JPH063183B2 - Internal combustion engine ignition device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a capacitor discharge type ignition device mainly applied to an internal combustion engine for automobiles.

[Conventional technology]

Conventionally, it is possible to continuously generate a plurality of sparks with an extremely short cycle for an appropriate period, and to secure the ignition energy at high speed and the spark duration at low speed, in order to secure the spark energy at low speed, Due to conduction, the capacitor is discharged through the primary coil of the ignition coil to generate a high voltage in the secondary coil of the ignition coil, and the charge of this capacitor is transferred to the primary coil of the ignition coil by conduction of the second switching element. There is a device in which a high voltage is generated in the secondary coil of the switching element by means of electric discharge, and these switching elements are alternately turned on at a predetermined timing (for example, Japanese Patent Laid-Open No. 59-54772).

[Problems to be solved by the invention]

However, in the above-mentioned conventional device, the first and second switching elements are connected in series between the terminals of the DC power supply, so that when both switching elements are simultaneously conducted due to noise or the like, the DC power supply is short-circuited. There is a problem that

Further, when the ignition coil is arranged in an atmosphere having a high ambient temperature, the heat resistance of the ignition coil may be exceeded due to self-heating of the ignition coil.

Therefore, the present invention is to prevent the DC power supply from being short-circuited by the switching element and suppress the heat generation of the ignition coil.

[Means for solving problems]

Therefore, the present invention charges a capacitor having a negative temperature coefficient through the first part of the primary coil of the ignition coil by conducting the first switching element from the DC power supply, and charges the capacitor with the second charge. The switching element conducts to discharge through the second portion of the primary coil, and
The above capacitor is included in an ignition coil.

[Action]

As a result, if the first and second switching elements are connected in series between the terminals of the DC power supply via the first and second portions of the primary coil of the ignition coil, and the temperature of the ignition coil rises. The capacity of the capacitor is reduced and the current flowing through the ignition coil is reduced.

〔Example〕

An ignition device for an internal combustion engine as an embodiment of the present invention is shown in FIG.

The DC power supply 1 is a power supply using a battery, for example, and supplies a DC voltage to the DC-SC converter 3 via the engine key switch 2. The engine key switch 2 is a switch that is closed during operation and opened during stop. The DC-DC converter 3 is a converter that converts a DC voltage of the DC power supply 1, for example, 12V into a DC voltage of about 200V, and oscillates a transistor to boost the voltage by a transformer and then rectifies it to supply a DC high voltage. It has a well-known circuit configuration. The capacitor 4 is for smoothing and storing the main power voltage of the DC-DC converter 3, and supplying a transient large current described later.

The ignition timing detection device 5 includes a signal rotor 51 and a pickup 53. The signal rotor 51 is made of a magnetic material for detecting ignition timing, has a number of protrusions 52 corresponding to the number of cylinders, and is a distributor (not shown) that rotates in synchronization with half the engine speed. -It is attached to the shaft. The puck-up 53 is for ignition timing detection, and is composed of a coil 533 wound around a magnetic core 531 made of a magnetic material and a permanent magnet 532, and the projection 52 of the signal rotor 51 has the magnetic core 531 of the pickup 53. Is arranged so that a closed magnetic circuit is formed when the magnetic field is opposed to

The phase relationship between the signal rotor 51 and the pickup 53 is
Although not shown, it is adapted to change appropriately according to the engine speed and the load, so that an optimum ignition timing can be obtained.

The shaping circuit 6 is a circuit that shapes the output signal of the pickup 53 and outputs a signal of "1" level (hereinafter, simply referred to as "1") corresponding to the ignition timing. Details of the shaping circuit 6 in the apparatus of FIG. 1 are shown in FIG. The bias voltage Vb set by the resistors 611 and 612 and the capacitor 613 is applied to one end of the coil 533 of the pickup 53 via the terminal 601. This bias voltage Vb
Is further applied as a reference voltage to the inverting input terminal of the comparator 614. The non-inverting input terminal of the comparator 614 is connected to the other end of the coil 533 via the terminal 602, and the output of the comparator 614 has a “1” or “0” level (depending on whether the electromotive force of the coil 533 is positive or negative). Hereinafter, a signal of "0") is generated.

A resistor 6 is connected from the output of the comparator 614 to the non-inverting input terminal.
Positive feedback is applied via 15, and since this positive feedback circuit has a function of a Schmitt trigger having hysteresis, it has an effect of preventing malfunction due to noise. The output of the comparator 614 is inverted by the inverter 616 and output via the terminal 603 as an ignition timing signal.

From the ignition timing signal from the shaping circuit 6, the trigger signal generation circuit 7 repeats 180 ° from each other for a predetermined period in a short cycle.
Two trigger signals S (A) and S (B) having different phases are created. Details of the trigger signal generating circuit 7 in the apparatus of FIG. 1 are shown in FIG. An ignition timing signal from the shaping circuit 6 is led to the one-shot multi 711 via the terminal 701. The one-shot multi 711 is triggered by the rise of this ignition timing signal and generates a signal of "1" at the output terminal Q for a fixed time (for example, 2 msec) determined by the capacitor 12 and the resistor 713.

The NOR gates 714 and 715 are connected to each other so as to function as a set reset and a flip-flop, and when the output of the one-shot multi 711 becomes "1", the NOR gate 7
The output of 14 is "0", and the output of NOR gate 715 is "1".
Becomes The binary presettable up / down counter 717 is a 4-bit counter circuit, the output of the NOR gate 714 is led to its reset terminal, and when the output of the NOR gate 714 becomes "0", it starts counting and becomes "1". Will be reset. The counter 717 is set to the down count mode,
The preset function is not used.

The clock generation circuit 716 is, for example, a circuit that continuously generates a clock signal having a frequency of about 80 KHz, and the clock signal is guided to the clock input terminal of the counter 717. One input terminal of the NOR gate 718 is connected to the output terminal of the one-shot multi 711, and the other input terminal is connected to the Q _D output terminal which is a 1/16 frequency division output of the counter 7171. And the level of both output terminals is "0"
Then, the output of the NOR gate 718 becomes "1". This output is led to the NOR gate 715 and inverts the flip-flop formed by the NOR gates 714 and 715.

The Q _D output of the counter 717 is further guided to the one-shot multi circuits 721 and 728 via the inverter buffers 719 and 720, respectively. One shot multi 721
Causes the output of the inverter buffer 719 to fall, and generates a signal of “0” at the output terminal for a fixed time (for example, 5 μsec) determined by the capacitor 722 and the resistor 723. This signal is conducted to the base of the transistor 726 via the resistors 724 and 725. When the terminal of the one-shot multi 721 is "0", the transistor 7
26 turns on and produces a "1" trigger signal S (A) at its collector or terminal 702.

The one-shot multi 728 is an inverter buffer 720.
Is triggered by the rising edge of the output of the above, and a signal of “0” is generated at the output terminal for a fixed time (for example, 5 μsec) determined by the capacitor 729 and the resistor 730. This signal is guided to the base of the transistor 733 via the resistors 731 and 732. One shot multi 728 Q terminal is "0"
At this time, the transistor 733 is turned on and outputs the trigger signal S (B) of “1” to its collector, that is, the terminal 703.

The thyristor 13 has its anode connected to the positive terminal of the capacitor 4 and its cathode connected to one end of the primary coil 161 of the ignition coil 16. The gate of the thyristor 13 has a trigger signal S from the trigger signal generating circuit 7.
(A) is supplied through the insulating pulse transformer 14, and further through the noise prevention circuit including the diode 131, the resistor 132, the capacitor 133, and the resistor 134. The resonance capacitor 15 is a capacitor having a negative temperature coefficient (for example, a ceramic capacitor), and is connected to the center tap of the primary coils 161 and 162 of the ignition coil 16. With this thyristor 13, the capacitor 4, the thyristor 13, the primary coil 161, and the resonance capacitor 1 are provided.
One closed circuit of 5 is formed.

The anode of the thyristor 20 is connected to one end of the primary coil 162, and the cathode thereof is connected to one end (GND) of the resonance capacitor 15. The gate of the thyristor 20 is supplied with the trigger signal S (B) from the trigger signal generation circuit 7 through the pulse transformer 21 and the noise prevention circuit including the diode 201, the resistors 202 and 204, and the capacitor 203. The thyristor 20 forms another closed circuit including the primary coil 162, the thyristor 20, and the resonance capacitor 15.

The ignition coil 16 includes primary coils 161, 162, a secondary coil 163, and a core 164. Primary coil 161, 1
The winding ratio of 62 and the secondary coil 163 is set to about 100 to 200, and the primary coils 161 and 162 are wound in the same direction. Primary coil 161, 162, secondary coil 1
63 is magnetically coupled via a core 164 and boosts the voltage generated in the primary coils 161 and 162 and outputs it from the secondary coil 163. The secondary coil 163 has one end grounded (GND) and the other end connected to the center electrode of the distributor 22 that distributes a high voltage to each cylinder.

The distributor 22 has a well-known configuration, and an ignition gap 241 arranged in a predetermined cylinder is provided by a distribution rotor 23 that rotates integrally with a shaft that rotates in synchronization with a rotation speed that is ½ of the engine rotation speed. 242,
High tension cords 251, 25 on 243, 244
Distribute the high voltage through 2, 253, 254.

Here, the structure of the ignition coil 16 of the apparatus shown in FIG. 1 will be described. The structure of the ignition coil 16 of the apparatus shown in FIG. 1 is shown in FIG. A capacitor 15 is built in the ignition coil 16, and the midpoint of the primary coils 161 and 162 is connected to one end of the capacitor 15 inside the coil 16. 1
Reference numeral 66 is a peripheral device, which is made of a heat resistant resin. Reference numeral 1631 denotes a secondary coil bobbin, which extends from the bottom of the peripheral device 166 to the protrusion 1
631a is projected, and the terminal portion 165 made of brass or tin-plated iron is provided inside the protruding portion 1631a.
Are integrally molded. A part of the bottom of the terminal portion 165 has a rod shape and protrudes from a part of the secondary coil bobbin 1631. One end of the secondary coil 163 is soldered to the projecting portion 165a, and the terminal 165 serves as a high voltage output terminal. The secondary coil bobbin 1631 is provided with 10 to 20 slots on the outer peripheral portion thereof, and the secondary coil 163 is divided and wound in the slots, so that the interlayer paper can be omitted. 16
11 is a primary coil bobbin and a secondary coil bobbin 1631
It is fitted in the hollow part of, and primary coils 161 and 162 are wound around it. An iron core 164 is inserted in the hollow portion of the primary coil bobbin 1611. A printed board 151 is fitted into one end of the primary coil bobbin 1611, and the capacitor 1 is attached to the printed board 151.
5 is installed. Both ends and middle points of the primary coils 161 and 162 and the other end of the secondary coil 163 are connected to the printed board 151 by soldering. Primary coil 1
Both ends of 61 and 162 are led to lead wires 1612 and 1613 via a printed board 151 so that power can be supplied from the outside. The midpoint of the primary coils 161 and 162 is also connected to one end of the capacitor 15 via the printed board 151. The other end of the secondary coil 163 is connected to the other end of the capacitor 15 via the printed board 151 and guided to the lead wire 1641. This lead wire 164
Reference numeral 1 is a GND (ground) wire, and a lug plate 1642 is crimped at its end. Reference numeral 167 denotes a metal stay wound around the outer circumference of the outer peripheral device 166, and M stays at both ends thereof.
There is a hole through which a bolt No. 5 or M6 can pass, and the lug plate 1642 can be mechanically and electrically connected to the engine or chassis together. The inner diameter of the terminal 165 is dimensioned so that a normal high tension cord terminal can be press-fitted, and is connected to the center electrode of the distributor via the high tension cord. The interior of the ignition coil 16 is filled with epoxy resin.

The following semiconductor devices were used as the semiconductor devices in the device shown in FIG.

One shot multi 711… Toshiba TC4528BP NOR gate 714, 715, 718… 〃 TC4001BP up / down counter 717… 〃 TC4516BP inverter 719, 720… 〃 TC4049BP One shot multi 721, 728… TI 74LS221 Next, the operation of the device in Fig. 1 is explained.

FIG. 4 is a signal waveform diagram of each part of the device shown in FIG.
(1) is the electromotive voltage of the coil 533, (2) is the output voltage of the pickup 53, (3) is the ignition timing signal that is the output of the shaping circuit 6, (4) is the ignition period signal that is the one-shot multi 711 output, (5) the output signal of NOR gate 714, (6) the output signal of the Q _D of the counter 717, (7) the output signal of the inverter buffer Wa 19,720, (8), (9) a trigger signal S
The waveforms of (A) and S (B) are shown.

First, when the engine key switch 2 is turned on, DC-
The DC voltage of + 12V is supplied from the DC power supply 1 to the DC converter 3, and the voltage is boosted to + 200V.
The DC voltage of V is always stored in the capacitor 4.

The signal rotor 51 rotates according to the rotation of the engine,
An electromotive force having a waveform shown in FIG. 4 (1) is generated in the coil 533 of the pickup 53. The ignition timing is the point at which the electromotive force switches from positive to negative. Since the coil 533 is biased with the bias voltage Vb by the shaping circuit 6, the output voltage of the pickup 53 becomes a value obtained by raising the generated potential of the coil 533 by the bias voltage Vb as shown in FIG. 4 (2). This signal is shaped by the shaping circuit 6 and becomes a signal that rises to "1" at the ignition timing shown in FIG. 4 (3).

The output signal of the shaping circuit 6 is input to the trigger signal generation circuit 7, which triggers the one-shot multi 711 at the rising edge thereof to generate a pulsed ignition period signal having a pulse width of about 2 msec shown in FIG. 4 (4). . The ignition period has this pulse width. The ignition period signal enters NOR gate 714 and inverts the flip-flop formed by NOR gates 714 and 715. As a result, the output of the NOR gate 714 becomes "0" as shown in FIG. 4 (5).

The output of the NOR gate 714 is led to the reset terminal of the counter 717, and when this output is "0", the reset of the counter 717 is released. By releasing this reset, the counter 717 starts counting at the clock frequency of about 80 KHz from the clock generation circuit 716. Since the counter 717 is a 4-bit binary counter and is set to the down count mode, the content of the counter 717 changes from 0 to 15 at the rising edge of the first clock signal. That is, the Q _D output of the counter 717 changes from “0” to “1”. After that, the down count is repeated every time the clock signal arrives, and 0, 15, 14, ..., 2,
The contents change cyclically as 1, 0, 15, .... At this time, the Q _D output which is the 1/16 frequency division output is the counter 7
When the content of 17 is 8 to 15, it becomes "1", so that a square wave having a duty ratio of 50% shown in FIG. 4 (6), which is a frequency 1/16 of the clock frequency, is generated. The width of one pulse in FIG. 4 (6) is 100 μsec, and the interval between pulses is 100 μsec.

About 2 msec after the ignition timing signal rises, the input of the NOR gate 714 becomes "0". If the counter 717 is immediately reset at this time, the time width of "1" of the Q _D output immediately before that is shortened, and commutation of the thyristor described later cannot be performed properly. As a countermeasure, the output of the one-shot multi 711 and the counter 717
By directing the output of and the output of NOR gate 718,
Only when the Q _D output is "0", the output of the NOR gate 718 becomes "1" and the flip-flop composed of the NOR gates 714 and 715 is inverted, whereby the NOR gate 71 is turned on.
The output of 4 is set to "1" and the counter 717 is reset.

As described above, from the ignition timing signal to the clock signal 1
With a delay within a period (12.5 μsec), an integral number of square waves of 1/16 (5 KHz) of the clock frequency are generated in the Q _D output at least during the ignition period. This signal is inverted by the inverter buffers 719 and 720 and becomes the signal shown in FIG. 4 (7).

One-shot multi 721 is an inverter buffer 719
The pulse is generated for about 5 μsec, the transistor 726 is turned on, and the trigger signal S (A) shown in FIG. 4 (8) is output to the terminal 702. Further, the one-shot multi 728 is triggered by the rising of the output of the inverter buffer 720, generates a pulse of about 5 μsec, turns on the transistor 733, and sends the trigger signal S (B) shown in FIG. 4 (9) to the terminal 703. Output. That is, the trigger signals S (A) and S (B) are 180 degrees out of phase with each other.
Signals having different periods of 200 μsec and a pulse width of 5 μsec.

Next, the operation of the high voltage generator will be described. FIG. 5 is a waveform diagram showing the signals of the respective parts in this embodiment in a time-enlarged manner compared to FIG. In FIG. 5, (1) is the trigger signal S (A), (2) is the trigger signal S (B), (3) is the terminal voltage of the capacitor 15, (4) is the cathode voltage of the thyristor 13, and (5 ) Represents the current flowing through the thyristor 13, (6) represents the anode voltage of the thyristor 20, and (7) represents the waveform of the current flowing through the thyristor 20.

The trigger signal S (A) shown in FIG. 5 (1) triggers the thyristor 13 via the pulse transformer 14 and the noise prevention circuit. Similarly, the trigger signal S (B) shown in FIG. 5 (2) triggers the thyristor 20 via the pulse transformer 21 and the noise prevention circuit.

First, when the thyristor 13 is triggered and turned on, a current flows through a closed circuit composed of the capacitor 4, the thyristor 13, the primary coil 161, and the capacitor 15. At this time,
Since the capacity of the capacitor 4 is sufficiently larger than the capacity of the capacitor 15, the capacitor 4 is kept at a constant voltage (200V).
Can be thought of as a power source. In addition, the primary coil 161
Since the resistance component of the circuit composed of the resistance of the thyristor 13 and the resistance of the thyristor 13 is sufficiently small, this first closed circuit is
Resonance occurs under the condition determined by the capacitance C of 5 (for example, 1 μF) and the inductance L of the primary coil (for example, 100 μH).

The current at resonance is the positive terminal of the capacitor 4 in FIG. 1, the thyristor 13, the primary coil 161, the capacitor 1
5, it flows in the direction of the ground electrode terminal of the capacitor 4, and becomes a sine wave shape expressed by the following equation (1) using the above C and L.

Further, the voltage generated in the primary coil 161 is expressed by the equation (2).

The voltage applied to the capacitor 15 is as shown in equation (3).

The thyristor 13 maintains the ON state only when i> 0, but when i ≦ 0, the thyristor 13 commutates and becomes the OFF state.

As described above, in the device shown in FIG. 1, since the oscillating current shown in the formula (1) flows in the circuit including the primary coil, the capacitor, the switching element, and the DC power source, the thyristor 1
Since 3 commutates automatically, it is not necessary to add a commutation circuit.

In the above equation (1), the time t _{1 when} i becomes zero is At this time, the thyristor 13 is turned off, and the voltage of the capacitor 15 expressed by the equation (2) at that time is DC-
Double the voltage of the DC converter (200V), that is 40
It becomes 0V and is held.

Next, the case where the thyristor 20 is triggered will be described. When the thyristor 20 is turned on, the capacitor 1
5, a closed circuit composed of the primary coil 162 and the thyristor 20 is formed, and the charge accumulated in the capacitor 15 is the upper terminal of the capacitor 15, the primary coil 162, and the thyristor 2.
0, the current flows in the direction of the downstream terminal of the capacitor 15, and the current value at this time is as shown in equation (5).

The thyristor 20 is the same as the thyristor 13 No special commutation circuit is required because it is turned on for a period of time and spontaneously commutates.

After that, the thyristor 13 and the thyristor 20 are continuously and alternately triggered, so that a current flows alternately through the primary coils 161 and 162. Assuming that there is no loss in the circuit, the current flowing in the circuit, the voltage of the capacitor 15, the primary coil 16
The voltage of 1, 162 increases and diverges each time switching is repeated, but in reality, energy is consumed through the secondary coil and there is a loss in each part,
The peak value becomes almost constant in the first few times.

In the description so far, the secondary coil 16 of the ignition coil 16 has been described.
3 is not mentioned, but the primary coils 161, 16
Since 2 and the secondary coil 163 are transformer-coupled,
Assuming that the transformation ratio is 1: 150, the primary coil 1
150 times the applied voltage of 61, 162 is the secondary coil 163.
Occurs in. That is, the voltage V ₂ generated in the secondary coil 163 is V ₂ = 200 × 150 = 30 KV (6) when the power supply voltage V = 200 V and the transformation ratio is 150, which is a voltage sufficient for ignition by discharge. .

The voltage generated by the secondary coil 163 is the
It is distributed to the specified cylinders with the high tension code 25.
Ignition gap 24 via 1, 252, 253, 254
It is supplied to 1, 242, 243, and 244, and is discharged to the ground electrode of the ignition gap to ignite.

Once the discharge path is formed by the discharge, the nearby air becomes an ionized arc discharge, and the induction discharge is continued until the discharge sustaining voltage (about 500 V to 1 KV) is reached. This duration is the same as that of a normal igniter (about 2ms
Although it is shorter than ec), the next cycle starts as soon as this induction discharge ends, so the ions remaining in the discharge gap easily cause a re-discharge, and the discharge is sustained without interruption. It Since this duration can be determined by the ignition period electrically set in the trigger signal generating circuit 7, it is easy to set a sufficiently long time for complete ignition.

Also, since the other thyristor is in the reverse blocking state for about half the time that one thyristor is on, the repetition cycle of the trigger signals S (A) and S (B) can be shortened. As described above, in the ignition control of the internal combustion engine for an automobile, the apparatus of FIG. 1 can continuously generate a plurality of sparks at an extremely short cycle for an appropriate time, so that the ignition performance of the internal combustion engine can be improved.

Further, in the device shown in FIG. 1, the primary winding 161 of the ignition coil 16 is provided between the thyristor 13 and the thyristor 20,
Even if the thyristor 13 and the thyristor 20 are simultaneously conducted due to noise or the like and the electric charge of the capacitor 4 is discharged all at once through the thyristor 13 and the thyristor 20, the primary winding 161,
Due to the inductance and resistance of 162, a rapid increase in current and overcurrent are prevented, and the thyristor di / d
It is possible to prevent the breakdown of the thyristor and the switching block other than the thyristor due to t or overcurrent.

Furthermore, by connecting the capacitor 15 to the center tap of the primary coils 161, 162, the thyristors 13, 2
The rate of increase dV / dt of the voltage applied in the forward direction of 0 is determined by the time constants of the capacitor 15 and the primary coil 162 and the time constant of the capacitor 15 and the primary coil 161, respectively. The rate of increase dV / dt is 100V. The value can be as low as / μsec or less. As a result, it is possible to eliminate a malfunction caused by dV / dt applied to the other thyristor by the operation of one thyristor.

Furthermore, the primary coils 161 and 162 are wound in the same direction so that magnetic fields in the same direction are generated,
As a result, the dV / dt applied to the switching element is reduced, and a complete and reliable operation of the switching element can be obtained.

Since the capacity of the capacitor 15 built in the ignition coil 16 has a negative temperature coefficient, the capacity of the capacitor 15 decreases as the temperature of the engine rises and the temperature of the ignition coil rises. The current supplied to the ignition coil is reduced, and the temperature rise of the ignition coil is suppressed.

By providing the circuit 18 including the thyristors 13 and 20, the ignition coil 16 and the capacitor 15 in the apparatus of FIG. 1 for each cylinder of the multi-cylinder internal combustion engine, high voltage distribution means such as a high tension cord or a distributor. It is possible to reduce the energy loss generated in the high voltage distribution means to increase the ignition energy, and to eliminate the need for the high voltage distribution means to reduce the cost.

Further, as another embodiment, one thyristor 20 in the apparatus shown in FIG. 1 is used in common for each cylinder of a multi-cylinder internal combustion engine, and the number of thyristors to be used is distributed by using a rectifying element such as a diode to distribute the cylinders. It is possible to reduce the cost and the cost. Another embodiment is shown in FIG. The same components as those of the apparatus shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In addition, capacitors 15a to 15d and diodes 17a to 1 are provided inside the ignition coils 16a to 16d.
7d is built in.

In FIG. 6, the cylinder discriminating device 8 includes a signal rotor 80.
And a pickup 82. The signal rotor 80 is for identifying the cylinder, and is a distributor (not shown) that rotates in synchronization with the engine speed of 1/2.
It is attached to the shaft and has one protrusion 81. The pickup 82 is a cylinder discrimination pickup and has the same principle as that of the pickup 53 of the above-mentioned embodiment, but the difference is that the magnetic core of the pickup 53 forms a closed magnetic circuit with two projecting portions of the signal rotor 51. On the other hand, the magnetic core of the pickup 82 is an open magnetic circuit.

The phase relationship between the signal rotor 80 and the pickup 82 is different from that of the signal rotor 51 and the pickup 53 described above.
It is a fixed type that does not change depending on the engine speed and load. When the signal rotor 80 makes one rotation, one pulse is output to the output of the pickup 82. This pulse position is set at a position 60 ° before the top dead center of the first cylinder. The output of the pickup 62 is guided to the shaping circuit 6 '. Shaping circuit 6 '
Has the same circuit configuration as the shaping circuit 6.

FIG. 6 shows a group of trigger signal generating circuits 9 in the apparatus as shown in FIG.
Shown in the figure. Further, FIG. 8 shows a signal waveform diagram of each part in FIG. 6 and FIG. In FIG. 8, (1) is the output of the pickup 53, (2) is the output of the pickup 82,
(3) and (4) are the outputs of the shaping circuits 6 and 6 ',
(5), (6), (7) and (8) are counters 9 respectively.
12 output terminals, output at ,, (9),
(10), (11), (12) and (13) are trigger signals S (A) ₁ , S (A) ₂ , S (A) ₃ , S (A) ₄ and S, respectively.
The waveforms of (B) are shown.

In FIG. 7, the circuit portion of the trigger signal generating circuit 9 designated by the reference numeral 7 surrounded by the one-dot chain line has the same configuration as the trigger signal generating circuit 7 in the above-mentioned embodiment, and therefore the description of this circuit portion is omitted. To do. Counter 912 (Toshiba TC4
017) is a counter with a decoder, and the output signal of the shaping circuit 6'shown in FIG. 8 (4) is input to its reset terminal R, and the counter 912 is reset by this output signal. The output signal of the shaping circuit 6 shown in FIG. 8 (3) is input to the clock terminal C, and the counter 912 counts this output signal.

Therefore, after the counter 912 is reset by the output signal from the shaping circuit 6'and receives the first signal from the shaping circuit 6, the output terminal of the counter 912 has the waveform shown in FIG. 8 (5). The decoded signal is output. Similarly, the waveform shown in FIG. 8 (6) is output to the output terminal by the second signal, and the waveform shown in FIG. 8 (7) is output to the output terminal by the third signal. The waveforms shown in Fig. 8 (8) appear.
The time of "1" at the output terminal is shorter than the other outputs because it is reset midway.

One of the inputs of the AND gates 908, 909, 910 and 911 has an output terminal of the counter 912,
, And the trigger signal S (A) obtained by the trigger signal generating circuit 7 is commonly input to the other input. Therefore, the terminal 903 receives the trigger signal S (A) ₁ for the first cylinder, the terminal 904 receives the trigger signal S (A) ₂ for the third cylinder, and the terminal 905 receives the trigger signal S (4) for the fourth cylinder. (A) ₃ is output to the terminal 906, and the trigger signal S (A) ₄ for the second cylinder is output. Also terminal 9
A trigger signal S (B) is output to 07. These trigger signals S (A) ₁ , S (A) ₂ , S (A) ₃ , S (A) ₄ ,
The signal waveforms of S (B) are shown in Fig. 8 (9), (10), (1
It is shown in 1), (12) and (13).

Next, the operation of the apparatus shown in FIG. 6 will be described. The trigger signal S (A) ₁ is input to the gate terminal of the thyristor 13a for the first cylinder via the pulse transformer 14a, whereby the thyristor 13a is turned on, and the ignition for the first cylinder is performed as in the above-described embodiment. A high voltage is generated in the secondary coil of the coil 16a to generate a spark in the ignition gap 241 to generate a spark in the ignition gap 241, and energy is stored in the capacitor 15a. At this time, the energy stored in the capacitor 15a is the diode 17
b, 17c, 17d, the ignition coil 16b of the other cylinder,
It does not flow to 16c and 16d.

Next, when the trigger signal S (B) is applied to the gate terminal of the thyristor 20 via the pulse transformer 21, the electric charge stored in the capacitor 15a is discharged through the primary coil of the ignition coil 16a, the diode 17a, and the thyristor 20. Along with this, a high voltage is generated in the secondary coil of the ignition coil 16a to cause sparks in the spark gap 241.

The above process is repeated a predetermined number of times to shift to the ignition of the next cylinder. At this time, since the ignition of the first cylinder is completed with the voltage of the capacitor 15a being negative, the diode 17a is in the reverse blocking state and has no influence on the ignition of the other cylinders.

By performing the above operation in the order of the first, third, fourth, and second cylinders, a spark having good ignitability can be obtained near the top dead center of each cylinder. Moreover, the diode 17
Since steps a to 17d are performed, the number of thyristors to be used can be significantly reduced, and there are effects such as downsizing of the device and cost reduction. Further, by distributing the cylinders by the diodes 17a to 17d and providing an ignition coil for each cylinder, it is possible to eliminate a high voltage distributing means such as a distributor or a high tension cord, and to eliminate energy loss due to heat generation of these. With this, the ignition energy can be increased and efficient ignition control can be performed.

Capacitors 15a to 15d and a diode 17 are provided inside the ignition coils 16a to 16d of the device shown in FIG.
The structure of the ignition coil incorporating a to 17d is shown in FIG. Since the ignition coils 16a to 16d are all the same, only the ignition coil 16a will be described as a representative. 166a is a peripheral device, 1631a is a secondary coil bobbin, 1611a is a primary coil bobbin, 164a.
Is an iron core, and 165a is a high-voltage terminal. The positional relationship between these is the same as that of the ignition coil 16 in FIG.

The capacitor 15a is mounted on the printed board 151a, one end of both ends of the primary coils 161a and 162a is connected to one terminal of the connector 167a via the printed board 151a, and the other end is yellow on the printed board. It is connected to the other terminal of the connector 167a through a diode 17a fixed by a copper stay 171a. The midpoint of the primary coils 161a and 162a is connected to one end of the capacitor 15a via the printed board 151a. One end of the secondary coil 163a is connected to the high voltage terminal 165a, the other end is connected to the other end of the capacitor 15a via the printed board 151a, and is further soldered to the tin-plated upper plate 168a. M4 or M5 nuts 1695a to 1698a are welded to the upper plate 168a at four locations. The upper plate 168a and the peripheral device 166a
Are connected by screws 1691a to 1694a. The screws 1691a to 1694a serve as ground terminals.

The ignition coils 16a to 16d are unit ignition coils and are directly connected to the ignition plug.
FIG. 11 shows a state in which the ignition coils 16a to 16d are attached to the engine. In FIG. 1, 27 is an engine head and 28 is an engine block. Ignition coil 16
a to 16d are screws 1691a on the metal plate 26.
Through 1694a, 1691b through 1694b, 16
91c to 1694c, 1691d to 1694d
The metal plate 26 is fixed to the engine head 27 with screws 321 and 322, and also serves as a ground. The following description is for the ignition coil 1
As a representative, only 6a is performed. High voltage terminal 165a
Is in contact with the center electrode of the ignition plug 29A via a spring 31A, and the surroundings of the ignition coil 16a and the ignition plug 29A are covered with a rubber bush 30A so that engine vibration can be absorbed. Thus, a unit ignition device in which one ignition coil corresponds to one ignition plug is constructed.

In the case of the above configuration, there is a danger that the heat resistance temperature of the ignition coil may be exceeded due to radiant heat of the engine and self-heating of the ignition coil. However, according to the present invention, since the capacitor having the negative temperature coefficient is built in the ignition coil, if the temperature of the ignition coil rises, the capacity of the capacitor decreases, and the energization current of the ignition coil accordingly. It is possible to control the temperature rise of the coil as a result.

〔The invention's effect〕

According to the present invention, at the time of ignition of an internal combustion engine, a plurality of sparks can be continuously generated for an appropriate period at an extremely short cycle, it is ensured that ignition energy is not insufficient at high speed, and flame non-growth occurs at low speed. Alternatively, the flame duration is secured so that misfire does not occur, thereby improving the ignition performance. Further, it is possible to prevent the switching elements such as thyristors from being destroyed and to operate these elements safely and reliably.

Further, by incorporating a capacitor having a negative temperature coefficient in the ignition coil, heat generation of the ignition coil can be suppressed.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the device of the present invention.
1 is an electric circuit diagram showing a detailed configuration of a shaping circuit in the apparatus shown in FIG. 1, FIG. 3 is an electric circuit diagram showing a detailed configuration of a trigger signal generation circuit in the apparatus shown in FIG. 1, FIGS. FIG. 6 is a waveform diagram of each part of the device shown in FIG. 1, FIG. 6 is an electric circuit diagram showing another embodiment of the device of the present invention, and FIG.
FIG. 8 is an electric circuit diagram showing a detailed configuration of a trigger signal generating circuit in the device shown in FIG. 8, FIG. 8 is a waveform diagram of each part of the device shown in FIG. 6, and FIG. 10 (A) and 10 (B) are a longitudinal sectional view and a partial sectional front view showing the ignition coil 16a in the device shown in FIG. 6, and FIG. 11 is an internal combustion engine of each ignition coil 16a to 16d in the device shown in FIG. FIG. 3 is a partial cross-sectional front view showing a mounting state on the device. 3 ... DC-DC converter, 7 ... Trigger signal generation circuit,
13 ... 1st thyristor which comprises a 1st switching element, 15 ... Resonance capacitor, 16, 16a-16d ...
Ignition coil, 20 ... Second forming second switching element
Thyristors, 161, 161a ... First primary coil,
162, 162a ... Second primary coil, 163, 163
a ... Secondary coil, 241-244 ... Ignition gap.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Koichi Mori, 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute, Inc. (72) Inventor Tokuhiko Nakamura 1-cho, Toyota-cho, Aichi Prefecture Toyota Automobile Incorporated (72) Inventor Tatsuo Kobayashi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) References JP 59-54712 (JP, A) JP 60-19961 (JP, A) )

Claims (5)

[Claims] 1. A primary coil and a secondary coil, wherein the primary coil is divided into two parts, a first and a second part, by a midpoint tap and connected to the midpoint tap of the primary coil. Which has a negative temperature coefficient,
An ignition coil for suppressing a temperature rise of the secondary coil, the secondary coil, an ignition gap connected to the secondary coil, a first portion of the primary coil, the capacitor, and the direct current power source to form a closed circuit. One switching element, a second part of the primary coil, and a second switching element that forms a closed circuit together with the capacitor, and the first switching element that operates in accordance with an ignition instruction signal coming from the outside, and An ignition device for an internal combustion engine, comprising: a signal generating circuit for generating an energization signal so that the second switching element is alternately turned on at a predetermined timing. 2. A circuit comprising the first switching element, the second switching element, and the ignition coil is provided commonly to each cylinder of a multi-cylinder internal combustion engine.
An ignition device for an internal combustion engine according to the paragraph. 3. The internal combustion engine according to claim 1, wherein a circuit including the first switching element, the second switching element, and the ignition coil is provided for each cylinder of a multi-cylinder internal combustion engine. Engine ignition device. 4. The ignition device for an internal combustion engine according to claim 3, wherein one of the second switching elements is provided commonly to all cylinders, and cylinders are distributed by rectifying elements such as diodes. 5. The ignition device for an internal combustion engine according to claim 4, wherein the rectifying element is built in the ignition coil.