JP2570678Y2 - 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 system for an internal combustion engine which prevents generation of an ignition voltage when the internal combustion engine is reversed, thereby preventing the engine from being reversed.

[0002]

2. Description of the Related Art A capacitor discharge type ignition device for an internal combustion engine includes an ignition energy storage capacitor provided on a primary side of an ignition coil, a charging circuit for charging the capacitor,
It has a discharge control thyristor provided to discharge the charge of the capacitor to the primary coil of the ignition coil, and a signal generator for inducing a signal of one cycle only once per rotation of the internal combustion engine.

In this type of ignition device, after charging a capacitor for storing ignition energy, a thyristor for discharging control is triggered by a signal of one polarity obtained from a signal generator to make the thyristor conductive. As a result, the charge of the ignition energy storage capacitor is discharged to the primary coil of the ignition coil, and a high voltage for ignition is induced in the secondary coil of the ignition coil.

[0004] As is well known, a capacitor discharge type ignition device requires a relatively high voltage of 200 V to 300 V to charge an ignition energy storage capacitor. Conventionally, as a power source for charging an ignition energy storage capacitor, a power generating coil provided in a magnet type AC generator driven by an engine has been often used. In this case, it is necessary to increase the number of turns of the power generation coil, so that the power generation coil becomes large.

A short-circuit switch that conducts when the power generating coil generates one half cycle of output voltage and short-circuits the power generating coil, and a short-circuit current flowing through the short-circuit switch reaches a predetermined magnitude. 2. Description of the Related Art An ignition device provided with a current interruption type booster circuit including an interruption control thyristor that conducts to turn off a short-circuit switch has been used. In an ignition device using such a booster circuit, a voltage of 200 V to 300 V is induced in the power generation coil by interrupting the short-circuit current after the power generation coil is once short-circuited, and the ignition energy storage capacitor is charged with this voltage. . Therefore, a coil having a small number of turns can be used as the power generation coil, and the size of the power generation coil can be reduced.

In a capacitor discharge type ignition device using a current interruption type booster circuit as a power source, even when a signal of one polarity is generated from a signal generator at the time of reverse rotation of the engine, the discharge control thyristor conducts and ignites. A high voltage for ignition may be generated in the coil, and the engine may be reversed. Therefore, when this type of ignition device is used in a two-cycle engine for a vehicle, it is necessary to prevent generation of a high voltage for ignition during reverse rotation for safety.

FIG. 3 shows a conventional capacitor discharge type ignition device for preventing induction of a high voltage for ignition at the time of reverse rotation of the engine. FIG. 4 shows voltage waveforms at various points in FIG. 3. In FIG. 4, the waveform at the time of normal rotation of the internal combustion engine is shown by a solid line, and the waveform at the time of reverse rotation is shown by a broken line. The rotation angle θ during forward rotation changes from left to right, and the rotation angle θ ′ during reverse rotation changes from right to left.

In FIG. 3, reference numeral 1 denotes a power generating coil which induces an AC voltage in synchronization with the rotation of the internal combustion engine, and which is driven by the AC voltage Veo as shown in FIG.
And at the time of reverse rotation of the engine, an AC voltage Veo 'is induced. Reference numeral 7 denotes a booster circuit connected in parallel to the power generating coil 1. This booster circuit is connected to the power generating coil 1 when the output voltage of one half cycle in the direction indicated by the solid line arrow (positive direction) is generated. 1 is substantially short-circuited, and when the short-circuit current reaches a set value, the short-circuit current is cut off, and a high voltage Ve (V'e) (FIG. 4B) is induced in the power generation coil 1 at that time. This voltage charges the ignition energy storage capacitor 3 through the diode 2 to the polarity shown.

Reference numeral 8 denotes a signal generator for inducing a signal voltage of one cycle only once per one revolution of the engine.
4D, a signal voltage Vp is induced when the power generating coil 1 generates one (positive direction) half-cycle output voltage during normal rotation of the engine, and the power generating coil 1 Is provided so as to induce the signal voltage V'p when the output voltage of the other half cycle in the direction of the dashed arrow (negative direction) is generated. An ungrounded output terminal of the signal generator 8 is connected to the gate of the discharge control thyristor 6 through a series circuit of a diode 9 and a resistor 10.

In order to prevent a signal voltage of one polarity (positive polarity) in the direction of the solid arrow shown in the figure induced in the signal generator 8 at the time of reverse rotation of the engine from being supplied to the gate of the discharge control thyristor 6, A diode 30 whose cathode is directed to the non-ground side of the power generation coil is connected between the cathode and the non-ground side terminal of the power generation coil 1, and the output of the power generation coil 1 in the direction of the dashed arrow shown in FIG. The diode 31 in the short-circuit direction is connected.

At the time of normal rotation of the internal combustion engine, a signal voltage of one polarity (positive polarity) is generated during a half cycle of one (positive direction) of the generating coil 1, and the signal voltage is bypassed through the diode 30. Without being supplied to the gate of the discharge control thyristor 6 as a trigger signal. As a result, the discharge control thyristor 6 becomes conductive, so that the electric charge of the ignition energy storage capacitor 3 is discharged to the primary coil 4a of the ignition coil 4 and a high voltage is generated in the secondary coil 4b. .

During the reverse rotation of the internal combustion engine, a signal voltage of one polarity (positive polarity) is generated during a period in which the power generation coil 1 generates an output voltage of the other (negative direction) half cycle. Diode 30 → generation coil 1 →
Since the thyristor 6 is bypassed on the ground path, no trigger signal is given to the gate of the thyristor 6 for discharge control. Therefore, the charge of the ignition energy storage capacitor 3 is not discharged at the time of reverse rotation of the engine, so that the generation of the ignition voltage is prevented. FIG. 4C shows the waveforms of the terminal voltages Vc and Vc 'of the ignition energy storage capacitor 3 during forward rotation and reverse rotation.

[0013]

In the above-mentioned conventional ignition device, after the output of one polarity of the power generating coil 1 is short-circuited by the booster circuit 7, it is cut off when the short-circuit current reaches a predetermined value. While charging the ignition energy accumulating capacitor 3 with the obtained boosted voltage, the output of the other polarity of the power generating coil is short-circuited by the diode 31 connected in parallel with the power generating coil 1, and the signal generator 8 is turned on when the internal combustion engine reversely rotates.
Is bypassed through the diode 30 and the power generating coil 1 which is short-circuited by the diode 31, so that a trigger signal is prevented from being applied to the gate of the discharge control thyristor 6. ing.

When the output of the other polarity of the power generating coil 1 is short-circuited by the diode 31 as described above, the armature reaction due to the short-circuit current flowing through the diode 31 causes the power generating coil 1 to generate one output voltage at high speed. The magnitude of the short-circuit current flowing through the booster circuit 7 may decrease, and the magnitude of the short-circuit current may not reach the set value required for causing the booster circuit to perform the shut-off operation. Therefore, in this type of conventional ignition device provided with the reverse rotation prevention circuit, there is a possibility that a high voltage for ignition is not generated at high speed.

An object of the present invention is to prevent generation of an ignition voltage at the time of reverse rotation without short-circuiting the output of the power generation coil, and to stably perform an ignition operation up to a high speed region at the time of normal rotation. And an ignition device for an internal combustion engine.

[0016]

According to the present invention, a power generating coil provided in a magnet type alternator driven by an internal combustion engine is electrically connected when the power generating coil generates an output voltage of one half cycle. A short-circuit switch for substantially short-circuiting the power generation coil, and conducting when a short-circuit current flowing through the short-circuit switch reaches a predetermined magnitude during a period in which the power generation coil generates one half cycle of output voltage. A shutoff control thyristor that turns off the short-circuit switch;
An ignition coil, an ignition energy storage capacitor provided on the primary side of the ignition coil, and charged with a voltage induced in the power generation coil when the short-circuit switch is turned off;
A discharge control thyristor provided to discharge the electric charge of the ignition energy storage capacitor to the primary coil of the ignition coil when the electric power is turned on; The present invention relates to an ignition device for an internal combustion engine including a signal generator for inducing a signal, and a signal supply circuit for providing a trigger signal to a gate of a discharge control thyristor with a signal of one polarity obtained from the signal generator.

In the present invention, the signal generator induces a signal of one polarity during the other half cycle of the power generating coil when the internal combustion engine rotates forward, and generates the signal of one polarity during the reverse rotation of the internal combustion engine during one half cycle of the power generating coil. It is provided so as to induce a signal of one polarity during the period. Also, when the shut-off control thyristor is turned on, the signal of one polarity obtained from the signal generator is bypassed from the signal supply circuit through the shut-off control thyristor, and the output terminals of the signal generator and Are combined.

[0018]

With the above arrangement, during normal rotation of the internal combustion engine, a signal is generated from the signal generator during the other half cycle of the power generation coil. At this time, the shutoff control thyristor is in a non-conductive state. The signal of one polarity obtained from the generator is given a trigger signal to the gate of the discharge control thyristor without being bypassed from the signal supply circuit.

At the time of reverse rotation of the internal combustion engine, a signal is generated from the signal generator during one half cycle of the power generation coil, and a signal of one polarity output from the signal generator when the shut-off control thyristor is in a conductive state. Is bypassed from the signal supply circuit through the shutoff control thyristor. Therefore, at the time of reverse rotation of the engine, no trigger signal is given to the gate of the discharge control thyristor, so that generation of an ignition voltage can be prevented.

With the above configuration, it is not necessary to short-circuit the output of the other half cycle of the power generating coil.
The short-circuit current of one half cycle of the power generation coil does not decrease at high speed due to the armature reaction. Therefore, during forward rotation, the ignition energy storage capacitor can be sufficiently charged up to the high speed region, and the ignition operation can be performed without any problem even at high speed.

[0021]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a power generating coil provided in a magnet type AC generator which is attached to an internal combustion engine (not shown) and rotates synchronously with the engine. One end of the generating coil 1 is grounded, and the other end is connected to one end of an ignition energy storage capacitor 3 through a diode 2.

The other end of the capacitor 3 is connected to one end of a primary coil 4a of the ignition coil 4, and the other end of the primary coil 4a is grounded. One end of a secondary coil 4b of the ignition coil 4 is grounded, and a non-ground side terminal of the secondary coil 4b is connected to a non-ground side terminal of a spark plug 5 attached to a cylinder of the engine. The connection point between the diode 2 and the capacitor 3 is connected to the anode of a discharge control thyristor 6.
The cathode of the thyristor 6 is grounded.

Reference numeral 7 denotes a booster circuit connected in parallel between both ends of the power generating coil 1. The high energy induced across the power generating coil 1 by the booster circuit charges the ignition energy storage capacitor 3 through the diode 2. You. Reference numeral 8 denotes a signal generator that is attached to the internal combustion engine and induces a signal voltage. The output terminal of the signal generator 8 is a gate of the discharge control thyristor 6 through a signal supply circuit 11 formed of a series circuit of a diode 9 and a resistor 10. It is connected to the.

The power generation coil 1, diode 2, ignition energy storage capacitor 3, ignition coil 4, discharge control thyristor 6, booster circuit 7, signal generator 8 and signal supply circuit 11 constitute a capacitor discharge ignition circuit. Have been.

In the booster circuit 7, the collector of an NPN transistor 12 is connected to the non-ground side terminal of the power generation coil 1, and a short-circuit current detecting resistor 13 is connected between the emitter of the transistor 12 and ground. This resistor 13 is set to a minimum value necessary for detecting a short-circuit current. The transistor 12 constitutes a short-circuit switch 14, and a resistor 1 is connected between the collector and the base of the transistor 12.
5 is connected. The anode of the diode 16 is also connected to the base of the transistor 12, and the diode 1
A shut-off control thyristor 17 having the cathode directed to the ground side is connected between the cathode of No. 6 and the ground.

A first trigger circuit 2 comprising transistors 18 and 19, diodes 20 and 21, a capacitor 22 and a resistor 23 is provided between both ends of the short-circuit current detecting resistor 13.
4 and a second trigger circuit 27 formed of a voltage dividing circuit composed of a series circuit of a resistor 25 and a resistor 26 are connected in parallel.

Transistor 19 of first trigger circuit 24
And the voltage dividing point of the voltage dividing circuit of the second trigger circuit 27 are connected to the gate of the thyristor 17 for shutoff control, and the shutoff control is performed by the first trigger circuit 24 and the second trigger circuit 27. A trigger circuit for triggering the thyristor 17 is configured.

The output voltage of the power generating coil 1 in one half cycle in the direction of the solid arrow shown in the drawing causes the transistor 12 to conduct, and a voltage drop corresponding to the short-circuit current of the power generating coil 1 is generated between both ends of the short-circuit current detecting resistor 13. Then, in the first trigger circuit 24, a current flows into the capacitor 22 through the space between the emitter and the base of the transistor 18, the transistor 18 is turned on, and the transistor 19 is kept in the cut-off state. When the short-circuit current of the power generation coil 1 reaches a peak state and the charging of the capacitor 22 is stopped, the transistor 18 is turned off, whereby the transistor 19 is turned on and the first trigger circuit 24 connects to the gate of the cutoff control thyristor 17. A trigger signal is provided.

When the magnitude of the short-circuit current of the power generation coil 1 reaches a set value, the divided voltage of the voltage dividing circuit constituting the second trigger circuit 27 reaches the trigger level of the cutoff control thyristor 17 and the thyristor Trigger 17

Therefore, when the peak value of the short-circuit current of the generating coil 1 is less than the set value, a trigger signal is given to the thyristor 17 by the first trigger circuit 24,
If the short-circuit current reaches the set value before the short-circuit current reaches the peak, the thyristor 17 is triggered by the output of the second trigger circuit 27.

The signal generator 8 of this embodiment comprises a rotor 28 having a reluctor and a signal coil 29 which generates a signal voltage by causing a change in magnetic flux by the rotation of the rotor 28. One cycle of signal voltage is generated only once per revolution. The signal generator 8 induces a signal during a period in which the voltage of the other half cycle in the direction indicated by the solid arrow (negative direction) is induced in the power generating coil 1 when the internal combustion engine is rotating forward, and generates the signal during the reverse rotation of the internal combustion engine In FIG. 1, a signal is induced during a period in which a voltage of one half cycle in the direction of the solid line arrow (positive direction) is induced. The mounting angle of the signal generator 8 to the engine is selected such that a signal of one polarity (positive polarity) is generated after the peak position of the short-circuit current of the power generation coil 1 in the direction indicated by the solid arrow in the drawing.

A trigger signal is given to the gate of the discharge control thyristor 6 through the signal supply circuit 11 by a signal of one polarity (positive polarity) in the direction of the solid line arrow shown in the figure obtained from the signal generator 8. Diode 9 of signal supply circuit 11
Is connected to the anode of the cutoff control thyristor 17 of the booster circuit 7, so that when the thyristor 17 is in a conductive state, a signal of one polarity obtained from the signal generator 8 is supplied to the signal supply circuit through the thyristor 17. 1
1, the trigger signal is no longer supplied to the gate of the discharge control thyristor 6.

Next, the operation of the above embodiment will be described with reference to FIGS. 2 (A) to 2 (E) show voltage waveforms at various parts in FIG. 1. In FIG. 2 (a), the waveform shown by a solid line shows the waveform at the time of normal rotation of the internal combustion engine, and the waveform shown by a broken line shows the engine Shows the waveform at the time of reverse rotation. The rotation angle θ of the engine during forward rotation is changed from left to right in the figure, and the rotation angle θ ′ during reverse rotation is changed from right to left.

In this embodiment, since the magnet generator has four poles, when the engine rotates, an AC voltage Veo (Veo ') is induced in the power generation coil 1 at two cycles per rotation.
When a voltage of one half cycle in the direction indicated by the solid line arrow (positive direction) is induced in the power generating coil 1, a base current is applied to the transistor 12 (short-circuit switch 14) through the resistor 15, and the transistor 12 is turned on. Generator coil 1
Is substantially short-circuited between the collector and the emitter of the transistor 12 and the short-circuit current detecting resistor 13. Resistance 13
The short-circuit current flowing through the rotating angle positions θ1 and θ2
When a peak value or a predetermined trigger level is reached at (θ1 ′ and θ2 ′), a trigger signal is given from the first trigger circuit 24 or the second trigger circuit 27 to the gate of the shutoff control thyristor 17, and the thyristor 17 Becomes conductive.

As a result, the transistor 12 is turned off, and the short-circuit current of the power generation coil 1 is cut off. At this time, the high voltage Ve (Ve ') induced in the power generation coil 1 causes
The ignition energy storage capacitor 3 is charged to the polarity shown. During a period in which the voltage of the other half cycle in the direction of the dashed arrow (negative direction) is induced in the power generation coil 1, the power generation coil 1 is kept in a no-load state. Therefore, the magnitude of the output voltage of the power generation coil 1 in the direction of the solid arrow shown in the drawing does not decrease in the high-speed region due to the armature reaction. The thyristor 17 is maintained in a non-conductive state during a period in which a voltage of a half cycle in the direction of the dashed arrow shown in FIG.

During normal rotation of the internal combustion engine, the signal voltage V is supplied from the signal generator 8 during the half cycle of the generator coil 1 in the negative direction.
p is output. When the signal voltage Vp is generated, the thyristor 17 is kept in the cut-off state.
A signal of one polarity (positive polarity) of the signal voltage Vp provides a trigger signal to the gate of the discharge control thyristor 6 through the signal supply circuit 11 without being bypassed. As a result, the thyristor 6 becomes conductive and the ignition energy storage capacitor 3
Is discharged to the primary coil 4a of the ignition coil 4, and at this time, sparks fly to the ignition plug 1 due to the ignition voltage induced in the secondary coil 4b of the ignition coil 4.

During the reverse rotation of the internal combustion engine, the signal generator 8 outputs the signal generating voltage Vp 'of one polarity during the half cycle of the power generating coil 1 in the forward direction. This signal voltage Vp '
Since the shut-off control thyristor 17 is in a conductive state when the occurrence of the signal, a signal of one polarity obtained from the signal generator 8 is bypassed from the signal supply circuit 11 through the shut-off control thyristor 17. Therefore, no trigger signal is given to the gate of the discharge control thyristor 6, so that the thyristor 6 does not conduct.

FIG. 2C shows the terminal voltages Vc and Vc of the ignition energy storage capacitor 3 at the time of forward rotation and reverse rotation of the engine.
The charge of the capacitor 3 does not discharge through the thyristor 6 and the primary coil 4a of the ignition coil when the engine rotates in the reverse direction.
No high voltage for ignition is induced in the next coil 4b. Therefore, the ignition operation is not performed during the reverse rotation of the engine, and the reverse rotation of the engine does not continue.

In the above embodiment, it is assumed that the magnet generator has four poles, and the generating coil 1 induces two cycles of AC voltage per one revolution of the internal combustion engine. However, in the present invention, the number of poles of the magnet generator is Optional.

In the above embodiment, the first trigger circuit 24 and the second trigger circuit 27 are provided as trigger circuits for applying a trigger signal to the cutoff control thyristor 17 of the booster circuit 7. The circuit 24 may be omitted and only the second trigger circuit 27 may be provided.

[0041]

As described above, according to the present invention, the generation of the high voltage for ignition is prevented when the engine tries to reversely rotate, so that the engine continuously rotates in the reverse direction. Can be prevented. In particular, according to the present invention, the output voltage of the power generation coil is prevented from being short-circuited, so that the output of the power generation coil is prevented from lowering due to the armature reaction, and the capacitor for storing ignition energy is sufficiently charged even at high engine speed. When the engine is running forward, there is an advantage that the ignition operation can be stably performed up to the high-speed region.

[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 voltage waveforms at various parts in FIG.

FIG. 3 is a circuit diagram showing a conventional example.

FIG. 4 is a waveform diagram showing voltage waveforms at various parts in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 generator coil 2 diode 3 capacitor for storing ignition energy 4 ignition coil 4 a primary coil 4 b secondary coil 5 ignition plug 6 thyristor for discharge control 7 booster circuit 8 signal generator 11 signal supply circuit 13 resistor for short-circuit current detection 14 short-circuit Switch (Transistor 12) 17 Interruption Control Thyristor 24 First Trigger Circuit 27 Second Trigger Circuit

Claims (1)

(57) [Scope of request for utility model registration] 1. A power generation coil provided in a magnet type alternator driven by an internal combustion engine, and is electrically connected during a period in which the power generation coil generates an output voltage of one half cycle. A short-circuit switch that short-circuits, and conducts when the short-circuit current flowing through the short-circuit switch reaches a predetermined magnitude when the generating coil generates an output voltage of one half cycle, and cuts off the short-circuit switch A shutoff control thyristor to be turned on, an ignition coil, and ignition energy storage provided on the primary side of the ignition coil and charged by a voltage induced in the power generation coil when the shorting switch is turned off. A discharge control thyristor provided to discharge the charge of the capacitor to the primary coil of the ignition coil when the capacitor is turned on; 1 per revolution of the internal combustion engine
An ignition for an internal combustion engine, comprising: a signal generator for inducing a signal of one cycle only once; and a signal supply circuit for providing a trigger signal to a gate of the discharge control thyristor by a signal of one polarity obtained from the signal generator. In the apparatus, the signal generator induces the signal of the one polarity during the other half cycle of the power generating coil when the internal combustion engine rotates forward, and during one half cycle of the power generating coil when the internal combustion engine rotates reversely. A signal of one polarity obtained from the signal generator when the shutoff control thyristor is turned on is bypassed from a signal supply circuit through the shutoff control thyristor. The ignition device for an internal combustion engine, wherein the shut-off control thyristor and the output terminal of the signal generator are connected to each other.