JPS6019960A - Ignition device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To keep off a power wastage, by detecting the charging state of a capacity discharge energy storage condenser for a current cutoff capacity discharge combined type ignition device, while controlling the working time of a booster circuit. CONSTITUTION:In time of engine starting, a transistor 30 is energyzed with a continuous rating current at T time late from the start of charging a condenser 29, and a power source is fed to a DC-DC converter 2, thus a condenser 3 is charged. When charging voltage to reference voltage comes to the specified one, a comparator 26 turns to an L level, making the transistor 30 nonconductive, whereby power supply to the converter 2 is stopped. With this constitution, oscillation in the DC-DC converter takes place as delayed for the specified time after discharge of the condenser 3 is all over, and when the charging voltage of the condenser 3 reaches to the preset voltage, it is stopped so that watt consumption is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition system for an internal combustion engine, and more particularly to an improvement of a current interrupting capacitive discharge combined type ignition system that combines a current interrupting type and a capacitive discharge type.

FIG. 1 shows a general current interrupting capacity discharge composite type ignition device, where l indicates a power source battery, A indicates a capacity discharging section, and B indicates a current interrupting section. Capacity discharge section A is a DC-DC that boosts the voltage of the power supply battery.
It has a converter (step-up circuit) ′.

The operation of this was proposed by the inventor in the patent application filed in 1205-1985.
65 (4? Kaisho 59-), so please refer to it for details.To summarize, when the interrupter 6 is closed, the current interrupting transistor is in the ON state, and the ignition coil 701 A current flows through the winding g. At this time, the capacitor 3 is charged by the DC-DC converter with the polarity shown in the drawing.

When the engine rotates and the interrupter 6 opens, the left current interrupting transistor (first switching element) turns OFF, and the primary current of the ignition coil is interrupted.

At this time, the voltage generated in the pulse transformer // turns on the thyristor (second switching element) lI, and the charge in the energy storage capacitor 3 flows to the primary winding g of the ignition coil 70. The voltage generated by current interruption and the voltage generated by capacitor discharge are combined to have the same polarity and phase, so a synergistic voltage is generated in the secondary winding 9 of the ignition coil 7, and a spark is generated at the ignition plug 10. fly.

In such an ignition device that generally has a capacitive discharge circuit, the semiconductor switching element becomes conductive and the secondary side of the oscillation transformer of the capacitor converter becomes short-circuited.

As a result, the DC-DC converter becomes overloaded9, causing excessive current to flow through the oscillation transistor, consuming power, and causing abnormal heat generation, which may lead to destruction. Further, during low-speed operation, as shown in FIG. 2, the DC-DC converter continues to oscillate even though the charging voltage of the capacitor is saturated. Therefore, it is not desirable to cause the DC-DC converter to oscillate even after the charging voltage is saturated, as this not only wastes unnecessary power but also causes a rise in the temperature of the entire ignition system.

Therefore, in view of the above-mentioned problems, an object of the present invention is to provide a current interrupting capacity discharge combined type ignition device that does not waste power by forcibly stopping the oscillation of a DC-DC converter with the charging pressure of a capacitor. shall be.

FIG. 5 shows an embodiment of the present invention, and parts having the same functions as those in FIG.

:l/,,2λ is a voltage dividing resistor that divides the charging voltage of capacitor 3 and adds it to the inverting input terminal 0 of comparator circuit 2B.
The power supply voltage is divided by a resistor, 23", and applied to the non-inverting input terminal (G) of the comparator circuit, and compared with the reference voltage to determine the state of charge. 2S is a resistor for creating hysteresis.
27 is a load resistance of the comparator circuit, and the output of the comparator circuit is added to the base of a transistor 30 via an integrating circuit consisting of a resistor 2g and a capacitor 9 to form a delay circuit, and the collector of this transistor 30 is connected to a DC=DC converter. Controls a control transistor 31 that controls power supply.

Next, the operation of the embodiment shown in FIG. 5 will be explained with reference to the voltage waveform diagram of each part shown in FIG. (11) in FIG. 4 is a waveform showing the open/closed state of interrupter B. When starting the engine for the first time, capacitor 3 is not yet charged at this time, so the output of comparator circuit 2B is "high level", so capacitor 9 is connected to capacitor and resistor 27 as shown in the waveform. , 2g. Then, if the operating point of transistor 3θ is set to point A of the waveform, transistor 3θ is a capacitor, 2? becomes conductive after a delay of T time from the start of charging, thereby lowering the base potential of control transistor 31 and making control transistor 3/ conductive.

Therefore, power is supplied to the DC-DC converter tacho, and at the same time as it starts oscillating as shown in waveform (A), the capacitor 3 is charged as shown in waveform (g). This charging voltage is divided by resistors 2/, , 2, and the power supply voltage is divided by resistors 3. Divide the voltage in detail and set this as a reference voltage, and set it so that when the charging voltage reaches a predetermined voltage with respect to this reference voltage, the output of comparator circuit 6 becomes "low level". . If the comparator circuit is set as described above, when the capacitor 3 is charged, the transistor 30 becomes non-conducting, and the control transistor 3/ also becomes non-conducting, causing the comparator to become non-conductive.
The power supply to the octopus is stopped, thereby stopping the oscillation.

Next, when the interrupter 6 is opened, a pulse is output from the pulse transformer /l, which interacts with the gate current of the thyristor Hiro as shown in the waveform (j) to make the thyristor Hiro conductive. As a result, the charge in the capacitor 3 is released to the primary coil of the ignition coil 7, and the ignition coil sends a waveform (i) to the secondary coil.
) outputs a voltage waveform. When the capacitor 3 is discharged and the charge becomes zero, the output of the comparator circuit becomes "high level" again, and the transistor 30 becomes conductive with a slight delay due to the aforementioned time constant circuit. Power supply to the DC converter tacho is resumed.

As explained above, the oscillation of the DC-DC converter tacho starts after the conduction of the thyristor Hiroshi is completed, that is, after the discharge of the capacitor 3 is completed, and a predetermined delay time elapses. It is stopped when the voltage is reached.

In this way, in the present invention, the oscillation period of the DC-DC converter is kept to the minimum necessary without reducing the energy at the time of ignition, so power consumption is greatly improved compared to conventional devices. is clear.

Further, by making the resistor details variable as shown in the figure, the charging voltage of the capacitor can be freely changed, thereby providing an ignition device in which the spark energy of the ignition coil is variable.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of a conventional current interrupting capacity discharge combined type ignition device, FIG. 2 is a waveform diagram explaining the same operation as above, and FIG. 6 is a circuit configuration diagram of an ignition device according to an embodiment of the present invention. Fig. 4 is a waveform diagram explaining the operation of the same as above, in which A is a capacitive discharge section, B is a current cutoff section, ko is a DC-DC converter which is a booster circuit, 3 is an energy storage capacitor, and ψ is a second 2g is a thyristor which is a switching element; 5 is a cutoff transistor which is a first switching element; 7 is an ignition coil; g is its primary winding; 29, 30, 3/ are comparison circuits forming the control circuit;
Showing resistors, capacitors, and transistors.

Claims (1)

[Scope of Claims] (1) A current interrupting section having a first switching element that interrupts the current in the primary winding of the ignition coil at the ignition timing in synchronization with the rotation of the engine; a booster circuit; an energy storage capacitor; A current interrupting and capacitive discharging compound having two switching elements, and a capacitive discharging section that causes the second switching element to flow the charged charge of the sien- ergy storage capacitor to the primary winding of the ignition coil at the ignition timing in synchronization with the rotation of the engine. The ignition system for an internal combustion engine of the above type is equipped with a detection circuit that detects the state of charge of the energy storage capacitor of the capacitive discharge section, and a control circuit that controls the operating time of the booster circuit based on the detection output of this detection circuit. Characteristics of the ignition system for internal combustion engines. (2. In the ignition system for an internal combustion engine according to claim (1), the control circuit determines to output when the output signal of the detection circuit corresponding to the state of charge of the capacitor reaches a predetermined signal level. An ignition device for an internal combustion engine, comprising: a circuit; and a sixth semiconductor switching element to which the output of the determination circuit is connected via a delay circuit and controls the operation time of the booster circuit. (3) Patent The ignition system for an internal combustion engine according to claim (2), wherein the control circuit includes a determination circuit that outputs the output signal of the detection circuit corresponding to the state of charge of the capacitor according to a selectively selectable signal level. Ignition system for internal combustion engines.