JPS6086323A - Plural spark ignition device - Google Patents

Abstract

PURPOSE:To eliminate a relay, a comparator or the like by a method wherein a transistor for stabilizing the operation of plural spark ignition device is used in common for stopping the operation of the samd device or a receptor element is connected in parallel to the capacitor of a time constant circuit for starting. CONSTITUTION:In the operation to stop igniting operation, in case fuel is not being ignited during the igniting operation, an electric current hardly flows through a resistor 24 and the receptor element 25 since the value of resistance of the receptor element 25 is very large, therefore, a transistor 17 is being operated by only the generating voltage of a feedback coil 8c. When the fuel is ignited, the resistance of the receptor element 25 becomes small and the base current of the transistor 17 is flowed, therefore, the collector and emitter of the transistor 17 are conducted. Then, the charge of a capacitor 11 of the starting circuit 13 is stopped and the starting operation thereof is stopped. According to this method, expensive relay or comparator may be eliminated.

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 a self-excited thyristor series inverter type multi-spark ignition device, which is characterized in that it is equipped with a flame detection circuit that detects ignition of fuel and stops the operation. Regarding the ignition device.

Traditionally, water heaters, bathtubs, etc. that use fluid fuels such as oil or gas require a fuel pump to send the fuel, a blower fan motor,
It is equipped with a combustion control device that controls the ignition device, etc., and uses this to control operation.

When the power is turned on, the blower fan is first driven to exhaust unburned gas that may have accumulated near the burner, and then the fuel pump and ignition device are driven after a predetermined time using a delay relay or timer. Starts ignition operation. After the ignition is confirmed, the power to the ignition device is cut off and normal operation begins, but the sequence requires various relays and semiconductor switching elements.

FIG. 1 shows a conventional example of a flame detection circuit, 3/, 33. J'1 is a resistor, 3 is a light receiving element such as CdS, 3S is a comparison circuit, 3
6 is the base resistance of transistor 3, 3g is contact 3 α
It is a relay with Also, 3? is an ignition device, which is connected to an AC power source via a relay contact 3tcL. To explain the operation, in the non-ignition state, the resistance value of the light receiving element 32 is high, and the non-inverting input terminal voltage of the comparator circuit 35 is
3.3'l is larger than the reference voltage obtained by dividing the power supply voltage, so the output of the comparator circuit 35 turns on the transistor 37, driving the relay 3g, applying AC voltage to the ignition device 39, and setting the ignition operating state. It is in. Next, when the fuel is ignited, the resistance value of the light receiving element 32 decreases in response to the light of the flame, so the output from the comparator circuit 3 is eliminated and the transistor 37 is turned off to stop driving the relay 3g.

Therefore, power supply to the ignition device is also stopped.

As mentioned above, the conventional method requires expensive comparison circuits, relays, etc., which increases costs.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-spark ignition device that is equipped with a flame detection circuit in the ignition device and that does not require a relay or semiconductor switching element as an intermittent means on the control circuit side or can be shared with others. This is a self-excited thyristor series inverter type multi-spark ignition in which a thyristor series inverter causes self-excited oscillation with an 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 poles. In the device, a time constant circuit for starting the thyristor and a feedback circuit for continuing self-excited oscillation are connected in parallel to the gate of the thyristor, the collector-emitter junction of a stabilizing transistor is connected in parallel to the capacitor of the time constant circuit, and the transistor The base circuit is characterized in that the feedback circuit is connected in parallel to the feedback winding of the ignition coil, and further includes a flame detection circuit for detecting flame light and stopping the operation.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, a choke coil coil and a capacitor 3 are connected in series to an AC power supply, and a known thyristor series inverter circuit 7 comprising a resonant inductor and a thyristor s1 resonant capacitor 6 is connected in parallel to the capacitor 3.

The primary winding α of the ignition coil g serving as a load is connected in parallel to the resonant capacitor B, and the discharge pole t is connected to the secondary winding tb. In addition, a time constant circuit for starting the thyristor /3 is formed by a capacitor l/ charged from the power supply side of the choke coil coil through a resistor 10 and a trigger element /l that discharges the charge of the capacitor l/ to the gate of the thyristor 5.
and a capacitor/4' at the gate of thyristor S.
A self-excited oscillation continuation return circuit /6 obtained from the series connection of the resistor l and the left resistor is connected in parallel with the time constant circuit /3.

The collector-emitter junction of the stabilizing transistor /7 is connected in parallel to the capacitor /l of the time constant circuit 13, and the base resistor /S of the transistor /1 and the resistor /S of the feedback circuit /B are connected in parallel. Connect the feedback winding tc of the ignition coil t. Resistor /9 is connected between the pace emitter of transistor /7, and the anode of diode -0 is connected to the connection point of capacitor /4' of feedback circuit /6 and resistor /j, and the cathode of diode -0 is connected to the thyristor. Connect to cathode 2 in of j. Furthermore, diode
The diode 3 and the capacitor A are connected in series.
Connect the anode of the resistor to the choke coil -〇 power supply side, connect the capacitor 2A to the cathode line of the thyristor j, connect the resistor, the light receiving element, and 2s in series, and connect one end of the resistor to the cathode of the diode a3, and connect one end of the light receiving element to the cathode of the diode a3. is connected to the base of the stabilizing transistor/70 to constitute a photodetection circuit. Note that the resistor 21 and the two capacitors are for maintaining the gate of the thyristor 5.

-Chu The trenchless ignition operation of the above configuration will be explained. When the voltage of the AC power supply / is applied to the capacitor 3 in the forward direction of the thyristor S and gradually increases from zero voltage, the capacitor // of the starting time constant circuit /3 is charged through the resistor /θ, and the charging voltage is triggered. When the breakdown voltage of element /,2 is reached, trigger element l:A becomes conductive and provides a trigger pulse to the gate of thyristor S. Therefore, the thyristor S becomes conductive at a voltage higher than a certain voltage of the positive half wave of the AC power supply. When thyristor S becomes conductive, a charging current flows to resonant capacitor B through the resonant inductor, but the current becomes oscillatory due to the resonance of the circuit, and when the polarity is reversed, thyristor 3 is turned off to reverse bias the left thyristor. Therefore, a voltage higher than the power supply voltage is held in the resonant capacitor O, and the primary winding G of the ignition coil, which is the load,
The electric charge of the resonant capacitor B is released at α, and a voltage shown in the figure is generated, and accordingly, a high voltage is generated in the secondary winding gb, causing sparks to fly at the discharge pole D. At this time, the feedback winding A'
A +/- polarity voltage is also generated at c, but it is short-circuited by a diode: 1O. Next, due to the resonance between the resonant capacitor 6 and the primary winding 11a, the discharge current of the capacitor B also becomes oscillatory, and the polarity is reversed to become 0 polarity (g) in the figure. Also at this time, the secondary winding t
A high voltage is generated at b and sparks fly. In addition, voltages of (g) and (c) polarity are generated in the feedback winding g, so the resistance, :l/
, /k, the capacitor /ri is charged with the polarity of (G) and (C), and when the generated voltage becomes zero, the capacitor /4
' is discharged to the gate of the thyristor 5, the thyristor S is made conductive again, and the above-described operation is repeated. In this way, the terminal voltage of the resonant capacitor B continues to oscillate in a sinusoidal manner during the positive half-wave period of the AC power supply, and the high voltage boosted by the ignition coil also continues to oscillate, causing the discharge polarity to continue to oscillate. Multiple consecutive sparks fly. However, the starting time constant circuit /3 repeats charging and discharging with the time constant of the capacitor // and the resistor 10, triggering the thyristor 5 regardless of the self-oscillation continuation feedback circuit 16, and the operation becomes unstable. If S is triggered, the voltage polarity of the feedback winding 16 will be 10-polarity-? − At the time of , a base current flows through the base of the transistor 17 through the base resistor /g, and the transistor /g becomes conductive so that a short circuit occurs before the voltage of the capacitor /l reaches the breakdown voltage of the trigger element /2. It's Nishide.

The above is the ignition operation (spark discharge operation) of the thyristor series inverter type multiple spark ignition device.

Next, the operation of detecting flame and stopping the ignition operation will be explained. The AC power supply l is rectified by a diode and 23, and a DC voltage is created by a capacitor 6. If the fuel is not ignited during the ignition operation, the resistance value of the light receiving element is very large, so almost no current flows through the resistor and the left side of the light receiving element 2, so the transistor/I is connected to the feedback winding. The above-mentioned operation is performed only by the voltage generated by the wire C. When the fuel ignites,
Due to the flame light, the resistance value of the light receiving element 2S becomes small, and the base current flows through the transistor 17.
conduction between collector and emitter. Then the starting circuit/
3 capacitor/l is no longer charged, and the startup becomes too strong and the operation stops.

10- FIG. 6 shows another embodiment of the present invention, and the main difference from FIG. 2 is that the light receiving element 2S is connected in parallel to the capacitor // of the starting time constant circuit /3. When it does not receive flame light, the starting time constant circuit is affected by the large resistance value on the left side of the light receiving element 2, but when it receives light, the light receiving element, 2S
When the resistance value of AC power source / decreases, the voltage of
After the voltage is divided by the resistance value of the light-receiving element 25, the charging voltage of the capacitor /l does not exceed the breakover voltage of the trigger element /2, and therefore it stops operating.

In addition, the diode of the embodiment shown in Fig. 2: 13, capacitor 6, and resistor! The same effect can be achieved even if the + symbol is omitted, and for this reason, these symbols are omitted in FIG.

As described above, the present invention adds inexpensive parts and uses the transistor for stabilizing the operation of multiple spark ignition devices in common for stopping the operation, or connects a light receiving element in parallel to the capacitor of the starting time constant circuit. In order to stop the operation after detecting flame,
Expensive relays, comparison circuits, etc. of the combustion control device can be omitted, and the effect is great.

[Brief explanation of the drawing]

FIG. 1 is a conventional flame detection circuit, FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIG. 3 is a circuit diagram of another embodiment of the present invention.
In the figure, 5 is a thyristor, 7 is a thyristor series inverter circuit, g is an ignition coil, gb is its secondary winding,
gc is also a feedback winding, de is a discharge electrode, /3 is a time constant circuit for starting the thyristor, // is its capacitor, 16 is a feedback circuit for continuing self-excited oscillation, 17 is a stabilizing transistor 1
．． 2S indicates a light receiving element, and 27 indicates a flame detection circuit. JP-A-Sho GO-86323 (4)

Claims (1)

[Claims] (1) A self-excited thyristor series in which a thyristor series inverter circuit automatically oscillates with an ignition coil as a load, and a high voltage generated on the secondary side of the ignition coil causes multiple sparks to fly to the discharge poles. In an inverter type multiple spark ignition device, a time constant circuit for starting the thyristor and a feedback circuit for continuing self-excited oscillation are connected in parallel to the gate of the thyristor, and the collector-emitter junction of the stabilizing transistor is connected in parallel to the capacitor of the time constant circuit. The base circuit of the transistor and the feedback circuit are connected in parallel to the feedback winding of the ignition coil, and further includes a flame detection circuit for detecting flame light and stopping the operation. Multi-spark igniter. (2) The multiple spark ignition device according to claim (1), wherein the flame detection circuit is configured with a series circuit of a diode and a light receiving element, and is applied to the pace of the stabilizing transistor. (3) A multi-spark ignition device according to claim (1), in which the light detection circuit is constructed by connecting a light receiving element in parallel to a capacitor of a time constant circuit.