JPH06624Y2 - Ignition device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a capacitor discharge type ignition device for an internal combustion engine.

[Prior Art] A capacitor discharge type ignition device for an internal combustion engine is electrically connected to an ignition coil and an ignition energy storage capacitor which is provided on the primary side of the ignition coil and which is charged to one polarity by an ignition power supply circuit. At this time, the discharge control thyristor is provided so as to discharge the charge of the ignition energy storage capacitor to the primary coil of the ignition coil, and the coil that outputs a voltage of positive and negative half cycles in synchronization with the rotation of the internal combustion engine is signaled. A thyristor trigger circuit that supplies a tri signal to the thyristor as a source.

In the two-cycle internal combustion engine, the Ketchin phenomenon occurs when the ignition timing advances at a low speed, and in the case of kick start, the kick petal may be pushed back and the driver may be injured. Further, in the medium and high speed range, it is necessary to advance the ignition timing in order to improve the output of the engine.

Therefore, in the two-cycle internal combustion engine, as shown in FIG. 3, the ignition characteristic is required such that the ignition timing is delayed when the engine speed is low and the ignition timing is advanced in the middle and high speed regions.

[Problems to be Solved by the Invention] As described above, in a two-cycle engine, an ignition characteristic in which the ignition timing is retarded in a low speed region and advanced in a medium and high speed region is required. The conventional igniter has had an inevitable circuit complexity and high cost.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a capacitor discharge type internal combustion engine ignition device capable of obtaining an ignition characteristic of retarding at low speed and advancing at medium and high speed with a simple circuit configuration.

[Means for Solving the Problems] An ignition device for an internal combustion engine according to the present invention includes an ignition coil, an ignition energy storage capacitor that is provided on the primary side of the ignition coil, and is charged to one polarity by an ignition power supply circuit. , 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 conducting, and outputs positive and negative half cycle voltages in synchronization with the rotation of the internal combustion engine It is the same as the conventional ignition device of this type in that it is provided with a thyristor trigger circuit that supplies a trigger signal to the thyristor using a coil as a signal source.

In the present invention, the thyristor trigger circuit comprises an ignition timing control capacitor charged by the output of one half cycle of a coil as a signal source, and a collector-emitter circuit connected in series with the collector-emitter circuit. Ignition timing control transistor switch connected in parallel to the coil as the signal source through the current limiting element and the transistor switch through the ignition timing control capacitor at the output voltage of the other half cycle of the coil as the signal source. A transistor trigger circuit that applies a base current to turn on the transistor switch and a series circuit of a collector-emitter circuit of the transistor switch and a current limiting element detects the voltage across the coil as a signal source from the both ends of the transistor switch, Raw at both ends of the coil while it is conducting When you are voltage exceeds the setting value,
Alternatively, it is configured by a trigger signal supply circuit that gives a trigger signal to the thyristor when the voltage induced in the coil when the transistor switch is cut off exceeds a set value.

[Operation] In the above ignition device, the ignition timing control capacitor is charged to one polarity by the output of one half cycle of the coil as the signal source. In the other half cycle of the coil as the signal source, the ignition timing control capacitor is charged in the opposite direction, and the base current is supplied to the transistor switch through the capacitor. The charging of the ignition timing control capacitor in the reverse direction continues until the output voltage of the other half cycle of the coil as the signal source reaches the vicinity of the peak,
A base current is applied to the transistor switch to conduct it while the capacitor is being charged. While the transistor switch is conducting, the voltage across the coil as the signal source decreases to a voltage equal to the sum of the voltage across the transistor switch and the voltage across the current limiting element, and when the engine is running at low speed the voltage across the thyristor. It cannot exceed the set value required to trigger. When the charging of the ignition timing control capacitor is completed, the transistor switch is cut off, and the current flowing from the coil as the signal source through the transistor switch is cut off. The voltage provides a trigger signal to the thyristor. As a result, the thyristor becomes conductive and the electric charge of the ignition energy storage capacitor is discharged through the primary coil of the ignition coil to perform the ignition operation. As described above, in the low speed region of the engine, since the trigger signal is given to the thyristor when the transistor switch is cut off, the ignition timing is delayed until the transistor switch is cut off.

Further, as described above, when the engine speed is low, a high voltage is induced in the coil as the signal source by shutting off the transistor switch, and the trigger signal is given to the thyristor by this high voltage, the engine speed is low, The thyristor can be reliably triggered even when the output voltage of the coil as the signal source is low. Therefore, the number of revolutions at which the ignition operation is started can be lowered, and the starting number of revolutions of the engine can be lowered to facilitate starting of the engine.

As the rotational speed of the engine increases, the output voltage of the coil as a signal source also increases, so the voltage across the coil (the voltage across the transistor switch and the current limiting element (A voltage equal to the sum of the voltages at both ends) reaches a level at which the thyristor can be triggered, and the ignition operation is performed at the timing advanced from the low speed. Since the output voltage of the coil as a signal source increases as the rotation speed increases, the voltage at both ends of the coil reaches a level at which it can trigger the thyristor, and the angle advances as the rotation speed increases. Saturate.

Therefore, according to the present invention, as shown in FIG.
It is possible to obtain a characteristic that _i is retarded at a low speed and advanced in a medium to high speed region, and it is possible to prevent the Ketchin phenomenon from occurring.

[Embodiment] An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which IG is an ignition coil, C1 is an ignition energy storage capacitor, and S1 is a capacitor for discharging the electric charge of the capacitor C1 to the primary coil of the ignition coil when conducting. A discharge control thyristor, Le is provided in the magnet generator driven by the internal combustion engine and an exciter coil that induces an AC voltage Ve in synchronization with the rotation of the engine. D1 is an output of the exciter coil Le. A diode rectified and applied to the capacitor C1, a diode D2 that short-circuits the reverse voltage of the exciter coil Le that does not contribute to the charging of the capacitor C1, and a diode P that is attached to the cylinder of the internal combustion engine
It is a spark plug connected to the next coil. Further, Lp is a pulser coil provided in a signal generator attached to the internal combustion engine, and a trigger signal is given from this pulser coil to the thyristor S1 through the thyristor trigger circuit T.

The thyristor trigger circuit T includes an ignition timing control capacitor C2, resistors R1 to R3, and diodes D3 to D5.
And it is made up of transistor T _r 1 and a Zener diode Z1 Metropolitan.

In the trigger circuit T, the pulser coil Lp
→ Diode D3 → Resistor R2 → Capacitor C2 → Pulser coil Lp circuit forms a charging circuit that charges the ignition timing control capacitor C2 with the output voltage of one half cycle of the pulser coil Lp (voltage in the direction of the broken arrow in FIG. 1). Further, the transistor T _r 1 constitutes an ignition timing control transistor switch. Transistor T _r 1
A resistor R1 as a current limiting element is connected in series to the collector-emitter circuit of the transistor. The series circuit of the collector-emitter circuit and the resistor R1 is connected in parallel to the pulsar coil L _p , and the transistor T _r 1 The voltage across the pulsar coil Lp is reduced to a voltage equal to the sum of the voltage across the resistor R1 and the collector-emitter voltage of the transistor T _{r1 while the} transistor is conducting.

Pulsar coil Lp → ignition timing control capacitor C2 → resistor R2 → base emitter of transistor T _r 1 → pulser coil Lp circuit causes the other half cycle output voltage of the pulser coil (voltage in the direction of the solid line arrow in Fig. 1) to fire the ignition timing. A transistor trigger circuit is configured to apply a base current to the transistor T _r 1 through the control capacitor C2 to make the transistor conductive, and the transistor T1 is supplied until the capacitor C2 is completely charged by the output voltage of the other half cycle of the pulser coil Lp. _r 1 is conducting.

Further, the Zener diode Z1 and the diode D5 detect the voltage across the coil L _p as a signal source from both ends of the series circuit of the collector-emitter circuit of the transistor T _r 1 (transistor switch) and the resistor R1 (current limiting element). Then, when the voltage across the coil L _p when the transistor switch is conducting exceeds the set value, or when the transistor switch is cut off, the coil L _p
Thyristor S1 when the voltage induced in
A trigger signal supply circuit is provided which gives a trigger signal to.

In the above ignition device, the exciter coil Le outputs the alternating voltage Ve as shown in FIG. 2A, for example, in synchronization with the rotation of the engine. In one half cycle of this voltage, the capacitor C1 causes the diode D1 and the ignition coil I to
It is charged to the polarity shown through the G primary coil. The output voltage of the other half cycle of the exciter coil Le is short-circuited through the diode D2.

The pulsar coil Lp outputs, for example, a signal voltage Vp as shown in FIG. 2B, and in one half cycle of this signal voltage (a half cycle in which the voltage Vp of the polarity shown by the broken line arrow in FIG. 1 is generated). The capacitor C2 is charged to the illustrated polarity through the diode D3 and the resistor R2.

When the pulsar coil Lp induces the voltage of the other half cycle, the base current is supplied from the pulsar coil to the transistor T _r 1 through the capacitor C2 and the resistor R2, and the transistor T _r 1 becomes conductive. When the positive half-cycle induced voltage of the pulser coil Lp reaches a peak, the reverse charging of the capacitor C2 is completed, and the supply of the base current to the transistor T _r 1 is stopped, so that the transistor is turned off. In FIG. 2 (C), the ON level period is
It indicates a period in which the base current is applied (period in which the transistor T _r 1 may be conductive) to the transistor T _r 1.

While the transistor T _r 1 is conducting, the pulsar coil Lp
Across the resistor R1 to a voltage V1 equal to the sum of the voltage across the resistor R1 and the collector-emitter voltage of the transistor T _r 1. The waveform of the voltage V1 across the pulsar coil Lp when the rotation speed N is N1 and N2 (<N1) is shown in FIG. 2 (D). While the engine rotation speed N is low (N = N1) and the induced voltage of the pulsar coil Lp is low, the voltage across the pulsar coil when the transistor T _r 1 is conducting is the zener voltage V _z 1 of the zener diode Z1 (accurately). Cannot reach a voltage obtained by adding the forward voltage drop of the diode D5 and the gate-cathode voltage drop of the thyristor S1 to the zener voltage V _z1 ). Therefore, the thyristor S1 is turned on while the transistor _Tr 1 is conducting. The trigger signal is prevented from being given. When the induced voltage of the pulsar coil reaches a peak at the angle θ1 and the transistor T _r 1 is cut off, a high voltage is momentarily induced in the pulsar coil Lp, so that the Zener diode Z1 becomes conductive and as shown in FIG. 2 (E). A trigger signal is applied from the pulser coil Lp to the thyristor S1 at an angle θ1. As a result, the thyristor S1 becomes conductive, and the charge of the ignition energy storage capacitor C1 is discharged through the thyristor S1 and the primary coil of the ignition coil IG. As a result, a high voltage is induced in the secondary coil of the ignition coil, a spark is generated in the ignition plug P, and the engine is ignited.

Thus, at low engine speeds, the trigger signal of the thyristor S1 is prevented from being supplied while the transistor T _r 1 is conducting, and the charging of the ignition timing control capacitor C2 in the reverse direction is completed and the transistor The high voltage induced in the pulsar coil when T _r 1 is cut off causes the thyristor S
Since the trigger signal is supplied to 1 and the ignition operation is performed,
The ignition timing of the engine is retarded.

In this embodiment, the diode D4 is connected between the collector of the transistor T _r 1 and the gate of the thyristor S1 so that the transistor T _r 1 is cut off and the pulsar coil L _p is cut off.
When high voltage is induced, the resistance from the coil L _p R1
The trigger signal can also be supplied to the thyristor S1 by a circuit that reaches the gate of the thyristor S1 through the diode D4 and the diode D4. In this way, the diode D4 is provided so that when the transistor T _r 1 is cut off, the coil L _p
When the resistance value of the resistor R1 is set so that the trigger signal can be supplied from the coil L _p to the thyristor S1 through the resistor R1 and the diode D4 when the voltage induced in the coil does not reach the Zener voltage of the zener diode Z1. Although it becomes possible to trigger the thyristor S1 at a lower rotation speed, a circuit for supplying a trigger signal to the thyristor S1 through the resistor R1 and the diode D4 is not necessarily required in the present invention.

When the rotation speed of the engine rises and, for example, N = N2, the induced voltage of the pulsar coil Lp rises, so that the transistor T
_{While r} 1 is conducting, voltage V1 across pulsar coil Lp
Exceeds the Zener voltage of the Zener diode Z1, and as shown in FIG. 2 (E), the voltage across the pulser coil is increased at an angle θ2 that leads the phase from the angle θ1 (the angle at which the output of the pulser coil reaches its peak). V1 comes to a trigger signal is applied to the thyristors S1 exceeds the Zener voltage V _z 1 of the Zener diode Z1. Since the position where the voltage across the pulser coil Lp exceeds the Zener voltage of the Zener diode Z1 advances with the rise of the induced voltage of the pulser coil accompanying the rise of the rotation speed, the ignition timing advances with the rise of the rotation speed. To go. The advance amount in this case is determined by the width of the output voltage of the pulsar coil Lp,
When advanced by a predetermined amount, the ignition timing becomes substantially constant. When the transistor T _r 1 is conducting, the potential of the anode of the diode D4 is kept substantially at the ground potential, and the circuit that supplies the trigger signal from the pulsar coil L _p to the thyristor through the resistor R1 and the diode D4 does not work. In the advance angle region, the trigger signal is given from the pulser coil L _p to the thyristor S1 through the Zener diode Z1 and the diode D5.

In the above embodiment, the rotational speed at which the advance operation is started can be adjusted by changing the resistance value of the resistor R1 or the Zener voltage of the Zener diode Z1. Further, the advance width α (see FIG. 3) can be changed by changing the output signal waveform of the pulsar coil Lp.

In the above embodiment, the pulsar coil Lp is provided separately from the exciter coil that charges the ignition energy storage capacitor.
And a thyristor S using the pulsar coil as a signal source.
Although the trigger signal is given to No. 1, the present invention can be applied to an ignition device of the type in which the exciter coil is also used as a signal source.

FIG. 4 shows an embodiment in which the present invention is applied to a pulsarless type ignition device in which the pulsar coil is omitted by sharing the exciter coil with the power source for charging the capacitor for storing the ignition energy and the signal source for giving the trigger signal to the thyristor. Is shown. In this embodiment, the pulser coil is omitted, and the exciter coil Le is connected between one end of the capacitor C2 on the zener diode Z1 side and the anode of the diode D1. The other points are similar to those of the embodiment shown in FIG.

In the embodiment of FIG. 4, in one half cycle of the exciter coil Le, a current flows in the path of the exciter coil Le → diode D1 → capacitor C1 → primary coil of the ignition coil → diode D3 → resistor R2 → capacitor C2. The capacitors C1 and C2 are charged. Then, in the other half cycle of the exciter coil Le, a base current flows through the transistor T _r 1 along the path of the exciter coil Le → capacitor C2 → resistor R2 → base of the transistor T _r 1 and emitter → diode D2 → exciter coil Le, and The transistor T _r 1 becomes conductive. Because while the voltage across the coil Le drops to transistor T _r 1 is conducting, during low-speed engine, the trigger signal during thyristors S1 to the transistor T _r 1 is conducting is applied is prevented, ignition operation is performed trigger signal is given to the thyristor S1 is a high voltage induced in the coil Le when the charging of the capacitor C2 is cut off transistor T _r 1 is completed. When the induced voltage of the exciter coil Le increases with the increase of the rotation speed of the engine, and the voltage across the exciter coil Le exceeds the Zener voltage of the Zener diode Z1 while the transistor T _r 1 is conducting, Advance of ignition timing is started.

[Advantage of the Invention] As described above, in the internal combustion engine ignition device according to the present invention, the collector-emitter circuit has the transistor switch connected to both ends of the coil as the signal source through the current limiting element, and one of the coils. An ignition timing control capacitor charged with an output of a half cycle, and a transistor for applying a base current to the transistor switch through the ignition timing control capacitor at the output voltage of the other half cycle of the coil as the signal source to make the transistor switch conductive. The voltage across the coil as a signal source is detected from both ends of the series circuit of the trigger circuit, the collector-emitter circuit of the transistor switch, and the current limiting element, and the voltage is applied to both ends of the coil while the transistor switch is conducting. When the generated voltage exceeds the set value or when the transistor switch A trigger signal supply circuit that provides a trigger signal to the discharge control thyristor when the voltage induced in the coil exceeds the set value when the coil is cut off, and when the engine is operating at low speed, the other half of the coil as the signal source is provided. When the output of the cycle peaked and the transistor switch was cut off, the trigger voltage was applied to the thyristor with the high voltage induced in the coil, so that the other half of the coil as the signal source was operated at low engine speed. The ignition timing can be retarded to almost the peak position of the output of the cycle. Further, in the medium to high speed region of the engine, the timing of triggering the thyristor can be advanced with the increase of the output voltage of the coil as the signal source, so that the ignition timing can be advanced with the increase of the rotation speed.

Therefore, according to the present invention, the ignition timing is retarded at the low speed and the ignition timing is controlled at the middle and high speed regions by the relatively simple circuit configuration including the transistor switch for controlling the ignition timing and the charging / discharging circuit of the capacitor for controlling the ignition timing. The characteristic of advancing can be obtained.

Further, according to the present invention, a high voltage is induced in the coil as a signal source by shutting off the ignition timing controlling transistor switch at a low speed, and the trigger signal is given to the thyristor by this high voltage. Is low and the voltage induced in the coil as the signal source is low, the thyristor can be reliably triggered. Therefore, the number of revolutions at which the ignition operation is started can be lowered, and the starting number of revolutions of the engine can be lowered to facilitate starting of the engine.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing signal waveforms of respective portions of FIG. 1 and operation timings of transistor switches, and FIG. 3 is obtained by the embodiment of FIG. FIG. 4 is a diagram showing an example of ignition characteristics, and FIG. 4 is a circuit diagram showing another embodiment of the present invention. IG ... Ignition coil, P ... Spark plug, C1 ... Ignition energy storage capacitor, C2 ... Ignition timing control capacitor, R1-R3 ... Resistors, D1-D5 ... Diode, Le
... exciter coil, Lp ... pulser coil, T _r 1 ...... transistor.

Claims (1)

[Scope of utility model registration request] 1. An ignition coil, an ignition energy storage capacitor provided on the primary side of the ignition coil and charged to one polarity by an ignition power supply circuit, and a charge of the ignition energy storage capacitor when electrically connected. And a discharge control thyristor provided to discharge the primary coil of the ignition coil, and a coil that outputs positive and negative half cycle voltages in synchronization with the rotation of the internal combustion engine as a signal source to give a trigger signal to the thyristor. In an internal combustion engine ignition device including a thyristor trigger circuit, the thyristor trigger circuit includes an ignition timing control capacitor charged by an output of one half cycle of a coil as the signal source, and a collector-emitter circuit. Through the current limiting element connected in series to the collector-emitter circuit, to the coil as the signal source And an ignition timing control transistor switch connected in parallel, and a base current is applied to the transistor switch through the ignition timing control capacitor at the output voltage of the other half cycle of the coil serving as the signal source to switch the transistor switch. A period in which the transistor switch is conducting by detecting the voltage across the coil as the signal source from both ends of a series circuit of a transistor trigger circuit for conducting and a collector-emitter circuit of the transistor switch and a current limiting element. A trigger signal supply circuit that gives a trigger signal to the thyristor when the voltage generated at both ends of the coil exceeds a set value, or when the voltage induced in the coil when the transistor switch is cut off exceeds the set value. An ignition device for an internal combustion engine, comprising: