is connected to the igniter 320, and the other end of the secondary coil is connected to the ignition plug 200.

The igniter 320 includes an electric control circuit 350 and a primary coil signal generation circuit 360 provided at the final stage thereof.

The electric control circuit 350 detects the operating conditions of the engine 100 such as the crank angle of the engine 100, the rotational speed of the engine 100, the load condition of the engine 100, and the cooling water temperature, and determines the ignition timing and closing rate according to each spark plug 200. A microcomputer 351 for setting and a pnp transistor 352 for controlling the primary coil signal generation circuit 360
Consisting of

The primary coil signal generation circuit 360 of this embodiment is an npn type power transistor 361, the collector of which is connected to the primary coil 311, the base of which is connected to the emitter of the transistor 352, and the emitter of which is body grounded.

As a result, when the microcomputer 351 generates a negative signal to the base of the transistor 352, the base of the power transistor 3610 is energized, so the primary coil signal generation circuit 360 generates an ignition signal that energizes the primary coil 311 to the transformer 310. do. On the other hand, when the microcomputer 351 generates a positive signal to the base of the transistor 352, the base of the power transistor 361 is de-energized.
60 generates an ignition signal to the transformer 310 to de-energize the primary coil 311.

An ignition coil 400 is attached to the ignition plug 200 within the plug hole 180 of the engine 100.

The ignition coil 40G includes a transformer 310 and a transformer 3.
10 secondary coil 312 and the head terminal 21 of the spark plug 200
A connecting fitting 410, which is a spark plug connecting means for connecting a power transistor 361 to a power transistor 361, is integrated with an aluminum transistor case 362 that houses a power transistor 361. Note that, as shown in FIG. 3, the transistor case 362 includes a flange 363 having a substantially rhombic shape, and holes 364 are provided at both ends of the flange 363. Further, on the lower surface of the transistor case 362, a male terminal for collector connection 510 connected to the collector of the internal power transistor 361 and a male terminal for base connection 520 connected to the base are protrudingly provided. The emitter of the power transistor 361 is the transistor case 36
Connected to 2.

Primary coil 311 and secondary coil 3 of transformer 310
One end of 12 has a female terminal 53 for connecting a common key switch.
0 is attached to the other end of the primary coil 311, and a female terminal for collector connection 511 connected to the male terminal for collector connection 510 is attached to the other end of the primary coil 311. In addition, the primary coil 311
The other end is connected to a connecting fitting 410.

The transformer 3101 connection fitting 4101 collector connection female terminal 511 and key switch connection female terminal 530 are housed in a cylindrical resin case 430, and a casting resin 420 is injected and hardened into the case 430. It is formed. Note that the key switch connection female terminal 530 and the collector connection female terminal 511 are provided so that their upper ends (upper side in FIG. 3) protrude from the resin 420. At the upper end of this case 430, there is a
A collar 431 corresponding to the shape of the lunge 363 is provided, and holes 432 are provided at both ends of the collar 431. In addition, at the end of the case 4300 on the side where the ignition plug 200 is connected,
A resilient cylindrical bush 440 that fits inside the insulator 220 of the spark plug 200 is attached.

In a space 450 formed by the upper end of the resin 420 and the inner periphery of the case 430, a connection is made between a base connection male terminal 520 and a base connection female terminal 521 provided in an L shape, and a key switch connection is also made. The female terminal 530 for key switch connection and the male terminal 531 for key switch connection are connected. The base connection female terminal 521 is connected to the collector of the transistor 352 of the electric control circuit 350 via a lead wire 522, and the key switch connection male terminal 531 is connected to the key switch 330 via a lead wire 532. connected.

Furthermore, a notch 433 is provided at the upper end of the case 430 to guide the lead wires 522 and 532 into the space 450, and the lead wires 522 and 532 are provided with a notch 433 to prevent water from entering the space 450. grommet 460
is provided.

Next, attachment of transistor case 362 and case 430 will be explained.

A bushing 44 is installed in the plug hole 180 of the engine 100.
0 is inserted, and the insulator 220 of the spark plug 200 fastened to the cylinder head 170 of the engine 100 is press-fitted into the bush 440. At this time,
A connecting fitting 410 inside the case 430 is connected to the head terminal 210 of the ignition plug 200. Next, the base connection male terminal 520 and the base connection female terminal 521 are connected, and the key switch connection female terminal 530 and the key switch connection male terminal 531 are connected. Next, the notch 433
Fit the grommet 460 into the.

Next, the base connection male terminal 520 is connected to the connection female terminal 5.
21 so that the flange 363 and the collar 43 are fitted together.
Match 1. Next, the hole 364 of the flange 363 and the hole 432 of the collar 431 are aligned, and the screw hole 161 provided around the plug hole 180 of the cam cover 160 is aligned. Then, insert the screw 470 into hole 3.
64 and 432 and are fastened to the screw hole 161, the case 430 and the transistor case 362 are integrally assembled, and the ignition coil 400 is fixed in the plug hole 180.

Next, the above operation will be explained.

When the key switch 330 is turned on, the electric control circuit 35
0, one end of the primary coil 311 and the secondary coil 312 of the transformer 310 are connected to the battery 340.

The microcomputer 351 of the electric control device 350 is
A plus signal and a minus signal are generated depending on the operating condition of the engine 100, such as the crank angle, rotational speed, load condition, and cooling water temperature of the engine 100.

When the microcomputer 351 generates a negative signal, the transistor 352 is ONu, and the base of the power transistor 361 is energized via the lead wire 522.

As a result, the power transistor 361 is turned ON and the primary coil 311 is energized.

The microcomputer 351 inverts the signal generated at the ignition timing from negative to positive. As a result, the transistor 352 is turned off, the base of the transistor 361 is de-energized, and the power transistor 361 is turned off.
F. When the power transistor 361 is turned off, 1
Since the current flowing through the next coil 311 is cut off, the second
A high voltage is generated in the next coil 312. The high voltage generated by this secondary coil 312 is directly applied to the head terminal 210 of the ignition plug 200 via the connecting fitting 410. As a result, the ignition plug 200 is connected to the combustion chamber 15 of the engine 200.
Generates a spark discharge within 0.

Thereafter, the output of the microcomputer 351 is reversed from positive to negative, and the above process is repeated.

According to the present invention, since the output generated by the power transistor 361, which is the primary coil signal generation circuit 360, can be directly supplied to the primary coil 311 without attenuation, the secondary coil 312 can be stably adjusted to the designed value. can generate high voltages.

Since the high voltage generated by the transformer 310 can be applied directly to the ignition plug 200 without going through a conventional high-voltage cable, the high voltage generated by the ignition plug 200 can be applied directly to the ignition plug 200 without attenuation.
0 can be supplied.

Since the high voltage generated by the transformer 310 can be applied to the spark plug 200 without going through the conventional high voltage cable, it is possible to eliminate the radiation noise generated by the conventional high voltage cable.

Since the primary coil signal generation circuit 360 is divided according to the number of spark plugs 200 and attached to the engine 100 by screws 470, if one primary coil signal generation circuit 360 fails, the failure Since only the primary coil signal generation circuit 360 needs to be replaced, the repair cost is significantly reduced compared to the conventional method of replacing the entire igniter including all the primary coil signal generation circuits 360. It can be held in place.

Since high voltage and high current are not generated in the lead wire 522 that connects the electric control device 350 and the primary coil signal generation circuit 360, there is no possibility of inducing an erroneous signal even if the lead wire 522 is bundled.

Power transistor 3 of primary coil signal generation circuit 360
61 has excellent heat dissipation because the transistor case 362 housing the power transistor 361 is exposed in the engine room and is fastened to the cam cover 160 via the screw 470.

The ignition coil 400 is connected to the plug hole 18 of the engine 100.
The lower end is supported by the ignition plug 200 which is fastened to the engine 100 via a bush 440, and the upper end is fixed to the cam cover 160 via a screw 470. The spark plug 200 is reliably supported even when subjected to vibrations during driving.

FIG. 4 shows a second embodiment.

In the embodiment described above, the primary coil signal generation circuit 360 was composed of only the power transistor 361, but in this embodiment, a constant current control circuit 600 is added to the power transistor 361. This constant current control circuit 600 divides the emitter current of the power transistor 361 detected between the current detection resistor 610 using the resistor 620 and the Ei 30, and when the current reaches a specified value, a negative feedback loop is applied to the power transistor 361 by the transistor 640. power transistor 361
emitter of? If current is controlled to a constant current.

This constant current control circuit 600 is integrated and housed in a transistor case 362 together with a power transistor 361.

FIG. 5 shows a third embodiment.

The above embodiment is an ignition coil 40 to which the present invention is applied to an engine 100 equipped with a direct drive type overdrive cam.
0 is shown, however, as shown in FIG.
00 may be provided to mount the ignition coil 400 to which the present invention is applied.

(Modified example) In the above embodiment, the transformer is configured with an open magnetic path transformer, but it may also be configured with a closed magnetic path transformer or a semi-closed magnetic path transformer.

Although we have shown an example in which the igniter uses a transistor ignition type and the final stage power transistor is used as the primary coil signal generation circuit, the igniter uses a capacitor discharge ignition type and the primary coil signal generation circuit is configured with a capacitor, Zyristor, etc. You may do so.

The primary coil signal generation circuit may be molded together with the transformer using resin.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an automobile gasoline engine, Figure 2 is an electric circuit diagram of a current interrupting type high voltage generation means, Figure 3 is an exploded view of an ignition coil, and Figure 4 shows a second embodiment. FIG. 5 is an electric circuit diagram of a current interrupting type high voltage generating means, and is a perspective view of an engine showing a third embodiment.

Claims (1)

[Scope of Claims] 1) A transformer comprising a primary coil and a secondary coil, a spark plug connection means for connecting one end of the winding of the secondary coil to a head terminal of a spark plug, and an internal combustion engine. An ignition coil for an internal combustion engine that is integrated with a primary coil signal generation circuit that generates a signal to the primary coil so that a high voltage is generated in the secondary coil depending on the operating state. 2) The ignition coil for an internal combustion engine according to claim 1, wherein the primary coil signal generation circuit is a final stage power transistor of a transistor ignition type. 3) The primary coil signal generation circuit is comprised of a transistor ignition type final stage power transistor and a constant current control circuit that controls the output of the power transistor to a constant current. An ignition coil for an internal combustion engine according to scope 1.