JP3146840B2 - Capacitor discharge type ignition device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Generally, an ignition device for a capacitor discharge type internal combustion engine includes an ignition signal generator for generating an ignition signal for determining an ignition timing, an ignition coil, and an ignition energy provided on a primary side of the ignition coil. And a discharge switch provided so as to conduct when an ignition signal is supplied and to discharge the charge of the ignition energy storage capacitor through the primary coil of the ignition coil. When the charge of the storage capacitor is discharged through the primary coil of the ignition coil, a high voltage for ignition is induced in the secondary coil of the ignition coil. Thyristors are often used as discharge switches, but other semiconductor switches such as transistors may be used.

When this type of igniter is driven by a battery, a commercial power supply, or a DC power supply that obtains a DC voltage by rectifying an AC output of a magnet generator attached to an internal combustion engine, the DC output is boosted. A booster circuit is provided on the primary side of the ignition coil, and the output of the booster circuit charges the ignition energy storage capacitor to one polarity.

As a boosting circuit for boosting a DC voltage, a boosting transformer to which a primary current is supplied from a power supply, an oscillation circuit for generating a pulse signal of a predetermined frequency, and a serial connection to a primary coil of the boosting transformer A DC-DC converter including a step-up switch that is turned on and off by an output pulse of an oscillation circuit is often used, and a field-effect transistor or another semiconductor switching element is used as the step-up switch. .

In a capacitor discharge ignition device using such a DC-DC converter as a booster circuit,
If a thyristor is used for the discharge switch, it is necessary to stop the operation of the converter when the thyristor is conducting to prevent a large short-circuit current from flowing from the converter through the thyristor in order to protect the converter. In order to prevent commutation failure, it is necessary to stop the converter when the thyristor is conducting. Furthermore, in order to prevent the charging voltage of the ignition energy storage capacitor from becoming excessive, the converter may be stopped when the voltage between both ends of the capacitor exceeds a set value. In such a case, while the voltage between the gate and cathode of the thyristor is equal to or higher than the reference value,
A gate circuit is provided to prevent the output pulse of the oscillation circuit from being supplied to the boosting switch.

[0006]

A booster circuit boosts the output of a battery or the output of a DC power supply that generates a DC voltage by rectifying an AC voltage from a commercial power supply or the like to charge an ignition energy storage capacitor. In the capacitor discharge type ignition device for an internal combustion engine, the power supply voltage abnormally decreases, the charging voltage of the ignition energy storage capacitor decreases, and the charging voltage of the ignition energy storage capacitor decreases.
As a result, if the ignition voltage induced in the secondary coil of the ignition coil decreases and a voltage sufficient to completely ignite the air-fuel mixture in the cylinder of the engine cannot be obtained, intermittent misfiring or mixing may occur. Or incomplete combustion of gas. If such a state occurs continuously for a long time, unburned gas or harmful gas of incomplete combustion is continuously emitted from the engine, causing pollution.In the case of an engine using gas fuel, the There is a problem that the discharged combustible unburned gas may stay and cause a gas explosion.

[0007] An object of the present invention is to stop the engine by stopping the engine when the length of time during which the voltage across the ignition energy storage capacitor is lower than the lower limit exceeds a set value. It is an object of the present invention to provide a capacitor discharge type ignition device for an internal combustion engine which prevents continuous discharge of incompletely burned gas and unburned gas.

[0008]

According to the present invention, there is provided a booster circuit for boosting an output of a power supply for generating a DC voltage, an ignition coil, and one of the outputs of the booster circuit provided on the primary side of the ignition coil. An ignition energy storage capacitor charged to a polarity and a discharge switch provided to conduct when an ignition signal is supplied and discharge the charge of the ignition energy storage capacitor through the primary coil of the ignition coil. The present invention relates to a capacitor discharge type ignition device for an internal combustion engine provided.

In the present invention, a capacitor voltage detecting circuit for detecting a voltage corresponding to the voltage between both ends of the ignition energy storage capacitor, and the voltage detected by the capacitor voltage detecting circuit is lower than an allowable lower limit. An engine stop signal generation circuit for generating an engine stop signal when the length of time exceeds a set value, and a boost operation stop circuit for stopping the boost operation of the boost circuit when the engine stop signal is generated.

The booster circuit includes, for example, a booster transformer to which a primary current is supplied from a power supply, an oscillator circuit for generating a pulse signal of a predetermined frequency, and an oscillator circuit connected in series to a primary coil of the booster transformer. And a step-up switch whose on / off control is performed by the output pulse.

The boosting operation stop circuit permits, for example, the output pulse of the oscillation circuit to be supplied to the boosting switch when the engine stop signal is not generated,
It can be constituted by a gate circuit that prevents the output of the oscillation circuit from being supplied to the boosting switch when the engine stop signal is generated.

In the present invention, a capacitor voltage detecting circuit for detecting a voltage corresponding to a voltage between both ends of the ignition energy storage capacitor, and a voltage detected by the capacitor voltage detecting circuit becomes lower than an allowable lower limit value. And an engine stop signal generating circuit for generating an engine stop signal when it is detected that the state has continued for a set time, and the engine cut signal is provided in a fuel supply system of the internal combustion engine. Is used as a signal for operating the.

Each of the above-mentioned engine stop signal generation circuits includes a timer capacitor charged by a DC voltage having a substantially constant value with a constant charge time constant, a discharge circuit for discharging the timer capacitor with a predetermined discharge time constant, A reset switch that detects the output of the capacitor voltage detection circuit and conducts when the output of the detection circuit is equal to or higher than a set value to discharge the charge of the timer capacitor, and compares the voltage across the timer capacitor with a reference voltage. And a comparator that outputs an engine stop signal when the voltage across the timer capacitor becomes equal to or higher than the reference voltage.

[0014]

With the above arrangement, the length of time during which the magnitude of the voltage corresponding to the voltage across the ignition energy storage capacitor detected by the capacitor voltage detection circuit is lower than the allowable lower limit is set. When the value exceeds the value, an engine stop signal is generated from the engine stop signal generation circuit. Therefore, if a boosting operation stop circuit for stopping the boosting operation of the boosting circuit when the engine stop signal is generated is provided, the boosting circuit does not generate the boosted voltage when the engine stop signal is generated, and the ignition energy storage capacitor. Is stopped, the ignition voltage stops being output, and the engine is stopped. When the engine stop signal is used as a signal for operating the fuel cut valve of the engine, the fuel cut valve can be closed when the engine stop signal is generated, and the supply of fuel to the engine can be stopped. .

As is well known, in a capacitor discharge type internal combustion engine ignition device, the magnitude of the ignition voltage induced in the secondary coil of the ignition coil is substantially proportional to the charging voltage of the ignition energy storage capacitor. If the allowable lower limit value for the voltage is set to the magnitude of the charging voltage of the ignition energy storage capacitor corresponding to the allowable lower limit value of the ignition voltage that can completely ignite the mixture in the cylinder of the engine, the ignition energy storage The engine can be stopped when the state in which the charging voltage of the capacitor becomes lower than the allowable lower limit and incomplete combustion may occur continues for a set time or more.

As described above, according to the present invention, when the length of time during which the voltage across the ignition energy storage capacitor is lower than the allowable lower limit exceeds the set value,
Since the engine is stopped so that incompletely burned gas and unburned gas are not continuously discharged for a long time, it is possible to prevent the possibility of exhaust pollution and gas explosion outside the engine.

[0017]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an ignition coil having a primary coil 1a and a secondary coil 1b, one end of which is grounded. The output voltage of the secondary coil 1b of the ignition coil is applied to the ignition plug 2 with the attached ignition plug. A diode D1 whose cathode is directed to the ground side is connected in parallel to both ends of the primary coil 1a, and one end of an ignition energy storage capacitor C1 is connected to a non-ground side terminal of the primary coil 1a. A thyristor Th as a discharging switch is connected between the other end of the capacitor C1 and the ground with its cathode facing the ground, and a capacitor C2 and a resistor R1 are connected in parallel between the gate and the cathode of the thyristor Th. Have been.

To charge the ignition energy storage capacitor C1, a booster circuit 5 comprising a converter main circuit 3 and an oscillation circuit 4 is provided.

The converter main circuit 3 includes a step-up transformer 6 and
It comprises a field effect transistor FET, rectifying diodes D2 and D3, and a smoothing capacitor C3. One end of the primary coil 6a of the step-up transformer 6 is connected to the cathode of the diode D4 and the other end of the surge absorbing capacitor C4 having one end grounded, and the anode of the diode D4 is connected to the positive electrode of the battery 7 having the negative electrode grounded. 8 are connected. The other end of the primary coil 6a of the step-up transformer is connected to the drain of the field effect transistor FET, and the source of the field effect transistor FET is grounded. One end of a secondary coil 6b of the step-up transformer is grounded, and the other end of the secondary coil is commonly connected to anodes of diodes D2 and D3. The cathode of the diode D2 is connected to the other end of the ignition energy storage capacitor C1. The anode of the diode D3 is connected to the non-ground side terminal of the secondary coil 6b of the step-up transformer, and the smoothing capacitor C3 is connected between the cathode of the diode D3 and the ground. In this example, a battery 7 constitutes a power supply 9 for generating a DC voltage.

The oscillation circuit 4 includes a field effect transistor FE
It generates a pulse signal of a predetermined frequency for turning on and off T, and is constituted by, for example, a known astable multivibrator including an operational amplifier, a resistor, and a capacitor. The output pulse Vp 'of this oscillation circuit 4 (FIG.
A) is supplied as a drive pulse Vp to the gate of the field effect transistor FET through the AND circuit AND1. The driving pulse V
The primary current of the step-up transformer 6 is turned on and off by turning on and off the field effect transistor. When the primary current of the step-up transformer 6 is interrupted, a high voltage is induced in the secondary coil 6b, and this voltage is rectified by the diode D2 and applied to the ignition energy storage capacitor C1. As a result, the capacitor C1 is charged to the polarity shown. In this example, the field effect transistor FET constitutes a boosting switch.

In order to obtain the rotation angle information and the speed information of the internal combustion engine, the rotor 10 having a reluctor 10a and rotating in synchronization with the rotation of the engine and the change in the magnetic flux generated by the rotation of the rotor are used to generate a voltage. Induced signal coil 11
And a known signal generator having the following. The output of the signal coil 11 is input to an ignition timing control circuit 13 using a stabilized power supply circuit 12 that outputs a constant voltage with the output voltage of the battery 7 as an input. The ignition timing control circuit 13 is, for example, a known arithmetic circuit using an integration circuit whose integration interval is determined by a signal voltage obtained from the signal coil 11, and the ignition position is advanced or retarded according to the engine speed. An angular ignition signal Vt (see FIG. 2B) is generated, which triggers the thyristor Th.

The gate-cathode voltage V of the thyristor Th
gk is input to the inverting input terminal of the first comparison circuit CP1. A first reference voltage Vr1 obtained by dividing the output voltage of the stabilized power supply 12 by a voltage dividing circuit including resistors R2 and R3 is input to the non-inverting input terminal of the comparison circuit CP1. The comparison circuit CP1 compares the gate-cathode voltage Vgk of the thyristor Th with the reference voltage Vr1, and when Vr1> Vgk, a high-level signal (a signal corresponding to a logical value "1").
And outputs a low-level signal (a signal corresponding to a logical value “0”) when Vr1 ≦ Vgk. The reference voltage Vr1 is set lower than the trigger level of the thyristor Th, so that the output of the comparison circuit CP1 becomes low before the gate-cathode voltage Vgk of the thyristor Th reaches the trigger level of the thyristor Th. The output V1 of the comparison circuit CP1 is input to the AND circuit AND1. Therefore,
While the thyristor Th is conducting and the anode current of the thyristor is flowing, the AND circuit AND1 blocks the output pulse of the oscillation circuit 4 from passing, and the field effect transistor F
The supply of the drive pulse Vp to the ET is stopped (FIG. 2C,
G) Since the operation of the booster circuit 5 is stopped, the commutation of the thyristor Th can be reliably performed.

In order to detect a voltage Vc1 between both ends of the ignition energy storage capacitor C1, a first capacitor charging voltage detecting circuit 14 formed by a voltage dividing circuit comprising a series circuit of resistors R4 and R5 is provided across the capacitor C3. And a first capacitor voltage detection signal Vc1 '(corresponding to the voltage across the ignition energy storage capacitor C1) obtained across the resistor R5 is connected to the second comparison circuit C
It is input to the inverting input terminal of P2. Comparison circuit CP2
The second reference voltage Vr2 obtained by dividing the output voltage of the stabilized power supply circuit 12 by a voltage dividing circuit composed of resistors R6 and R7 is input to the non-inverting input terminal of the comparator circuit CP.
2 is input to the AND circuit AND1.

The comparison circuit CP2 receives the charging voltage detection signal Vc1.
Is compared with the reference voltage Vr2, a high-level signal is output when Vr2> Vc1 ', and a low-level signal is output when Vr2≤Vc1'. The reference voltage Vr2 is equal to the capacitance of the capacitor C1.
Is set to a value corresponding to the allowable upper limit value Vc1h of the charging voltage of the comparator circuit CP2 while Vc1h ≦ Vc1.
2 becomes low level, during which the supply of the driving pulse Vp to the field effect transistor FET is stopped, and the charging voltage Vc1 of the capacitor C1 is prevented from exceeding the allowable upper limit value Vc1h and becoming excessive (FIG. 2D, G , H).

A resistor R8 is connected between both ends of the capacitor C3.
And a second capacitor charging voltage detecting circuit 15 formed by a voltage dividing circuit comprising a series circuit of R9 and R9. The detection circuit 15 detects a voltage corresponding to the voltage Vc1 across the capacitor C1, and inputs a second capacitor voltage detection signal Vc1 ″ obtained across the resistor R9 to the engine stop signal generation circuit 16. I do.

The engine stop signal generation circuit 16 generates an engine stop signal when the length of time during which the magnitude of the capacitor voltage detection signal Vc1 "is lower than the allowable lower limit exceeds a set value. The engine stop signal generation circuit 16
A timer capacitor C5, which is charged with a constant charging time constant through a resistor R10 by a substantially constant DC voltage obtained by the stabilized power supply 12, and connected in parallel between both ends of the capacitor C5 to discharge the capacitor with a predetermined discharging time constant A resistor R11 constituting a discharge circuit for discharging, and resistors R8 and R9
And a Zener diode DZ having a cathode connected to the voltage dividing point of the voltage dividing circuit comprising a base current supplied through the Zener diode to discharge the electric charge of the timer capacitor C5 through the resistor R12 when the base is supplied. A reset switch composed of a transistor TR, a third comparator CP3 in which a voltage Vc5 across a timer capacitor C5 is input to an inverting input terminal, and a series circuit of resistors R13 and R14. And a voltage dividing circuit for inputting a third reference voltage Vr3 obtained by dividing the output voltage to the non-inverting input terminal of the comparing circuit CP3. The output signal V3 of the comparing circuit CP3 is
Input to ND1. The comparison circuit CP3 compares the voltage Vc5 between both ends of the timer capacitor C5 with the reference voltage Vr3, and when Vr3> Vc5, the output voltage V3 becomes high, and when Vr3 ≦ Vc5, the output signal V3 becomes low. Level. In this embodiment, a low-level output signal of the comparison circuit CP3 is used as an engine stop signal.

The magnitude of the Zener voltage of the Zener diode DZ is determined by the capacitor corresponding to the allowable lower limit Vc1L at which the magnitude of the charging voltage of the ignition energy storage capacitor C1 can generate an ignition voltage that can normally ignite the engine. When the magnitude of the voltage Vc1 across the capacitor C1 is equal to or greater than the permissible lower limit value Vc1L, the Zener diode DZ is turned on and the reset transistor TR is turned on. When the charge of the capacitor C1 is discharged by the conduction of the thyristor Th at the ignition timing of the engine, the magnitude of the voltage Vc1 across the capacitor C1 is allowed. The transistor TR is cut off when the voltage falls below the lower limit value Vc1L, and the timer capacitor is turned off. 5 begins to be charged with a constant charging time constant starts the timer operation, the voltage Vc5 of both ends of the timer capacitor rises (see FIG. 2E).

The length of time Ts required for the voltage Vc5 across the timer capacitor C5 to be charged to the reference voltage Vr3 while the transistor TR serving as the reset switch is shut off is determined by the value of the stabilized power supply circuit 12. The magnitude of the output voltage, the capacitance of the timer capacitor C5 and the resistance R10,
The charging time constant determined by the resistance value of R11 and the reference voltage V
It can be set by the size of r3. The set value Ts of this time length can be tolerated in a state where the charging voltage of the ignition energy storage capacitor C1 becomes lower than the permissible lower limit value and incomplete combustion gas or unburned gas may be discharged from the engine. If the battery 7 is used as a drive source for a starter motor or the like of the engine within the range of the time length, the starter motor or the like operates when the engine is started, and the voltage of the battery 7 decreases to reduce the capacitor. It is set to a value longer than the length of time during which the voltage at both ends of C1 is lower than the allowable lower limit value Vc1L, for example, a length of about several seconds.

FIG. 2 shows waveforms at various points in FIG. 1 when the voltage Vc1 across the ignition energy storage capacitor C1 rises above the allowable lower limit Vc1L within a time shorter than the set value Ts of the time length. In this case, Vc5 <
Since the timer capacitor C5 is reset during the state of Vr3 (see FIG. 2E), the output signal V3 of the comparison circuit CP3 is maintained at a high level (see FIG. 2F).
Accordingly, the output signal V1 of the comparison circuit CP1 and the comparison circuit C
While the output signal V2 of P2 is at the high level, the driving pulse Vp is supplied to the middle field effect transistor FET (see FIG. 2G).

FIG. 3 shows a capacitor C for storing ignition energy.
FIG. 3 (E) shows an operation waveform in a case where the time during which the magnitude of the voltage Vc1 at both ends of 1 exceeds the allowable lower limit value Vc1L exceeds the set value Ts. As described above, since the timer capacitor C5 is not reset, the voltage Vc5 across the timer capacitor becomes the reference voltage Vc5.
rises beyond the value of r3, and when Vc5 ≧ Vr3, the comparison circuit CP
3 output signal V3 (see FIG. 3F) goes low,
This low level signal is the engine stop signal. Comparison circuit C
The engine stop signal output from P3 is an AND circuit AND1
Is input to the field effect transistor FET, the output pulse Vp 'of the oscillation circuit 4 is prevented from being supplied to the field effect transistor FET.
The supply of p (FIG. 3G) stops. Therefore, the booster circuit 5
, The ignition energy storage capacitor C1 is not charged (see FIG. 3H), so that the generation of the ignition voltage is stopped and the engine is stopped. Therefore, it is possible to prevent a state in which incomplete combustion gas or unburned gas may be discharged from the engine from continuing.

When the power switch 8 is turned off after the engine has stopped, the charge of the timer capacitor C5 is discharged at a predetermined discharge time constant through the resistor R11 as a discharge circuit, and the timer capacitor returns to the state before charging.

In this embodiment, the AND circuit AND1 permits the output pulse of the oscillation circuit 4 to be supplied to the boosting switch (field effect transistor FET) when the engine stop signal is not generated. A gate circuit for preventing the output of the oscillation circuit 4 from being supplied to the boosting switch when the engine stop signal is generated, and the boosting operation stopping circuit is configured by the gate circuit.

In the above embodiment, the first capacitor voltage detecting circuit 14 for detecting the voltage between both ends of the ignition energy storage capacitor C1, and the first comparing circuit for comparing the output of this detecting circuit with the first reference voltage CP1 is provided to stop the operation of the booster circuit when the voltage across the capacitor C1 exceeds the allowable upper limit. However, if the withstand voltage of the ignition energy storage capacitor C1 does not matter, These circuits can be omitted. In this case, a three-input AND circuit is used as the AND circuit AND1.

FIG. 4 shows another embodiment of the present invention. In this embodiment, a three-input AND circuit AND1 is used instead of the AND circuit AND1 in the embodiment shown in FIG.
2, the output of the third comparison circuit CP3 is input to the fuel cut valve 17. Other points are the same as those of the embodiment shown in FIG.

The fuel cut valve 17 is provided in a fuel supply system of an internal combustion engine (not shown). The fuel cut valve receives a high level signal corresponding to a logical value "1" from the third comparison circuit CP3. The valve is opened to permit the supply of fuel to the engine when the valve is closed, and when a low level signal (engine stop signal) corresponding to the logical value "0" is input from the comparison circuit CP3, the valve is closed and the engine It is configured to block the supply of fuel to the fuel cell.

The length of time during which the magnitude of the voltage Vc1 across the ignition energy storage capacitor C1 detected by the second capacitor charging voltage detection circuit 15 is lower than the allowable lower limit value Vc1L is determined by the set value Ts. When exceeded,
The engine stop signal is output from the comparison circuit CP3 to the fuel cut valve 1
7, the fuel cut valve closes to stop the engine. Therefore, it is possible to prevent a state in which incompletely burned gas or unburned gas may be discharged from continuing.

In this embodiment, if the withstand voltage of the ignition energy storage capacitor C1 does not matter, the first capacitor charging voltage detection circuit 14 and the first comparison circuit CP1 can be omitted. In this case, a two-input AND circuit is used as the AND circuit AND2.

In the embodiment shown in FIG. 4, when the voltage Vc5 across the timer capacitor C5 becomes higher than the reference voltage Vr3, the third comparison circuit CP3 outputs a low-level engine stop signal, Although the fuel cut valve is closed by the engine stop signal at the level, the third comparator CP
3 is configured to output a low-level signal when the voltage Vc5 across the timer capacitor C5 is lower than the reference voltage Vr3, and to output a high-level signal when the voltage Vc5 exceeds the reference voltage Vr3. (Comparison circuit CP3 shown in FIG.
May be reversed), and this high-level output signal may be used as an engine stop signal. In this case, a fuel cut valve 17 having a structure that closes the valve when a high-level engine stop signal is input is used.

In the embodiment shown in FIG. 1, the comparison circuit CP3
Is input to a gate circuit composed of an AND circuit AND1, and the boosting operation of the booster circuit 5 is stopped when the engine stop signal is output from the comparator circuit CP3. The signal is input to AND1 and also to a fuel cut valve provided in the fuel supply system of the engine, so that when the engine stop signal is output from the comparison circuit CP3, the boosting operation of the booster circuit 5 is stopped, The engine may be stopped by closing the valve. In this case, the unburned gas discharged from the stop of the ignition voltage to the complete stop of the engine can be further reduced.

In the above embodiment, a booster circuit is provided with a capacitor C3 for detecting a voltage corresponding to the voltage across the ignition energy storage capacitor C1, and the voltage across the capacitor C3 is detected. However, by detecting the voltage between the connection point between the ignition energy storage capacitor C1 and the anode of the thyristor Th and the ground, a voltage corresponding to the voltage between both ends of the ignition energy storage capacitor C1 may be detected. Good.

In each of the above embodiments, the power supply 9 for generating a DC voltage is constituted by the battery 7.
As shown in FIG. 5, the output of an AC power supply 18 such as a commercial power supply or a magnet generator driven by an engine is connected to a diode D5.
Or a power supply which is rectified by a full-wave rectifier circuit composed of C8 to generate a DC voltage.

As described above, according to the present invention, the voltage corresponding to the voltage between both ends of the ignition energy storage capacitor is detected by the capacitor voltage detection circuit, and the detected voltage is lower than the allowable lower limit. When the length of time exceeds the set value, the boosting operation of the boosting circuit for charging the ignition energy storage capacitor is stopped, or the fuel cut valve provided in the fuel supply system of the internal combustion engine is operated. To stop the engine, the charging voltage of the ignition energy storage capacitor is lower than the allowable lower limit, and there is a possibility that incomplete combustion gas or unburned gas may be discharged from the engine for a long time. It can be prevented from continuing.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram showing waveforms of respective parts when the charging voltage of the ignition energy storage capacitor is equal to or higher than an allowable lower limit in the embodiment of FIG.

FIG. 3 is a waveform chart showing waveforms of respective parts when the charging voltage of the ignition energy storage capacitor is lower than an allowable lower limit in the embodiment of FIG.

FIG. 4 is a circuit diagram showing another embodiment of the present invention.

FIG. 5 is a circuit diagram showing a different configuration example of a power supply used in the embodiments of FIGS. 1 and 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 ignition coil 2 spark plug 3 converter main circuit 5 step-up circuit 6 step-up transformer 9 power supply 11 signal coil 14 capacitor voltage detection circuit 15 capacitor voltage detection circuit 16 engine stop signal generation circuit C1 ignition energy storage capacitor C2 to C4 capacitor C5 timer capacitor CP1 to CP3 Comparison circuit D1 to D8 Diode DZ Zener diode FET Field effect transistor (step-up switch) Th Thyristor (discharge switch) TR Transistor (reset switch) R11 Resistance (discharge circuit) R1 to R10, R12 to R14 Resistance AND1 AND circuit (gate circuit) AND2 AND circuit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI F02P 11/00 F02P 11/00 Z (58) Field of investigation (Int.Cl. ⁷ , DB name) F02P 11/04 302 F02D 17 / 00 F02M 37/00 311 F02P 3/08 301 F02P 11/00

Claims (3)

(57) [Claims] A booster circuit for boosting an output of a power supply for generating a DC voltage; an ignition coil; and ignition energy provided on a primary side of the ignition coil and charged to one polarity by an output of the booster circuit. A capacitor discharge type internal combustion engine comprising: a storage capacitor; and a discharge switch provided to conduct when an ignition signal is supplied to discharge the charge of the ignition energy storage capacitor through the primary coil of the ignition coil. In the engine ignition device, a capacitor voltage detection circuit that detects a voltage corresponding to a voltage between both ends of the ignition energy storage capacitor, and a time during which the voltage detected by the capacitor voltage detection circuit is lower than an allowable lower limit value An engine stop signal generating circuit for generating an engine stop signal when the length of the engine exceeds a set value; and A boost operation stop circuit for stopping the boost operation of the boost circuit , wherein the engine stop signal generation circuit uses a substantially constant DC voltage.
A timer capacitor charged with a constant charging time constant,
Discharge the timer capacitor with a predetermined discharge time constant
A discharge circuit and an output of the capacitor voltage detection circuit are detected.
And when the output of the detection circuit is equal to or higher than the set value,
A reset switch for discharging the charge of the timer capacitor
Switch and the voltage across the timer capacitor
The voltage across the timer capacitor is the reference voltage
A comparator that outputs the engine stop signal when the above is reached
Capacitor discharge ignition device for an internal combustion engine, characterized in that it consists of a. 2. An output of a power supply for generating a DC voltage is boosted.
Booster circuit, an ignition coil, and a primary side of the ignition coil
Is charged to one polarity by the output of the booster circuit.
The ignition energy storage capacitor and the ignition signal
When it is obtained, it becomes conductive and accumulates ignition energy
The charge of the battery is discharged through the primary coil of the ignition coil.
With a discharge switch provided to
In the sensor discharge type ignition device for an internal combustion engine, the voltage between both ends of the ignition energy storage capacitor is
A capacitor voltage detecting circuit for detecting a voltage response, the detected voltage is allowed by the capacitor voltage detecting circuit
The length of time that is lower than the lower limit exceeds the set value
The engine stop signal is generated when an engine stop signal is generated
Path and boosting of the booster circuit when the engine stop signal is generated.
A boost operation stop circuit for stopping the operation, wherein the boost circuit is configured to receive a primary current from the power supply.
Pressure transformer, and a source for generating a pulse signal of a predetermined frequency.
Circuit and the primary coil of the step-up transformer in series.
On / off control by the output pulse of the oscillation circuit
The boosting operation stop circuit generates the engine stop signal.
The output pulse of the oscillation circuit
Pressure switch and the engine stop signal
When this occurs, the output of the oscillation circuit
The engine stop signal generation circuit comprises a gate circuit for preventing the supply of the power.
A timer capacitor charged with a constant charging time constant,
Discharge the timer capacitor with a predetermined discharge time constant
A discharge circuit and an output of the capacitor voltage detection circuit are detected.
And when the output of the detection circuit is equal to or higher than the set value,
A reset switch for discharging the charge of the timer capacitor
Switch and the voltage across the timer capacitor
The voltage across the timer capacitor is the reference voltage
A comparator that outputs the engine stop signal when the above is reached
A capacitor discharge type ignition device for an internal combustion engine, comprising: 3. A primary current is generated from a power supply that generates a DC voltage.
A given boost transformer and a pulse signal of a predetermined frequency
The generated oscillation circuit and the primary coil of the step-up transformer
And connected in series by the output pulse of the oscillation circuit.
An on-off controlled boost switch.
A booster circuit for obtaining a boosted voltage on the secondary side of the transformer;
An ignition coil and a primary coil provided on the primary side of the ignition coil.
Ignition energy charged in one polarity at the output of serial booster circuits
Energy storage capacitor and when an ignition signal is given
Conducts to charge the ignition energy storage capacitor.
To discharge through the primary coil of the ignition coil
Capacitor discharge type with provided discharge switch
In the ignition device for an internal combustion engine, the voltage across the ignition energy storage capacitor is
A capacitor voltage detecting circuit for detecting a voltage response, the detected voltage is allowed by the capacitor voltage detecting circuit
The state where the value is lower than the lower limit
Generates an engine stop signal when the connection is detected
An engine stop signal generation circuit, wherein the engine stop signal is provided in a fuel supply system of the internal combustion engine.
Used as a signal to operate the fuel cut valve
The engine stop signal generation circuit uses a substantially constant DC voltage.
A timer capacitor charged with a constant charging time constant,
Discharge the timer capacitor with a predetermined discharge time constant
A discharge circuit and an output of the capacitor voltage detection circuit are detected.
And when the output of the detection circuit is equal to or higher than the set value,
A reset switch for discharging the charge of the timer capacitor
Switch and the voltage across the timer capacitor
The voltage across the timer capacitor is the reference voltage
A comparator that outputs the engine stop signal when the above is reached
A capacitor discharge type ignition device for an internal combustion engine, comprising: