JP2594058Y2 - Ignition device for internal combustion engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor discharge type ignition device for an internal combustion engine using a battery as a power source.

[0002]

2. Description of the Related Art FIG. 3 shows a known ignition system of this type. In FIG. 3, reference numeral 1 denotes a converter circuit for converting the output of the battery 2 into an AC voltage. This converter circuit includes a step-up transformer 3 having one end of a secondary coil 3b grounded, a pulse oscillator 4 oscillated by supplying a power supply voltage from a battery 2 through a key switch SW, and a primary coil 3a of the step-up transformer. A current control switch 5 that is connected in series and is turned on and off in synchronization with the output of the oscillator 4, and controls a current supplied from the battery 2 to the primary coil 3 a of the step-up transformer 3 through the switch SW. 5 is turned on and off to induce a relatively high voltage of about 200 [V] in the secondary coil 3b of the step-up transformer 3. In the example shown in FIG. 3, the switch 5 is an NPN transistor Tr whose emitter is grounded.
Whose collector is the primary coil 3a of the transformer 3.
, The primary coil 3a and the collector-emitter circuit of the transistor are connected in series. Further, in the illustrated example, a diode 6 whose anode is directed to the ground side is connected to both ends of the secondary coil of the transformer 3.

[0003] Reference numeral 7 denotes an ignition coil having a primary coil 7a and a secondary coil 7b.
One end of the next coil is grounded. One end of a primary coil 7a of the ignition coil is grounded, and one end of an ignition energy storage capacitor 8 is connected to the other end of the primary coil. The other end of the capacitor 8 is connected to a non-ground side terminal of a secondary coil of the step-up transformer 3 through a diode 9.

[0004] Reference numeral 10 denotes a discharge thyristor for discharging the charge of the ignition energy storage capacitor 8 to the primary coil 7a of the ignition coil when conducting, and 11 denotes an ignition signal to the discharge thyristor 10 at the ignition timing of the internal combustion engine. An ignition signal supply device for conducting the thyristor. In the illustrated example, a discharge thyristor 10 is connected between the connection point of the capacitor 8 and the diode 9 and the ground, and a resistor 12 is connected between the gate and cathode of the thyristor Th.

Reference numeral 13 denotes an oscillation stop circuit for stopping the oscillation of the oscillator 4 for a predetermined time every time the ignition operation is performed. The oscillation stop circuit 13 detects the supply of the ignition signal and sets the timing for stopping the oscillation. An oscillation stop timing setting circuit that determines an oscillation stop timing setting circuit and an oscillation restart timing setting circuit that determines a timing at which oscillation is restarted by measuring a certain time when the oscillation is stopped, and it is detected that the ignition signal is supplied. Sometimes, the operation of the oscillator 4 is stopped for a certain period of time by short-circuiting some of the components of the oscillator 4.

In the ignition device for an internal combustion engine shown in FIG. 3, the transistor Tr is turned on every time a pulse signal is supplied from the oscillator 4, and is turned off when the pulse signal disappears. Therefore, the transistor Tr repeatedly turns on and off in synchronization with the output of the oscillator 4, and the current supplied from the battery 2 to the primary coil 3a of the transformer 3 is intermittently turned on and off as the transistor Tr turns on and off. Therefore, a relatively high voltage of about 200 [V] is induced in the secondary coil 3b of the transformer, and the capacitor 8 is charged to the polarity shown in FIG. When an ignition signal is given to the gate of the thyristor Th at the ignition timing of the engine, the thyristor Th conducts and discharges the charge of the capacitor 8 to the primary coil 7a of the ignition coil. Due to the current change at this time, a high voltage is induced in the secondary coil 7b of the ignition coil. Since this high voltage is applied to the spark plug 14 attached to the cylinder of the engine, a spark is generated in the spark plug 14 and the engine is ignited.

[0007] In the ignition device of FIG.
Assuming that the thyristor 3 is not provided, when the oscillation cycle of the oscillator 4 is shorter than the turn-off time of the thyristor 10, the thyristor is kept conductive, and the output of the converter circuit 1 is short-circuited through the thyristor 10. Therefore, the capacitor 8 is not charged, and the ignition operation is not performed. In order to prevent this, in this type of conventional ignition device, an oscillation stop circuit 13 is provided to stop the oscillation of the oscillator 4 for a certain period of time when the ignition signal is supplied to the discharge thyristor 10, and the converter The output of the circuit 1 was stopped.

[0008]

In the conventional ignition device shown in FIG. 3, in order to constitute the oscillation stop circuit 13, an oscillation stop timing setting circuit for determining the timing for stopping the oscillation and a timing for restarting the oscillation are provided. Therefore, there has been a problem that the configuration of the oscillation stop circuit 13 is complicated because two timing setting circuits are required.

An object of the present invention is to provide an ignition device for an internal combustion engine that can simplify the configuration of a circuit for stopping the operation of a converter circuit during an ignition operation.

[0010]

The present invention comprises a step-up transformer and a current control switch connected in series to a primary coil of the step-up transformer and turned on and off in synchronization with the output of an oscillator. , From battery to step-up transformer
A converter circuit for interrupting the current supplied to the next coil by turning on and off the current control switch to induce a voltage in the secondary coil of the step-up transformer; an ignition coil; and a primary circuit provided on the primary side of the ignition coil. An ignition energy storage capacitor charged to one polarity through a rectifier by an output of the converter circuit; and a discharge thyristor provided to discharge the charge of the ignition energy storage capacitor to a primary coil of the ignition coil when the capacitor is turned on. And an ignition signal supply circuit for supplying an ignition signal to a discharge thyristor at the time of ignition of the internal combustion engine to make the thyristor conductive, and to an ignition device for an internal combustion engine.

In the present invention, a power generating coil disposed in a generator for outputting an AC voltage in synchronization with the rotation of the internal combustion engine, and a period during which the power generating coil generates a half cycle output voltage of one polarity. The current control switch is turned on / off, and the current control is performed in accordance with the output of the power generation coil so as to stop the on / off operation of the current control switch while the power generation coil is generating the output voltage of the other half cycle. And a converter control circuit for controlling the switch. The ignition signal supply circuit is configured to supply the ignition signal during a period when the power generation coil is generating the output of the other half cycle.

The converter control circuit may control the current control switch by controlling the operation of the oscillator, or may directly control the current control switch.

That is, in order to stop the ON / OFF operation of the current control switch, the oscillation of the oscillator may be stopped, or the ON / OFF operation of the current control switch itself may be stopped. In order to stop the oscillation of the oscillator, for example, the power supply of the oscillator may be cut off, some of the components of the oscillator may be short-circuited by the switch means, or a part of the circuit of the oscillator may be disconnected by the switch means. In order to stop the on / off operation of the current control switch, for example, it is sufficient to prevent a trigger signal from being supplied from the oscillator to the current control switch.

[0014]

With the above configuration, a period in which the operation of the converter circuit is stopped and a period in which the operation of the converter circuit is performed can be set using the waveform of the power generation coil.
No special timing setting circuit is required.

The converter control circuit may be any circuit that stops or restarts the oscillator according to the output of the power generation coil, or any circuit that blocks or permits the supply of the oscillation output to the current control switch. As a result, the circuit configuration is not particularly complicated.

For example, a switch is provided in the converter control circuit to short-circuit a part of the oscillator circuit when conduction occurs and to stop the operation of the oscillator, so that when the power generating coil generates an output voltage of one polarity, The switch may be held in the cutoff state, and the switch may be turned on when the power generation coil generates the output voltage of the other polarity.
In addition, a pulse signal (trigger signal) supplied from the oscillator to the current control switch when the current is turned on is provided in the converter control circuit with a switch bypassing the current control switch, and the power generation coil generates an output voltage of one polarity. In such a case, the switch may be held in the cut-off state when the switch is turned on, and the switch may be turned on when the power generation coil generates the output voltage of the other polarity.

In any case, since the converter control circuit can be constituted by a simple circuit, the operation of the converter circuit can be stopped at the time of the ignition operation and the ignition operation can be reliably performed without using a complicated circuit.

[0018]

FIG. 1 shows an embodiment of the present invention. In this embodiment, parts that are the same as the respective parts of the ignition device shown in FIG. 3 are given the same reference numerals. In this embodiment, the configuration of the converter circuit 1 and the configuration of the primary side and the secondary side of the ignition coil 7 are the same as those in the example shown in FIG.

In the present invention, a magnet generator is mounted on an output shaft of an internal combustion engine, and a load 1 such as a battery charging circuit or a lamp is mounted on a generating coil 15 provided in the magnet generator.
6 are connected. The generator coil 15 outputs an AC voltage VL as shown in FIG. 2A in synchronization with the rotation of the engine.

In this embodiment, there is provided a converter control circuit 17 for oscillating the oscillator 4 or stopping the oscillation in accordance with the polarity of the output voltage of the power generation coil 15. The converter control circuit 17 includes, for example, a transistor 18 having a collector-emitter circuit connected between a trigger signal input terminal of an active element included in the oscillator 4 and ground,
A resistor 19 for providing a base current to the transistor 18;
On / off control transistor 20 having a collector-emitter circuit connected between the base and emitter of transistor 18
And a waveform shaping circuit 21 for converting the output of the power generation coil 15 into a rectangular control signal Vq as shown in FIG. 2B. The control signal Vq obtained from the waveform shaping circuit 21 Has been given to.

In this embodiment, the ignition signal supply circuit 11 is configured to generate an ignition signal during a period when the power generation coil 15 is generating a negative half cycle output voltage.

In the embodiment shown in FIG. 1, the waveform shaping circuit 21 generates the control signal Vq while the power generating coil 15 is generating the voltage of the positive half cycle. While the control signal Vq is being generated, the transistor 20 is turned on and the transistor 18 is kept off. Transistor 1
When the transistor 8 is in the cutoff state, the transistor does not affect the operation of the oscillator 4, so that the oscillator 4 generates a pulse signal and turns on and off the transistor 5 constituting the current control switch. Therefore, in this state, the transformer 3
A high voltage is induced in the secondary coil, and the capacitor 8 is charged by this voltage.

Next, when the generating coil 15 generates a voltage of a negative half cycle, the waveform shaping circuit 21 stops generating the control signal Vq, so that the transistor 20 is turned off and the transistor 18 is turned on. . In this state, the trigger signal input terminal of the active element of the oscillator 4 is substantially short-circuited by the transistor 18, so that the oscillator 4
Stops, and the transformer 3 stops outputting the voltage.
When an ignition signal is generated in this state, the thyristor 10 conducts, and charges the capacitor 8 to the primary coil 7 of the ignition coil.
Discharge through a. As a result, a high voltage is induced in the secondary coil of the ignition coil, and the ignition operation is performed. When the generating coil 15 again generates a voltage of a positive half cycle, the control signal Vq is generated, so that the transistor 18 is turned off, and the oscillator 4 resumes the oscillating operation.

As described above, in the present invention, the period for oscillating the oscillator 4 and the period for stopping the oscillation are determined by using the output waveform of the power generation coil provided in the generator mounted on the engine. Therefore, the circuit configuration of the converter control circuit 17 can be simplified.

In the above embodiment, the transistor 18 is connected between the trigger signal input terminals of the active elements of the oscillator and the operation of the oscillator 4 is stopped when the transistor 18 is turned on, but the transistor 18 is connected. The portion may be any portion of the oscillator that can stop the operation of the oscillator when short-circuited by the transistor 18.

In the above embodiment, the transistor 18
Is connected to the oscillator 4 to stop the operation of the oscillator, thereby stopping the on / off operation of the current control switch 5. However, as shown by the broken line in FIG. By connecting to the base of the transistor Tr constituting the switch 5, the transistor Tr may be kept in the cut-off state when the transistor 18 is turned on, and the operation of the converter circuit 1 may be stopped.

In the above embodiment, the converter circuit is operated when the power generation coil 15 is generating a positive half cycle voltage, and the converter circuit is operated when the power generation coil 15 is generating a negative half cycle voltage. Although the operation of the circuit is stopped, the converter circuit is operated when the power generation coil 15 is generating a voltage of a negative half cycle,
The operation of the converter circuit may be stopped when the power generation coil 15 is generating a voltage of a positive half cycle.

In the above embodiment, the transistor 18 constituting a switch for stopping the operation of the converter circuit is used.
In addition to the above, a circuit for controlling the on / off of the transistor 18 (in the above example, constituted by the resistor 19 and the transistor 20) is provided, but the transistor 18 is directly on / off controlled by the output of the waveform shaping circuit 21. You may. For example, in the embodiment of FIG.
The control signal Vq becomes zero during a period when the output voltage of the positive half cycle is generated, and the control signal Vq becomes a high level during a period when the power generation coil 15 is generating the output voltage of the negative half cycle. By configuring the waveform shaping circuit 21, the resistor 19 and the transistor 20 can be omitted.

Further, the switch element for stopping the operation of the converter is not limited to the transistor 18, but may be any switch element (for example, FET or the like) as long as it can be turned on and off.

In the above embodiment, the current control switch 5
A transistor is used as the current control switch 5, but another switch element capable of ON / OFF control such as an FET may be used as the current control switch 5.

[0031]

As described above, according to the present invention, the period during which the operation of the converter circuit is stopped and the period during which the operation of the converter circuit is performed are determined by using the waveform of the power generation coil. The converter control circuit can be configured without providing the timing setting circuit described above, and the operation of the converter circuit can be stopped at the time of the ignition operation, and the ignition operation can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram showing an output voltage waveform of a power generation coil and a waveform of a control signal in the embodiment of FIG.

FIG. 3 is a circuit diagram showing a circuit configuration of a conventional ignition device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Converter circuit 2 Battery 3 Step-up transformer 4 Oscillator 5 Transistor (current control switch) 6 Diode 7 Step-up transformer 8 Ignition energy storage capacitor 10 Discharge thyristor 15 Generator coil 16 Load 17 Converter control circuit

Claims (1)

(57) [Scope of request for utility model registration] A step-up transformer connected in series with a primary coil of the step-up transformer and turned on and off in synchronization with an output of an oscillator; A converter circuit for interrupting a current supplied to the coil by turning on / off the current control switch to induce a voltage in a secondary coil of the step-up transformer; an ignition coil; and a converter circuit provided on a primary side of the ignition coil. An ignition energy storage capacitor that is charged to one polarity through a rectifier by the output of the converter circuit; and a discharge energy storage device that discharges the charge of the ignition energy storage capacitor to a primary coil of the ignition coil when the capacitor is turned on. A thyristor, and an ignition for applying an ignition signal to the discharge thyristor at the ignition timing of the internal combustion engine to make the thyristor conductive. An ignition device for an internal combustion engine, comprising: a signal supply circuit; a power generation coil provided in a generator that generates an AC voltage in synchronization with rotation of the internal combustion engine; During the period in which the current control switch is turned on and off, and while the power generation coil is generating the output voltage of the other half cycle, the on / off operation of the current control switch is stopped. A converter control circuit for controlling a current control switch according to the output of the coil, wherein the ignition signal supply circuit supplies the ignition signal during a period when the power generation coil is generating the output of the other half cycle. And an ignition device for an internal combustion engine.