JPS6021659Y2 - multiple spark igniter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a self-excited thyristor series inverter type multi-spark ignition device, and particularly to this type of multi-spark ignition device which does not require a feedback winding of an ignition coil and has a simple structure.

Conventionally, the present inventors have already developed a multi-spark ignition device that causes a Cyrisk series inverter to self-oscillate with an ignition coil as a load, and uses the high voltage generated on the secondary side to send sparks to a discharge electrode, as shown in Figures 1 to 4. Various circuits have been proposed as shown in Figure 1, but all of these require a feedback winding in the ignition coil, and with the exception of the basic one shown in Figure 1, the feedback circuit for continuing self-excited oscillation is complex, which increases costs. It had become.

It is an object of the present invention to provide a low-cost circuit that does not require the ignition coil feedback winding of the conventional examples and allows automatic oscillation to occur with a simple circuit configuration.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 5, an input choke coil 2 and a capacitor 3 are connected in series to an AC power supply 1, and the capacitor 3 is connected to a well-known thyrisk series inverter circuit 7 consisting of a resonant inductor 4, a thyristor 5, and a resonant capacitor 6. are connected in parallel.

A primary winding 8a of an ignition coil 8 serving as a load is connected in parallel to the resonance capacitor 6, and a discharge electrode 9 is connected to the secondary winding 8b.

A parallel resistor 1° and a capacitor 11 are connected to the gate of the thyristor 5, and the other end of the resistor 10 is connected to a parallel second resistor 12 and the cathode of a Zener diode 13. The other end of the resistor 12 is connected to the thyristor 5.
The anode of the Zener diode 13 and the other end of the capacitor 11 are connected to the cathode of the thyristor 5, respectively.

The circuit operation of the embodiment of the present invention with the above configuration is as follows: AC NII
1 is applied to the capacitor 3 in the forward direction of the thyristor 5 and gradually increases from zero voltage, the capacitor 11 is charged through the resistor 10 and the second resistor 12, and therefore the voltage between the gate and cathode of the thyristor 5 increases. Since a gate current commensurate with the voltage flows, the thyristor 5 becomes conductive at a voltage equal to or higher than the positive half wave of the AC power supply 1.

When the thyristor 5 becomes conductive, a charging current flows through the resonant inductor 4 to the resonant capacitor 6, but the current becomes oscillatory due to the resonance of the circuit, and after half a cycle, the polarity is reversed and a reverse current flows through the thyristor 5, turning it off.

Therefore, the resonant capacitor 6 is charged to a voltage higher than the power supply voltage, and the primary winding 8 of the ignition coil 8, which is the load, is charged to a voltage higher than the power supply voltage.
A is discharged and a high voltage is generated in the secondary winding 8b.

At this time, the terminal voltage polarity of the resonant capacitor 6 is 10, - in the figure.
At the same time, since a voltage of opposite polarity appears between the anode and cathode of thyristor 5, the voltage between the gate and cathode of capacitor 11 and therefore thyristor 5 also has opposite polarity.

The discharge current of the resonant capacitor 6 resonates with the inductance of the primary winding 8a and becomes oscillatory, and the polarity is reversed after a half cycle.

The terminal voltage polarity of the resonant capacitor 6 at this time is (+) in the figure.
, (-), a high voltage of the same polarity is generated in the secondary winding 8b, and at the same time, the voltage between the anode and cathode of the thyristor 5 returns to positive polarity, so the capacitor 11 is connected again to the resistor 10 and the second The thyristor 5 is charged through the resistor 12, the voltage between the gate and cathode of the thyristor 5 rises, and a gate current flows, so the thyristor 5, which had been turned off, becomes conductive again and repeats the same operation.

Anode-cathode voltage VAK of thyristor 5.

Gate-cathode voltage ■.

Anode current I A% Terminal voltage of resonant capacitor 6 V
C6 and the terminal voltage VzD of the Zener diode 13 change over time as shown in FIG. The high voltage boosted in step 8 also continues to oscillate, and a plurality of continuous sparks fly to discharge electrode 9.

The vibration period at this time is the sum of the resonance half-cycle period between the resonant inductor 4 and the resonant capacitor 6, the resonant half-cycle period t2 between the resonant capacitor 6 and the primary winding 8a, and the charging period of the capacitor 11. However, by appropriately selecting the constants of each component, the second resistor 1
Since the capacitor 11 is charged with the voltage stabilized by the AC power source 2 and the Zener diode 13, stable self-oscillation with less influence from the voltage of the AC power source 1 can be achieved.

As described above, in the embodiment of the present invention, the resistor 10 and the capacitor 11 are connected to the gate of the thyristor 5, and the second resistor 12 is connected to the gate of the thyristor 5.
The capacitor 11 is charged with the voltage stabilized by the Zener diode 13. Constants of the resonant inductor 4, the resonant capacitor 6, the primary winding 8a of the ignition coil 8, etc. are appropriately selected to ensure stable self-oscillation. As in the conventional example, the feedback winding of the ignition coil 8,
It is possible to realize an inexpensive self-excited thyristor series inverter type multiple spark ignition device with a simple circuit configuration without requiring a complicated feedback circuit.

Although the second resistor 12 is connected to the anode of the thyristor 5 in the embodiment, it may also be connected from the power supply side of the input choke coil 2 as shown in FIG. If necessary in between, the second
It is free to use auxiliary means such as connecting diodes, resistors, etc. in parallel as shown in the figure, or inserting a gate series resistor to suppress induced voltage and adjust gate current.

[Brief explanation of the drawing]

1 to 4 are circuit diagrams of a conventional multiple spark ignition device, and FIG. 5 is a circuit diagram of a multiple spark ignition device according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating the operation of the embodiment of the present invention. 2... Input choke coil, 5... Thyristor, 7... Thyristor series inverter,
Death: Ignition coil, 9: Discharge electrode, 10: Resistor, 11: Capacitor, 12: Second resistor, 13・・・・・・
Zener diode.

Claims (1)

[Scope of utility model registration request] In a self-excited thyristor series inverter type multi-spark ignition device, the thyristor series inverter causes self-excited oscillation with the ignition coil as a load, and the high voltage generated on the secondary side of the ignition coil causes multiple sparks to fly to the discharge electrode. A parallel resistor and a capacitor are connected to the gate of the resistor, and the other end of the resistor is connected to a parallel second resistor and the cathode of a Zener diode, and the other end of the second resistor is connected to the anode of the thyristor or the cathode of the Zener diode. A multiple spark ignition device, characterized in that the anode of the Zener diode and the other end of the capacitor are connected to the cathode of the thyristor on the power supply side of the input choke coil to cause self-oscillation.