JPH0115703B2 - - 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, in order to make the capacitor's charging voltage almost uniform from low to high engine speeds, this type of capacitor's charging source used a thin wire with a large number of turns to charge the capacitor mainly at low speeds during low-speed rotation. It consisted of a coil and a high-speed coil with a large wire diameter and a small number of turns that charged the capacitor mainly during high-speed rotation, and the capacitor was directly charged by the output of these two coils. In addition, the output of the capacitor charging coil was made into a constant voltage by a constant voltage circuit and used as a constant voltage source for the ignition signal generating circuit.

However, in the above-mentioned conventional device, (1) two coils are required as the capacitor charging coils, one for low speed and one for high speed, and the structure is complicated with two stories in the axial direction. Moreover, the axial dimension becomes large, and the size of the magnet generator becomes large.

(2) The low-speed charging coil is a thin wire (wire diameter 0.13 to 0.16
mm) are wound in large numbers (3000 to 7000 turns), resulting in poor workability and quality problems.

(3) If an attempt is made to increase the secondary voltage, ie, the capacitor voltage, at low speeds, the secondary voltage, ie, the capacitor voltage at medium and high speeds will increase, and the heat resistance of the ignition coil or semiconductor element will be insufficient.

(4) The fluctuation of the capacitor charging voltage with respect to the rotational speed is large, and the capacity of the constant voltage circuit element of the ignition signal generation circuit becomes large, resulting in an increase in cost. There are problems such as.

In order to solve the above problem, the present invention substantially short-circuits the generated output of the capacitor charging coil by a shorting semiconductor switching element connected in parallel with the capacitor, and when the semiconductor switching element is cut off, the capacitor charging is stopped. The high voltage induced in the coil charges the capacitor and
By operating the constant voltage circuit of the ignition signal generation circuit, the capacitor can be charged satisfactorily using a capacitor charging coil with a large wire diameter and a small number of turns, and the constant voltage circuit element for the ignition signal generation circuit can be made smaller. The purpose of the present invention is to provide a non-contact ignition device for an internal combustion engine that can be

The present invention will be described below with reference to embodiments shown in the drawings. First, in Fig. 1, 3 is a capacitor charging coil of a magnet generator.In a magnet generator of the same size, the wire diameter is about four times thicker than the conventional one (for example, wire diameter 0.5 to 0.9 mm), and the winding is different from that of the conventional magnet generator. The number of turns (for example, 200 to 600 turns) 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.
8 is a timing sensor that generates an output signal at a reference position, and 9 receives the output signal of the timing sensor 8 as an input, and operates as a constant voltage source using the output from a constant voltage circuit for an ignition signal generation circuit, which will be described later, for charging a capacitor, for example. This is a known electronic ignition signal generation circuit that electrically determines ignition timing by electrical discharge and generates an ignition signal. The thyristor 10 becomes conductive when the ignition signal from the ignition signal generation circuit 9 is applied to its gate, and supplies the charge in the capacitor 6 to the primary coil 7a of the ignition coil 7.
It constitutes a semiconductor switching element for ignition. 11
is 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. Reference numeral 12 denotes a transistor whose collector-emitter path is connected between the terminals of the capacitor charging coil 3, and which short-circuits the half-wave output of the capacitor charging side of the charging coil 3 via a diode 19, which constitutes a short-circuiting semiconductor switching element. .
13 is a base resistor connected between the collector and base of the transistor 12; 14 is a thyristor whose anode-cathode path is connected between the base and emitter of the transistor 12; 15 and 16 are a diode 19 connected between the terminals of the capacitor charging coil 3; The voltage dividing resistors are connected in series with each other, and the voltage dividing point a thereof is connected to the gate of the thyristor 14. Then, base resistor 13, thyristor 14 and voltage dividing resistor 1
5 and 16 constitute a cutoff control circuit 24 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 is a resistor for adjusting the gate sensitivity of the thyristor 10, 20 is a diode, 21
22 is a current limiting resistor, 22 is a DC power supply capacitor, and 23 is a DC power supply constant voltage Zener diode. These Zener diode 23, capacitor 22, diode 20, and resistor 21 form a constant voltage circuit 25 for the ignition signal generation circuit. Configure.

Next, the operation of the above configuration will be explained.
When a four-pole magnet generator is used as the magnet generator, two cycles of no-load AC voltage are generated in the capacitor charging coil 3 per one rotation of the rotor of the magnet generator, as shown in FIG. 2a. Now, when an output begins to occur in the direction of the solid line arrow in Figure 1 (half-wave on the capacitor charging side), a base current flows through the transistor 12 in the circuit of coil 3 → diode 19 → resistor 13 → base/emitter of transistor 12 → ground. As a result, conduction occurs between the collector and emitter of this transistor 12, and the output of the coil 3 is short-circuited. Second
With increasing short circuit current in figure b, transistor 1
The voltage drop between the collector and emitter of 2 becomes large, and the connection point a of the voltage divider circuit consisting of resistors 15 and 16
voltage increases. When this voltage reaches the set value, the thyristor 14 becomes conductive and short-circuits the base and emitter of the transistor 12.
2's collector and emitter are turned OFF, and the short circuit current is abruptly cut off. At this time, the coil 3 has a second
As shown in Figure c, a large induced voltage is generated, and this high voltage causes the capacitor 6 to be activated in the same way when the voltage is in the direction of the next solid arrow in the circuit of coil 3 → diode 5 → capacitor 6 → diode 17 → ground. fully charge the battery as shown by the solid line in Figure 2d. At the same time, coil 3 → diode 19 → resistor 2
The capacitor 22 is charged with a constant voltage via the diode 20 by the 1→Zena diode 23 circuit. Next, using the constant voltage output of the constant voltage circuit 25 as a power source, the ignition timing is electronically calculated in the ignition signal generation circuit 9 based on the generated output of the timing sensor 8, and an ignition signal as shown in FIG. 2e is generated. This ignition signal is applied to the gate circuit of the thyristor 10, making the thyristor 10 conductive. Due to the conduction of the thyristor 10, the charge in the capacitor 6 is discharged in the circuit of the capacitor 6 → thyristor 10 → 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 ignition. Stopper 1
1 to get the ignition spark. The above operation is repeated once per rotation of the rotor of the magnet generator.

In the above embodiment, since the transistor 12 is cut off when the short-circuit current of the transistor 12 reaches a certain value, the charging voltage of the capacitor 6 can be kept almost constant regardless of the engine speed, and the voltage can be stabilized. Ignition performance is obtained.

In the above embodiment, the thyristor 10 was used as the ignition semiconductor switching element, but a transistor could also be used.Although the transistor 12 was used as the short-circuiting switching element, a gate turn-off thyristor (GTO) could also be used. can.

Furthermore, in the embodiment described above, the thyristor 1
Of course, a transistor may be used instead of 4.

As described above, in the present invention, there is provided a short-circuiting semiconductor switching element that substantially short-circuits the half-wave output of the capacitor charging coil, and a short-circuit current caused by the capacitor charging-side half-wave output of the charging coil. and a cutoff control circuit for cutting off the shorting semiconductor switching element when the shorting semiconductor switching element is sufficiently flowing, and charging the ignition capacitor with the high voltage induced in the capacitor charging coil when the shorting semiconductor switching element is cut off. At the same time, the constant voltage circuit of the ignition signal generating circuit is operated, so there are excellent effects as described below.

(1) Conventionally, a capacitor charging coil required two coils arranged in a two-story structure or radially, a coil with a thin wire with many turns and a thick wire with a small number of turns, but a coil with a thick wire with a small number of turns was used. Can be made with only one coil,
The structure is simple and the body size can be reduced.

(2) There is a large degree of freedom in setting the capacitor voltage and secondary voltage, sufficient ignition performance can be obtained from low speeds, and starting performance can be improved.

(3) Since there is no need to use thin wire as a capacitor charging coil, quality problems can be resolved.

(4) Since the constant voltage circuit for the ignition signal generation circuit is operated with a voltage that is almost constant with respect to rotation and has a narrow pulse width when the current is cut off, stable input and output voltages can be ensured from low speeds to high speeds. Since it does not overload constant voltage circuit elements such as Zener diodes, it can be made smaller.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing one embodiment of the device of the present invention, and FIG. 2 is a waveform diagram of various parts for explaining the operation of the device shown in FIG. 3...Capacitor charging coil, 6...Capacitor, 7...Ignition coil, 7a...Primary coil, 7
b...Secondary coil, 9...Ignition signal generation circuit, 1
0...Thyristor as a semiconductor switching element for ignition, 11...Ignition plug, 12...Thyristor as a semiconductor switching element for short circuit, 24...
...Break control circuit, 25... Constant voltage circuit for ignition signal generation circuit.

Claims (1)

[Claims] 1. A capacitor charging coil of a magnet generator, a short-circuiting semiconductor switching element that substantially shorts the output of this charging coil, and a short-circuiting semiconductor switching element that short-circuits when a sufficient short-circuit current flows through this short-circuiting semiconductor switching element. an ignition coil having a primary coil and a secondary coil; a constant voltage circuit for an ignition signal generation circuit that generates a constant voltage output by inputting the high voltage induced in the charging coil when the shorting semiconductor switching element is cut off; and a constant voltage circuit for generating an ignition signal using the constant voltage output of the constant voltage circuit as a power source. an ignition signal generation circuit that generates an ignition signal; an ignition semiconductor switching element that is electrically connected by the ignition signal from the ignition signal generation circuit to supply the charge charged in the capacitor to the primary coil of the ignition coil; A non-contact ignition device for an internal combustion engine, comprising an ignition plug connected to a secondary coil.