JPH0363673B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an ignition device for an internal combustion engine using an ignition spark method. This device is mainly used for ignition of internal combustion engines for automobiles.

(Prior Art) Conventional ignition devices used in internal combustion engines reduce ignition energy at high speeds and generate only one spark, making them vulnerable to blowout. In particular, the CDI method has the problem that it is prone to misfires because the flame does not grow during startup or at low speeds.

(Objective of the Invention) The object of the present invention is to ensure that the ignition energy is not insufficient at high speeds, and to prevent flame growth at low speeds, based on the concept of continuously generating multiple sparks for an appropriate period in an extremely short cycle. Alternatively, the flame duration is ensured to prevent misfires, thereby improving ignition performance, and even if the ignition device malfunctions due to a malfunction of the switching element, it is automatically restored to normal operation to ensure that Our goal is to provide a reliable ignition system.

(Structure of the Invention) In the present invention, a DC power source that generates a DC voltage, an ignition coil that has a primary coil and a secondary coil, and the primary coil is divided into two parts by a tap at the center; A spark plug connected to the secondary coil, a capacitor connected to the center tap of the primary coil, a first portion of the primary coil, the capacitor, and the DC power source form a closed circuit. A first switching element, a second portion of the primary coil, and a second switching element forming a closed circuit together with the capacitor; A signal generation circuit that generates an energization signal so that the second switching element is alternately conductive at a predetermined timing, and a signal generation circuit that generates an energization signal so that the first and second switching elements are conductive at the same time so that the output voltage of the DC power supply is lower than a predetermined value. An ignition device for an internal combustion engine is provided that includes a voltage abnormality detection circuit that detects abnormal voltage and generates a signal with a predetermined time width to temporarily stop operation of a DC power source.

(Embodiment) An ignition system 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 DC voltage to the DC-DC converter 3 via the engine key switch 2. The engine key switch 2 is a switch that is closed when the engine is running and opened and closed when the engine is stopped. In addition, the DC-DC converter 3 converts the DC voltage of the DC power supply 1, for example, 12V, to approximately 20V.
It is a converter that converts the voltage into DC voltage, and after self-oscillating the transistor and boosting the voltage with the transformer,
It rectifies and supplies high voltage DC. 1st
Details of the DC-DC converter 3 in the device shown in FIG. 2 are shown in FIG.

In FIG. 2, it has a primary coil 311, a secondary coil 312, and a tertiary coil 313, and the turns ratio of the primary coil 311 and the secondary coil 312 is approximately
The primary coil 311 of the transformer 310, which is set at 20, is energized by switching the current supplied from the DC power supply 1 through the terminal 302 by the Darlington-connected transistors 322 and 323. Due to the turns ratio, a voltage boosted to approximately 200V is generated in the secondary coil 312, and the diode 32
The signal is rectified at 9 and output to the terminal 304. The capacitor 328 is an element for switching the DC-DC converter 3 at a resonant frequency determined together with the secondary coil 312. Tertiary coil 31
3 is for applying positive feedback to the base of the transistor 323 to cause it to oscillate. Resistance 325,3
26, the capacitor 327 is for stabilizing the bias voltage at the base of the transistor 323, and the resistor 324 is the input resistance of the transistor 322. The terminal 305 controls the operation of the DC-DC converter 3 according to the voltage applied to the terminal 305, and the voltage applied to the terminal 305 is turned on or off in response to an output signal from an abnormal voltage detection circuit 8, which will be described later.
It will be turned off.

In FIG. 1, a capacitor 4 is used to smooth and store the output voltage of the DC-DC converter 3 and to supply a large transient current.

The ignition timing detection device 5 includes a signal rotor 51 and a pickup 53. The signal suiter 51 is made of a magnetic material and is used for detecting ignition timing.
It has a number of protrusions 52 corresponding to the number of cylinders, and is attached to a distributor shaft (not shown) that rotates synchronously at half the engine speed. The pick-up 53 is for detecting ignition timing, and includes a coil 533 and a permanent magnet 532 wound around an iron core 531 made of magnetic material.
and a protrusion 5 of the signal rotor 51.
2 is arranged so that a closed magnetic path is formed when the magnetic core 531 of the pickup 53 faces the magnetic core 531 of the pickup 53.

Although not shown, the phase relationship between the signal rotor 51 and the pickup 53 changes appropriately depending on the engine speed and load, so that optimal ignition timing can be obtained.

The shaping circuit 6 is a circuit that shapes the waveform of 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 device of FIG. 1 are shown in FIG. In this Figure 3, the resistor 61
1,612, and a bias voltage Vb set by a 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 to the inverting input terminal of comparator 614 as a reference voltage. 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 comparator 6
At the output of 14, a signal of "1" or "0" level (hereinafter simply referred to as "0") is generated.

Positive feedback is applied from the output of the comparator 614 to the non-inverting input terminal via a resistor 615.
Since this positive feedback circuit has a Schmitt trigger function with hysteresis, it is effective in preventing malfunctions due to noise. The output of comparator 614 is inverted by inverter 616 and output as an ignition timing signal via terminal 603.

In FIG. 1, a trigger signal generation circuit 7 generates two trigger signals S(A) and S(B) having a phase difference of 180° from each other, which are repeated in short cycles for a predetermined period, from the ignition timing signal from the shaping circuit 6. . Details of the trigger signal generation circuit 7 in the apparatus shown in FIG. 1 are shown in FIG. In FIG. 4, the ignition timing signal from the shaping circuit 6 is led to the one-shot multi 711 via the terminal 701. One shot multi 711
is triggered by the rising edge of this ignition timing signal,
A signal of "1" is generated at the output terminal Q for a certain period of time (for example, 2 msec) determined by the capacitor 712 and the resistor 713.

Noah gates 714 and 715 are reset,
They are connected together to form a flip-flop, and the output of the washing machine multi 711 is "1".
Then, the output of the NOR gate 714 becomes "0" and the output of the NOR gate 715 becomes "1".

The binary presettable up-down counter 717 is a 4-bit counter circuit, and its reset terminal is led to the output of the NOR gate 714. When the output of the NOR gate 714 becomes "0", it starts counting and returns to "1". It will be reset when it becomes. Note that this counter 717 is set to down count mode and does not use the preset function.

Clock generating circuit 716 is a circuit that continuously generates a clock signal having a frequency of, for example, about 80 KHz, and the clock signal is introduced to a clock input terminal of 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 output terminal of the counter 717.
Connected to the Q _D output terminal, which is a 1/16 frequency division output. When the levels of both output terminals become "0", the output of the NOR gate 718 becomes "1".
This output is led to NOR gate 715, which inverts a flip-flop composed of NOR gates 714 and 715.

The _QD output of counter 717 is further guided to one-shot multis 721 and 728 via inverter buffers 719 and 720, respectively. One shot multi 721 is inverter buffer 71
It is triggered by the fall of the output of 9, and is held for a certain period of time determined by the capacitor 722 and resistor 723 (for example,
A “0” signal is generated at the output terminal for 5μsec). This signal is led to the base of transistor 726 via resistors 724 and 725. When the terminal of the one-shot multi 721 is "0", the transistor 726 is turned on and generates a "1" trigger signal S(A) at its collector, that is, the terminal 702.

The one-shot multi 728 is triggered by the rise of the output of the inverter buffer 720, and outputs a "0" signal to the output terminal Q for a certain period of time (for example, 5 μsec) determined by the capacitor 729 and resistor 730.
occurs in This signal is guided to the base of transistor 733 via resistors 731 and 732. When the terminal of the one-shot multi 728 is "0", the transistor 733 is turned on, and the trigger signal S of "1" is applied to its collector, that is, the terminal 703.
Output (B).

In FIG. 1, 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. A trigger signal S(A) is supplied from the trigger signal generation circuit 7 to the gate of the thyristor 13 through an insulating pulse transformer 14 and further through a noise prevention circuit consisting of a diode 131, a resistor 132, a capacitor 133, and a resistor 134. Ru. The resonance capacitor 15 is one of the ignition coils 16.
It is connected to the midpoint tap of the next coils 161 and 162. By this thyristor 13, the capacitor 4,
One closed circuit consisting of the thyristor 13, the primary coil 161, and the resonance capacitor 15 is formed.

The thyristor 20 has an anode connected to the primary coil 1.
62, and its cathode is connected to one end (GND) of the resonance capacitor 15. A trigger signal generation circuit 7 is connected to the gate of the thyristor 20.
Trigger signal S(B) is passed through a pulse transformer 21, and then a diode 201, resistors 202, 20
4. The signal is supplied through a noise prevention circuit consisting of a capacitor 203. 1 by this thyristor 20
Another closed circuit consisting of the next coil 162, the thyristor 20, and the resonance capacitor 15 is formed.

The ignition coil 16 includes primary coils 161, 162,
It consists of a secondary coil 163 and a core 164. The turns ratio between the primary coils 161 and 162 and the secondary coil 163 is set to about 100 to 200.
1,162 are wound in the same direction. The primary coils 161, 162 and the secondary coil 163 are connected to the core 164.
The primary coil 16
1,162 is boosted and output from the secondary coil 163. One end of the secondary coil 163 is grounded (GND), and the other end is connected to the center electrode of the distributor 22 that distributes high voltage to each cylinder.

The distributor 22 has a well-known configuration, and uses a shaft that rotates synchronously at one half of the engine speed and a distribution rotor 23 that rotates in unison to control the ignition provided in a predetermined cylinder. High tension cords 251, 252, 253, 254 to plugs 241, 242, 243, 244
Distribute high voltage through.

The abnormal voltage detection circuit 8 is for temporarily stopping the operation of the DC-DC converter 3 when the voltage of the capacitor 4 falls below a certain value. Details of the abnormal voltage detection circuit 8 in the device shown in FIG. 1 are shown in FIG. In this FIG. 5, the terminal 80
1 leads to the voltage of capacitor 4, and resistor 8
After the voltage is divided by 11 and 812, the comparator 815
is input to the non-inverting input terminal of Resistor 813,8
The voltage Vc set in 14 is input as a reference voltage to the inverting input terminal of the comparator 815, and when the voltage of the capacitor 4 becomes below a certain comparison voltage Vd, the output of the comparator 815 becomes "1", exceeding Vd. When it gets old, it becomes "0". However, this comparison voltage Vd is the voltage V and the resistors 811, 8
It is determined by 12,813,814.

The output of the comparator 815 is the AND gate 81
When the output of the AND gate 816 changes from "0" to "1", a "1" signal is sent to the output terminal Q for a certain period of time (for example, 4 msec) determined by the capacitor 818 and resistor 819. Output. This signal is connected to resistors 823, 8
24 to the base of transistor 825. When the Q terminal of the one shot multi 817 is "1", the transistor 825 is turned on,
The voltage at its collector, terminal 802, becomes zero, and this voltage is led to terminal 305 in FIG.
The operation of the DC-DC converter 3 is stopped.

The output of the Q terminal of the one-shot multi 817 is led to the one-shot multi 820, and the capacitor 8
21, a certain period of time determined by the resistor 822 (e.g.
Outputs a “0” signal to the output terminal for 10msec). This signal is led to an AND gate 816, and by setting the output of the AND gate 816 to "0" for the predetermined period of time (for example, 10 msec), re-triggering of the one-shot multi 817 is prevented for a predetermined period of time.

The following semiconductor devices were used in the apparatus shown in FIG.

One shot multi 711...Toshiba TC4528BP Noah Gate 714, 715, 718
...Toshiba TC4001BP up-down counter 717
...Toshiba TC4516BP Inverter 719, 720 ...Toshiba TC4049BP One Shot Multi 721, 728, 817, 8
20...TI company 74LS221 AND gate 816...Toshiba TC4081BP Next, the operation of the device shown in FIG. 1 will be explained. 6th
The figure is a signal waveform diagram of each part of the device shown in FIG. The output ignition timing period signal, 5, is the Noah gate 714
6 is the Q _D output signal of counter 717,
7 represents the output signals of the inverter buffers 719 and 720, 8 represents the waveform of the trigger signal S(A), and 9 represents the waveform of the trigger signal S(B).

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

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

The output signal of the shaping circuit 6 is sent to the trigger signal generation circuit 7.
is input, and the one-shot multi 711 is triggered at the rising portion thereof to generate a pulse-shaped ignition period signal with a pulse width of approximately 2 msec as shown in FIG. 6. This pulse width is defined as the ignition period. The ignition period signal enters the Noah gate 714 and the Noah gate 71
4,715 flip-flops are inverted. As a result, the output of the NOR gate 714 becomes "0" as shown in FIG. 6.

The output of NOR gate 714 is led to the reset terminal of counter 717, and when this output is "0", counter 717 is released from reset. Upon release of this reset, the counter 717 starts counting at a clock frequency of about 80 KHz from the clock generation circuit 716. Here, the counter 717 is a 4-bit binary counter and is set to the down count mode, so the contents of the counter 717 change from 0 to 15 at the first rise of the clock signal. That is, the _QD output of the counter 717 changes from "0" to "1". From then on, each time a clock signal arrives, the down count is repeated until 0,
The contents change periodically as 15, 14, ..., 2, 1, 0, 15, .... At this time, the _QD output, which is a 1/16 frequency divided output, becomes "1" when the content of the counter 717 is 8 to 15, so the frequency is 1/16 of the clock frequency, as shown in FIG. 6. Duty ratio 50
% square wave. The width of one pulse in Fig. 6 is 100μsec, and the interval between pulses is
It is 100μsec.

Approximately 2 msec after the ignition timing signal rises,
The input of the NOR gate 714 becomes "0". If the counter 717 is reset immediately at this time, the time width of the _QD output "1" immediately before that reset will be shortened, and the commutation of the thyristor, which will be described later, will not be carried out properly. As a countermeasure for this, by leading the output of the one-shot multi 711 and the output of the counter 717 to the input of the NOR gate 718, the Q _D
Only when the output is "0", the output of the NOR gate 718 becomes "1", inverting the flip-flop consisting of the NOR gates 714 and 715, thereby setting the output of the NOR gate 714 to "1" and resetting the counter 717. I have to.

As explained above, an integral number of square waves of 1/16 of the clock frequency (5KHz) are generated at the _QD output at least during the ignition period with a delay of less than one clock signal period (12.5μsec) from the ignition timing signal. . This signal is inverted by inverter buffers 719 and 720 to become the signal shown in FIG. 6.

The one-shot converter 721 is triggered by the falling edge of the inverter buffer 719, generates a pulse of approximately 5 μsec, turns on the transistor 726, and outputs the trigger signal S(A) shown in FIG. 6 to the terminal 702. Also, the wash shot multi 728 is triggered by the rising edge of the output of the inverter buffer 720, generates a pulse of approximately 5 μsec, turns on the transistor 733, and outputs the trigger signal S(B) shown in FIG. 6 to the terminal 703. do. In other words, the trigger signals S(A) and S(B) have a period with a phase difference of 180° from each other.
It is a signal with a pulse width of 200μsec and a pulse width of 5μsec.

Next, the operation of the high pressure generator will be explained. FIG. 7 is a waveform diagram showing the signals of each part in this embodiment in a temporally enlarged manner compared to FIG. 6. In FIG. 7, 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 is the thyristor 1
3 represents the current flowing through the thyristor 20, 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.
trigger. Similarly, the trigger signal S(B) shown in FIG. 72 triggers the thyristor 20 via the pulse transformer 21 and the noise prevention circuit.

First, when the thyristor 13 is triggered and turned on, current flows through a closed circuit consisting of the capacitor 4 , the thyristor 13 , the primary coil 161 , and the capacitor 15 . At this time, since the capacitance of capacitor 4 is sufficiently larger than that of capacitor 15, capacitor 4 can be considered as a constant voltage (200V) power source. Furthermore, since the resistance of the circuit consisting of the resistance of the primary coil 161 and the resistance of the thyristor 13 is sufficiently small, this first closed circuit consists of the capacitance C of the capacitor 15 (for example, 2 μF) and the inductance L of the primary coil ( For example, it resonates under conditions determined by 50μH).

The current at resonance flows through the positive terminal of capacitor 4, thyristor 13, primary coil 161, and
It flows in the direction of the ground terminals of capacitor 15 and capacitor 4, forming a half-sine waveform as shown in FIG. 7. Its peak current value is approximately 150A, and the energizing time is approximately
It is 20μsec. Due to this energization, the voltage applied to the capacitor 15 increases to about 600V as shown in FIG. 7. The thyristor 13 remains on only when i>0, but as shown in FIG.
When it becomes 0, the current is commutated and the state is turned off. In this way, in the device shown in FIG. 1, since an oscillating current due to resonance flows through the circuit including the primary coil, capacitor, switching element, and DC power supply, the thyristor 13 automatically commutates, so a special commutation circuit is used. There is no need to add .

When thyristor 13 turns off, capacitor 15
The voltage stored in the power source is about 600V, which is about three times the DC power supply voltage of 200V, and this is due to the amplification effect based on the resonance phenomenon.

Next, a case where the thyristor 20 is triggered will be explained. When the thyristor 20 is turned on, a closed circuit consisting of the capacitor 15, the primary coil 162, and the thyristor 20 is formed, and the charge stored in the capacitor 15 is transferred to the upper terminal of the capacitor 15, the primary coil 162, the thyristor 20, and the capacitor 15. The current flows in the direction of the lower terminal, forming a half-sine waveform as shown in FIG. As with the thyristor 13, the thyristor 20 has a peak current value of about 150 A and a current conduction time of about 20 μsec. The voltage applied to the capacitor 15 due to this energization is shown in FIG.
As shown in the figure, it decreases from about 600V to about -400V. 7. When the current waveform of the thyristor 20 shown in FIG. 7 becomes zero, the thyristor 20 naturally commutates as in the case of the thyristor 13, so a special commutation circuit is not required.

After that, the primary coil 16 is continuously triggered by alternately triggering the thyristor 13 and the thyristor 20.
Current flows alternately through 1,162.

In the explanation so far, the secondary coil 163 of the ignition coil 16 has not been described, so this will be explained next.

Primary coils 161, 162 and secondary coil 163
Since the turns ratio is set to approximately 150, a voltage approximately 150 times the voltage applied to the primary coil is generated in the secondary coil.

The voltage applied to the primary coils 161 and 162 is approximately
Since it is 600V, the turns ratio is 600 (V) from about 150.
It is calculated that a high voltage of ×150=90 (KV) is generated in the secondary coil 163, but in reality, the ignition coil 16
Approximately 40 KV is generated due to the loss in the spark plugs, the capacitance of the spark plugs 241 to 244, and the stray capacitance of the distributor 22, which is sufficient voltage to ignite by discharging.

The voltage generated by the secondary coil 163 is distributed to predetermined cylinders by the distributor 22, and is supplied to the spark plugs 241, 242, 243, 244 via high tension cords 251, 252, 253, 254 to ground the spark plugs. Ignition occurs by discharging to the electrodes.

Once a discharge path is formed by the discharge, the nearby air is ionized and becomes an arc discharge, and the dielectric discharge continues until the voltage drops below the discharge sustaining voltage (approximately 500V to 1KV). Although this duration is shorter than that of a normal ignition device (approximately 2 msec), the next cycle starts immediately after this inductive discharge ends, so the ions remaining between the discharge gap can easily cause a re-discharge. occurs, and the discharge continues almost without interruption. Since this duration can be determined by the ignition period electrically set in the trigger signal generating circuit 7, it is easy to set it to a sufficiently long time to ensure complete ignition.

Furthermore, since the other thyristor is in the reverse blocking state for about half of the time that one thyristor is on, the repetition period of the trigger signals S(A) and S(B) can be shortened.

Next, the operation of the voltage abnormality detection circuit 8 will be explained. FIG. 8 is a waveform diagram showing signals of various parts in this embodiment in a temporally reduced manner compared to FIG. 6. In Fig. 8, each 1 is a one shot multi 71
1 is the output of the ignition period signal, 2 is the capacitor 4
3 is the voltage across the comparator 81 shown in FIG.
5 represents the output signal of the one shot multi 817, 4 represents the Q output signal of the one shot multi 817, and 5 represents the waveform of the output signal of the one shot multi 820.

In Fig. 8, before time t ₁ , Fig. 6 and 7
The figure shows a case in which the device is operating normally, as described above. That is, during the approximately 2 msec ignition period shown in FIG. 8, the thyristors 13 and 20 of the device shown in FIG. As shown in Figure 8-2, the voltage drops from 200V to a certain voltage. And when the ignition period ends
Once again due to the current supply from DC-DC converter 3
Charged to 200V and ready for the next ignition period.

By the way, if both thyristors 13 and 20 are turned on at the same time due to some reason such as noise intrusion, the electric charge of the capacitor 4 is transferred to the thyristors 13 and 20.
The current flows through a closed circuit consisting of primary coils 161, 162, thyristor 20, and capacitor 4. As a result,
In FIG. 8, when the thyristors 13 and 20 are simultaneously turned on at time _t1 , the voltage across the capacitor 4 shown in FIG. 8 and 2 instantly abnormally drops to several volts. Here, in order to detect this abnormal drop, the comparator 815 shown in FIG.
The comparison voltage Vd determined by 11,812 is set higher than the voltage at the time of the abnormal drop. Therefore, the eighth
The output of the comparator 815 shown in FIG. 3 changes from "0" to "1" at time _t1 . This "1" output is led to a one-shot multi 817 via an AND gate 816. One shot multi 817
is triggered at this rising edge from "0" to "1" and generates a pulse signal with a pulse width of about 4 msec as shown in FIG. 8. This pulse signal turns on the transistor 825 and passes through the terminals 802 and 305 to the transistor 323 of the DC-DC converter 3.
The base voltage of DC-DC converter 3 is set to zero.
A signal to stop the operation of is output to terminal 802.
Therefore, from time t ₁ to t ₂ shown in FIG.
The operation of the DC-DC converter 3 is stopped for a period of 4 msec. During this stop period, the charge in the capacitor 4 is almost eliminated and the voltage across it becomes zero, so the current flowing through both thyristors 13 and 20 becomes zero, and both thyristors 13 and 20 naturally commutate to a blocking state. become.

Since the output of the one-shot multi 817 shown in FIG. 8 changes from "0" to "1" at time _t2 ,
Transistor 825 is turned off, restoring the base voltage of transistor 323 to normal and DC-DC.
Restart operation of converter 3.

The voltage across the capacitor 4 shown in FIG. 82 increases due to the reactivation of the DC-DC converter 3 at time _t2 , and becomes equal to or higher than the comparison voltage Vd at time _t3 , returning to the normal state. Further, at time _t3 , the output of the comparator 815 shown in FIG. 8 changes from "1" to "0", and the abnormal drop in the voltage across the capacitor 4 is no longer detected.

The output signal of the one-shot multi 20 shown in FIG. 85 is the output signal of the one-shot multi 8 shown in FIG.
It is triggered at the rising edge of the Q output of No. 17 at time t ₁ , and the pulse width is approximately 10 msec as shown in Fig. 8.
generates a negative logic pulse signal of AND gate 8
16 input terminal. During the period of this pulse signal, that is, from immediately after time t ₁ to time t ₄ , the output of the AND gate 816 remains in the “0” state. Therefore, the one-shot multi 817 shown in FIG.
Even if the pulse of the Q output becomes "0" after time _t2 , the one-shot multi 817 can be prevented from being retriggered until time _t4 . Then, at time _t4 when the voltage across the capacitor 4 becomes sufficiently higher than the comparison voltage Vd, the output of the one-shot multi 820 shown in FIG. 8 changes from "0" to "1" and is in a normal state. to return to. After time _t4 , the normal operation of the apparatus shown in FIG. 1 continues in exactly the same way as before time _t1 . As described above, even if a malfunction occurs and both thyristors 13 and 20 are turned on at the same time, the voltage abnormality detection circuit 8 shown in FIG. 1 can automatically return to normal state within a short time.

As mentioned above, the device shown in Fig. 1 can continuously generate multiple sparks over an appropriate period of time in an extremely short cycle in ignition control of an automobile internal combustion engine, thereby improving the ignition performance of the internal combustion engine. .

Furthermore, in the device shown in FIG. 1, even if both thyristors 13 and 20 are turned on at the same time due to malfunction, they can automatically return to the normal state within a short period of time, resulting in extremely high reliability. There are no problems, it is very practical, and reliable operation can be obtained.

In carrying out the present invention, various modifications are possible in addition to the embodiments described above. For example, in the above embodiment, the detection section of the abnormal voltage detection circuit 8 includes a comparator 815, resistors 811, 812, 813, and 8.
14, but instead of using these, a Zener diode 830 and a photocoupler 832 can be used as shown in FIG.

The abnormal voltage detection circuit 8' shown in FIG.
Comparator 81 of abnormal voltage detection circuit 8 shown in the figure
5. Instead of resistors 811, 812, 813, and 814, it is composed of a Zener diode 830, a resistor 831, and a photocoupler 832 (for example, Toshiba TLP552), and the other configuration is exactly the same as that shown in Figure 5. It is.

The operation of this abnormal voltage detection circuit 8' is as follows:
When the voltage across the capacitor 4 applied to the capacitor 1 becomes lower than the comparison voltage Vd, the light emitting element 832a of the photocoupler 832 is turned off, and the light receiving element 832 of the photocoupler 832 is turned off.
The output of b becomes "1", and the occurrence of an abnormal voltage is detected and output to one terminal of the AND gate 816. On the other hand, the voltage across capacitor 4 is the comparison voltage
When the voltage exceeds Vd, the light emitting element 832a of the photocoupler 832 turns on, and the light receiving element 832b of the photocoupler 832 turns on.
output becomes "0", and a normal state signal "0" is output to one terminal of the AND gate 816. Here, the Zener voltage of the Zener diode 830 is
Vz is set several volts lower than the comparison voltage Vd, so that when a voltage equal to or higher than the comparison voltage Vd is applied to the terminal 801, the light emitting element of the photocoupler 832 is turned on. Here, the resistor 831 is for current limiting, and the photocoupler 832 due to large current
light emitting element 832a and Zener diode 8
Prevent the destruction of 30.

By adopting the circuit configuration of the abnormal voltage detection circuit 8' shown in FIG. 9, the configuration can be simplified compared to that shown in FIG. It becomes possible to electrically isolate the logic circuit portion, and it is possible to prevent noise from entering the logic circuit portion via the ground line.

Furthermore, as another embodiment, a pulse transistor 21, a diode 201, and a resistor 20 constituting the gate circuit of the thyristor 20 in the device shown in FIG.
By replacing resistor 205 with resistor 205 as shown in FIG. 10, the circuit can be simplified and costs can be reduced. The operation is such that the output current from the collector of the transistor 733 shown in FIG. 4 is passed through the terminal 703 to the gate of the thyristor 20 after being limited by the resistor 205.

(Effects of the Invention) As described above, according to the present invention, when igniting an internal combustion engine, multiple discharges can be repeated in extremely short cycles, reducing unburned gas by improving ignitability, and reducing combustion during low speed rotation. Improved stability reduces rotational irregularities, improves fuel efficiency by lowering idle speed, and improves ignition performance during medium-high speed rotation, making it possible to achieve lean burn, which has the excellent effect of significantly improving fuel efficiency. be.
Furthermore, even if the thyristor malfunctions and remains energized, it is possible to automatically restore it within a short period of time, and there is no problem such as engine stalling, thereby providing an extremely reliable ignition system. It has great effects.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing an ignition device for an internal combustion engine as an embodiment of the present invention, FIG. 2 is a detailed electric circuit diagram of a DC-DC converter in the device shown in FIG.
Figure 3 is a detailed electric circuit diagram of the shaping circuit in the apparatus shown in Figure 1, Figure 4 is a detailed electric circuit diagram of the trigger signal generation circuit in the apparatus shown in Figure 1, and Figure 5 is a detailed electric circuit diagram of the abnormal voltage detection circuit in the apparatus shown in Figure 1. Detailed electrical circuit diagram, Figure 6 is a signal waveform diagram of each part of the device in Figure 1, Figure 7 is a detailed electric circuit diagram.
The figure is a waveform diagram in which the signal waveforms of each part in the apparatus shown in FIG. 1 are temporally enlarged compared to those in FIG. 6, and FIG. FIG. 9 is a detailed electrical circuit diagram of a main part of an abnormal voltage detection circuit showing another embodiment of the device of the present invention, and FIG. 10 is a main part electrical circuit of a gate circuit of a thyristor 20 showing another embodiment of the device of the invention. It is a diagram. 1, 3, 4...battery that constitutes the DC power supply,
DC-DC converter, capacitor, 5...Ignition timing detection device, 7...Trigger signal generation circuit, 8...
Abnormal voltage detection circuit, 13, 20... Thyristor forming the first and second switching elements, 15... Resonance capacitor, 16... Ignition coil, 161,
162...Primary coil, 163...Secondary coil,
241 to 244... Spark plug, 830... Zener diode forming a constant voltage element, 832... Photo coupler.

Claims (1)

[Scope of Claims] 1. A DC power source that generates a DC voltage; an ignition coil having a primary coil and a secondary coil, at least the primary coil being divided into two parts by a center tap; a spark plug connected to a secondary coil; a capacitor connected to a center tap of the primary coil; a second switching element that constitutes a closed circuit together with a second portion of the primary coil and the capacitor; a second switching element that operates in accordance with an ignition instruction signal; a signal generation circuit that generates an energization signal so that the switching elements of the switching elements are alternately conductive at a predetermined timing; An ignition device for an internal combustion engine, which is equipped with a voltage abnormality detection circuit that detects this voltage and generates a signal with a predetermined time width to temporarily stop the operation of the DC power source. 2. The ignition device according to claim 1, wherein the voltage abnormality detection circuit has a circuit configuration including a constant voltage element and a photocoupler element connected to the output side of the DC power source. 3. The ignition device according to claim 1, wherein each of the first and second switching elements is a thyristor, and the signal generation circuit has a circuit configuration in which the gate of each thyristor is directly driven by a transistor. 4. The ignition device according to any one of claims 1 to 3, wherein the DC power source includes a DC-DC converter that converts battery voltage into a DC high voltage.