JPH0670427B2 - Ignition device for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ignition device for an internal combustion engine mainly used in automobiles.

[Conventional technology]

Conventionally, in the one in which the power transistor is turned on and off by the ignition signal from the engine control unit to interrupt the primary current of the ignition coil, the voltage induced in the collector of the power transistor becomes a predetermined value or more when the power transistor is cut off. It has been considered that a trigger signal is generated in the trigger circuit and the trigger signal is supplied to the engine control unit as an ignition monitor signal (for example, Nippon Denso Public Technical Report, reference number 37-
063).

[Problems to be solved by the invention]

However, during spark discharge after the power transistor is cut off, noise voltage is induced on the primary side of the ignition coil due to disturbance of the spark discharge current, and this noise voltage may exceed the predetermined value of the trigger circuit depending on the engine operating condition. However, in such a case, there is a problem that a trigger pulse is generated a plurality of times within one ignition interval or the pulse width is extended, so that a correct ignition monitor signal cannot be generated.

Therefore, the present invention generates one correct ignition monitor signal within one ignition interval.

[Means for solving problems]

In view of the above problems, the present invention provides a transistor drive circuit that generates a rectangular wave output in response to an ignition signal, and a power transistor that turns on and off by the rectangular wave output of the transistor drive circuit to interrupt the primary current of the ignition coil. , A trigger circuit that generates a trigger signal when the voltage induced in the collector of the power transistor becomes a predetermined value or more when the power transistor is cut off, a trigger signal of the trigger circuit, and a signal from the transistor drive circuit side. , The gate is opened by the signal on the side of the transistor drive circuit only during the interruption period of the power transistor just after the interruption of the power transistor, and the gate which outputs the trigger signal output from the trigger circuit during this period. Circuit and the ignition monitor signal according to the output from this gate circuit. An ignition monitor signal generating circuit for generating a, adopt the technical means of the ignition apparatus for internal combustion engine, characterized in that it comprises a.

[Action]

 The operation of the configuration of the present invention will be described.

When the transistor drive circuit generates a rectangular wave signal in response to the ignition signal, the power transistor interrupts the primary current of the ignition coil in response to the rectangular wave signal, and an ignition spark is generated when the primary current is cut off.

When the power transistor is cut off, a voltage of a predetermined value or more is induced in the collector of the power transistor, and in response thereto, the trigger circuit generates a trigger signal.

On the other hand, the gate circuit inputs a signal from the transistor drive circuit side, and in response to this signal, during the power transistor cutoff period, the gate is opened only immediately after the power transistor cutoff during that period. Therefore, of the trigger signals output from the trigger circuit, only the trigger signal generated immediately after the power transistor is cut off passes through the gate, and the ignition monitor signal generation circuit generates the ignition monitor signal.
Therefore, even if the trigger signal is output from the trigger circuit due to the noise voltage generated considerably late after the power transistor is shut off, the noise trigger signal is blocked by the gate circuit and the normal ignition is performed. Only the monitor signal will be generated.

〔Example〕

 The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 3 is a block diagram showing the entire basic configuration of the first embodiment of the device of the present invention.
An engine control unit (EC that controls the amount of fuel supplied to the engine and the ignition timing based on factors such as intake air volume and water temperature)
U), 2 is an ignition device, which sends an ignition signal to each ignition coil 3, 4 in response to a signal from the ECU 1. The ignition coil includes one provided for each cylinder, one provided for each pair of cylinders combined with a cylinder in the opposite process, and the like, in which the two coils of the latter method are used. These are for generating a high voltage for igniting a spark plug (not shown), and the number of them naturally changes depending on the number of cylinders of the engine, etc., but the general appearance is almost the same as the case shown. It is the same. Reference numeral 5 is a storage battery that supplies electric power to each unit constituting the control system, and reference numeral 6 is a switch for turning on and off the current from the storage battery 5. 7,8,9 and 10
Is a connection line between the ECU 1 and the ignition device 2, and IGf
1, IGf2, IGd and IGt are signals appearing on these respective connection lines. That is, IGf1 and IGf2 are ignition monitor signals that notify the ECU 1 of a failure of the ignition device, IGd is an ignition distribution signal for switching the energization to the ignition coils 3 and 4 according to the ignition order, and IGt is an ignition timing determining ignition timing. It is a timing signal. Hereinafter, the ignition distribution signal and the ignition timing signal are collectively referred to as an ignition signal.

Further, the detailed configuration of the ignition device 2, which is a main part of the device of the present invention, will be described with reference to FIG. 2
Reference numerals 0 and 22 are waveform shaping circuits that form an ignition signal from the ECU 1. Reference numeral 21 is a closing angle control circuit for calculating the energization time to each ignition coil 3, 4 from the ignition timing signal. 23 is an inverter. Reference numerals 24 and 25 are gate circuits that output an ignition energization signal according to the ignition sequence according to the ignition distribution signal. 26,2
Reference numeral 7 is a power transistor for turning on / off the current flowing through the ignition coils 3 and 4. Reference numeral 19 is a current detection resistor for detecting the current flowing through the gates 3 and 4. Reference numerals 28 and 29 are trigger circuits that output a high level when the collector voltage of each power transistor 26, 27, which is the primary coil voltage of each ignition coil 3, 4, exceeds a predetermined value. Reference numerals 30 and 31 are AND circuits that perform logical operation between the outputs of the trigger circuits 28 and 29 and the ignition distribution signal. 32,33
Is a monostable multivibrator that produces a pulse output with a certain pulse width when the input goes high. 34,3
Reference numeral 5 is a drive circuit that amplifies the output of each monostable multivibrator 32, 33.

The operation of the apparatus shown in FIG. 1 will be described with reference to the waveform chart of each part in FIG. The engine control unit 1 outputs to the ignition device 2 a signal IGt for giving an ignition timing and an ignition distribution signal IGd for giving an energization order to the plurality of ignition coils 3, 4 according to the ignition order. Ignition signals IGt, IGd
Respectively enter the waveform shaping circuits 20 and 22 in the ignition device 2 and undergo waveform shaping as shown in FIG. At this time, the phase relationship of each ignition signal is such that even if the power transistor connected to the ignition coil is turned off according to the ignition signal, it does not turn off already due to the switching delay of the power transistor, etc.
By 22, the phase of the ignition distribution signal is slightly delayed with respect to the ignition signal. Among the shaped ignition signals, the IGt signal is the closing angle control circuit 21, the rotation speed of the engine, the current value of the ignition coils 3 and 4 detected by the current detection resistor 19,
The pulse width is controlled according to the power supply voltage and the like. The energizing pulse (waveform) of the ignition coil generated by the closing angle control circuit 21 enters one terminal of the gate circuits 24 and 25.
The ignition distribution signal becomes two signals (,) which sequentially go through the inverter 23 and become high level according to the ignition order.
Next, the AND circuits 24 and 25 are the power transistors 26 and 27 corresponding to the next stage only when each ignition distribution signal becomes high level.
Generate an output that turns on (waveform,). In this way, the power transistors 26 and 27 are turned on and off sequentially according to the outputs of the AND circuits 24 and 25, but when they are turned off, a high voltage is generated on the secondary side of the ignition coil and the spark plug ignites. To do. At this time, the primary voltage of the ignited coil is several 100V
Pulse is generated. Normally, only this pulse has a predetermined value or more, but depending on conditions, the primary voltage of the coil during plug discharge also has a predetermined value or more. Therefore, the logical product of this trigger circuit output (waveform) and the ignition distribution signal (the phase is slightly delayed with respect to the ignition signal for the above-mentioned reason) is taken, and the primary voltage of the coil during plug discharge is equal to or higher than a predetermined value. The pulse generated due to the above is removed, and only the pulse (waveform) generated due to the primary voltage of the coil becoming a predetermined value or more at the time of ignition is input to the monostable multivibrators 32 and 22. The monostable multivibrators 32 and 33 start operating by the pulses generated by this ignition, respectively, and generate pulses with a constant time width (waveform,). Thus, even if the coil primary voltage exceeds the predetermined value a plurality of times within one ignition interval, the unnecessary output signal of the trigger circuit is masked by the ignition distribution signal, and the correct ignition monitor signal can be generated. .

FIG. 4 shows a second embodiment of the device of the present invention. Compared to the first embodiment, the ECU 1 uses the ignition timing signal as an ignition signal.
Only the IGt is output, and the primary angle of the ignition coil 3 is interrupted by the single power transistor 26 via the waveform shaping circuit 20 and the closing angle control circuit 21 by this ignition timing signal. The output signal of the circuit 21 is slightly delayed by the delay circuit 36 and applied to one input of the AND circuit 30.
The gate of the AND circuit 30 is opened and closed.
FIG. 5 is a waveform chart of each part of the device shown in FIG. 4, and in this second embodiment as well as in the first embodiment, the coil primary voltage is set to a predetermined value a plurality of times within one ignition interval. Even in the above case, the unnecessary output signal of the trigger circuit is masked by the delay signal, and the correct ignition monitor signal can be generated.

In the embodiment shown in FIG. 4, as the output signal of the delay circuit 36, the output signal (waveform) of the waveform shaping circuit 20 can be used instead of the output signal (waveform) of the closing angle control signal 21.

FIG. 6 shows the essential structure of a third embodiment of the device of the present invention. In the second embodiment shown in FIG. 4, instead of using the delay circuit 36, the output signal or waveform of the closing angle control circuit 21 is shown. An RS flip-flop set by the output signal of the shaping circuit 20 and reset by the output signal of the trigger circuit 24 or the output signal of the monostable multivibrator 32.
The output signal of the RS flip-flop 37 is used to open and close the gate of the AND circuit 30. FIG. 7 shows the waveform of each part of the circuit shown in FIG. 6, and in this third embodiment as well, even if the coil primary voltage exceeds a predetermined value a plurality of times within one ignition interval, an unnecessary trigger is generated. The output signal of the circuit is masked by the output signal of the RS flip-flop 37 so that the correct ignition monitor signal can be generated. Further, in the configuration shown in FIG. 6, the RS flip-flop 37 is set in synchronization with the fall (ignition timing) of the output signal of the closing angle control circuit 21 or the waveform shaping circuit 20, so that the short circuit after ignition can be achieved. Time only
The gate of the AND circuit 30 may be opened.

In the embodiment described above, the monostable multivibrator 32 and the drive circuit 34, or the monostable multivibrator 33 and the drive circuit 35 constitute an ignition monitor signal generation circuit.

〔The invention's effect〕

As described above, in the present invention, the noise voltage induced on the primary side of the ignition coil due to the disturbance of the spark discharge current or the like is prevented from being supplied to the engine control unit as the ignition monitor signal, and within one ignition interval. An excellent effect is that one correct ignition monitor signal can be generated.

Furthermore, since it only controls whether the gate of the gate circuit is opened and closed to pass the trigger signal and no special processing is applied to the output itself of the gate circuit, the circuit configuration of the latter stage of the gate circuit is Can be implemented without any special consideration to the conventional one.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of the device of the present invention, and FIG. 2 is a waveform diagram of each part used for explaining the operation of the device shown in FIG.
FIG. 3 is a block diagram showing the overall configuration of the first embodiment,
FIG. 4 is an electric circuit diagram showing a second embodiment of the device of the present invention, and FIG. 5 is a waveform diagram of each part used for explaining the operation of the device shown in FIG.
FIG. 6 is an electric circuit diagram showing a main part configuration of a third embodiment of the device of the present invention, and FIG. 7 is a waveform diagram of each part used for explaining the operation of the circuit shown in FIG. 1 ... Engine control unit, 2 ... Ignition device, 3, 4 ... Ignition coil, 20-25 ... Waveform shaping circuit, closed angle control circuit, waveform shaping circuit, inverter, AND circuit, which constitutes a transistor drive circuit 26,27 …… Power transistor, 28,29 ……
Trigger circuit, 30,31,36,37 …… AND that composes gate circuit
Circuit, delay circuit, RS flip-flop.

Claims (6)

[Claims] 1. A transistor drive circuit that generates a rectangular wave output in response to an ignition signal, a power transistor that turns on and off by the rectangular wave output of the transistor drive circuit to interrupt the primary current of the ignition coil, and the power transistor. A trigger circuit for generating a trigger signal when the voltage induced in the collector of the power transistor becomes a predetermined value or more at the time of shutting off, a trigger signal of this trigger circuit and a signal from the transistor drive circuit side are input, A gate circuit that opens the gate only immediately after the power transistor is interrupted during the interruption period of the power transistor by the signal from the transistor drive circuit side, and outputs the trigger signal output from the trigger circuit during this period; Ignition that generates an ignition monitor signal according to the output from the gate circuit An ignition device for an internal combustion engine, comprising: a monitor signal generating circuit. 2. The ignition device for an internal combustion engine according to claim 1, wherein the gate of the gate circuit is opened during energization of the power transistor. 3. The gate circuit is provided with a logic circuit that receives a signal that changes from the transistor drive circuit side with a slight delay from the ignition timing and opens the gate until the signal changes. An ignition device for an internal combustion engine according to claim 1. 4. The delay circuit, wherein the gate circuit receives an ignition timing signal as the ignition signal indicating the ignition timing from the transistor drive circuit side, and generates a delay signal slightly delayed from the ignition timing. An ignition device for an internal combustion engine according to claim 1, further comprising: a logic circuit that opens the gate according to a delay signal. 5. The gate circuit receives an ignition timing signal as the ignition signal for instructing an ignition timing from the transistor drive circuit side, and is reset in synchronization with a trigger signal from the trigger circuit. A flip-flop circuit that is reset in synchronization with the time when the power transistor is turned on by a signal, and a period from when the power transistor is turned on by the output signal of the flip-flop circuit until the first trigger signal is generated in the trigger circuit. The ignition device for an internal combustion engine according to claim 1, further comprising: a logic circuit that opens the gate. 6. The ignition monitor signal generation circuit generates a pulse signal having a predetermined time width as the ignition monitor signal in response to a trigger signal output from the gate circuit. 1st to 5th
An ignition device for an internal combustion engine according to any one of items.