JP3136407B2 - Capacitor charge / discharge igniter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reverse rotation prevention circuit for a capacitor charge / discharge type ignition device.

As shown in FIGS. 2 (a) and 2 (b), this kind of conventional device outputs a high positive signal following a low negative signal during normal rotation, and a high negative signal following a low positive signal during reverse rotation. Using a pulsar coil that outputs a signal, a signal voltage difference is produced between the normal rotation direction and the reverse rotation direction, and a circuit as shown in FIG. 1 is used to prevent ignition at the time of reverse rotation.

That using a circuit including transistors Q ₁ to ON-OFF of the gate circuit of the reverse bias circuit and thyristor S ₁ including the capacitor C ₂ of FIG. 1 a resistor R _3, the capacitor C due to the negative polarity signal pulser coil during forward rotation _second charging voltage level, the transistor Q ₁ lower than the positive polarity signal from the pulser coil coming next is not reverse biased, thyristors S ₁
Receives the signal of the pulsar coil and fires. Also, at the time of reverse rotation, since the negative polarity signal from the pulsar coil is higher than the positive polarity signal level, the voltage level charged in the capacitor C ₂ is high, and the transistor Q ₂ is reverse-biased and does not receive the positive polarity signal from the pulsar coil. ₁ does not fire.

However, this circuit has a drawback that forward and reverse rotation detection becomes unstable due to variations in the signal level of the pulsar coil output voltage.

The present invention eliminates the instability due to the variation of the positive and negative signal levels from the conventional pulsar coil, so that the signal voltage level is not detected, and the reversal by determining the firing state of the thyristor based on the number of positive and negative pulses. This is to prevent ignition at the time.

FIG. 3 shows an embodiment of the present invention, wherein I is a basic circuit of a capacitor charge / discharge type ignition device, and an exciter coil EX
Capacitor C a positive half-wave voltage of T via the diode D ₁
Charge ₁ At the same time diode D _3, through a resistor R ₁ and held in the voltage of the zener diode Z ₁ charges the capacitor C _2, to form an arc power supply point will be described later thyristor S1. On the other hand, the negative half-wave voltage of the coil EXT is short-circuited by the diode D2. Next, the pulsar coil PC is preset so that the output signal waveform is shifted by 90 ° from the phase of the exciter coil EXT. Thus when negative half wave cycle of the exciter coil is held voltage before positive half wave capacitor C ₂ charged during the timing of the signal waveform at this time pulser coil, i.e. thyristors S1 during negative cycles of the exciter coil-on Or, it is controlled so as to be kept off. II is part of the present invention, the timing signal input from the pulser coil PC, forward, to determine the reverse rotation, firing the thyristors S ₁ by the transistor Q ₁ in the positive waveform timing of the pulser coil output during forward rotation Circuit.

To operate this, a pulser coil output waveform as shown in FIG. 4A is input from a PC. First, at the time of forward rotation, the output waveform of the pulsar coil is input in the order of negative waveform → positive waveform → negative waveform. The first time the negative waveform is input, detected by the transistor Q _2, through transistor Q _3, to charge the capacitor C ₅ at a time constant of R _6, R _5. Then when a positive waveform is input is detected by the transistor Q ₄ to discharge the capacitor C ₅ at a time constant of R _7, R ₅ to the forward voltage of the diode D _6. Now negative waveform is input, R ₆ through the transistor Q _3,
A time constant of R ₅ to charge the capacitor C _5. After that capacitor C ₅ charges are held. Result pulser coil output as is input, when When constant _{R 6 .C 5 = R 7 .C} 5,
Charges the capacitor C ₅ at a level which has been charged with R ₆ .C ₅ is held until the next pulser coil output is input, each time the pulser coil output is input, the capacitor C ₅
Because charges are gradually charged constant fraction when R ₆ .C _5, eventually IC2
Of reaching threshold level of the gate opening, the output becomes LOW pulsar coil output of the positive waveform at the timing t ₁ input IC 2, thyristors S ₁ through the transistor Q ₁
Is fired.

Next, at the time of reverse rotation, the pulser coil output is a positive waveform → negative waveform → positive waveform input from the PC. When a positive waveform is input, it detected by the same transistor Q _4, to discharge the capacitor C ₅ to the forward voltage of the diode D ₆ with a time constant of R _7, C ₅ through the transistor Q _4. Now negative waveform is input is detected by the transistor Q _2, charges the capacitor C ₅ at a time constant of R _6, R ₅ through the transistor Q _3. Now positive waveform is input through the transistor Q _4, to discharge the capacitor C ₅ to the forward voltage of the diode D ₆ with a time constant of R _7, C _5. Then the charge in the capacitor C ₅ is held. As a result after pulser coil output is the capacitor C ₅ is not charged only the forward voltage of the diode D _6, does not reach the threshold level of the gate opening of the IC2, the thyristor is always a High output of IC2 is quite Not fired.

With this configuration, the ignition is performed at the positive waveform timing of the pulsar coil output during normal rotation, and is not fired at all during reverse rotation, and no pulse is generated in the ignition coil ING.

Therefore, the present invention can be applied to a capacitor charge / discharge type ignition device that can prevent malfunction due to an ignition pulse at the time of reverse rotation.
Utilizing the fact that there is a difference in the output form between the pulsar coil output in the normal rotation direction and the reverse rotation direction, the output form of the pulsar coil is converted to a voltage level, so that it is possible to easily distinguish between forward rotation and reverse rotation. . By utilizing this, the present invention can be applied to a capacitor charge / discharge type ignition device that requires prevention of ignition at the time of reverse rotation.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a conventional capacitor charge / discharge type ignition device,
FIG. 2 is a signal waveform of the pulsar coil, FIG. 3 is a circuit diagram of the capacitor charge / discharge type ignition device of the present invention, and FIG. 4 is an operation waveform of the present invention. In FIG, D ₁ ~D ₆ ...... rectifying diode, S ₁ ...... firing thyristors, C ₁ ...... ignition capacitor, R ₁ ~ ₁₀ ...... resistance, Q ₁ ...... firing transistor , Q ₂ , ₃ , ₄ ... switching transistors, C ₂ to ₄ ... capacitors, C ₅ ...
… Level conversion capacitor, IC1 …… Inverter IC, IC2
…… Nando IC.

Claims (1)

(57) [Claims] The charge of a capacitor charged via a diode for rectifying a positive half-wave voltage of an output of an exciter is discharged by a thyristor fired during a negative half-wave cycle of the output of the exciter. In a capacitor charge / discharge ignition system, a positive signal is output following a negative signal when the engine rotates forward, and a negative signal is output after that, and a positive signal follows when the engine reverses. The output voltage of a charge / discharge circuit that charges with the negative signal and discharges with the positive signal, using the signal of the pulsar coil that outputs a signal of the negative polarity and subsequently outputs the signal of the positive polarity, The ignition signal control switch means for enabling the gate signal of the thyristor to be ignited only during normal rotation of the engine by the logical product output of the thyristor Capacitor discharge ignition system that is characterized in that allowed to ignite.