JPH09273469A - Ignition device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly start a protection action, by which an engine misfires and its rotational speed is restricted, following the detection of an abnormality when the engine malfunctions. SOLUTION: A rotational speed detection voltage Vn outputted from a rotation detecting circuit 6 and a reference voltage Vr outputted from a reference voltage generating circuit 8 are inputted to an ignition allowing/forbidding determination circuit 9, and then, it is determined whether the rotational speed exceeds the restriction value or not. If it is determined that the rotational speed exceeds the restriction value, feeding of an ignition signal from an ignition position controlling circuit 5 to an ignition circuit 1 is prohibited, so that the engine misfires. An ignition device for an internal combustion engine is provided with a restriction value correcting circuit 10, by which the restriction value is corrected to be equal to the present value of the engine rotational speed if the engine rotational speed is lower than the restriction value at that time when a maximum advance position is detected for the first time after the abnormal condition detecting sensor 7 detects an abnormal condition. As a result, a protecting action can be quickly started if an abnormal condition is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine ignition device having a function of lowering the engine speed and protecting the engine when an abnormality occurs in the internal combustion engine.

[0002]

2. Description of the Related Art When an internal combustion engine has an abnormality such as overheating or a decrease in oil (lubricant) level, it is necessary to reduce the engine speed to prevent the engine from being damaged. Although it is possible to stop the engine when an abnormality occurs, when an abnormality occurs in a vehicle such as an outboard motor or a water vehicle traveling on water or a vehicle such as a snowmobile traveling in a mountain area. Since there is a danger of distress if the engine is stopped at any time, it is desirable to protect the engine by reducing its rotation speed to a safe speed instead of stopping the engine when an abnormality occurs.

As an internal combustion engine ignition device having a function of protecting an internal combustion engine when an abnormality such as overheating or a decrease in oil level occurs, the engine misfires by stopping the ignition operation when the abnormality is detected. There is one that is made to suppress the number of rotations.

In order to provide the ignition function for an internal combustion engine with the above-mentioned protection function, a protection is provided to keep the engine in a misfire state until an engine speed falls below a set value when an abnormality is detected. Some circuits have a circuit, but in the case of such a configuration, there is a risk of shocking the driver because the engine speed drops sharply when an abnormality occurs.

Therefore, when an abnormality is detected, a reference voltage generating circuit for continuously charging a capacitor with a constant time constant and generating a reference voltage at both ends of the capacitor, the level of which rises with time, The engine is equipped with a rotation detection circuit that generates a rotation speed detection voltage whose level decreases with an increase in the rotation speed of the engine, and allows ignition of the engine when the rotation speed detection voltage exceeds a reference voltage, An ignition device has been proposed that includes a protection circuit that prohibits ignition of the engine when the detected voltage falls below a reference voltage. With this configuration, as shown in FIG. 7, when an abnormality is detected, the limit value of the engine speed (the lower limit value of the engine speed range that causes the engine to misfire) is set to the maximum value (the limit value during steady operation). ) It is possible to gradually decrease from N4 over time, and after the time t1 has passed, the engine speed can be converged to the allowable upper limit value N1 at the time of abnormality, so that the engine speed can be reduced without shocking the driver. The rotation speed can be limited to a safe rotation speed N1 or less.

[0006]

In the conventional ignition device that performs the control shown in FIG. 7 when an abnormality is detected, the engine speed when the abnormality of the engine is detected is the initial value of the limit value. When it is lower than (maximum value) N4, for example, when the rotation speed at the time of abnormality detection is the rotation speed N2 in FIG. 7, the engine is misfired and the rotation speed is changed unless a relatively long time t2 elapses after the abnormality detection. There was a risk that the protection of the engine could not be properly achieved because the restricting protective action was not started.

In order to solve the above problem, as shown in FIG. 6, the engine speed N is N when an abnormality is detected.
4, N3 and N2 (N4>N3> N1),
With the respective rotation speeds N4, N3 and N2 as limit values,
Immediately, the protective action for causing the engine to misfire may be started. In this way, when the number of revolutions when the abnormality is detected is N4, N3 and N2, the time required for the limit value to converge to the final value N1 is t14, respectively.
Since t13 and t12 (t14>t13> t12), the time required for the engine speed after the abnormality detection to converge to the final value becomes shorter as the engine speed at the time of abnormality detection becomes lower.

If the characteristics shown in FIG. 6 are obtained, the protection operation can be started immediately when an abnormality is detected, so that the engine can be properly protected.

An object of the present invention is to start a protective operation immediately when an abnormality of the engine is detected, and limit the engine speed to a safe value or less without giving an unnecessary shock to the driver. An object of the present invention is to provide an ignition device for an internal combustion engine having a protection function capable of performing

[0010]

SUMMARY OF THE INVENTION The present invention provides an ignition position control circuit for outputting an ignition signal whose position changes between a maximum advance position and a minimum advance position of an internal combustion engine, and an ignition signal. Ignition circuit that generates a high voltage for ignition when
An abnormality detection sensor that detects an abnormality in the internal combustion engine, and prevents the ignition signal from being given to the ignition circuit when the engine speed exceeds the limit value while the abnormality detection sensor is detecting the abnormality. The present invention relates to an ignition device for an internal combustion engine, which includes a protection circuit that misfires the engine. It is assumed that the protection circuit is configured to gradually reduce the limit value of the rotation speed when an abnormality is detected with the passage of time.

According to the present invention, when the maximum advance position is detected in the protection circuit for the first time after the abnormality detection sensor detects the abnormality, the rotation speed of the internal combustion engine is higher than the limit value at that time. A limit value correction circuit for correcting the limit value so as to be equal to the current value of the engine speed when low is provided.

As described above, when the maximum advancing position is detected for the first time after the abnormality is detected, when the engine speed of the internal combustion engine is lower than the current limit value, the limit value is set to the engine speed. If the correction is made to a value equal to the current value, the protection operation can be started immediately (within the time corresponding to one revolution of the engine) when an abnormality of the engine is detected.
It is possible to properly protect the institution.

The protection circuit charges a section integration capacitor from a fixed position slightly delayed from the minimum advance position to a maximum advance position with a constant time constant, and then charges the maximum advance position to the minimum advance position. In the state where the abnormality detection sensor does not detect an abnormality, the rotation detection circuit that generates the integrated voltage obtained by discharging the electric charge of the integration capacitor in a section to a position slightly behind After holding the first level from the maximum advance position to the minimum advance position, hold the second level lower than the first level from the minimum advance position to the next maximum advance position, and an abnormality is detected. The reference voltage generation circuit for generating a substantially rectangular reference voltage whose level in the section from the maximum advance position to the minimum advance position gradually increases with the passage of time, and the rotation speed detection voltage. The reference power An ignition permission / prohibition determination circuit that generates an ignition permission signal when the rotation speed detection voltage exceeds the reference voltage and generates an ignition prohibition signal when the rotation speed detection voltage becomes equal to or lower than the reference voltage, An ignition signal supply control circuit that permits the ignition signal to be given to the ignition circuit when the ignition permission signal is generated and prohibits the ignition signal from being given to the ignition circuit when the ignition inhibition signal is generated. Can be configured.

In this case, when the ignition advance signal is generated at the time when the maximum advance position is first detected after the abnormality detection sensor is in the state of detecting an abnormality, the limit value correction circuit generates the reference voltage. Can be configured by a circuit for increasing the voltage until it becomes equal to the rotation speed detection voltage.

In the ignition device of the present invention,
In many cases, in order to obtain the rotation angle information and the rotation speed information of the engine, a pulsar coil that generates first and second signals of pulse waveforms at the maximum advance position and the minimum advance position of the internal combustion engine is used. In this case, the ignition position control circuit
Rotation angle information and rotation obtained from the first and second signals, with the section from the maximum advance position to the minimum advance position being the ignition section, and the section from the minimum advance position to the maximum advance position being the ignition prohibition section. The ignition position is calculated using the speed information, and an ignition signal whose generation position changes within the ignition section is output.

In this case, in order to facilitate the integral operation of the rotation detection circuit and the generation of the reference voltage, the first signal and the second signal
It is preferable to provide a control voltage generation circuit that receives the signal of (3) as an input and generates a control voltage that maintains a high level state from the maximum advance position to the minimum advance position. If such a control voltage generating circuit is provided, the rotation detecting circuit and the reference voltage generating circuit can be configured as follows.

That is, the rotation detection circuit includes a charging circuit for charging the rotation speed detection integrating capacitor with a first time constant, and a first circuit.
From the generation of the signal to the generation of the second signal, and a charging prevention circuit that prevents the charging of the integration capacitor by the charging circuit, and a drive signal is applied during the generation of the second signal to conduct electricity. And a discharge circuit that discharges the integration capacitor with a second time constant sufficiently smaller than the first time constant while the discharge switch is in a conducting state. A circuit for generating a rotation speed detection voltage whose level decreases as the rotation speed of the internal combustion engine rises can be formed across the integrating capacitor.

The reference voltage generating circuit further includes a first resistor having one end connected to an output terminal of the control voltage generating circuit, and the first resistor.
The second resistor connected in series with the first resistor and the first resistor and the second resistor through the diode to which the control voltage is applied in the forward direction from the control voltage generating circuit through the first resistor and the second resistor. An abnormality detecting capacitor connected in series and charged with a third time constant through the first and second resistors and the diode by a control voltage, and a series circuit of the diode and the abnormality detecting capacitor or a second resistor and diode A voltage dividing circuit having a third resistor connected in parallel to the series circuit of the abnormality detecting capacitor, and a charging control switch provided so as to short-circuit the abnormality detecting capacitor when conducting. , The charge control switch is turned on when the abnormality detection sensor detects no abnormality, and the charge control switch is turned off when the abnormality detection sensor detects an abnormality. As described above, a charge control switch control circuit for ON / OFF controlling the charge control switch according to the state of the abnormality detection sensor is provided, which corresponds to the voltage across the series circuit of the second resistor, the diode and the abnormality detection capacitor. It can be configured by a circuit using a voltage as a reference voltage.

In the above reference voltage generating circuit, when no abnormality of the internal combustion engine is detected (during steady operation),
Since the abnormality detecting capacitor is short-circuited by the charge / discharge control switch, the reference voltage generating circuit uses the voltage obtained by dividing the control voltage by the resistance voltage dividing circuit including the first to third resistors as the reference voltage. Output. This reference voltage is
The signal has a rectangular waveform similar to that of the control voltage.

When the abnormality detection sensor detects an abnormality of the engine, the charge control switch is turned off to release the short circuit of the abnormality detection capacitor. When the short circuit of the abnormality detecting capacitor is released, the abnormality detecting capacitor is charged with the third time constant through the first and second resistors each time the control voltage is generated. At this time, the reference voltage becomes higher than the value when the abnormality is not detected by the amount corresponding to the increase in the voltage across the abnormality detecting capacitor.

The ignition permission / prohibition determination circuit compares the rotation speed detection voltage with the reference voltage, and generates an ignition permission signal when the rotation speed detection voltage exceeds the reference voltage, and the rotation speed detection voltage falls below the reference voltage. It is configured to generate an ignition prohibition signal when

The ignition signal supply control circuit permits the ignition signal to be supplied to the ignition circuit when the ignition permission signal is generated, and the ignition signal is supplied when the ignition prohibition signal is generated. Configured to be prohibited from being given to.

In this case, the limit value correction circuit includes the abnormality detection capacitor when the abnormality detection sensor detects the abnormality and the ignition permission / prohibition determination circuit generates the ignition permission signal while the first signal is generated. 4th smaller than the 3rd time constant
It can be configured by a circuit that corrects the reference voltage by charging with the time constant of.

In the case of configuring the protection circuit as described above, when the rotation speed detection voltage becomes equal to the reference voltage, it is determined whether or not ignition is permitted so that the rotation speed detection integrating capacitor of the rotation detection circuit is discharged with the second time constant. A feedback circuit for providing a drive signal from the output side of the circuit to the discharge switch of the rotation detection circuit is provided.

Further, in a state where the abnormality detection sensor does not detect an abnormality, when the engine speed exceeds the maximum limit value, the rotation speed detection voltage becomes equal to or lower than the reference voltage at the maximum advance position. The circuit constants of the rotation detection circuit and the reference voltage generation circuit are set in advance.

When the internal combustion engine is an engine for driving an outboard motor or a vehicle such as a snowmobile, the limit value of the rotational speed at the time of detecting an abnormality (determined by the saturation value of the reference voltage) is for maintaining the operation of the vehicle. Set a value that gives the upper limit of the minimum necessary range (the range required to operate to a port or repair shop).

The control voltage generating circuit is a circuit for charging the control voltage generating capacitor when the first signal is generated and discharging the control voltage generating capacitor when the second signal is generated. , A flip-flop circuit which is set by the first signal and reset by the second signal.

Further, the ignition position control circuit includes, for example, a first integrator circuit which generates a first integrated voltage with an interval from the generation of the first signal to the generation of the second signal as an integration interval. A second integration circuit that generates a second integrated voltage with an interval from the generation position of each second signal to the generation position of the next second signal as an integration interval, a first integration voltage and a second integration voltage And a circuit for generating an ignition signal from the comparison circuit when the first and second integrated voltages match each other.

In the above structure, when no abnormality is detected in the internal combustion engine and the rotational speed of the internal combustion engine is equal to or less than the limit value during steady operation, the internal combustion engine is rotated at a position ahead of the ignition signal generation position in phase. Since the number detection voltage never becomes lower than the reference voltage (the ignition permission signal is generated when the ignition signal is generated), the ignition prohibition signal does not inhibit the supply of the ignition signal. Driving is done without any problems. When the engine speed exceeds the limit value during steady operation, the rotation speed detection voltage becomes lower than the reference voltage at the position where the phase advances from the ignition signal generation position. The ignition prohibition signal is generated at the position where the phase leads the position. As described above, when the ignition prohibition signal is generated at the position where the phase is advanced from the ignition signal generation position, the supply of the ignition signal to the ignition circuit is prohibited, so that the ignition circuit cannot perform the ignition operation. , The engine misfires. As a result, when the engine speed falls below the limit value, the engine speed detection voltage cannot fall below the reference voltage at a position ahead of the ignition signal generation position in phase, and the engine is ignited again. By repeating these operations, the engine speed is controlled so as not to exceed the limit value during steady operation.

When the abnormality detection sensor detects an abnormality of the engine, the charge control switch is turned off to release the short circuit of the abnormality detection capacitor. Therefore, the first and second resistors are passed through each time the control voltage is generated. The abnormality detecting capacitor is charged with the third time constant, and the reference voltage is
The value corresponding to the amount of increase in the voltage across the abnormality detecting capacitor is higher than the value when no abnormality is detected.

When the ignition permission / prohibition determination circuit generates the ignition permission signal when the engine abnormality is detected, the limit value correction circuit detects the abnormality when the pulsar coil generates the first signal. Since the capacitor is charged with the fourth time constant smaller than the third time constant, the voltage across the abnormality detecting capacitor rises rapidly and the reference voltage becomes equal to the rotation speed detection voltage in a short time. When the reference voltage becomes equal to the rotation speed detection voltage that gives the current value of the rotation speed, the ignition permission / prohibition determination circuit will generate an ignition prohibition signal, so that the charging of the abnormality detection capacitor by the fourth time constant is stopped. By these operations, the limit value of the engine speed is corrected to a value equal to the current value of the engine speed. When the ignition prohibition signal is generated, the ignition signal is not given to the ignition circuit, so that the ignition operation is stopped and the engine misfires. When the engine misfire causes the rotation speed detection voltage to become lower than the reference voltage, an ignition permission signal is generated, so that the ignition signal is supplied again to the ignition circuit, and the ignition operation is performed. These operations keep the engine speed below the limit value.

After the limit value of the rotation speed is corrected, the abnormality detecting capacitor is charged with the third time constant every time the control voltage is generated, so that the reference voltage gradually rises. Therefore, the limit value of the engine speed gradually decreases.
Since the reference voltage cannot be higher than the control voltage, it will be saturated soon. When the reference voltage is saturated, the rotational speed limit value settles at the allowable upper limit value during abnormal conditions.

If the ignition prohibition signal is already generated when the engine abnormality is detected, the protection operation is continued. The ignition permission signal is generated at the point where the reference voltage rises every time the control voltage is generated, the engine speed is gradually decreased, and the engine speed is converged to the final limit value (upper limit value in case of abnormality). This is the same as when an abnormality is detected in the state.

As described above, according to the present invention, when the engine abnormality is detected in the state where the ignition permission signal is generated, the first signal is output at the maximum advance position that first arrives after the abnormality detection. When the above occurs, the reference voltage is corrected to be equal to the rotation speed detection voltage and the ignition prohibition signal is generated. Therefore, when an abnormality of the engine is detected, the protection operation can be started in a short time. After the abnormality is detected, the reference voltage is raised every time the control voltage is generated, so that the engine speed limit value is gradually decreased to finally converge to the allowable upper limit value at the time of abnormality. Therefore, the engine can be protected without giving unnecessary shock to the driver.

Further, in the present invention, since the abnormal voltage detecting capacitor is intermittently charged by the control voltage, the time until the rotational speed at the time of abnormality converges to the allowable upper limit value is sufficiently long without using a large capacity capacitor. can do. Therefore, the ignition device can have the function of protecting the engine without increasing the size of the ignition device.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall construction of an ignition device according to the present invention. In the figure, 1
Is an ignition circuit, 2 is an ignition plug attached to a cylinder of an internal combustion engine, 3 is a pulser coil, 4 is a control voltage generation circuit, 5 is an ignition position control circuit, 6 is a rotation detection circuit, 7 is an abnormality detection sensor, and 8 is a reference. A voltage generation circuit, 9 is an ignition approval / disapproval determination circuit,
Reference numeral 10 is a limit value correction circuit, 11 is a feedback circuit, and 12 is an ignition signal supply control circuit.

The ignition circuit 1 is a circuit which generates a high voltage Vh for ignition when an ignition signal Vi is supplied and supplies the high voltage Vh to a spark plug 2 attached to a cylinder of an engine. The ignition circuit 1 generally includes an ignition coil having a primary coil and a secondary coil, and a primary current of the ignition coil for inducing a high voltage for ignition in the secondary coil of the ignition coil when an ignition signal Vi is given. And a primary current control circuit that causes a sudden change.

The primary current control circuit induces a high voltage for ignition in the secondary coil of the ignition coil by interrupting the primary current flowing in the primary coil of the ignition coil when the ignition signal is given. The current cut-off type circuit and the electric charge of the ignition energy storage capacitor, which is installed on the primary side of the ignition coil and charged by the output of the ignition power source, passes through the primary coil of the ignition coil when the ignition signal is given. A capacitor discharge type circuit for inducing a high voltage for ignition in a secondary coil of an ignition coil by discharging is known. In the present invention, any type of circuit may be used.

The pulsar coil 3 is provided in the signal generator attached to the internal combustion engine, and as shown in FIG. 4 (A), the maximum advance position θ1 and the minimum advance position θ2 of the engine.
Generate a first signal Vs1 and a second signal Vs2 which have different polarities.

In the present specification, the position where the signal reaches a predetermined threshold level (the level that can be recognized by the circuit) Vt is defined as the signal generation position.

The control voltage generating circuit 4 receives the first signal Vs1 and the second signal Vs2 output from the pulsar coil 3 as input, and has the first level Vq1 between the maximum advance position θ1 and the minimum advance position θ2. A rectangular wave control voltage Vq that holds the state and holds the second level Vq2 lower than the first level between the minimum advance angle position θ2 and the next maximum advance angle position θ2.
(FIG. 4B) is generated, and the minimum advance angle position signal Vp2 having a pulse waveform is output at the minimum advance angle position θ2.

The circuit for generating the rectangular wave control voltage Vq is set by the first signal Vs1 and the second signal Vs2.
And a circuit for charging the capacitor when the first signal Vs1 is generated and discharging the capacitor when the second signal Vs2 is generated.

The circuit for generating the minimum advance position signal Vp2 is
It can be configured by a circuit that shapes the second signal Vs2 into a pulse waveform. The minimum advance position signal Vp2 is input to the ignition position control circuit 5 as an initial ignition position signal for determining the ignition position at low speed of the engine, and is also input to the rotation detection circuit as a signal for controlling the rotation detection circuit 6. Has been done.

The ignition position control circuit 5 is a circuit for generating an ignition signal Vio at the ignition position of the internal combustion engine, with the interval from the maximum advance position to the minimum advance position being the ignition interval. For example, it is possible to use an engine in which the ignition position of the engine is calculated by integral calculation and the ignition signal Vio is generated at the calculated ignition position.

The rotation detecting circuit 6 includes, for example, a rotating speed detecting integrating capacitor, a charging circuit for charging the rotating speed detecting integrating capacitor with a first time constant, and a first signal Vs1 after the first signal Vs1 is generated. A charge blocking circuit that blocks charging of the integration capacitor by the charging circuit until the second signal Vs2 is generated, and a discharge that is provided so that a drive signal is applied and conducts while the second signal Vs2 is generated. And a discharge circuit for discharging the integrating capacitor with a second time constant sufficiently smaller than the first time constant while the discharging switch is conducting, and the internal capacitor is provided at both ends of the integrating capacitor. It is a circuit that generates a rotation speed detection voltage Vn (FIG. 4G) whose level decreases as the rotation speed of the engine increases. The specific configuration of this circuit will be described later.

The abnormality detection sensor 7 is composed of a switch provided to detect whether or not there is an abnormality in the internal combustion engine, and has different states depending on whether or not the abnormality is detected. The switch forming the illustrated abnormality detection sensor 7 is provided so as to maintain an open state when no abnormality is detected in the engine and to close the state when an abnormality is detected. The abnormality detected by the abnormality detection sensor 7 is, for example, an abnormal decrease in the level of the lubricating oil, overheat of the engine, or the like. The change in the voltage V1 across the illustrated abnormality detection sensor 7 is, for example, as shown in FIG. 4 (C). In the example, it falls to the ground potential).

The reference voltage generating circuit 8 includes a voltage dividing circuit 8A,
It is composed of a charge control switch 8B and a charge control switch control circuit 8C.

The illustrated voltage dividing circuit 8A has a first resistor R whose one end is connected to the control voltage output terminal of the control voltage generating circuit 3.
1 and a second resistor connected in series with the first resistor R1
Of the control voltage generating circuit 3 and the diode D1 to which the control voltage Vq is applied in the forward direction from the control voltage generating circuit 3 through the first and second resistors R1 and R2.
And R2 connected in series and charged by the control voltage Vq through the first and second resistors R1 and R2 and the diode D1, and a series circuit of the diode D1 and the abnormality detection capacitor C1. And a third resistor R3 connected in parallel with respect to. In the illustrated example, the diode D1 of the capacitor C1
The terminal on the opposite side is grounded. This voltage dividing circuit 8A
Outputs as reference voltage Vr a voltage corresponding to the voltage across the series circuit of the second resistor R2, the diode D1 and the abnormality detecting capacitor C1.

The charge control switch 8B is a switch provided so as to short-circuit the abnormality detecting capacitor when it becomes conductive. In the illustrated example, the emitter is grounded to the NPN transistor TR1, the collector and the capacitor of the transistor TR1 are connected to each other. It is composed of a diode D2 whose anode is connected to the non-grounded side terminal of C1 and facing the capacitor C1 side, and a diode D3 whose cathode is connected to the collector of the transistor TR1.

The charging control switch control circuit 8C conducts the charging control switch 8B when the abnormality detecting sensor 7 does not detect an abnormality, and controls the charging control when the abnormality detecting sensor 7 detects an abnormality. It is a circuit that controls on / off of the charge control switch 8B according to the state of the abnormality detection sensor 7 so that the switch 8B is turned off.

In the illustrated example, the Zener diode ZD1 having the anode connected to the base of the transistor TR1
A charging control switch control circuit 8C is constituted by a diode D4 whose anode is connected to the cathode of the zener diode ZD1 and a resistor R4 whose one end is connected to the connection point of the diode D4 and the zener diode ZD1. The abnormality detection sensor 7 is connected between the cathode and the ground. The other end of the resistor R4 is connected to an ungrounded output terminal of a constant voltage DC power supply (not shown), and the power supply voltage Vcc is applied from the DC power supply to the base of the transistor TR1 through the resistor R4 and the Zener diode ZD1.

The operation of the illustrated reference voltage generating circuit 8 is as follows. That is, there is no abnormality in the engine, and the abnormality detection sensor 7
In the open state (the state in which V1 is at a high level shown in FIG. 4C), the base current is applied to the transistor TR1 through the resistor R4 and the Zener diode ZD1 by the power supply voltage Vcc, so that the transistor TR1 becomes conductive. At this time, the potential of the collector of the transistor TR1 is in a substantially zero level state as shown at the left end of FIG. 4 (D), and the abnormality detecting capacitor C1 is substantially short-circuited by the transistor TR1. Therefore, the abnormality detecting capacitor C1 is not charged. At this time, the reference voltage generating circuit 8 sets the control voltage Vq to the resistance value of the first resistor R1 and the second control voltage Vq each time the rectangular wave control voltage Vq is generated.
A rectangular wave reference voltage Vr corresponding to the voltage obtained by dividing the voltage by a voltage division ratio determined by the resistance value of the resistor R2 is output.
This reference voltage Vr holds the first level Vr1 during the section (ignition section) from the maximum advance position to the minimum advance position, as indicated by the solid line at the left end of FIG. During the section from the minimum advance position to the next maximum advance position (ignition prohibited section), it exhibits a rectangular wave-like waveform that holds the second level Vr2 lower than the first level.

When an abnormality occurs in the engine and the switch forming the abnormality detecting sensor 7 is closed, all the current supplied from the power source through the resistor R4 flows through the diode D4 and the abnormality detecting sensor 7, so that the base current to the transistor TR1 is increased. Is blocked and the transistor is turned off. Therefore, the control voltage Vq charges the abnormality detecting capacitor C1 to the polarity shown by the third time constant through the first and second resistors R1 and R2 and the diode D1, and the voltage across the capacitor C1 rises. To go. Therefore, in the section (ignition section) from the maximum advance position to the minimum advance position where the capacitor C1 is charged, the control voltage Vq
The first level Vq1 of the first and second resistors R1 and R2
The voltage of the first level Vr1 obtained by superimposing the voltage across the capacitor C1 on the voltage obtained by the voltage division ratio determined by the above is output as the reference voltage Vr. When the control voltage Vq drops to the second level Vq2, the diode D1 is cut off, so that the terminal voltage of the capacitor C1 does not affect the reference voltage and the section from the minimum advance position to the maximum advance position (ignition). In the prohibited section), the reference voltage is the control voltage V
It is equal to the voltage obtained by dividing the second level Vq2 of q by the division ratio determined by the first to third resistors R1 to R3.

Therefore, the waveform of the reference voltage Vr shows the first level Vr1 during the ignition period as shown at the left end of FIG. 4 (G) when the abnormality detecting sensor does not detect any abnormality. After being held, it falls to the second level Vr2 which is lower than the first level at the minimum advance angle position, and becomes a rectangular wave-like waveform which holds the second level during the ignition prohibition section. The waveform of the reference voltage Vr when an abnormality is detected is shown in FIG.
As can be seen from the waveforms shown from the second from the left in (G), the low level state is maintained during the ignition prohibition section from the minimum advance position to the maximum advance position, and at the maximum advance position 1 After rising to the maximum value of the level in the preceding ignition section, the level gradually increases with the elapse of time, and returns to a low level at the minimum advance position, which is a substantially rectangular wave shape. The peak value of the reference voltage Vr in the ignition section is finally as shown in FIG.
As shown at the right end of (G), the control voltage Vq is saturated to a voltage obtained by dividing the control voltage Vq by the resistance value of the first resistor R1 and the sum of the resistance values of the second and third resistors R3. . The charging time constant (third time constant) of the abnormality detecting capacitor C1 is determined by the resistance values of the resistors R1 and R2 and the electrostatic capacitance of the capacitor C1.

The reference voltage Vr is input to the ignition approval / disapproval determination circuit 9 together with the rotation speed detection voltage Vn. The ignition permission / prohibition determination circuit 9 includes a comparison circuit for comparing the rotation speed detection voltage Vn and the reference voltage Vr. As shown in FIG. 4H, the rotation speed detection voltage Vn is equal to or higher than the reference voltage Vr. When the engine speed is set to 0 (when the engine speed is below the limit value), a low level ignition permission signal Va is generated, and the engine speed detection voltage Vn
Is lower than the reference voltage Vr (when the rotational speed exceeds the limit value), a high-level ignition prohibiting signal Vb is generated. A specific configuration example of the ignition permission / prohibition determination circuit will be described later.

In FIG. 4B, the crest value of the control voltage Vq is shown to be lower than the crest value of the reference voltage Vr due to the space of the drawing, but in reality, the crest value of the control voltage Vq is shown. The high value is sufficiently higher than the peak value of the reference voltage Vr.

In the limit value correction circuit 10, the emitter is connected to the non-ground side terminal of the capacitor C1 and the collector is the resistor R.
NPN transistor TR2 connected to the control voltage output terminal of the control voltage generation circuit through 5, and transistor TR
An NPN transistor TR3 having a collector connected to the base of 2 and an emitter grounded; a capacitor C2 having one end connected to the base of the transistor TR2 and the other end connected to the anode of the diode D3 of the charge control switch 8B; The cathode is connected to the connection point between the other end of the capacitor C2 and the anode of the diode D3, and the anode is connected between the diode D5 whose anode is connected to the control voltage output terminal of the control voltage generation circuit through the resistor R6 and the collector-emitter of the transistor TR3. Is connected to the ground side, and a resistor R is connected between the base of the transistor TR3 and the output terminal of the ignition permission / prohibition determination circuit 9.
It consists of 7.

In the limit value correction circuit 10, the transistor TR1 is cut off because an engine abnormality is detected, and the ignition permission / prohibition determination circuit 9 generates a low level ignition permission signal Va so that the transistor TR3 is cut off. In this state, when the control voltage Vq is applied, the base current i2 (FIG. 4E) flows through the transistor TR2 through the capacitor C2 and the transistor TR2 becomes conductive. FIG.
(F) shows changes in the potential V3 of the collector of the transistor TR2.

When the transistor TR2 is turned on, the control voltage Vq charges the abnormality detecting capacitor C1 through the resistor R5 and the transistor TR2 with a fourth time constant smaller than the third time constant. When the ignition permission / denial determination circuit 9 is generating the high-level ignition prohibition signal Vb, the transistor TR3 is in the conductive state and the transistor TR2 is in the cutoff state. Therefore, the abnormality detecting capacitor C1 based on the fourth time constant is used. Is not charged.

When the abnormality detecting capacitor C1 is charged with the fourth time constant, the reference voltage Vr rapidly rises, as shown in the second waveform from the left end of FIG. 4 (G).
When the reference voltage Vr becomes equal to the rotational speed detection voltage Vn indicating the rotational speed of the engine at that time, the ignition permission / prohibition determination circuit 9 outputs a high-level ignition prohibition signal Vb, so that the transistor T
R2 is cut off, and charging of the abnormality detecting capacitor C1 is stopped. By these operations, the reference voltage Vr is corrected by the correction value ΔVr as shown in FIG.
As a result, the limit value of the engine speed is corrected to a value equal to the engine speed at that time.

That is, the limit value correction circuit 10 ignites at the time when the maximum advance position is first detected (the first signal Vs1 is generated) after the abnormality detection sensor is in the state of detecting the abnormality of the engine. When the permission signal Va is generated (when the operation of limiting the engine speed is not started), the reference voltage Vr is increased until it becomes equal to the engine speed detection voltage Vn. Correct the limit value so that it is equal to the current engine speed.

In the illustrated limit value correction circuit 10, the transistor TR2 constitutes a reference voltage correction charge switch, and the charge detection switch and the resistor R5 form an abnormality detection capacitor when the reference voltage correction charge switch is turned on. A reference voltage correction charging circuit is configured to charge C1 with a fourth time constant smaller than the third time constant. In addition, with resistor R6, diode D5 and capacitor C2,
Reference voltage correction charge switch drive circuit for supplying a drive signal for turning on the reference voltage correction charge switch (transistor TR2) when the control voltage Vq is generated in a state where an abnormality of the engine is detected The transistor TR3 and the resistor R7 allow the drive signal to be supplied to the reference voltage correction charging switch while the ignition permission / prohibition determination circuit 9 is generating the ignition permission signal, and generate the ignition prohibition signal. The reference voltage correction charge switch control circuit is configured to prevent the drive signal from being applied to the reference voltage correction charge switch while the switch is operating.

The feedback circuit 11 is provided between the output terminal of the ignition permission / prohibition determination circuit 9 and the rotation detection circuit 6, and when the rotation speed detection voltage Vn becomes equal to the reference voltage Vr, the rotation speed of the rotation detection circuit. A drive signal (current i1 shown in FIG. 4I) is applied to the discharge switch of the rotation detection circuit from the output side of the ignition permission / prohibition determination circuit in order to discharge the detection integration capacitor with the second time constant.

The ignition signal supply control circuit 12 provides the ignition signal Vi to the ignition circuit 1 when the ignition permission signal Va is generated by the ignition permission determination circuit 9 and the ignition permission determination circuit. Generates an ignition prohibition signal Vb, prohibits the ignition signal Vi from being given to the ignition circuit 1. This ignition signal supply control circuit can be configured by, for example, a switch circuit that conducts when an ignition prohibition signal is given and bypasses the ignition signal from the ignition circuit.

In the ignition device of FIG. 1, when the engine speed of the engine exceeds the maximum limit value while the anomaly detection sensor 7 does not detect an anomaly, the engine speed detection voltage at the maximum advance position θ1 is reached. The circuit constants of the rotation detection circuit 6 and the reference voltage generation circuit 8 are set so that Vn becomes equal to or lower than the reference voltage Vr.

In the example shown in FIG. 1, the control voltage generating circuit 4
The rotation detection circuit 6, the abnormality detection sensor 7, the reference voltage generation circuit 8, the ignition approval / disapproval determination circuit 9, the limit value correction circuit 10, the feedback circuit 11, and the ignition signal supply control circuit 12 cause an abnormality. Protection that protects the engine by preventing the ignition signal from being given to the ignition circuit and misfiring the engine when the engine speed exceeds the limit value while the detection sensor detects an abnormality The circuit is configured.

In the ignition device shown in FIG. 1, when the internal combustion engine has no abnormality, the switch constituting the abnormality detection sensor 7 is closed, and when the rotation speed of the internal combustion engine is below the limit value during steady operation, Since the rotation speed detection voltage Vn does not become lower than the reference voltage Vr at the position where the phase advances from the ignition signal generation position, the low level ignition permission signal is generated at the time of the ignition signal generation. for that reason,
The ignition signal Vi is supplied to the ignition circuit 1 so that the engine can be operated without any trouble. When there is no abnormality in the engine, the transistor TR1 is conducting. Therefore, even if the control voltage Vq is generated, the base current does not flow in the transistor TR2 of the limit value correction circuit 10, and the operation of correcting the limit value is not performed.

When the engine speed exceeds the limit value during steady operation, the engine speed detection voltage becomes equal to or lower than the reference voltage at a position ahead of the ignition signal generation position. 9 produces the ignition prohibiting signal Vb at a position where the phase advances from the generation position of the ignition signal Vi. In such a state where the ignition prohibition signal is generated at the position in which the phase is advanced from the position where the ignition signal is generated, the ignition signal supply control circuit 12 prohibits the supply of the ignition signal to the ignition circuit, so that the ignition circuit performs the ignition operation. The engine will misfire. As a result, when the engine speed falls below the limit value, the engine speed detection voltage cannot fall below the reference voltage at a position ahead of the ignition signal generation position in phase, and the engine is ignited again. By repeating these operations, the engine speed is controlled so as not to exceed the limit value during steady operation.

When the abnormality detection sensor detects an abnormality of the engine, the transistor TR1 of the charge control switch 8B is turned off to release the short circuit of the abnormality detection capacitor C1, so that the control voltage Vq becomes the first level Vq1. Every time, the abnormality detecting capacitor C1 is charged with the third time constant through the first and second resistors R1 and R2.
The waveform of the reference voltage Vr is maintained at a low level during the ignition prohibition section from the minimum advance position to the maximum advance position and rises to the maximum level in the immediately preceding ignition section at the maximum advance position. The level rises with the passage of time and returns to a low level at the minimum advance position.

When the engine speed is lower than the limit value at that time when the engine abnormality is detected and the ignition permission / prohibition determination circuit 9 generates the low level ignition permission signal Va,
Since the transistor TR3 of the limit value correction circuit 10 is in the cut-off state, when the pulsar coil 3 generates the first signal Vs1 and the control voltage Vq is generated, the resistor R6, the diode D5 and the capacitor C2 of the limit value correction circuit 10 are generated. A base current flows through the transistor TR2 through and, and the transistor TR2 becomes conductive. When the transistor TR2 becomes conductive, the abnormality detecting capacitor C1 is charged with the fourth time constant smaller than the third time constant, so that the voltage across the abnormality detecting capacitor rises rapidly and the reference voltage is reduced in a short time. It becomes equal to the rotation speed detection voltage. When the reference voltage becomes equal to the rotation speed detection voltage that gives the current value of the rotation speed, the ignition permission / prohibition determination circuit will generate an ignition prohibition signal, so that the charging of the abnormality detection capacitor by the fourth time constant is stopped.
By these operations, the limit value of the engine speed is corrected to a value equal to the current value of the engine speed. After that, the abnormality detecting capacitor C1 has the first control voltage Vq at the maximum advance position.
Since the battery is charged with the third time constant every time the level Vq1 of the reference voltage becomes Vq1, the level of the reference voltage gradually increases in the section from the maximum advance position to the minimum advance position as shown in FIG. The engine speed limit value gradually decreases.

In the state where the engine speed is higher than the limit value and the engine speed detection voltage cannot exceed the reference voltage at the maximum advance position, the reference voltage Vr rises to a high level at the maximum advance position θ2, The base current i1 (FIG. 4I) is applied to the transistor TR11 through the feedback circuit 11 when the high level ignition prohibiting signal is generated from the comparison circuit CM2. As a result, the transistor TR11 becomes conductive and discharges the electric charge of the rotational speed detecting integration capacitor C9. Therefore, the rotational speed detection voltage Vn rises at a constant inclination from the position where the minimum advance position signal Vp2 disappears and then reaches the maximum advance. It has a waveform that drops rapidly from the angular position and returns to zero.

When the number of revolutions is higher than the limit value, as shown in FIG.
As shown in (H), at the maximum advance position, the rotation speed detection voltage V
When n becomes lower than the reference voltage Vr, the comparison circuit CM2
Outputs a high level ignition prohibition signal Vb, the transistor TR12 conducts and prohibits the supply of the ignition signal to the ignition circuit 1. As a result, the engine misfires and the engine speed is limited below the limit value. Although the rotational speed limit value gradually decreases as the reference voltage increases, the reference voltage eventually saturates, and the rotational speed limit value settles at the allowable upper limit value during abnormal conditions.

If the ignition prohibition signal Vb has already been generated when the engine abnormality is detected, the protection operation is continued. The ignition permission signal is generated at the point where the reference voltage rises every time the control voltage is generated, the engine speed is gradually decreased, and the engine speed is converged to the final limit value (upper limit value in case of abnormality). This is the same as when an abnormality is detected in the state.

As described above, when an abnormality of the engine is detected while the ignition permission signal is being generated, the reference when the first signal is generated at the maximum advance position that first arrives after the abnormality is detected. If the voltage is corrected to be equal to the rotation speed detection voltage and the ignition prohibition signal is generated, the protection operation can be started in a short time when an abnormality of the engine is detected. It can be done accurately.

In the example of FIG. 1, in the reference voltage generating circuit 8, the third resistor R3 is the diode D1 and the capacitor C.
1 is connected in parallel with the series circuit, but as shown in FIG. 2, the third resistor R3 is connected in parallel with the series circuit of the second resistor R2 diode D1 and capacitor C1. You may do it.

When the reference voltage generating circuit 8 is constructed as shown in FIG. 2, the control voltage Vq is set to the resistance value of the first resistor R1 when the abnormality detection sensor 6 is open without any abnormality in the engine. A reference voltage Vr corresponding to a voltage divided by a voltage dividing ratio determined by the parallel combined resistance value of the second resistor R2 and the third resistor R3 is obtained. Further, when an abnormality occurs in the engine and the abnormality detection sensor 7 is closed, the first level Vq1 of the control voltage Vq is set to the resistance value of the first resistor R1 in the section from the maximum advance position to the minimum advance position. And a reference voltage Vr of a value obtained by superimposing a voltage corresponding to the charging voltage of the capacitor C1 on a voltage divided by a voltage division ratio determined by the parallel combined resistance value of the second and third resistors R2 and R3. This reference voltage is
Finally, the first level of the control voltage Vq is saturated with a voltage divided by a voltage division ratio determined by the resistance value of the first resistor R1 and the resistance value of the third resistor R3.

[0077]

FIG. 3 shows an embodiment of the present invention in which each part of FIG. 1 is concretely shown. In FIG. 3, an ignition circuit 1 has a primary coil W1 and a secondary coil W2. An ignition coil IG whose one end is grounded, an ignition energy storage capacitor Ci whose one end is connected to the non-grounded side terminal of the primary coil W1, and an anode directed to the ground side between the other end of the capacitor Ci and ground. Connected thyristor Th1 and diode D whose cathode is connected to the other end of the capacitor Ci.
10, an exciter coil EX having one end connected to the anode of the diode D10, a diode D11 connected to both ends of the primary coil W1 with the cathode facing the ground side, and an exciter coil EX having the anode facing the ground side. A diode D12 connected between the end and ground. The other end of the exciter coil EX is also connected to the anode of the diode D13 and the anode of the thyristor Th2, and the power supply capacitor C3 is connected between the cathode of the diode D13 and the ground. The gate of the thyristor Th2 is a Zener diode ZD2 whose anode is directed to the thyristor Th2 side.
Is connected to the non-grounded side terminal of the capacitor C3. A diode D14 with its anode facing the ground side is connected between one end of the exciter coil and ground. In the illustrated example, the power supply capacitor C3, the thyristor Th2,
Diodes D13 and D14 and Zener diode ZD2
DC power supply circuit 13 for generating a DC constant voltage Vcc by
Is configured.

The ignition circuit 1 shown in FIG. 3 is known as a capacitor discharge type ignition circuit. In this ignition circuit, the exciter coil EX is provided in a magneto generator attached to the engine, and an AC voltage is induced in the exciter coil in synchronization with the rotation of the engine. Due to the positive half-cycle voltage induced in the exciter coil EX, the diode D10, the capacitor Ci and the diode D11 are
Also, current flows through the primary coil W1 of the ignition coil and the diode D12, and the capacitor Ci is charged to the polarity shown. When the ignition signal Vi is applied to the gate of the thyristor Th1 at the ignition position of the engine, the thyristor Th1 becomes conductive, so that the electric charge of the capacitor Ci is discharged through the thyristor Th1 and the primary coil W1 of the ignition coil. This discharge induces a high voltage in the primary coil W1, and the voltage is further boosted to induce a high ignition voltage in the secondary coil W2 of the ignition coil. Since this high voltage is applied to the spark plug 2, a spark is generated in the spark plug to ignite the engine.

Reference numeral 3 denotes a pulsar coil provided in a signal generator attached to the internal combustion engine. As shown in FIG. 4 (A), the pulsar coil has a maximum advance position θ1 and a minimum advance position θ2 of the ignition position of the engine, respectively. The first signal Vs1 and the second signal Vs2 are output. These signals are input to the control voltage generation circuit 4.

The control voltage generating circuit 4 includes PNP transistors TR5 and TR6, NPN transistors TR7 and TR8, a control voltage generating capacitor C4, biasing capacitors C5 and C6, and resistors R10 to R13.
It is composed of diodes D15 to D17.

The pulsar coil 3 has the negative first signal Vs1.
Is generated, a base current is given to the transistor TR7 through a bias circuit composed of the capacitor C5 and the resistor R11. The bias circuit composed of the capacitor C5 and the resistor R11 is provided in order to increase the threshold value that the first signal Vs1 needs to take in order to make the transistor TR7 conductive and prevent malfunction due to noise. The capacitor C5 of this bias circuit is charged by the first signal Vs1 and discharged through the resistor R11. When the first signal Vs1 exceeds the voltage (threshold value) -Vt across the capacitor C5, a base current flows through the transistor TR7 and the transistor TR7 becomes conductive. When the transistor TR7 becomes conductive, the base current flows through the transistor TR5,
The transistor TR5 becomes conductive, and the power supply voltage Vcc
As a result, the control voltage generating capacitor C4 is charged to the polarity shown through the emitter-collector of the transistor TR5. As a result, the control voltage V appears across the capacitor C4.
q rises.

Next, when the pulser coil 3 generates the positive second signal Vs2, when the signal Vs2 exceeds the threshold value Vt determined by the voltage across the bias circuit formed by the parallel circuit of the capacitor C6 and the resistor R12. Since the base current is applied to the transistor TR8, the transistor TR8 becomes conductive. When the transistor TR8 is turned on, the charge of the control voltage generating capacitor C4 is discharged through the diode D17 and the transistor TR8, so that the voltage across the capacitor C4 decreases. Transistor T
When R8 becomes conductive, a voltage drop occurs between both ends of the diode D17 and between the collector and emitter of the transistor TR8, so that the voltage remains in the capacitor C4. Therefore,
As shown in FIG. 4 (B), both ends of the control voltage generating capacitor C4 are connected.
As shown in, the state of the first level Vq1 is maintained from the rotation angle position θ1 at which the first signal Vs1 reaches the threshold value to the rotation angle position θ2 at which the second signal Vs2 reaches the threshold value. 1st from the minimum advance position to the next maximum advance position
A rectangular wave-shaped control voltage Vq that holds a second level Vq2 lower than the level Vq1 of the above is obtained. The pulsar coil is arranged so that the rotation angle position θ1 at which the first signal Vs1 reaches the threshold value and the rotation angle position θ2 at which the second signal Vs2 reaches the threshold value coincide with the maximum advance position and the minimum advance position of the engine, respectively. 3 is provided. The minimum advance position θ2 is an ignition position at low speed of the engine, and is usually set to a position slightly advanced from the rotation angle position where the piston reaches the vicinity of the top dead center.

When the transistor TR8 becomes conductive, a base current flows through the transistor TR6 and the transistor TR6 becomes conductive, and the minimum advance position signal V indicating the minimum advance position is passed through between the emitter and collector of the transistor TR6.
p2 is output.

In the illustrated example, the diode D15, the transistors TR5 and TR7, the resistor R10, and the bias circuit including the capacitor C5 and the resistor R11 cause the first signal Vs1 to be generated when the pulsar coil is at the maximum advance position (correctly). Is a charging circuit for charging the control voltage generating capacitor C4 almost instantly when the first signal reaches the threshold level. Further, when the pulsar coil generates the second signal Vs2 at the minimum advance position by the bias circuit consisting of the diode D16, the transistor TR8, the capacitor C6 and the resistor R12 and the diode D17 (the second signal reaches the threshold value). At this time), a discharge circuit is configured to discharge the control voltage generating capacitor C4 almost instantaneously.

The ignition position control circuit 5 comprises an NPN transistor TR9, resistors R14 to R19, diodes D18 to D21, a first integrating capacitor C7 and a second integrating capacitor C8, and a comparing circuit CM1. There is. This ignition position control circuit is a known circuit for calculating an ignition position at each rotation speed by integral calculation and generating an ignition command signal at the calculated ignition position.

Signal waveform diagrams for explaining the operation of the ignition command signal generating circuit are shown in FIGS. 5 (A) to 5 (F). 5A and 5B show the same waveforms as FIGS. 4A and 4B, respectively. In the ignition position control circuit 5 shown in the figure, when the control voltage Vq is generated, the transistor T
R9 becomes conductive, and the control voltage Vq causes the transistor TR to
The first integrating capacitor C through the collector and emitter of 9
7 is charged to the polarity shown. First integration capacitor C
When the voltage across 7 reaches the set value Vo corresponding to the voltage obtained by dividing the control voltage Vq by the voltage dividing circuit consisting of the series circuit of the resistors R14 and R15, the transistor TR9 is turned off. After the transistor TR9 is turned off, the control voltage Vq causes the first integrating capacitor C7 to be additionally charged through the resistor R16 with a constant time constant. When the second signal is generated at the minimum advance position θ2 and the transistor TR8 of the control voltage generating circuit 4 becomes conductive, the charge of the first integrating capacitor C7 is changed to the diode D18 and the transistor TR8.
Discharges almost instantly between the collector and emitter of 8. Therefore, as shown in FIG. 5 (C), both ends of the first integrating capacitor C7 instantly rises to the set value Vo at the maximum advance position θ1 and then rises at a constant slope and reaches the minimum advance. A first integrated voltage Vc1 having a waveform that returns to zero at the angular position θ2 is obtained.

The second integrating capacitor C8 is the power supply circuit 13
Is charged with a constant time constant through a resistor R17. When the second signal Vs2 is generated at the minimum advance position θ2 and the transistor TR8 of the control voltage generating circuit 3 becomes conductive, the charge of the second integrating capacitor C8 is discharged almost instantly between the diode D19 and the collector-emitter of the transistor TR8. To do. Therefore, at both ends of the second integrating capacitor C8, as shown in FIG. 5 (C), the first waveform of the waveform that rises from each minimum advance angle position with a constant inclination and returns to zero at the next minimum advance angle position. An integrated voltage Vc2 of 2 is obtained.

The comparison circuit CM1 compares the first integrated voltage Vc1 and the second integrated voltage Vc2 to determine the first integrated voltage Vc1.
Is at the second integrated voltage Vc2 or higher, the potential V3 of the output terminal is set to the high level. This rise of the potential V3 is output to the output terminal 5 of the ignition position control circuit through the diode D20 as the ignition command signal Vio which determines the ignition position in the advance region.
It is transmitted to a.

Further, when the second signal Vs2 is generated at the minimum advance position θ2 and the transistor TR6 of the control voltage generating circuit 4 becomes conductive, the minimum advance is made from the power supply circuit 10 between the emitter and collector of the transistor TR6 and the resistor R19. The angular position signal Vp2 (FIG. 5D) is the output terminal 5 of the ignition position control circuit 5 as the ignition command signal Vio that determines the ignition position at low speed.
a.

That is, when the first integrated voltage Vc1 matches the second integrated voltage Vc2, the ignition position control circuit 5 appropriately changes the advance position of the ignition position in accordance with the change of the rotation speed. The ignition command signal Vio that determines the ignition position in the rotation speed range) is output. When the pulsar coil 3 generates the second signal Vs2 at the minimum advance position, the ignition command signal Vio that determines the ignition position at low speed is output. To do. Ignition position control circuit 5
The waveform of the ignition command signal Vio output by is, for example, FIG.
become that way.

In the illustrated example, the transistor TR9, the resistors R14 to R16, and the first integrating capacitor C7
When the control voltage Vq is generated, the first integration capacitor is instantaneously charged by the control voltage to the set value Vo, and then the first integration capacitor is additionally charged with a constant time constant.
Integral capacitor charging control circuit is constructed. Also, the diode D18 and the transistor TR of the control voltage generation circuit
Position at which the second signal was generated by 8 (minimum advance position)
The reset circuit configured to instantly discharge the first integration capacitor is configured by the reset circuit and the first integration capacitor charging control circuit, and the section in which the control voltage Vq is generated is used as the integration section for the first integration. A first integrator circuit that generates the voltage Vc1 is configured.

Further, the resistor R17 and the second integrating capacitor C8
Constitutes a second integrating capacitor charging circuit for charging the second integrating capacitor with a constant time constant, and the diode D19 and the transistor TR8 of the control voltage generating circuit form the second signal generation position (minimum advance angle). A reset circuit is configured to instantly discharge the second integrating capacitor at the position). With this reset circuit and the second integration capacitor charging circuit, the section from the generation position of each second signal to the generation position of the next second signal is set as the second integration section.
A second integrator circuit for generating the integrated voltage Vc2 of is constructed.

Further, by the diodes D20 and D21, an OR circuit for outputting the ignition command signal Vio when the ignition command signal for the advance region or the ignition command signal for the low speed (minimum advance position signal Vp2) is generated. It is configured.

In the illustrated example, the transistor TR8 has a reset switch for discharging the control voltage generating capacitor C4 and a reset switch for discharging the first integrating capacitor C7 and the second integrating capacitor C8, respectively. Also serves as capacitors C4, C7 and C8
A reset switch may be provided for each of the above.

The rotation detection circuit 6 includes an NPN transistor T
R10 and TR11, resistors R20 to R24, a rotation speed detecting integrating capacitor C9, and a diode D21. The base of the transistor TR10 and the transistor T10.
The control voltage Vq and the minimum advance position signal Vp2 are input to the bases of R11.

A capacitor C10 forming a feedback circuit is connected between the base of the transistor TR11 and the output terminal of the ignition permission / prohibition determination circuit 9.

In the illustrated rotation detecting circuit 6, the transistor TR10 is in the cutoff state when the control voltage Vq is not generated. At this time, the rotation speed detecting integrating capacitor C9 is charged from the power supply circuit 13 through the resistor R21, the diode D21 and the resistor R23 to the polarity shown in the figure with a constant time constant
The terminal voltage rises. When the control voltage Vq is generated, the transistor TR10 becomes conductive, so that the charging current of the rotational speed detecting integrating capacitor C9 is shunted from the capacitor, and the charging of the rotational speed detecting integrating capacitor C9 is blocked. Next, when the pulsar coil 3 generates the second signal Vs2 and the transistor TR6 becomes conductive, a base current flows through the transistor TR11 and the transistor TR11 becomes conductive. When the transistor TR11 becomes conductive, the electric charge of the rotational speed detecting integrating capacitor C9 is discharged through the resistor R24 and the collector-emitter of the transistor TR11. Since the resistance value of the resistor R24 is set to be sufficiently small, the rotation speed detecting integrating capacitor is discharged in a short time. Further, when the ignition permission / prohibition determination circuit 9 to be described later generates a high level ignition prohibition signal Vb, the base current i1 (FIG. 4I) is given to the transistor TR11 through the feedback circuit 11, so that integration is performed when the ignition prohibition signal Vb is generated. The capacitor C9 is discharged in a short time.

The waveform of the rotation speed detection voltage Vn obtained at both ends of the rotation speed detection integrating capacitor C9 is shown by a chain line in FIG. 4 (G). Since the time for charging the rotation speed detecting integration capacitor C9 becomes shorter as the rotation speed of the engine increases, the peak value of the rotation speed detection voltage Vn becomes lower as the rotation speed increases. Therefore, the rotational speed information of the engine can be obtained from this rotational speed detection voltage Vn.

In the rotation detection circuit 6 shown in FIG. 3,
The resistor R21, the diode D21, and the resistor R23 form a charging circuit that charges the rotation speed detection integrating capacitor C9 with the first time constant, and after the resistor R21 and the transistor TR10 generate the first signal Vs1. A charge blocking circuit is configured to block charging of the integrating capacitor by the charging circuit until the second signal Vs2 is generated. Further, the transistor TR11 constitutes a discharge switch which is electrically connected by being supplied with a drive signal while the second signal Vs2 is generated, and the discharge switch and the resistor R24 make the discharge switch conductive. A discharging circuit is configured to discharge the integrating capacitor with a second time constant sufficiently smaller than the first time constant.

The structure of the reference voltage generating circuit 8 is the same as that shown in FIG. 1 and outputs the reference voltage Vr shown by the solid line in FIG. 4 (G).

The ignition approval / disapproval determination circuit 9 includes a comparison circuit CM2.
And a resistor R25, and the rotation speed detection voltage Vn and the reference voltage Vr are input to the inverting input terminal and the non-inverting input terminal of the comparison circuit CM2, respectively. The output terminal of the comparison circuit CM2 is connected to the base of the transistor TR11 of the rotation detection circuit 6 through the capacitor C10 which constitutes the feedback circuit 11.

The limit value correction circuit 10 is constructed similarly to the example shown in FIG. 1, and the transistor TR of the limit value correction circuit is formed.
The base of 3 and the output terminal of the comparison circuit CM2 of the ignition permission / denial determination circuit 9 are connected through a resistor R7.

The ignition signal supply control circuit 12 has an emitter grounded and a collector connected between the NPN transistor TR12 whose collector is connected to the gate of the thyristor Th1 and a resistor connected between the base of the transistor and the output terminal of the comparison circuit CM2. R26 and R26 inhibit the supply of the ignition signal to the ignition circuit 1 when the transistor TR12 is conductive.

The comparison circuit CM2 of the ignition permission / prohibition determination circuit 9 is
The rotation speed detection voltage Vn is compared with the reference voltage Vr, and when the rotation speed detection voltage Vn exceeds the reference voltage Vr, the ignition permission signal Va is output, and the rotation speed detection voltage Vn is output as the reference voltage Vr.
When it becomes r or less, the ignition prohibition signal Vb is output.

The voltage or current waveform of each part of the ignition device shown in FIG. 3 is as shown in FIGS. 4 (A) to 4 (L). That is, FIG. 4A shows the waveforms of the first signal and the second signal output from the pulser coil, and FIG. 4B shows the waveform of the control voltage Vq. 4 (C), (D),
(E) and (F) are the voltage V1 across the abnormality detection sensor 7 and the collector potential V2 of the transistor TR1, respectively.
, Waveforms of the base current i2 given to the transistor TR3 through the capacitor C2 and the collector potential V3 of the transistor TR2 are shown. FIG. 4G shows the waveforms of the rotation speed detection voltage Vn and the reference voltage Vr.
(H) shows the ignition permission signal Va and the ignition prohibition signal Vb output from the comparison circuit CM2. Further, FIG. 4 (I) shows the base current i1 given to the transistor TR11 through the feedback circuit 11, and FIG. 4 (J) shows the transistor TR12.
The change in the collector potential V4 of the transistor TR3 and the collector potential V5 of the transistor TR3 is shown. 4 (K) shows an example of the waveform of the ignition command signal Vio output from the ignition position control circuit 5, and FIG. 4 (L) shows the waveform of the ignition signal Vi given to the ignition circuit 1.

In the ignition device of FIG. 3, when the engine speed is lower than the limit value and the ignition permission / prohibition determination circuit 9 is generating the low level ignition permission signal Va, the transistor TR12 of the ignition signal supply circuit 12 is turned on. Since the potential V4 (FIG. 4J) of the collector of the transistor TR12 is in the high level in the cutoff state, the ignition signal Vi is supplied from the ignition position control circuit 5 to the ignition circuit 1 to perform the ignition operation.

When the ignition permission signal Va is generated, the transistor TR3 of the limit value correction circuit 10 is in the cutoff state, and the collector potential V3 of the transistor TR3 is V3.
Since transistor 5 (FIG. 4J) is in the high level state, transistor TR2 is in a state in which it can conduct. In this state, if an abnormality of the engine is detected and the transistor TR1 is turned off, the transistor TR2 is generated when the control voltage Vq is generated.
Is applied with a base current i2 to turn on the transistor TR2, and as described above, the capacitor C1 is charged with the fourth time constant to correct the reference voltage Vr. Therefore, when the abnormality of the engine is detected, the protection operation is immediately started.

In the state where the engine abnormality is detected, the transistor TR1 is in the cut-off state, and the abnormality detection capacitor C1 is charged through the first and second resistors R1 and R2 every time the control voltage Vq is generated. Therefore, the voltage across the abnormality detecting capacitor C1 gradually rises, and the reference voltage Vr becomes equal to the amount of increase in the voltage across the abnormality detecting capacitor when an abnormal state is not detected. Higher than the value. Abnormality detection capacitor C1
Since the control voltage Vq is charged every time the control voltage Vq is generated, the reference voltage Vr gradually increases and the engine speed limit value gradually decreases.

When the reference voltage Vr is saturated in due course, the ignition command signal V
The rotation speed detection voltage Vn exceeds the reference voltage Vr to cause the engine to misfire at a position where the phase advances from the generation position of io, and the rotation speed of the engine cannot exceed the allowable upper limit value at the time of abnormality.

[0110]

As described above, according to the present invention, when the maximum advancing position is first detected after the abnormality is detected, the internal combustion engine rotation speed is lower than the limit value at that time. By correcting the limit value to a value equal to the current value of the engine speed, the protective action can be started immediately when an abnormality of the engine is detected, so the engine can be protected properly. Can be planned.

[Brief description of drawings]

FIG. 1 is a configuration diagram specifically illustrating only a main part of a configuration example of an ignition device according to the present invention.

FIG. 2 is a circuit diagram showing a modified example of the main part of the ignition device in FIG.

FIG. 3 is a circuit diagram showing a more specific configuration example of the ignition device according to the present invention.

FIG. 4 is a waveform diagram showing voltage and current waveforms of respective parts of the ignition device of FIGS. 1 and 3.

5 is a waveform diagram for explaining the operation of an ignition position control circuit used in the ignition device shown in FIG.

FIG. 6 is a diagram showing an example of control characteristics of an ignition device having a function of protecting an engine by misfiring the engine at the time of abnormality.

FIG. 7 is a diagram showing another example of the control characteristics of the ignition device having the function of protecting the engine by misfiring the engine at the time of abnormality.

[Explanation of symbols]

 1 Ignition circuit 2 Spark plug 3 Pulser coil 4 Control voltage generation circuit 5 Ignition position control circuit 6 Rotation detection circuit 7 Abnormality detection sensor 8 Reference voltage generation circuit 8A voltage dividing circuit 8B Charge control switch 8C Charge control switch control circuit C1 Abnormality detection Capacitor 9 Ignition permission / denial determination circuit 10 Limit value correction circuit 11 Feedback circuit 12 Ignition signal supply control circuit

Claims (3)

[Claims] 1. An ignition position control circuit for outputting an ignition signal whose generation position varies between a maximum advance position and a minimum advance position of an internal combustion engine, and an ignition high control circuit when the ignition signal is given. An ignition circuit that generates a voltage, an abnormality detection sensor that detects an abnormality of the internal combustion engine, and the ignition circuit when the engine speed exceeds a limit value while the abnormality detection sensor is detecting an abnormality A protection circuit for preventing the ignition signal from being given to the engine and causing the engine to misfire, the protection circuit gradually decreasing the limit value of the rotational speed when an abnormality is detected with the passage of time. In the internal combustion engine ignition device configured, the protection circuit, the rotation speed of the internal combustion engine at the time when the maximum advance position is first detected after the abnormality detection sensor is in a state of detecting an abnormality Below the limit Ignition device for an internal combustion engine characterized by comprising a limit value correction circuit for correcting to equal the limit value to the current value of the rotational speed of the engine. 2. An ignition position control circuit for outputting an ignition signal whose generation position varies between a maximum advance position and a minimum advance position of an internal combustion engine, and an ignition high control circuit when the ignition signal is given. An ignition circuit that generates a voltage, an abnormality detection sensor that detects an abnormality of the internal combustion engine, and the ignition circuit when the engine speed exceeds a limit value while the abnormality detection sensor is detecting an abnormality In an ignition device for an internal combustion engine, comprising: a protection circuit for preventing an ignition signal from being given to the engine, and the protection circuit, wherein the protection circuit has a maximum advance angle from a fixed position slightly delayed from the minimum advance position. The integration obtained by charging the integration capacitor to a position with a constant time constant, and then discharging the charge of the integration capacitor in the interval from the maximum advance position to a position slightly delayed from the minimum advance position. Rotate voltage A rotation detection circuit that generates a detection voltage and, in a state where the abnormality detection sensor does not detect an abnormality, holds a first level from a maximum advance position to a minimum advance position and then from the minimum advance position to the next maximum advance position. The second level, which is higher than the first level, is maintained up to the angular position, and when an abnormality is detected, the level of the section from the maximum advance position to the minimum advance position changes with time. A reference voltage generating circuit that generates a substantially rectangular reference voltage that gradually increases, and compares the rotation speed detection voltage with a reference voltage, and outputs an ignition permission signal when the rotation speed detection voltage exceeds the reference voltage. An ignition permission / prohibition determination circuit that generates an ignition prohibition signal when the rotational speed detection voltage becomes equal to or lower than a reference voltage, and permits the ignition signal to be given to the ignition circuit when the ignition permission signal is generated. And ignite An ignition signal supply control circuit that prohibits the ignition signal from being given to the ignition circuit when a stop signal is generated, and the maximum advance position is first detected after the abnormality detection sensor is in a state of detecting an abnormality. When the ignition permission signal is generated at the time point, the limit value of the engine speed is made equal to the current value of the engine speed by raising the reference voltage until it becomes equal to the engine speed detection voltage. An ignition device for an internal combustion engine, comprising: 3. A pulser coil for generating first and second pulse waveform signals at the maximum advance position and the minimum advance position of the internal combustion engine, respectively, and rotation angle information obtained from the first and second signals, An ignition position control circuit that calculates an ignition position using the rotational speed information and outputs an ignition signal whose generation position changes between a maximum advance position and a minimum advance position, and when the ignition signal is given An ignition circuit that generates a high voltage for ignition, an abnormality detection sensor that detects an abnormality of the internal combustion engine, and the engine speed exceeds the limit value while the abnormality detection sensor detects the abnormality. An ignition device for an internal combustion engine, comprising: a protection circuit that sometimes prevents an ignition signal from being given to the ignition circuit to misfire the engine, wherein the protection circuit inputs the first signal and the second signal. As the maximum advance position To a minimum advance angle position, a control voltage generation circuit that generates a control voltage that maintains a high level state, a charging circuit that charges the rotation speed detection integrating capacitor with a first time constant, and the first signal From the occurrence of the second signal to the generation of the second signal, and a charge blocking circuit that blocks the charging of the integration capacitor by the charging circuit, and a drive signal is applied during the generation of the second signal to conduct electricity. And a discharge circuit that discharges the integrating capacitor with a second time constant sufficiently smaller than the first time constant while the discharge switch is conducting. And a rotation detection circuit that generates a rotation speed detection voltage whose level decreases as the rotation speed of the internal combustion engine increases at both ends of the integration capacitor; and a first end whose one end is connected to an output terminal of the control voltage generation circuit Resistance and A second resistor connected in series to the first resistor, and a diode to which the control voltage is forwardly applied from the control voltage generation circuit through the first and second resistors. An abnormality detecting capacitor connected in series with the second resistor and charged by the control voltage through the first and second resistors and the diode at a third time constant; and the diode and the abnormality detecting capacitor. A third circuit connected in parallel to the series circuit or the series circuit of the second resistor, the diode, and the abnormality detection capacitor
A voltage dividing circuit having a resistor, a charge control switch provided to short-circuit the abnormality detection capacitor when conducting, and the charge control switch when the abnormality detection sensor does not detect an abnormality. Charge control for turning on / off the charge control switch according to the state of the abnormality detection sensor so that the charge control switch is turned off when the abnormality detection sensor detects an abnormality. A reference voltage generation circuit that includes a switch control circuit and outputs a voltage corresponding to the voltage across the series circuit of the second resistor, the diode, and the abnormality detection capacitor as a reference voltage; and the rotation speed detection voltage. An ignition permission signal is generated when the rotation speed detection voltage exceeds the reference voltage by comparing with the reference voltage, and when the rotation speed detection voltage becomes equal to or lower than the reference voltage. An ignition permission / prohibition determination circuit that generates an ignition prohibition signal, and permits the ignition signal to be supplied to the ignition circuit when the ignition permission signal is generated, and the ignition is performed when the ignition prohibition signal is generated. An ignition signal supply control circuit that prohibits a signal from being given to the ignition circuit, the first abnormality detection sensor detects an abnormality, and the ignition permission / prohibition determination circuit generates an ignition permission signal.
Is generated, the abnormality detecting capacitor is charged with a fourth time constant smaller than the third time constant to correct the reference voltage, thereby limiting the rotational speed to the engine rotational speed. And a limit value correction circuit for correcting the rotation speed detection voltage to be equal to the present value, and discharging the rotation speed detection integrating capacitor of the rotation detection circuit with a second time constant when the rotation speed detection voltage becomes equal to a reference voltage. Therefore, a feedback circuit for supplying a drive signal from the output side of the ignition permission / denial determination circuit to the discharge switch of the rotation detection circuit is provided, and in a state where the abnormality detection sensor does not detect an abnormality, the engine speed is a limit value. The circuit constants of the rotation detection circuit and the reference voltage generation circuit are set so that the rotation speed detection voltage becomes equal to or lower than a reference voltage at the maximum advance position when the maximum value of is exceeded. Ignition device for an internal combustion engine that.