JPH0375752B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an ignition device.

Conventionally, when the engine speed drops to the point where the engine stops when the ignition system is in operation, if the engine ignites before top dead center just before stopping, it becomes even more difficult to cross top dead center, and the crankshaft movement becomes less smooth. , the vehicle may shake or come to a standstill.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ignition device that inhibits the ignition operation when the engine rotates at a very low speed, thereby suppressing the shaking of the vehicle body especially when the engine is stopped.

a pickup means for generating first and second timing pulses of mutually different polarities in synchronization with the rotation of the internal combustion engine such that as the engine rotational speed increases, the interval between occurrences of the first and second timing pulses becomes shorter; an ignition control means for generating an ignition control signal in response to the first and second timing pulses; and an ignition control means for generating a spark discharge in a spark plug connected to a secondary winding when a back electromotive force signal is generated in the primary winding. an ignition drive means connected to the primary winding and configured to interrupt the current flowing through the primary winding in response to an ignition control signal and generate a back electromotive force signal in the primary winding; and a first timing pulse. A constant time width pulse is generated in response to the constant time width pulse, and when a second timing pulse is generated outside the generation period of the constant time width pulse, the back electromotive force signal is suppressed, and the engine rotation speed is lower than the idle rotation speed of the engine. The present invention is characterized in that it includes a prohibition means configured to prohibit spark discharge when the following conditions are met.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the present invention. In the figure, 1 is a battery, 2 is a main switch, 3 is a starter switch, 4 is a starter relay, 5 is a starter motor, 6 is an ignition coil, and 7 is a spark plug. A rotor 8 has a projection 8a and is made of a ferromagnetic material, and rotates together with a crankshaft of an engine (not shown).
Reference numeral 9 designates an electromagnetic pickup arranged close to the rotor 8, in which a pulser coil 11 is wound around a magnetic core 10 and is biased by a permanent magnet 12. The rotor 8 rotates in the direction of the arrow in the figure, and its protrusion 8
When a passes in front of the magnetic core 10 of the electromagnetic pickup 9, a timing pulse (synchronization signal) having a waveform as shown in FIG. 2 is generated at the output end of the pulser coil 11. In FIG. 2, a positive timing pulse a is generated when the front end of the projection 8a faces the magnetic core 10 of the electromagnetic pickup 9, and a negative timing pulse b is generated when the rear end of the projection 8a faces the magnetic core 10. The phase of the crankshaft at the time of generation of each timing pulse a and b corresponds to the most advanced ignition timing (advance end timing) θa and the latest ignition timing (initial ignition timing) θb of the advance angle characteristics shown in Fig. 3. The angle of the protrusion 8a of the rotor 8 and the angle of attachment to the crankshaft are set so that.

13 is an ignition circuit in which timing pulses a,
an ignition control circuit 14 that generates an ignition control signal based on b, and a primary winding 6 of the ignition coil 6;
a power transistor Q1 which is connected in series with the ignition control signal Q1 and turns off in response to the ignition control signal to generate high voltage in the secondary winding 6b of the ignition coil 6 and cause a spark discharge in the spark plug ₇ ; A prohibition circuit 1 that prohibits spark discharge at the spark plug 7 regardless of the generation of the ignition control signal when the rotation speed is below a predetermined rotation speed lower than the idle rotation speed.
5, and a driving power supply section 16 for an ignition control circuit 14 and an inhibition circuit 15.

In the inhibition circuit 15, the transistor Q ₂ and the Zener diode ZD ₁ are connected to the power transistor Q ₁
is connected in series between the collector and the base. The Zener diode ZD ₁ has a Zener voltage Vz that is higher than the output voltage of the power supply section 16, for example, 20V so as not to normally conduct. Resistors R _{1 ,} R ₂ and transistor Q ₃ are connected in series between the emitter of transistor Q 2 and ground, and the base of transistor Q ₂ is connected to a common connection point of resistors R ₁ and R ₂ . The base of transistor Q ₃ is connected to the output end of power supply section 16 via resistor R ₃ . One end of the capacitor C ₁ is connected to the base of the transistor Q ₃ , and the other end of the capacitor C ₁ is connected to the output end of the power supply section 16 via a resistor R ₄ and also to the collector of the transistor Q ₄ . transistor
The emitter of Q ₄ is grounded and its base is resistor R ₅
It is connected to the output terminal of the power supply section 16 via a resistor _R6 , and further connected to the collector of the transistor _Q3 via a resistor _R7 . A positive timing pulse a (FIG. 2) is applied to the base of transistor Q ₄ via resistor R ₈ and diode D.

In this configuration, each resistance value is set so that the transistor _Q4 is turned on only when a positive timing pulse a is generated. transistor
When _Q4 is off and transistor _Q3 is on, capacitor _C1 is charged through resistor _R4 , and when a positive timing pulse a occurs and transistor _Q4 is on, capacitor C1 is charged. ₁ is charged, the positive side is the transistor
is grounded through Q ₁ and biases the base of transistor Q ₃ deeply negative, so that
Q ₃ is in the off state. In this state, the capacitor
The charge on C ₁ is discharged through resistor R ₃ and is held for a time T until the base voltage of transistor Q ₃ recovers to the threshold voltage. During that period T, the collector voltage of transistor Q ₃ is The level becomes high as shown in each c of FIGS. 4 and 5. Here, the time T is determined by the capacitor _C1 and the resistor _R3 , and when the engine speed is a predetermined speed number lower than the idling speed, the time T is determined by the negative timing pulse from the time when the positive timing pulse a is generated. It is set to correspond to the time until the timing pulse b is generated.

The power supply unit 16 is composed of a capacitor C ₂ charged by battery voltage via a resistor R ₉ and a Zener diode ZD ₂ for charging the capacitor C ₂ with a constant voltage.

Next, the operation of the present invention will be explained.

If the engine speed exceeds a predetermined speed number lower than the idle speed, as shown in Figure 4,
When the time Ta from the generation of the positive timing pulse of the pulsar output a to the generation of the negative timing pulse is short compared to the time T during which the collector voltage c of the transistor _Q3 is at a high level, and the engine speed increases. The time Ta becomes even shorter,
During time T, transistor _Q2 is in the off state;
Normal ignition operation takes place. That is, the ignition control circuit 14 generates an ignition control signal as shown in FIG. 4b in response to the pulsar output as shown in FIG. 1 of the ignition coil 6 at the timing when the power transistor _Q1 shifts from the on state to the off state.
A very large back electromotive force is generated in the secondary winding 6a as shown in FIG.
Since a high voltage is generated which is twice the turn ratio of the secondary winding 6a and the secondary winding 6b, spark discharge occurs in the ignition plug 7.

On the other hand, when the engine speed falls below the predetermined speed No., as shown in FIG _.
With respect to the time T during which the collector voltage c is at a high level, the time Tb from the time when the positive timing pulse of the pulsar output a is generated until the time when the negative timing pulse is generated becomes longer, and the time when the negative timing pulse is generated, that is, At the ignition timing, transistor _Q2 is in the on state, so ignition operation is prohibited. That is, when the power transistor _Q1 is turned off at the ignition timing when the ignition control signal b changes from high level to low level, a back electromotive force is generated in the primary winding 6a of the ignition coil 6, but this voltage is Since it is fed back to the base of _the power transistor Q1 through the transistor _Q2 and the Zener diode _ZD1 , the power transistor
The collector voltage d of Q ₁ , that is, the primary voltage of the ignition coil 6 is approximately the Zener diode ZD ₁
Therefore, the secondary voltage of the ignition coil 6 is suppressed to a low voltage, and no spark discharge occurs in the ignition plug 7.

Therefore, if the engine speed drops to the point where the engine stops while the ignition system is in operation, ignition operation will be automatically prohibited, and no reverse torque will be generated on the crankshaft. Instead, the engine will stop naturally. Further, since the ignition operation is prohibited not only when the engine is stopped but also when the engine is started and rotates at a very low speed, it is possible to prevent the engine from reversing due to the generation of reverse torque.

FIG. 6 is a circuit diagram showing another embodiment of the present invention. In this embodiment, the output of the starter switch 3 is applied to the base of the transistor _Q4 via the resistor _R10 . The rest of the configuration is exactly the same as in FIG. 1. According to this configuration, when the starter switch 3 is turned on, a starter signal of approximately battery voltage is applied to the base of the transistor _Q4 , turning on the transistor _Q4 and turning off the transistor _Q3 regardless of the level of the engine speed. , will not adversely affect engine starting.

As explained above, according to the present invention, the ignition operation is prohibited regardless of the generation of the ignition control signal when the engine speed is below a predetermined speed lower than the idle speed, so that, for example, the engine stops. Even when the engine speed is extremely low, smooth movement of the crankshaft can be maintained, and shaking of the vehicle body can be suppressed, especially when the engine is stopped.

[Brief explanation of drawings]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing an embodiment of the present invention.
The figure is the output waveform diagram of the pulsar coil in Figure 1,
FIG. 3 is a diagram showing advance angle characteristics, FIGS. 4 and 5 are waveform diagrams for explaining the operation of FIG. 1, and FIG. 6 is a circuit diagram showing another embodiment of the present invention. Explanation of the symbols of the main parts, 1...Battery, 2...
...Starter switch, 4...Starter relay, 6
...Ignition coil, 7...Spark plug,
11... Pulsar coil, 14... Ignition control circuit,
15...Prohibited circuit.

Claims (1)

[Claims] 1. Pickup means for generating first and second timing pulses of mutually different polarities in synchronization with the rotation of the internal combustion engine such that as the engine speed increases, the interval between occurrences of the first and second timing pulses becomes shorter; , ignition control means for generating an ignition control signal in response to the first and second timing pulses; and generating a spark discharge in a spark plug connected to a secondary winding when a back electromotive force signal is generated in the primary winding. The ignition coil and
is connected to the primary winding and interrupts the current flowing through the primary winding in response to the ignition control signal.
ignition driving means for generating the counter electromotive force signal in a second winding; and generating a constant time width pulse in response to the first timing pulse, and generating the second timing pulse outside the generation period of the constant time width pulse. and inhibiting means for suppressing the back electromotive force signal when the engine speed is lower than the idle speed of the engine, and inhibiting the spark discharge when the engine speed is lower than the idle speed of the engine. .