JPS63131862A - Contactless ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE:To miniaturize a transformer and shorten charging hours for a capacitor by providing a charging circuit with the diode which charges the capacitor by means of electric charge discharging in a reverse direction after the capacitor has been charged in reversed polarity by the discharge current of the capacitor. CONSTITUTION:A semiconductor switching element is conducted to discharge electric charge for a capacitor 7, and the reverse discharge current of the capacitor a charged in reversed polarity by the above-mentioned discharge current is charged in the capacitor 7 through a diode 15 provided in a charging circuit 2. Thus large charging current from a transformer 3 and a rectifier 4 connected to the side of a power source 1 becomes unnecessary, and reduction in a flowing electric current makes the use of the transformer 3 and the rectifier 4 having small capacity possible. In addition to that, since the charging performed by the diode 15 has increased the voltage of the capacitor 7 to a certain extent in charging by means of the charging current from the side of the power source 1, the charging hour can be shortened and demand electric power can be also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a non-contact ignition device for an internal combustion engine, which is equipped with a charging circuit having a transformer and a rectifier on the power source side.

(Prior Art) For example, a gas engine that drives a heat pump device is driven by a non-contact ignition device that uses commercial power. A capacitor discharge type is used as this ignition device, and power from a commercial power source is converted to a predetermined voltage by a transformer and a rectifier in a charging circuit and supplied to the capacitor. The charge in this capacitor is controlled by a thyristor and discharged to the primary side of the ignition coil through the thyristor, and the high voltage induced on the secondary side of the ignition coil generates an ignition spark at the ignition plug.

(Problems to be Solved by the Invention) Incidentally, the capacitance of the capacitor, the charging speed of the capacitor, etc. are determined according to the ignition voltage of the internal combustion engine and the rotational speed of the internal combustion engine. For this reason, when there is a limit to the charging current to a capacitor, such as when using commercial power as a power source, a transformer with a large capacity is used to increase the charging current to the capacitor or to speed up the charging speed. However, as the capacity of the transformer increases, the equipment becomes larger.

This invention was made in view of the above circumstances, and charges a capacitor with a reverse discharge current (oscillating current) after ignition.
The object of the present invention is to provide a non-contact ignition device for an internal combustion engine that reduces the size of the transformer and the charging time.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides power from an AC power supply to a capacitor via a charging circuit having a transformer and a rectifier, and transfers the charge of the capacitor to a semiconductor. In a non-contact ignition device for an internal combustion engine that discharges under the control of a switching element and generates an ignition voltage in an ignition coil, the charging circuit includes a capacitor that is charged to the opposite polarity by the discharge current of the capacitor and then reversed. The device is characterized in that it includes a diode that charges the capacitor with the discharged charge.

(Function) In this invention, the semiconductor switching element is made conductive by the ignition signal to discharge the charge charged in the capacitor, and the capacitor is charged to the opposite polarity by the discharge current, and then the charge discharged in the reverse direction is A diode provided in the circuit charges the capacitor. Therefore, the charging current from the transformer connected to the power supply side is small, and the current flowing through the transformer itself is reduced, so a transformer with a small capacity can be used. In addition, when charging with the charging current from the power source, the potential of the capacitor has increased to a certain extent, so the charging time can be shortened, and conventionally,
Current that would otherwise have been wasted can be used effectively, and power consumption can be reduced.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

The primary side of a transformer 3 constituting a charging circuit 2 is connected to the commercial power supply 1, and a full-wave rectifier 4 composed of diodes is connected to the secondary side of the transformer 3. The AC power is full-wave rectified by a full-wave rectifier 4. The DC output obtained by the full-wave rectifier 4 is controlled by a limiting resistor 5 and a transistor 6.
is supplied to the capacitor 7 to charge the capacitor 7. The limiting resistor 5 limits the charging current flowing through the transformer 3 and the full-wave rectifier 4 during charging. The primary side of an ignition coil 8 is connected to the capacitor 7, and the secondary side of the ignition coil 8 is connected to an ignition plug 9 provided in a combustion chamber of an internal combustion engine that uses city gas as fuel.

Between the transistor 6 and the capacitor 7, the anode side of a thyristor 10, which is a semiconductor switching element for discharging the charge of the capacitor 7, is connected, and the cathode side of the thyristor 10 is grounded.

A control circuit 11 is connected to the base of the transistor 6 and the gate of the thyristor 10, and an ignition timing signal generating coil 13 is connected to the control circuit 11 via a waveform shaping circuit 12.
is connected. The ignition timing signal generating coil 13 is composed of, for example, a balsa coil, and outputs an ignition timing signal according to the rotation angle of the crankshaft from a rotating body 14 that rotates in synchronization with the crankshaft of the internal combustion engine. .

The control circuit 11 does not output a base current to the transistor 6 and makes the transistor 6 non-conductive when the internal combustion engine is stopped. When the internal combustion engine is operating, the control circuit 11 outputs a base current to make the transistor 6 conductive to charge the capacitor 7, and when the thyristor 10 is made conductive by the ignition timing signal, the transistor 6 is made non-conductive.
The supply of charging current is cut off.

The cathode side of a diode 15 is connected between the transistor 6 and the capacitor 7 of the charging circuit 2, and the anode side is grounded.
is charged.

Next, the operation of this embodiment will be explained.

First, when the charging circuit 2 is connected to the commercial power supply 1, the alternating current is made to a predetermined voltage by the transformer 3, and then rectified into direct current by the full-wave rectifier 4.

By the way, when the internal combustion engine is stopped and the crankshaft is stopped, the ignition timing signal generating coil 13 does not output the ignition timing signal, so the control circuit 11 keeps the transistor 6 in a non-conducting state, and the capacitor 7 is not charged. No current is supplied.

Therefore, even if the thyristor 10, which is energized by the ignition timing signal when the internal combustion engine is operating, is out of order, the transistor 6 is non-conductive when the internal combustion engine is stopped, so the transformer 3. It is possible to prevent a short-circuit current from flowing through the full-wave rectifier 4 and the limiting resistor 5, and in particular, it is possible to suppress heat generation in the limiting resistor 5 that limits the charging current.

When the crankshaft is rotated by a starting device (not shown) such as a starter motor to start the internal combustion engine, an ignition timing signal is output from the ignition timing signal generating coil 13 and sent to the control circuit 11 via the waveform shaping circuit 12. is input. The control circuit 11 makes the transistor 6 conductive by inputting this ignition timing signal, and supplies the charging current to the capacitor 7.
is charged.

The control circuit 11 makes the thyristor 10 conductive and the transistor 6 non-conductive at the timing when the ignition timing signal is inputted from the waveform shaping circuit 12. By this conduction of the thyristor 10, the charge in the capacitor 7 is discharged through the thyristor 10 to the primary side of the ignition coil 8, a high voltage is generated on the secondary side of the ignition coil 8, and an ignition spark is generated at the ignition plug 9. bring about

Then, due to the discharging current of the capacitor 7, after the discharge is completed, the capacitor 7 is charged to a polarity opposite to that shown in the figure and then discharged in the opposite direction. Therefore, a reverse voltage is applied to the thyristor 10, turning it off.

At this time, the control circuit 11 makes the transistor 6 non-conductive, cutting off the connection with the power supply side and preventing the supply of charging current to the anode side of the thyristor 10, so that the forward current of the thyristor 10 is maintained. The current will be lower than that and the turn-off operation will be ensured.

After the thyristor 10 is turned off, the capacitor 7 is charged via the diode 15 by the reverse discharge current of the capacitor 7. Then, the transistor 6 becomes conductive and the capacitor 7 is connected to the power supply side and charged, but since the capacitor 7 is charged by the reverse discharge current at the time of ignition, the supply from the transformer 3 connected to the power supply side is The current required is small, and by reducing the current flowing through the transformer 3 itself, the capacitance of the diodes of the transformer 3 and the full-wave rectifier 4 can be reduced, and the size of the transformer 3 and the full-wave rectifier 4 can be reduced.

In addition, by charging the capacitor 7 with the reverse discharge current of the capacitor 7 via the diode 15 of the charging circuit 2,
Electric power that was previously wasted can be used effectively, and power consumption can be reduced. Furthermore, since the potential of the capacitor 7 rises to a certain value when charging from the power supply side, the charging time is shortened, sufficient charge can be charged for ignition in a high speed rotation range, and ignition energy is secured.

In addition, in this embodiment, the capacitor 7 is always connected to the charging circuit 2.
Transistor 6 that prevents charging current from being supplied to
However, it is also applicable to an ignition device that does not include this transistor 6. Furthermore, this ignition system can be similarly applied to internal combustion engines installed in vehicles, especially internal combustion engines where the electric power supplied from a power source such as a generator does not increase much as the rotational speed of the engine increases. It is effective for

(Effects of the Invention) As described above, the present invention makes the semiconductor switching element conductive to discharge the charge of the capacitor, and the charging circuit is equipped with a reverse discharge current of the capacitor charged with the opposite polarity by the discharge current. Since the capacitor is charged by the diode connected to the power source, the charging current from the transformer or rectifier connected to the power supply side is small, and the current flowing through these transformers and rectifiers themselves is reduced, making it possible to use smaller capacitors. I can do it. Also, by charging with this diode,
When charging with the charging current from the power supply, the potential of the capacitor has risen to a certain level, so the charging time can be shortened, and the current that was previously wasted can be used effectively, reducing power consumption. It is possible to reduce

[Brief explanation of the drawing]

The figure is a circuit diagram of a non-contact ignition device for an internal combustion engine using a commercial power source, showing an embodiment of the present invention. 1.-Commercial power supply 2..Charging circuit 3.--Transformer 4.--Full wave rectifier 5.--Limiting resistor 6.-) Ranjistaf fist - Capacitor 10-..Thyristor 15.--Diode

Claims (1)

[Claims] A non-contact point in an internal combustion engine in which power from an AC power supply is supplied to a capacitor via a charging circuit that includes a transformer and a rectifier, and the charge in the capacitor is discharged under the control of a semiconductor switching element to generate ignition voltage in an ignition coil. A non-contact ignition device for an internal combustion engine, wherein the charging circuit includes a diode that charges the capacitor with charge that is discharged in the opposite direction after the capacitor is charged with the discharge current of the capacitor.