JPH0681758A - Noncontact point ignitor for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a noncontact point ignition device for an internal combustion engine which can prevent the burning due to the abnormal electric current of a DC-DC converter part, accompanied with the boosting operation of the DC-DC converter. CONSTITUTION:A battery voltage is converted to a high voltage by a DC-DC converter 5. A capacitor 28 is connected with the primary side coil of an ignition coil 14. An SCR 29 for ignition conducts at each ignition timing of an engine, and electric-discharges the electric charge of the capacitor 28 to the primary side coil of the ignition coil 14. A DC-DC converter operation control circuit 61 suspends the autoexciting oscillation operation of the DC-DC converter 5 at a G1 signal generating angle position, and starts the autoexciting oscillating operation of the DC-DC converter 5 after the lapse of a certain time from the gate voltage application completion of the SCR 29 for ignition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contactless ignition device for an internal combustion engine.

[0002]

2. Description of the Related Art An ignition device of this type includes a converter circuit for obtaining a high voltage on the secondary side of a transformer by intermittently connecting a current supplied from a DC power source to a primary coil of a converter transformer with a switching element, and an ignition coil. , The ignition coil 1
An ignition energy storage capacitor that is provided on the secondary side and is charged to one polarity by the output of the converter circuit, and an electric charge of the ignition energy storage capacitor that is discharged when conducting, are discharged through the primary coil of the ignition coil. And a trigger signal supply circuit that gives a trigger signal to the discharge switch element at the ignition timing of the internal combustion engine.

In this type of ignition device, since the converter circuit outputs a voltage in a short cycle, when the discharge switch element is composed of a thyristor, the converter circuit operates when the thyristor is triggered. Then, the thyristor may not be able to commutate.

Therefore, for example, Japanese Patent Laid-Open No. 3-279676.
In the gazette, the operation of the converter is stopped for a certain period of time before the trigger signal is applied to the gate of the thyristor.
After the thyristor is triggered and energized, the converter is restarted after a certain time has elapsed. That is, in order to prevent the commutation error of the SCR, the oscillation operation is stopped by the input of the ignition timing sensor, and the ignition signal is given after a certain period of time.

Further, in Japanese Utility Model Laid-Open No. 2-92065, the primary operation of the transformer is integrated to stop the converter operation.

[0006]

SUMMARY OF THE INVENTION However, Japanese Unexamined Patent Publication No.
In Japanese Patent No. 279676, since an ignition signal is given after a certain time from the timing sensor input, the degree of freedom in setting the ignition timing is extremely small and only a constant retard type ignition timing can be realized, and in Japanese Utility Model Laid-Open No. 2-92065, the circuit is complicated. There was a problem that it became expensive. Furthermore, in these methods, the sensor output is small at the time of extremely low rotation such as when the engine is stopped and the ignition thyristor can be turned on.
-When the DC converter stop circuit cannot be driven, a commutation error is likely to occur, and an abnormal current continues to flow even after the engine is stopped, resulting in burning.

That is, in the device disclosed in Japanese Patent Laid-Open No. 3-279676, the delay circuit (CR circuit) does not invert at extremely low rotation, and there is no output to the comparator and no output to the discharge control thyristor. Therefore, the converter operates, and the electric charge is accumulated in the capacitor, which causes the destruction of the capacitor. Also, the actual Kaihei 2
In the device disclosed in Japanese Patent No. 92065, the thyristor is triggered even at an extremely low speed, but the trigger does not occur on the integrating circuit side, the converter operation of the transformer works, and commutation of the ignition thyristor does not occur. Therefore, the operation of the DC-DC converter is continued, and the transistor of the converter is destroyed.

Further, there is a problem that the capacitor voltage cannot be detected when the ignition coil is not connected, the converter operation does not stop, and the capacitor is burned. Therefore, an object of the present invention is to provide a non-contact ignition device for an internal combustion engine, which can avoid burnout due to an abnormal current in the DC-DC converter portion that accompanies the step-up operation of the DC-DC converter.

[0009]

SUMMARY OF THE INVENTION The present invention is connected to an ignition coil, a DC-DC converter for converting a DC power supply into a high voltage, and a primary coil of the ignition coil.
A capacitor charged by the output of the DC converter,
A thyristor that conducts at the ignition timing of the internal combustion engine to discharge the electric charge of the capacitor to the primary coil of the ignition coil;
DC- at the first angle signal position advanced from the maximum advance position
A contactless ignition device for an internal combustion engine, comprising: an operation control circuit that stops the step-up operation of the DC converter and restarts the step-up operation of the DC-DC converter after a lapse of a certain time from the timing of ending the voltage applied to the gate of the thyristor. It is a summary.

Further, the operation control circuit stops the step-up operation of the DC-DC converter when the angle signal input is not generated for a certain period of time, and the DC signal is detected after a certain period of time from the detection of the angle signal input.
-It is desirable to restart the boosting operation of the DC converter.

[0011]

The operation control circuit stops the step-up operation of the DC-DC converter at the first angle signal position advanced from the maximum advance position, and after a certain time has elapsed from the end timing of the voltage applied to the thyristor, the DC-DC converter The boosting operation of the DC converter is restarted. Therefore, the boosting operation of the DC-DC converter can be stopped during the ignition operation when the ignition thyristor is turned on, and commutation error of the thyristor can be prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a non-contact ignition device for an internal combustion engine.

An output regulator / rectifier 1 is provided for the magnet AC generator 62 and is connected to a battery 2 as a DC power source. Further, the battery 2 is connected to a DC-DC converter 5 via a series circuit of a main switch 3 and a diode 4. At a connection point a between the diode 4 and the DC-DC converter 5, a microcomputer circuit constant voltage circuit 6 is connected and a circuit power supply capacitor 7 is connected.

At a connection point b between the diode 4 and the DC-DC converter 5, a resistor 8 and a boosting operation control transistor 9 are connected in series. The connection point c between the resistor 8 and the transistor 9 is a diode 10, a resistor 11 and Vc.
A series circuit with the regulator zener diodes 12 and 13 is connected, and the other end is connected to the ignition capacitor 28 side.

The connection point d between the diode 10 and the resistor 11 is connected to the base terminal of the DC-DC converter controlling transistor 16 via the resistor 15. Further, the base terminal of the transistor 16 is grounded via the resistor 17.

The DC-DC converter controlling transistor 16 is a transistor for turning on / off the step-up operation of the DC-DC converter 5. DC-DC converter 5
Are diodes 18, 19 and resistors 20, 21, 22,
23, 24 and 25, a converter transformer 26, and transistors 59 and 60. Further, one end of the primary coil 26a of the converter transformer 26 is connected to the battery 2
The transistor 59 is connected to the other side and the other end is connected to the transistor 59. The current I ₁ flowing through the primary coil 26a of the converter transformer 26 is shown in FIG.

The output side (secondary coil) of the converter transistor 26 is connected to the primary coil of the ignition coil 14 through a series circuit of a rectifying diode 27 and an ignition capacitor 28. The voltage Vc applied to the ignition capacitor 28 is shown in FIG. A connection point e between the rectifying diode 27 and the ignition capacitor 28 is grounded via an ignition SCR (thyristor) 29. A DC arc diode 30 is connected in parallel with the primary coil of the ignition coil 14.

The gate terminal of the ignition SCR 29 is grounded via the SCR drive circuit resistor 31. Further, the gate terminal of the ignition SCR 29 is the resistor 32 for the SCR drive circuit.
The gate of the ignition SCR 29 is triggered when the transistor 33 is turned on via a series circuit of the drive transistor 33 and the drive transistor 33.

Further, an ignition plug 34 is connected to the secondary coil of the ignition coil 14. The SCR drive circuit resistor 35 and the SCR drive circuit resistor 36 are connected between the drive transistor 33 and the power supply voltage.

On the other hand, a microcomputer (hereinafter referred to as a microcomputer) 37 is provided, and a clock crystal 38 is connected to the microcomputer 37. Further, the microcomputer 37 includes the 0th port to the 3rd port P _{0 to} P ₃ and the interrupt port IR.
A Q bar and a reset port RESET bar are provided.

The booster operation control transistor 9 has its base terminal grounded via a microcomputer output operation resistor 39 and has a power supply voltage applied thereto via a series circuit of microcomputer output operation resistors 40 and 41. The connection point f between the resistors 40 and 41 is D of the microcomputer 37.
It is connected to the C-DC converter control signal output first port P ₁ . The signal contents of the first port P ₁ of the microcomputer 37 are shown in FIG.

The input signal transistor 4 is connected to the second port P ₂ of the microcomputer 37 via the output operation resistors 42 and 43.
4 base terminals are connected. The signal contents at the second port P ₂ of the microcomputer 37 are shown in FIG.

The 0th port P ₀ of the microcomputer 37 is grounded via the series circuit of the second angle signal G2 signal input transistors 44 and 45. A resistor 46 is connected between the emitter and base of the G2 signal controlling transistor 44. A resistor 50 is connected between the emitter and base of the input signal transistor 45. The voltage Vθ at the 0th port P ₀ of the microcomputer 37 is shown in FIG.

A signal input resistor 47, a sensor signal rectifying diode 48, and an ignition timing sensor 49 are connected in series to the base terminal of the input signal transistor 45. The detection signal of the ignition timing sensor 49 is shown in FIG. 2 (indicated by S). This sensor signal indicates G at every predetermined crank angle and at a position advanced from the maximum advance position.
1 signal and a G2 signal corresponding to the ignition position at the time of engine start.

A connection point g between the sensor signal rectifying diode 48 and the ignition timing sensor 49 is grounded via a series circuit of a sensor signal rectifying diode 51 and G1 signal input resistors 52 and 53. Signal input resistor 52
A connection point h between the signal input terminal 53 and the signal input terminal 53 is connected to the power supply through a series circuit of a G1 signal input transistor 54 and signal input resistors 56 and 55. At the connection point i between the signal input resistors 55 and 56, the interrupt port IRQ bar of the microcomputer 37 is connected. FIG. 2 shows the signal contents at the interrupt port IRQ bar, and interrupts the microcomputer 37 at the falling position of the IRQ bar.

The third port P ₃ of the microcomputer 37 is connected to the collector terminal (voltage V 1) of the transistor 45 via the diode 57. This collector voltage V1
Is shown in FIG. Reset port RESE of microcomputer 37
The T bar is connected to the microcomputer circuit constant voltage circuit 6.

In this embodiment, the boost operation control transistor 9 and the microcomputer output operation resistors 8, 39, 40,
The DC-DC converter operation control circuit 61 is configured by 41 and the diode 10. Also, the resistance 11, Vc
Zener diode for regulator 12, 13, resistor 1
5, the DC-DC converter controlling transistor 16 and the resistor 17 constitute a voltage detecting circuit 58.

Next, the operation of the contactless ignition device for an internal combustion engine configured as described above will be described. First, the operation when the engine is stopped will be described using the processing (flowchart) by the microcomputer 37 with reference to FIGS. Further, FIG. 2 shows a hard ignition region where the engine speed is lower than a predetermined value N1, and FIG. 3 shows respective waveforms in a soft ignition region where the engine speed is higher than the predetermined value N1. Further, FIG. 4 shows the relationship between the engine speed and the ignition timing.

In FIG. 1, when the main switch 3 is turned on, power is supplied from the battery 2, and when the microcomputer circuit constant voltage circuit 6 secures the circuit power, a reset signal is given to the microcomputer 37.

At the time of reset, the microcomputer 37 outputs an H level signal from the port P ₁ to turn on the transistor 9. Therefore, the DC-DC converter control transistor 16 is turned off, the DC-DC converter 5 repeats the self-excited oscillation operation, and the ignition capacitor 28 is charged.

Then, the capacitor voltage Vc changes to the voltage detection circuit 58 (Vc regulator Zener diodes 12, 1).
3, when the set value determined by the resistors 11, 15, 17) is reached, the transistor 16 is turned on, the base of the transistor 59 is grounded, and the oscillation operation is stopped.

When the oscillation is stopped, the capacitor voltage Vc gradually decreases due to the discharge to the voltage detection circuit 58, and when the voltage becomes lower than the set voltage, the transistor 16 is turned off and the self-excited oscillation is restarted. Repeatedly, the capacitor voltage Vc is controlled to a constant value.

On the other hand, when a timer (indicated by 6a in FIG. 1) of the microcomputer circuit constant voltage circuit 6 starts a timekeeping operation in synchronization with the ON operation of the main switch 3, a constant voltage for the microcomputer circuit is reached. The circuit 6 releases the reset of the microcomputer 37. Then, the microcomputer 37 initializes in step 100 of FIG. 5 (flag FG2 = 0 and port P
₀ = P ₁ = H level). Then, the base routine of FIG. 5 is executed.

First, the microcomputer 37 inputs the ignition timing sensor for a predetermined time (for example, 0.5 seconds) using a timer which is cleared to "0" by the signal input to the interrupt port IRQ bar of the microcomputer 37 in step 110. When the noise does not occur, the L level is output to the first port P ₁ of the microcomputer 37 to turn off the transistor 9 and turn on the transistor 16 to stop the self-excited oscillation operation. As a result, the current consumption before engine start can be reduced.

When the ignition coil is not connected, the secondary side of the ignition coil (transformer) 14 becomes unloaded and the detection voltage is several μs.
Therefore, the transistor 16 does not operate, the converter operation does not stop at the set voltage, and the primary coil of the transformer 26 or the transistor 59 may burn out. On the other hand, if there is no sensor signal within 0.5 seconds after the power is turned on in step 180 of FIG.
_Since the L level is output to ₁ and the DC-DC converter operation is stopped, this can be prevented and the sensor output is small at extremely low rotations such as when the engine is stopped, and the ignition SCR is used.
Although 29 can be turned on, burnout due to commutation error that occurs when the oscillation stop circuit cannot be driven can be prevented because the converter operation is stopped within a certain time after the engine is stopped.

Next, the operation before the advance of N ₁ revolutions or less in FIG. 4 before the start of advance will be described with reference to FIG. When the engine rotates and the G ₁ signal corresponding to the sensor signal S in FIG. 3 is generated in the ignition timing sensor 49 (timing t1 in FIG. 3), current flows through the resistors 52 and 53 and the diode 51, and the transistor 54 is turned on. The interrupt port IRQ bar becomes "0" and interrupts the microcomputer 37. When the IRQ interrupt is generated in this manner, the base routine process of FIG. 5 currently being executed is interrupted and the interrupt routine of FIG. 7 is started.

In this interrupt routine, step 20
At 0, the first port P ₁ of the microcomputer 37 is set to the L level to stop the oscillation, and at step 212, the P ₂ port is set to the H level to turn on the transistor 44, and the G2 signal corresponding to the ignition signal position at the start time is set. Is allowed. Then, after returning to the base routine of FIG. 5, in step 110, the G ₁ signal interrupt time is measured for the time calculation of the G ₁ signal interval (rotation speed determination etc.) and the ignition timer calculation. When the engine further rotates and the G2 signal of the sensor signal S of FIG. 2 is generated, the transistor 45 is turned on by the diode 48, the resistors 47 and 50, and the transistor 44 is turned on. Therefore, the transistor 33 is turned on and the ignition is performed. The SCR 29 turns on. When the SCR 29 is turned on, the electric charge of the capacitor 28 is rapidly released to the primary coil of the ignition coil 14, and the ignition operation is performed.

On the other hand, in the base routine of the microcomputer 37 shown in FIG.
It is activated with a sufficiently short period depending on the pulse width, and P ₀
When the level of the port becomes L level, it is determined that there is a G2 signal input, and after several hundreds of μs (set to be equal to or more than the required gate pulse width of the SCR 29), L level is output to the port P ₂ and the transistor 44 and the transistor 33 are output. To turn off S
The application of the gate voltage of CR29 is terminated.

After a certain period of time (time tD1 in FIG. 2, the discharge of the ignition capacitor 28 is completed and the SCR 29 is surely switched from ON to OFF, for example, after several hundreds of μs), the P ₁ port is set to the H level. , The self-oscillation operation is restarted to prepare for the next ignition.

As described above, the G2 signal can be blocked by the P ₂ port to determine the end point of the SCR29 gate voltage application at the G2 signal. Therefore, the down time of tD1 can be reliably ensured, and converter burnout due to SCR commutation error can be prevented.

Further, the engine speed is increased and N in FIG.
The operation at the time of _one or more soft ignition will be described with reference to FIG. When the G1 signal is generated, the interrupt routine shown in FIG. 6 is started as in the case of N ₁ or less, the oscillation is stopped at the L level output to the P ₁ port, and the ignition timer is counted down by the base routine shown in FIG. Then, the L level is output to the P ₀ port, the transistor 33 is turned on, the SCR 29 is turned on, and the soft ignition operation is performed. Then, the P ₂ port is output to the L level, and only the first time the H level changes to the L level. Is L level → L level as P ₂ in FIG. 3) G
The two signals are cut off so that the ignition SCR 29 is not turned on again by the G2 signal.

After that, the G1 signal interrupt time is measured,
P ₀ port turns off the gate voltage applied SCR29 in the H level the predetermined time (tD2 hours 3, time reliably SCR29 discharge end of the ignition capacitor 28 is turned off from on) after P ₁ port To H level to restart the self-excited oscillation operation and prepare for the next ignition. This allows
The dwell time of tD2 can be surely taken from the end point of the SCR 29 gate voltage application, and converter burnout due to SCR commutation mistake can be prevented.

As described above, in this embodiment, the DC-DC converter operation control circuit 61 (transistor 9, diode 10, resistors 8, 39, 40, 41) enables the DC-DC converter operation to be turned on and off, and the microcomputer 37
The (ON / OFF control means) controls the converter operation control circuit 61 at the G1 signal generation angular position to stop the self-excited oscillation operation of the DC-DC converter 5, and the gate voltage application end point of the ignition SCR (thyristor) 29. After a lapse of a certain time from, the converter operation control circuit 61 is controlled to control the DC-DC.
The self-excited oscillation operation of the converter 5 is restarted.
Therefore, when the ignition SCR 29 is on, the self-excited oscillation operation of the DC-DC converter 5 can be surely stopped, and the commutation error of the SCR (thyristor) 29 can be prevented in advance. As a result, it is possible to avoid the burnout due to the abnormal current of the DC-DC converter unit that accompanies the boosting operation of the self-excited oscillation type DC-DC converter, and also to operate the converter even when there is no signal input within a certain period of time. The DC-DC converter 5 is controlled by controlling the control circuit 61.
Since the engine is stopped, it is possible to avoid burnout due to SCR commutation error that occurs when the engine is stopped or when the ignition coil comes off.

The present invention is not limited to the above-described embodiment. For example, the detection of the G2 signal is not a judgment in the base routine, but a dedicated port (for example, P in FIG. 1).
3) may be used to perform an interrupt.

Further, the G1 and G2 signal input circuit may be a known comparator circuit instead of using a transistor. Further, the DC-DC converter section is disclosed in Japanese Patent Laid-Open No.
A device without a tertiary winding, such as the one disclosed in 4-63651,
The self-excited oscillation type may not be used, and the battery of the DC power supply unit may be a large capacity capacitor or the like.

[0046]

As described above in detail, according to the present invention,
This has an excellent effect of avoiding burnout due to an abnormal current in the DC-DC converter portion due to the step-up operation of the DC-DC converter.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a non-contact ignition device for an internal combustion engine.

FIG. 2 is a time chart.

FIG. 3 is a time chart.

FIG. 4 is a relationship diagram showing a relationship between a rotation speed and ignition timing.

FIG. 5 is a flowchart.

FIG. 6 is a flowchart.

FIG. 7 is a flowchart.

[Explanation of symbols]

 2 Battery as DC power supply 5 DC-DC converter 14 Ignition coil 28 Ignition capacitor 29 Thyristor (SCR) 61 DC-DC converter operation control circuit

Claims (2)

[Claims] 1. An ignition coil, a DC-DC converter for converting a DC power supply into a high voltage, and a DC-DC connected to a primary coil of the ignition coil.
A capacitor charged by the output of the converter, a thyristor that conducts at the ignition timing of the internal combustion engine to discharge the electric charge of the capacitor to the primary coil of the ignition coil, and a first angle signal position advanced from the maximum advance position. DC-
An operation control circuit for stopping the step-up operation of the DC converter and restarting the step-up operation of the DC-DC converter after a lapse of a certain time from the timing of ending the voltage applied to the gate to the thyristor. Contact ignition device. 2. The operation control circuit stops the step-up operation of the DC-DC converter when the angle signal input is not generated for a certain period of time to stop the DC-DC converter after a certain period of time from the detection of the angle signal input.
The contactless ignition device for an internal combustion engine according to claim 1, wherein the boosting operation of the DC converter is restarted.