JPH0333917B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitor discharge type non-contact ignition device for an internal combustion engine.

Conventionally, as shown in Japanese Patent Application Laid-Open No. 57-13864,
The generated output of the capacitor charging coil is essentially short-circuited by a shorting semiconductor switching element connected in parallel with the capacitor, and the capacitor is charged by the high voltage generated in the capacitor charging coil when this semiconductor switching element is cut off. It is known that by doing this, a capacitor can be charged satisfactorily using a capacitor charging coil having a large wire diameter and a small number of turns. This device also includes a separate ignition semiconductor switching element for discharging the charge in the capacitor to the primary coil of the ignition coil.

However, in the conventional device described above, as a large current capacity semiconductor switching element, there is an ignition semiconductor switching element for discharging the charge of the capacitor to the primary coil of the ignition coil, and a short-circuiting semiconductor switching element for shorting the output of the charging coil. The drawback is that it requires two components, including a semiconductor switching element, and is bulky and expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks by using one semiconductor switching device as both an ignition semiconductor switching device and a short-circuiting semiconductor switching device.

The present invention will be described below with reference to embodiments shown in the drawings. First, a first embodiment shown in FIG. 1 will be described. 3 is a capacitor charging coil of a magnet generator, for example, a wire diameter of 0.5 to 0.9 mm and a number of turns of 200 to 600 is used. 5 is a rectifying diode, 6 is a capacitor charged by the half-wave output on the capacitor charging side of the capacitor charging coil 3, 7 is an ignition coil, 7a is its primary coil, and 7b is its secondary coil. Reference numeral 12 denotes a transistor, which becomes conductive when a base current is applied to the capacitor 6.
This charge is supplied to the primary coil of the ignition coil 7. Reference numeral 11 denotes an ignition plug connected to the secondary coil 7b of the ignition coil 7 and attached to the cylinder head of the internal combustion engine. transistor 1
Reference numeral 2 is a semiconductor switching element for ignition and short-circuiting, which has a collector-emitter path connected in parallel between the terminals of a capacitor charging coil 3 via a diode 5, and short-circuits the half-wave output on the capacitor charging side of this charging coil 3. Configure. 13 is a base resistor connected between the diode 5 and the collector and base of the transistor 12 via the diode 1;
4 is a thyristor whose anode-cathode path is connected between the base and emitter of the diode 1 and the transistor 12; 15 and 16 are voltage dividing resistors connected in series between the terminals of the capacitor charging coil 3;
The voltage dividing point a is connected to the gate of the thyristor 14. And 1 diode, 1 base resistor
3. The thyristor 14 and the voltage dividing resistors 15 and 16 constitute a cut-off control circuit for cutting off the transistor 12. Reference numeral 17 denotes a diode for extending the arcing time of the ignition plug 11 by passing a flywheel current through the primary coil 7a of the ignition coil 7. 18 and 19 are a resistor and a thyristor connected in series between the collector and base of the transistor 12;
20 is a resistor connected between the gate and cathode of the thyristor 19, 21 is a diode connected between the ground and the gate of the thyristor 19, and 22 and 23 are between the base of the transistor 12 and the anti-ground side of the charging coil 3. It is a resistor and a diode connected in series. The resistors 18, 20, 22, the thyristor 19, and the diodes 21, 23 constitute an ignition signal generation circuit for re-conducting the transistor 12 at the ignition timing.

Next, the operation of the above configuration will be explained.
Now, when the output (half-wave on the capacitor charging side) in the direction of the solid line arrow in Figure 1 begins to occur, coil 3 → resistor 1
3 → Diode 1 → Base of transistor 12
A base current flows through the transistor 12 in the emitter-to-ground circuit, the collector and emitter of the transistor 12 are electrically connected, and the output of the coil 3 is short-circuited by the transistor 12 via the diode 5. As this short-circuit current increases, the voltage drop between the diode 5 and the collector-emitter of the transistor 12 increases, and the voltage at the connection point a of the voltage divider circuit made up of resistors 15 and 16 increases. When this voltage reaches the set value, the thyristor 14 becomes conductive and short-circuits the base and emitter of the transistor 12.
OFF, and the short circuit current is abruptly cut off. At this time, a large induced voltage is generated in the coil 3, and this high voltage sufficiently charges the capacitor 6 through the circuit of the coil 3→diode 5→capacitor 6→diode 17→earth. Next, when the output of the coil 3 is reversed and becomes in the direction of the dashed arrow in FIG. Current flows through the circuit and thyristor 19 becomes conductive. Due to the conduction of this thyristor 19, the resistor 18 is connected to the capacitor 6.
A base current flows through the transistor 12 through the transistor 12, and the transistor 12 becomes conductive. Due to the conduction of the transistor 12, the charge in the capacitor 6 is discharged in the circuit of the capacitor 6 → transistor 12 → the primary coil 7a of the ignition coil 7, and a high voltage is generated in the secondary coil 7b of the ignition coil 7, causing the spark plug 11 to get the ignition spark.

As a result, one transistor 12 can serve as a large current capacity semiconductor switching element for ignition and short circuit.

FIG. 2 shows a second embodiment of the present invention, in which a transistor 14a is used instead of the thyristor 14, a capacitor 24 is connected between its base and collector, and a resistor 1 is used in place of the first embodiment.
The charge of the capacitor 24 is transferred between the connection point a of the transistors 5 and 16 and the base of the transistor 14a.
A diode 25 is connected to prevent discharging through the ignition signal generating circuit, and a voltage dividing circuit is connected in series between the thyristor 26 connected in parallel with the resistor 16 and the terminals of the charging coil 3 as an ignition signal generating circuit. The connection point b is connected to the gate of the thyristor 26 using resistors 27 and 28.

According to this second embodiment, when the short circuit current of the transistor 12 exceeds a predetermined value, the transistor 14
When a becomes conductive and short-circuits the base current of the transistor 12, the transistor 12 is cut off and a high voltage is generated in the charging coil 3, and the capacitor 6 is charged by this high voltage. When this capacitor 6 is sufficiently charged and its charging voltage exceeds a predetermined value, the output generated by the charging coil 3 exceeds a predetermined value, which causes the thyristor 26 to conduct and short-circuit the base current of the transistor 14a. The generated output of the charging coil 3 is applied again to the base of the transistor 12 via the resistor 13 and the diode 1, thereby making the transistor 12 conductive again and igniting the charge in the capacitor 6. The discharge is made to the primary coil 7a of the coil 7. This second
In the embodiment, the diode 5 can also be omitted.

FIG. 3 shows a third embodiment of the present invention, in which, in contrast to the second embodiment, as an ignition signal generation circuit,
A series circuit of a resistor 29 and a thyristor 30 is connected between the ground and the base of the transistor 12, and a series circuit of a diode 31 and voltage dividing resistors 32 and 33 is connected in parallel with this series circuit.
The connection point c of 2 and 33 is connected to the gate of the thyristor 30, and a series circuit of a capacitor 34 and a diode 35 is connected between the ground and the anti-ground side of the charging coil 3. The connection point of the transistor 12 is connected to the emitter of the transistor 12. 36 is a diode for preventing backflow.

In this third embodiment, the capacitor 34 is charged by the anti-capacitor charging side output of the charging coil 3, and when the charging voltage of the capacitor 34 exceeds a predetermined value, the thyristor 30 becomes conductive and the charged charge of the capacitor 34 is transferred to the transistor 12. The transistor 12 is made conductive by supplying it to the base of the transistor 12.

[Brief explanation of drawings]

1 to 3 show the first to third parts of the device of the present invention.
FIG. 2 is an electrical circuit diagram showing an example. 3...Capacitor charging coil, 6...Capacitor, 7...Ignition coil, 7a...Primary coil, 7
b...Secondary coil, 11...Ignition plug, 12...Transistor forming a semiconductor switching element for ignition and short circuit, 1, 13 to 16, 14a, 24...Diode, base resistor, thyristor forming a cutoff control circuit , voltage dividing resistor, transistor, capacitor, 18-23, 26-35... Resistor, thyristor, resistor, diode, resistor, diode, thyristor, voltage dividing resistor, configuring the ignition signal generation circuit,
Resistors, thyristors, diodes, voltage divider resistors, capacitors, diodes.

Claims (1)

[Claims] 1. A capacitor charging coil of a magnet generator, a capacitor charged by the generated output of this charging coil, an ignition coil having a primary coil and a secondary coil, and an ignition plug connected to the secondary coil of this ignition coil. In order to supply the charging charge of the capacitor to the primary coil of the ignition coil, the capacitor is inserted into a closed circuit including the primary coil and the capacitor, and the capacitor charging side half-wave output of the charging coil is substantially A semiconductor switching element for ignition and shorting is connected in parallel with this charging coil in order to short-circuit the battery. The circuit includes a cutoff control circuit for cutting off the semiconductor switching element for short circuiting, and an ignition signal generation circuit for forcibly re-conducting the semiconductor switching element at the ignition timing, and charging the capacitor when the semiconductor switching element is cut off. A non-contact ignition device for an internal combustion engine that charges the capacitor with a high voltage induced in a coil.