JPS6115406Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ignition device with a timer circuit that performs an ignition operation for a certain period of time after power is turned on.

In the case of igniting gas, kerosene, etc., after the fuel is supplied, it is necessary to operate the ignition device for a certain period of time to generate a spark discharge in order to prevent misignition and ensure stable combustion. Furthermore, even if the power is turned off after a certain period of time has passed and the spark discharge has stopped, and the power is turned on again in a short period of time, the ignition device must always operate for a certain period of time to prevent misignition.

FIG. 1 shows a basic ignition device with a timed circuit that was proposed earlier by the present inventor. In this figure, an AC power supply 1 is connected to a series circuit of a resistor 3 and a diode 4 as a voltage drop element through a power switch 2, and is connected in parallel to the resistor 3 through a resistor 5 and a diode 6. A capacitor discharge type ignition circuit 7 is connected. This capacitor discharge type ignition circuit 7 includes a capacitor 8 and a high voltage transformer 9.
It has a series circuit with the primary winding 9A, and a thyristor 10 connected in parallel to this, and a diode 11 is connected in antiparallel to the thyristor 10. Further, a resistor 12 is inserted between the gate and cathode of the thyristor 10, and the gate is connected to the cathode side of the diode 4 via a resistor 13. A spark electrode 14 is connected to the secondary line 9B of the high voltage transformer 9.

On the other hand, a timer circuit 20 is provided on the gate circuit side of the thyristor 10. That is, the n-gate thyristor (hereinafter referred to as PUT) 22 of the time limit circuit 20 connects to the diode 4 via the diode 21.
are connected in parallel. The capacitor 23 is charged via a diode 24 and a resistor 25, and a value obtained by dividing the charging voltage of the capacitor 23 by resistors 26 and 27 is applied to the gate of the PUT 22. In addition, a resistor 30, a capacitor 31, and a resistor 3 are connected in parallel to the capacitor 23.
A CR time constant series circuit consisting of 2 is connected, and the connection point between the resistor 30 and the capacitor 31 and the PUT 22
A diode 33 is connected between the anode and the anode.
A capacitor 34 is provided between the gate of PUT 22 and the anode.

In the above configuration, if the polarity of the AC power source 1 is as shown in FIG.
The capacitor 8 is charged through the path of the next winding 9A, the diode 4, and the AC power source 1. Next, when the polarity of the AC power source 1 is reversed, a current flows through the path of the AC power source 1, resistor 13, resistor 12, resistor 3, power switch 2, and AC power source 1, and a gate voltage is applied to the gate of the thyristor 10. applied. As a result, the thyristor 10 becomes conductive, and the electric charge in the capacitor 8 is discharged in the closed circuit of the capacitor 8, the thyristor 10, and the primary winding 9A of the high-voltage transformer 9.
A spark discharge is generated between the spark electrodes 14 of the next winding 9B.

On the other hand, when the polarity of the AC power source 1 is as shown in the figure, the capacitor 23 is precharged in the path of the AC power source 1, switch 2, resistor 5, diode 24, resistor 25, capacitor 23, diode 4, and AC power source 1. The voltage V ₁ charged in the capacitor 23 is divided by the resistors 26 and 27 and sent to PUT2.
2 gates. This gate voltage is calculated as follows when the resistance values of resistors 26 and 27 are R ₁ and R ₂ .
V ₁ , R ₂ /R ₁ +R ₂ . Further, the capacitor 31 is gradually charged by the voltage V ₁ via the resistors 30 and 32. Then, when the anode breakover voltage V ₂ is applied to PUT22, PUT2
2 is conductive. In this case, from power on to PUT2
2, where T is the time required to reach conduction, T≒CR ln(V ₁ /V ₁ -V ₂ ) (C: capacitance of capacitor 31, R: sum of resistance values of resistors 30 and 32) It is expressed as

Now, before the PUT 22 of the timer circuit 20 becomes conductive, a sufficiently large gate voltage is applied to the thyristor 10 via the resistor 13 every time the polarity of the AC power supply 1 becomes opposite to that shown in the figure, as described above. The thyristor 10 is fired, but when the PUT 22 becomes conductive, the gate voltage of the thyristor 10, which is generated each time the polarity of the AC power source 1 becomes opposite to that shown in the figure, drops significantly as expressed by the following equation.

Gate voltage = (forward voltage of diode 21 + PUT
(forward voltage of 22) - (voltage drop of resistor 13) As a result, after PUT 22 becomes conductive, the gate voltage becomes equal to or lower than the gate non-trigger voltage of thyristor 10, and thyristor 10 becomes unable to fire from then on. Therefore, the ignition operation of the capacitor discharge type ignition circuit 7 is stopped after the time T has elapsed since the power was turned on.

By the way, in the conventional configuration described above, when the power switch 2 is turned on after the power switch 2 is turned on and the PUT 22 becomes conductive through the above-described operation, the capacitor 31 is charged by the discharge of the capacitor 23. The conduction continues until the anode voltage ≦ the gate voltage due to the charging voltage of 31. Therefore, if the power switch 2 is turned on again while the PUT 22 is conducting, the timer circuit 20 will lose its timer function. Therefore, the conventional ignition device with a time limit circuit has the disadvantage that it takes time until the ignition operation can be performed again.

The present invention aims to eliminate the above-mentioned drawbacks and provide an ignition device with a time-limited circuit that can always generate spark discharge for a certain period of time and can quickly restart the operation.

Embodiments of the ignition device with a timed circuit according to the present invention will be described below with reference to the drawings.

In FIG. 2, capacitor 23 is connected to resistor 4.
0 are connected in parallel, resistor 3 of the timer circuit 20A
A diode 41 is connected in parallel to 0. Further, a resistor 42 for stabilizing timed operation is connected in parallel to the diode 33 of the timed circuit 20A. Here, the resistance values of the resistors 26, 27, 30, 32, and 40 are expressed as R ₂₉ , R ₂₇ , R ₃₀ , R ₃₂ , and R _40, respectively, and the capacitance values of the capacitors 23 and 31 are expressed as C ₂₃ and C _{31 ,} respectively. The resistance value of the resistor 40 is selected so that R ₄₀ C ₂₃ <C ₃₁ {R ₃₀ +R ₃₂ +R ₄₀ R ₂₆ +R ₂₇ }.
Note that the other configurations are the same as in FIG. 1.

In the above configuration of the present invention, when the power switch 2 is turned on, the timer circuit 20 is activated as in the case of FIG.
The capacitor discharge type ignition circuit 7 performs the ignition operation for a time T determined by A. When the power switch 2 is opened after the ignition operation is completed, the charge in the capacitor 23 is quickly discharged mainly through the resistor 40. Further, since the diode 41 is provided in parallel with the resistor 30, the charge in the capacitor 31 is quickly discharged through the diode 41 and the resistor 40. Therefore, after opening the power switch 2, the PUT22
will return to the cut-off state within a short time (within a few seconds). As a result, the re-ignition operation can be performed quickly, and the spark discharge time due to the re-ignition is always kept constant.

Furthermore, even if the power switch 2 is opened after the power switch 2 is turned on but before the PUT 22 becomes conductive, the charge in the capacitor 31 is quickly discharged through the diode 41 and the resistor 40, so it can be restarted in a short time. This makes it possible to significantly improve characteristics.

FIG. 3 shows another embodiment of the invention. In this figure, a capacitor discharge type ignition circuit 7A includes a series circuit of a primary winding 9A of a high voltage transformer 9 and a thyristor 10, and a capacitor 8 connected in parallel to this series circuit. The rest of the structure is the same as the embodiment described above, and the embodiment shown in FIG. 3 can also achieve similar effects.

In each of the above embodiments, the diode 4 is used as a voltage drop element for obtaining the firing voltage of the thyristor 10, but a resistor may be used instead.

As described above, the present invention provides an ignition device with a time-limited circuit that can generate spark discharge for a certain period of time and can quickly restart operation.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional ignition device with a timed circuit, Fig. 2 is a circuit diagram showing an embodiment of the ignition device with a timed circuit according to the present invention, and Fig. 3 is a circuit diagram showing another embodiment. be. 1... AC power supply, 2... Power switch, 3,
5, 12, 13, 25, 26, 27, 30, 32
...Resistor, 4, 6, 11, 21, 24, 33...
...Diode, 7,7A...Capacitor discharge type ignition circuit, 8,23,31,34...Capacitor,
9...High voltage transformer, 10...Thyristor, 14
...Spark electrode, 20,20A...Timed circuit, 22
...PUT.

Claims (1)

[Claims for Utility Model Registration] A series circuit of a first resistor 3 receiving AC power input, a first diode 4 or a second resistor as a voltage drop element, a control element 10, and a second resistor for charging and discharging. 1 capacitor 8
and a capacitor discharge type ignition circuit 7, 7A having a closed circuit with a primary winding 9A of a high voltage transformer 9, and the capacitor discharge type ignition circuit is connected to the first resistor 3 via a second diode 6. 7A, 7B
In this ignition device, a third diode 21 is connected to the voltage drop element, and the voltage appearing across the voltage drop element is used as the gate voltage of the control element 10.
n-gate thyristor 2 connected in parallel via
2, and a second charged via a fourth diode 24.
It includes a series circuit of a capacitor 23, a third resistor 30 and a third capacitor 31 connected in parallel to the second capacitor 23, and makes the n-gate thyristor 22 conductive after a certain period of time.
CR time constant series circuit, the third resistor 30 and the third capacitor 31
a fifth diode 33 which applies a voltage to the anode of the n-gate thyristor 22 at the connection point thereof; resistors 26 and 27, and a sixth diode 41 connected in parallel to the third resistor 30 in a direction that discharges the charge of the third capacitor 31 when the AC power input is disconnected.
An ignition device with a timer circuit, characterized in that the gate voltage of the control element 10 is made equal to or lower than the gate non-trigger voltage when the n-gate thyristor 22 is conductive.