JPH0119071B2 - - 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.

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 you try to increase the secondary voltage at low speeds, that is, the capacitor voltage, the secondary voltage at medium and high speeds, that is, the capacitor voltage, will become too high, causing problems such as insufficient withstand voltage of the ignition coil or semiconductor element. be.

In order to solve the above problems, 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 output of the capacitor charging coil is short-circuited. By charging the capacitor with the high voltage generated by
It is an object of the present invention to provide a non-contact ignition device for an internal combustion engine that can satisfactorily charge a capacitor using a capacitor charging coil having a large wire diameter and a small number of turns.

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 the capacitor charging coil of the magnet generator, and in a magnet generator of the same size, the wire diameter is about 4 times thicker than the conventional one (for example, wire diameter 0.5 to 0.9 mm).
The number of turns is about 1/10 less than before (e.g.
200 to 600 times) have been used. 6 is a capacitor charged by the capacitor charging side half-wave output of the capacitor charging coil 3, 7 is an ignition coil, and 7a
is its primary coil, and 7b is its secondary coil. A diode 8 serves as a voltage drop element, and its anode is connected to one end of the capacitor 6 via the primary coil 7a of the ignition coil 7, and its cathode is connected to the ground side of the charging coil 3. A thyristor 10 has an anode connected to the other end of the capacitor 6, a cathode connected to the anode of the diode 8, and a gate connected to the cathode of the diode 8 via a resistor 21. The thyristor 10 becomes conductive when an ignition signal is applied to its gate, supplies the charge in the capacitor 6 to the primary coil of the ignition coil 7, and constitutes a semiconductor switching element for ignition. 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. Reference numeral 12 denotes a transistor whose collector-emitter path is connected between the terminals of the capacitor charging coil 3 to short-circuit the half-wave output on the capacitor charging side of the charging coil 3, and constitutes a short-circuiting semiconductor switching element. 13 is a base resistor connected between the collector and base of transistor 12, 14 is a thyristor whose anode-cathode path is connected between the base and emitter of transistor 12, and 15 and 16 are connected in series between the terminals of capacitor charging coil 3. It is a voltage dividing resistor, and its voltage dividing point a is connected to the gate of the thyristor 14. The base resistor 13, the thyristor 14, and the voltage dividing resistors 15 and 16 constitute a cut-off control circuit for cutting off the transistor 12. 17 is a diode for extending the arc time of the ignition plug 11 by passing a flywheel current through the primary coil 7a of the ignition coil 7. 18 is thyristor 10
19 and 20 are thermistors and resistors for temperature compensation of the thyristor 10;
1 is a resistor for limiting the gate current of the thyristor 10, 2
2 and 23 are a temperature compensating thermistor and a resistor of the thyristor 14, and these components 18 to 2
3 may be omitted in some cases.

Next, the operation of the above configuration will be explained.
N, S, S, S pole or S as a magnet generator
When using a four-pole magnet generator magnetized to N, N, and N poles, the capacitor charging coil 3 is
1 per rotation of the magnet generator rotor as shown in
A cycle and a half of no-load AC voltage is generated. Now, when a half-wave output on the capacitor charging side in the direction of the solid arrow in Figure 1 begins to occur, a base current flows to the transistor 12 in the circuit from the coil 3 to the resistor 13 to the base emitter of the transistor 12 to the ground, and this transistor 12 conduction between the collector and emitter of
The output of coil 3 is short-circuited. As the short-circuit current increases, the voltage drop between the collector and emitter of transistor 12 increases, and the voltage at 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.
Since the base and emitter of the transistor 12 are short-circuited, the collector and emitter of the transistor 12 are turned off, and the short-circuit current is abruptly cut off. At this time, a large induced voltage is generated in the coil 3, as shown by the solid line in Fig. 2b, and this high voltage causes the capacitor 6 to be connected to the Charge the battery sufficiently as shown in Figure c. Next, the charging of the capacitor 6 is completed, and immediately after that, the induced voltage of the coil 3 becomes lower than the charging voltage of the capacitor 6, so that the capacitor 6 → coil 3 (resistance 13 in parallel with this coil 3 → thyristor 14, and resistor 15 → parallel circuit of resistor 16 also passes) → ground → resistor 21 → gate/cathode of thyristor 10 → primary coil 7a of ignition coil 7 →
Current flows through the circuit of capacitor 6, and thyristor 1
0 conducts. Due to this 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 the secondary coil 7b of the ignition coil 7 has a high charge as shown in FIG. 2d. Generates voltage and fires the ignition plug 11
Get the ignition spark. The above operation is repeated once per rotation of the rotor.

Note that in the first embodiment, the diode 8
A resistor with a small resistance value can also be used instead.

FIG. 3 shows a second embodiment of the device of the present invention, in which a diode 5 is inserted between the connection point between the charging coil 3 and the collector of the transistor 12 and the capacitor 6, in contrast to the first embodiment. A thinning ignition switch 1, which is opened during thinning ignition, is connected in parallel between the terminals of this diode 5, and a Zener diode 2 is inserted between the connection point between the cathode of the diode 5 and the capacitor 6, and the gate of the thyristor 10. ,
A resistor 4 is connected between the gate of this thyristor 10 and the cathode of the diode 8, and a diode 5a is connected between one end of the ground side of the capacitor charging coil 3 and the resistor 16 (this diode 5a can be omitted). is inserted. The thinning ignition switch 1 detects when the throttle valve is fully closed, when the internal combustion engine is suddenly decelerating, when the internal combustion engine is overspeeding, etc., based on the throttle valve position, intake negative pressure, engine speed, etc. It automatically opens (shuts off) only when the Further, the Zener voltage of the Zener diode 2 is set to a value slightly higher than the voltage at which the capacitor 6 is charged by one induced voltage of the coil 3.

In this second embodiment, first, the operation when the thinning ignition switch 1 is opened will be explained. Now, when a voltage is generated in the coil 3 in the direction of the solid line (positive direction) in Figure 3, the coil 3 → resistor 13 → transistor 1
The base current flows through the transistor 12 in the circuit of base emitter 2 → diode 5a → ground,
The collector and emitter are electrically connected, and the output of the coil 1 is short-circuited. As the short circuit current increases, the voltage drop across the transistor 12 increases, and the resistor 1
The voltage at the connection point a between 5 and 16 increases. When this voltage reaches a set value, the thyristor 14 becomes conductive, the transistor 12 turns off, and the short circuit current is abruptly cut off. At this time, a large induced voltage is generated in the coil 3 as shown by the solid line in FIG.
8, 5a→Charge capacitor 5 through the ground circuit. At this time, since the Zener voltage ZD of the Zener diode 2 is higher than the capacitor voltage at this time, the thyristor 10 is not conductive and does not ignite. When the rotor further rotates and a second voltage in the direction of the solid line is generated in the coil 3, a large voltage is again induced in the coil 3 by the same operation as described above, and the capacitor 6 is charged as shown in FIG. 2e. At this time, the capacitor 6 remains charged due to its discharge being blocked by the diode 5, so the coil 3
Since the load becomes lighter, the generated voltage becomes higher than that during the first charging, as shown by the broken line in FIG. 2b. Then, by setting the Zener voltage ZD of the Zener diode 2 between the voltage at this time and the first charging voltage, the Zener diode 2 becomes conductive, and the gate voltage of the thyristor 10 rises. conducts the charge in the capacitor 6 to the primary coil 7a of the ignition coil 7.
The second
A high voltage as shown in FIG. f is obtained to generate an ignition spark at the ignition plug 11. Repeat the above operation, and the rotor 2
Thinned ignition of one ignition per rotation is performed.

Next, the operation when the thinning ignition switch 1 is closed (conducted) to cancel the thinning ignition will be described.
The operation at that time is basically the same as the operation of the first embodiment, and when a voltage in the direction shown by the solid line is generated in the coil 3, the coil 3
A large induced voltage is generated in the coil 3 → switch 1 → capacitor 6 → diode 17, 8, 5a.
→Charge the capacitor 6 using the ground circuit as shown in Figure 2c. When the charging of this capacitor 6 is completed and the induced voltage of the coil 3 becomes lower than the charging voltage of the capacitor 6, the capacitor 6→switch 1→
A current flows through the circuit of resistor 13 → thyristor 14 → resistor 4 → gate/cathode of thyristor 10 → primary coil 7a of ignition coil 7 → capacitor 6, and thyristor 10 becomes conductive. As a result, the charge in the capacitor 6 is transferred to the primary coil 7a of the ignition coil 7.
The secondary coil 7b of the ignition coil 7 receives a high voltage as shown in FIG. 2d, and the ignition plug 1
1 to generate an ignition spark. The above operation is repeated every time a positive output is generated in the coil 3, and normal ignition is performed once per rotation of the rotor. In both normal ignition and thinned ignition, the ignition occurs almost in synchronization with the generation of narrow pulse-like induced voltage in the coil 3, so the ignition timing between normal ignition and thinned ignition is There is almost no change. Furthermore, by opening the thinning ignition switch 1 when the throttle valve is fully closed or when the internal combustion engine suddenly decelerates, it is possible to prevent irregular combustion in the internal combustion engine at that time, as is well known, and to prevent the ignition switch 1 from overspeeding. By opening it, over-rotation can be prevented.

FIG. 4 shows the configuration of main parts of a third embodiment of the device of the present invention. It is designed to be connected in series to the thyristor 10.

FIG. 5 shows a fourth embodiment of the device of the present invention, in which a gate sensitivity adjustment resistor 18 is connected in parallel between the gate and cathode of the thyristor 10, and the diodes 5 and 5a are omitted compared to the second embodiment. At the same time, the thinning ignition switch 1 is connected in series with the resistor 4. According to this fourth embodiment, during thinning ignition, the switch 1 is open, so that the discharge of the first charge in the capacitor 6 is prevented, and ignition is caused by the second charge, resulting in two revolutions and one ignition. In addition, since the switch 1 is closed during normal operation, each time the induced voltage of the coil 3 becomes lower than the charging voltage of the capacitor 6, the charged charge of the capacitor 6 is sent to the gate of the thyristor 10 via this switch 1 as an ignition signal. It is applied as follows, resulting in one firing per rotation.

As described above, the present invention includes a short-circuiting semiconductor switching element that substantially short-circuits the half-wave output of the capacitor charging coil, and a short-circuit that flows through the short-circuiting semiconductor switching element due to the half-wave output of the capacitor charging side of the charging coil. and a cut-off control circuit for detecting when the current exceeds a set value and cutting off the short-circuiting semiconductor switching element, and the high voltage induced in the capacitor charging coil when the short-circuiting semiconductor switching element is cut off. Since the capacitor is charged and the ignition semiconductor switching element is made conductive by the discharge current immediately after charging, there are excellent effects as described below.

(1) Conventionally, capacitor charging coils required two coils arranged in two stories or radially, a coil with a large number of turns of thin wire and a coil with a small number of turns of thick wire, but a coil with a small number of turns of thick wire was used. It is possible to use only one small coil, and the structure is simple and the 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 impedance of the capacitor charging coil is small, there is little delay in the cutoff position, and even if the discharge current immediately after charging by the output of this charging coil is used as the ignition signal, there is little delay in the ignition timing at high speeds.

(5) By effectively utilizing the capacitor charging coil, the capacitor can be sufficiently charged with a small, simple, and inexpensive circuit configuration without the need for a battery or step-up transformer.

(6) When the short-circuit current of the capacitor charging coil exceeds the set value, it is configured to detect it and cut off the short-circuit current.Although the circuit configuration is simple, the capacitor The charging voltage of the internal combustion engine can be well controlled, and stable ignition performance can be obtained from low to high speeds of the internal combustion engine without using a battery.

(7) Since the induced voltage of the charging coil is lower than the charging voltage of the capacitor, the charging voltage of the capacitor is applied as an ignition signal between the gate and cathode of the ignition semiconductor switching element, so a special ignition signal generator is required. There is no need to provide

Furthermore, the capacitor is provided with a switch means that is opened when the ignition is thinned out, and a voltage detection element that detects when the switch means is opened that the charging voltage of the capacitor has become higher than that during a single charge, and makes the semiconductor switching element for ignition conductive. The switch means is closed and the ignition semiconductor switching element is made conductive each time by the capacitor charging voltage immediately after charging via the switch means, or the switch means is opened and the capacitor is charged multiple times. If the semiconductor switching element for ignition is made conductive by the voltage detection element when the ignition occurs, thinned ignition and normal ignition can be arbitrarily performed, and the width induced in the capacitor charging coil can be controlled both during thinned ignition and normal ignition. Since ignition occurs almost in synchronization with a narrow pulse-like induced voltage, there is an excellent effect that there is almost no ignition timing variation between normal ignition and thinned ignition.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram showing a first embodiment of the device of the present invention, Fig. 2 is a waveform diagram of various parts for explaining the operation of the device shown in Fig. 1, and Fig. 3 shows a second embodiment of the device of the present invention. FIG. 4 is an electric circuit diagram showing the configuration of a main part of a third embodiment of the device of the present invention, and FIG. 5 is an electric circuit diagram showing a fourth embodiment of the device of the present invention. DESCRIPTION OF SYMBOLS 1... Thinning ignition switch as a switching means, 2... Zener diode as a voltage detection element, 3... Capacitor charging coil, 6... Capacitor, 7... Ignition coil, 7a... Primary coil, 7b ...Secondary coil, 8...Diode as a voltage drop element, 10...Thyristor as an ignition semiconductor switching element, 11...Ignition plug, 12...Transistor as a short circuit semiconductor switching element, 13, 14, 15, 16...
Base resistor, thyristor, and resistor that make up the cut-off control circuit.

Claims (1)

[Claims] 1. A capacitor charging coil of a magnet generator, a capacitor charged by the generated output of this charging coil, a voltage drop element inserted between this capacitor and the charging coil, a primary coil and An anode/cathode circuit is connected to form a closed circuit through an ignition coil having a secondary coil, the primary coil of the ignition coil, and the capacitor;
and an ignition semiconductor switching element whose gate and cathode are connected between the terminals of the voltage drop element and which supplies the charged charge of the capacitor to the ignition coil through conduction, and two of the ignition coils.
A short-circuiting semiconductor switching element that substantially shorts the spark plug connected to the next coil and the capacitor-charging-side half-wave output of the charging coil, and a short-circuiting semiconductor switching element that connects the capacitor-charging side half-wave output of the charging coil to the short-circuiting semiconductor switching element. and a cutoff control circuit for detecting a flowing short-circuit current exceeding a set value and cutting off the short-circuiting semiconductor switching element, the high voltage being induced in the charging coil when the short-circuiting semiconductor switching element is cut off. A closed circuit is formed from one end of the capacitor through at least one of the charging coil and the cutoff control circuit, the gate/cathode of the ignition semiconductor switching element, and the other end of the capacitor. Immediately after charging of the capacitor is completed, the induced voltage of the charging coil becomes lower than the charging voltage of the capacitor, so that the charging voltage of the capacitor becomes an ignition signal between the gate and cathode of the ignition semiconductor switching element. A non-contact ignition device for an internal combustion engine that has a circuit configuration that applies power as follows. 2. A capacitor charging coil of a magnet generator, a capacitor charged by the generated output of this charging coil, and a capacitor inserted between this charging coil and the capacitor with this capacitor side as an anode side and the charging coil side as a cathode side. diode and
An ignition coil having a primary coil and a secondary coil, an anode/cathode circuit connected to form a closed circuit through the primary coil of the ignition coil and the capacitor, and a cathode connected to the anode side of the diode. a semiconductor switching element for ignition, the gates of which are connected to the cathode sides of the capacitors, for supplying the charge charged in the capacitor to the primary coil of the ignition coil through conduction; The semiconductor switching element is connected between the side to be charged to the positive electrode and the gate of the semiconductor switching element, and detects that the charging voltage of the capacitor is higher than that during one charge when the switching means is opened, and the switching element is connected to the semiconductor switching element. a voltage detection element for conducting, a spark plug connected to the secondary coil of the ignition coil, a shorting semiconductor switching element for substantially shorting the capacitor charging side half-wave output of the charging coil, and a shorting semiconductor switching element for shorting the capacitor charging side half-wave output of the charging coil; and a cut-off control circuit for detecting when a short-circuit current flowing through the semiconductor switching element due to the half-wave output on the capacitor charging side of the charging coil exceeds a set value and cutting off the short-circuiting semiconductor switching element, A capacitor is charged by a high voltage induced in the charging coil when the semiconductor switching element is cut off, and from one end of the capacitor, at least one of the charging coil and the cutoff control circuit, the switching means, and the ignition semiconductor are charged. A closed circuit is formed through the gate and cathode of the switching element and the other end of the capacitor,
When the switch means is closed, the induced voltage of the charging coil becomes lower than the charging voltage of the capacitor immediately after charging of the capacitor is completed, so that the gate and cathode of the ignition semiconductor switching element are connected via the switch means. A non-contact ignition device for an internal combustion engine, which has a circuit configuration in which the charging voltage of the capacitor is applied as an ignition signal between the two.