JPS6311482Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device, and particularly to an improvement of a timed repeated discharge type ignition device that repeats a discharge operation for ignition for a certain period of time after power is turned on.

BACKGROUND OF THE INVENTION There is an ignition device for igniting various fuels such as gas and kerosene, which repeats a discharge ignition operation after power is turned on in order to ensure the ignition operation. In this type of device, a series circuit consisting of an energy storage capacitor and an ignition coil primary winding is connected across an alternating current power source, and said energy storage capacitor charged in a first polarity of the alternating current source is connected to a subsequent second polarity. When the polarity of the AC power source is 1, the energy is discharged via the energy emitting switching element, and therefore, the above-mentioned discharging operation is repeated as the first and second polarities of the AC power source are repeated. However, unless the user turns off the power, the above-mentioned repeated discharge operation will continue indefinitely, which makes things worse. It is also possible to make the power switch a momentary type so that the above operation is repeated only when the user continues to press the switch, but this will reduce the amount of time the user is operating the switch. Otherwise, reliable ignition would not be achieved, and the repeated discharge type would lose its meaning.On the other hand, in order to achieve reliable ignition, the user would have to hold down the switch for a considerable period of time, making it extremely difficult to operate. Getting worse.

Therefore, while repetitive discharge automatically begins to occur when the power is turned on, the above-mentioned repetitive discharge operation is terminated when a predetermined period of time (for example, about 20 seconds) has elapsed after the power was turned on. Ivy igniters were proposed. In this type of time-limited repeated discharge type ignition device, as a measuring means until a predetermined time after power is turned on,
CR typically consists of a time setting capacitor and a resistor
A time constant circuit is built in, and the potential across the above time setting capacitor in this circuit is set after the power is turned on.
This objective is achieved by operating the clamp circuit when a predetermined potential is reached, thereby reducing the trigger voltage generated by the trigger voltage generating section described above to a level below the conduction level of the energy emitting switching element.

These devices are certainly superior in principle. However, in order to properly follow this principle, the time setting capacitor in the CR time constant circuit must be placed under a certain charge accumulation condition (for example, completely discharged) before or at least immediately after turning on the AC power. ). That is, the initial conditions must be standardized. However, in this type of conventional ignition system,
It is often impossible to completely discharge the time setting capacitor in this CR time constant circuit in a short period of time. If the alternating current power supply is immediately turned on again, the remaining charge in the time setting capacitor often causes serious drawbacks such as variations in operating time or no ignition operation at all.

In view of this point, the present invention ensures that the time setting capacitor in the time constant circuit is discharged immediately after the AC power is turned on, fundamentally eliminating the conventional inconvenience, and improving the principle of this type of ignition device. The main purpose of this design was to provide a device configuration that could take advantage of the excellent features of the system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the time-limited repeated discharge type ignition device of the present invention will be described below with reference to the accompanying drawings.

When the power supply 1 is in the first polarity of + and - shown in the figure,
switch 2, resistor 3, diode 12, energy storage capacitor 19, ignition coil primary winding 25,
The energy storage capacitor 19 is similarly charged to the polarities shown by + and - in the figure through the path of the diode 15. Therefore, the potential across the energy storage capacitor 19 is also applied to both ends of the main current line of the thyristor 16, which serves as the energy release switching element 16, which is connected in parallel to the series circuit of the energy storage capacitor 19 and the ignition coil primary winding 25. applied.

When the polarity of the AC power source is reversed and becomes the second polarity shown in the figure, a current flows through the path of resistor 4, resistor 5, diode 13, resistor 3, and switch 2, and the current flows between both ends of resistor 5 in this path. , a direct current potential with the polarity is generated. When this potential reaches the trigger potential of the thyristor 16, the thyristor 1
6 is conductive. Then, as mentioned above, the stored charge or stored energy of the energy storage capacitor 19, which was charged when the AC power supply was first polarized, is discharged to the ignition coil primary winding 25 via the main current line of this thyristor 16. , ignition coil secondary winding 2
A discharge spark is generated between the discharge electrodes 31, 31 connected to the discharge electrode 6, and the operation of igniting the fuel begins. Therefore, in this circuit, the resistor 5 serves as a trigger voltage generating section for the thyristor 16. Note that the series circuit of the energy storage capacitor 19 and the ignition coil primary winding 25 constitutes a series resonant circuit, so although it is not essential for the present invention, it is possible that the current is reversed in the opposite direction to the previous flow due to resonance. Sometimes, the current will flow through the path of diode 13 and diode 12. Generally, discharge energy is generated in the ignition coil 26 at this time as well.

The discharge operation is repeated by the mechanism described above, but after the power is turned on, the discharge operation is repeated for a certain period of time, for example 20 minutes.
The circuit for forcibly ending this repetitive operation after about a second is as follows.

When the power supply 1 is turned on, a current flows in the path of the switch 2, the resistor 3, the resistor 11, the diode 14, the zener diode 17, and the diode 15 at the first polarity, and the zener diode 17 in this path flows. A regulated DC voltage is obtained at both ends. A constant voltage circuit 27 including this Zener diode 17 generally includes a filter capacitor 21.
However, in this circuit, in accordance with the idea of the present invention described later, when configuring the differential circuit 28, this filter capacitor 21 is used, and a resistor 1 is connected in series.
By connecting 0 to this connection point, a differential pulse is generated at this connection point in a transient state when the power is turned on.

A time constant circuit 29 consisting of a resistor 9, a time setting capacitor 20, and a Zener diode 18 is connected to the outputs of the DC constant voltage power supply circuit 27 and the Zener diode 17. After the power is turned on, both ends of the time setting capacitor 20 are connected. The potential is Zener diode 18
When the Zener breakdown voltage of transistor 22,
The amplification type switching circuit composed of transistor 23 performs a switching operation, and transistor 22 is turned on. The main current line of this transistor 22, that is, the collector-emitter line is inserted in parallel to both ends of the resistor 5 as the trigger voltage generating section mentioned above, so when this transistor 22 is turned on, the potential across the resistor 5 is Even at the second polarity of the AC power supply, the thyristor 16 is no longer conductive, and the repetitive discharging operation described above is forced to stop. Therefore, this switching circuit 30 can be called a clamp circuit 30 that clamps the trigger voltage below a value that can trigger the thyristor 16.

It is obvious that the time required to reach the Zener breakdown voltage of the Zener diode 18 after the power is turned on is the set time, but this time depends on the values of the resistor 9 and time setting capacitor 20, and the Zener voltage of the Zener diode 18. It can be set as desired. That is, all of these components serve as time setting means, but in this book, especially for convenience of explanation, the capacitor 20 is referred to as a time setting capacitor.

As mentioned above, in the past, the residual charge in the time setting capacitor 20 caused uneven control and operation, but in the present invention, this problem is avoided by the following configuration.

As mentioned above, in the circuit of the present invention, the differentiator circuit 2
8 is provided. In this embodiment, by using the filter capacitor 21 and inserting the resistor 10 in series with it, a differential pulse is generated at the connection point when the power is turned on.

On the other hand, at both ends of the time setting capacitor 20,
A transistor 24 having collector-emitter current lines connected in parallel is provided, and its base is connected to the differential pulse generating portion of the differential circuit 29 (in this case, the connection point between the capacitor 21 and the resistor 10).

Therefore, each time the power is turned on, the transistor 24 is switched on for a short time in a transient state, so that the accumulated charge in the time setting capacitor 20 can be rapidly discharged each time. That is, it can be said that the transistor 24 is an initial state setting transistor for the time setting capacitor 20.

In any case, in the present invention, with such a configuration, the initial state of the time setting capacitor 20 can be made uniform even when the power is turned on again at any timing, and no discharge operation occurs. The disadvantages of the conventional example, such as variations in repeated discharge duration, can be completely eliminated. The present invention, which can provide such a highly reliable device with a simple configuration, is therefore extremely significant.

[Brief explanation of the drawing]

The drawing is a schematic diagram of an embodiment of the repeated discharge type ignition device of the present invention. In the figure, 1 is a power supply, 2 is a switch, 3 and 4 are resistors, 5 is a resistor as a trigger voltage generator, 12,
13 and 15 are diodes, 16 is a thyristor as a switching element for energy release, 19 is an energy storage capacitor, 20 is a time setting capacitor, 22 and 23 are transistors, 4 is a transistor for initial state setting, and 25 is an ignition coil primary winding, 26 is an ignition coil secondary winding, 27 is a DC constant voltage circuit, 28 is a differentiation circuit, 29 is a time constant circuit, 3
0 is a clamp circuit, and 31 is a discharge electrode.

Claims (1)

[Utility Model Claims] A time-limited repeated discharge type ignition device comprising: a series circuit in which an energy storage capacitor, which is charged to a first polarity when the AC power supply has a first polarity, and a primary winding of an ignition coil are connected in series to the AC power supply; a trigger voltage generating section which generates a trigger voltage of a predetermined level when the AC power supply has a second polarity; an energy release switching element which becomes conductive when receiving the trigger voltage as a trigger input, and discharges the charge stored in the energy storage capacitor, which is charged when the AC power supply has the first polarity, to the primary winding of the ignition coil, and generates a discharge spark between a pair of discharge electrodes connected to the secondary winding of the ignition coil; and a time constant circuit which has a time-setting capacitor which begins charging when the AC power supply is turned on, and which operates a clamp circuit when the potential across the capacitor reaches a predetermined potential, thereby making the trigger voltage generated by the trigger voltage generating section equal to or lower than the conduction level of the energy release switching element, and thereby terminating the repeated discharge operation accompanying the repetition of the first and second polarities of the AC power supply; and a differential pulse generating circuit which generates a differential pulse when the AC power supply is turned on; an initial state setting switching element which is temporarily made conductive by said differential pulse to discharge said time setting capacitor to an initial state.