JP3019667B2 - Ignition device for internal combustion engine with overspeed prevention function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for an internal combustion engine having an overspeed prevention function for limiting the rotation speed of the internal combustion engine to a certain value or less.

[0002]

2. Description of the Related Art There is known an electronic advance type ignition device in which an ignition position at each rotation speed of an engine is obtained by an integral operation. Generally, as shown in FIG. 3, this type of ignition device includes an ignition circuit 1 for generating a high voltage for ignition when an ignition timing signal Vt is given, a maximum advance position θ1 and a minimum advance angle of the internal combustion engine. A signal generator 2 that generates first and second pulse signals Vs1 and Vs2 (see FIG. 4A) that exceed a threshold level Vo at a position θ2, respectively.
Is controlled by the first and second pulse signals to generate an advance ignition signal Vtn whose position changes between a maximum advance position and a minimum advance position with a change in the rotational speed of the internal combustion engine. The generated ignition position calculating circuit 3 and the starting ignition signal Vts during the period when the signal generator is generating the second pulse signal Vs2
And an ignition timing signal supply circuit 5 for supplying the ignition signal Vt for the advance angle and the ignition signal Vts for the start to the ignition circuit 1 as the ignition timing signal Vt. The ignition timing signal supply circuit 5 comprises an OR circuit composed of, for example, diodes 5a and 5b, and ignites an earlier ignition signal of the advance ignition signal Vtn and the starting ignition signal Vts. It is given to the ignition circuit 1 as a timing signal Vt.

[0003] The ignition position calculation circuit 3 receives the first and second pulse signals Vs1 and Vs2 and receives an angle between the maximum advance position θ1 and the maximum advance position θ2 as shown in FIG. By generating a control signal Vq having a signal width corresponding to the following formula, and controlling a predetermined integrating circuit by this control signal, for example, as shown in FIG. First integrated voltage V having a waveform that rises at a constant slope to angular position θ2 and returns to zero at each minimum advance position
c1 and a second integrated voltage Vc2 having a waveform that instantaneously rises to a constant voltage at the maximum advance position θ1, then rises at a constant slope to the minimum advance position θ2, and returns to zero at the minimum advance position. Then, these two integrated voltages are compared to obtain a second integrated voltage Vc2.
Is greater than the first integrated voltage Vc1 when the ignition signal V
Generate tn.

In the above-described ignition system, when starting the engine in which the ignition position calculating circuit 3 cannot calculate the ignition position, the starting ignition signal Vts obtained from the starting ignition signal generating circuit is used as the ignition timing signal Vt. The ignition operation is performed by being applied to the ignition circuit 1.

The peak value of the first integrated voltage Vc1 decreases as the engine speed increases, and the peak value of the second integrated voltage Vc2 exceeds the first integrated voltage Vc1 as the engine speed increases. Proceeds, the generation position of the advance ignition signal Vtn obtained from the ignition position calculation circuit 3 advances as the rotational speed increases. When the advance ignition signal Vtn is generated at a position advanced from the minimum advance position, the advance ignition signal Vtn is given to the ignition circuit 1 as the ignition timing signal Vt, and the ignition position θi is It advances as the rotation speed increases. Ignition timing signal Vt
Is restricted to a range between the minimum advance position θ1 and the maximum advance position θ2.

The ignition circuit 1 is composed of a well-known circuit such as a capacitor discharge type. When an ignition timing signal is given, the ignition circuit 1 causes a sudden change in the primary current of the ignition coil, thereby making the ignition coil 2 A high voltage Vh is induced in the next coil. Since this high voltage is applied to a spark plug P attached to a cylinder of the engine, a spark is generated in the spark plug and the engine is ignited.

Conventionally, when this kind of ignition device is provided with an overspeed prevention function, when the rotation speed of the engine reaches a set value, the ignition position is retarded to suppress the increase in the rotation speed. The limiting circuit 6 'was provided. The speed limiting circuit 6 'includes a speed limiting switch circuit 7 for bypassing the ignition timing signal Vt from the ignition circuit 1 and a speed limiting switch circuit 7 when the rotation speed of the internal combustion engine exceeds a set value. A speed limiting trigger circuit 8 'for providing a trigger signal Vj.

The trigger circuit 8 'for limiting the speed is shown in FIG.
As shown in the figure, each minimum advance position θ
2 is provided with an integrating circuit for generating a speed limiting integrated voltage VcL having a waveform that returns to zero at 2 and compares the integrated voltage VcL with a constant reference voltage Vr.
The trigger signal Vj is generated during the period when the signal level is below the level of r. In this trigger circuit, when the rotational speed of the engine is lower than the set value, the level of the speed limiting integrated voltage VcL is changed to the reference voltage VcL at a position advanced from the maximum advance position θ1.
r so that the level of the speed limiting integrated voltage VcL at the maximum advance position θ1 becomes lower than the level of the reference voltage Vr when the rotational speed reaches the set value. The level of the voltage Vr is set.
Therefore, in the region where the engine speed is lower than the set value,
As shown by the solid line in FIG. 4G, the trigger signal Vj disappears at a position advanced from the maximum advance position θ1, and the speed limiting circuit 6 'does not affect the ignition operation. In a region where the rotational speed of the engine exceeds the set value, the trigger signal Vj is generated up to a position delayed from the maximum advance position θ1, as indicated by a broken line in FIG. Since the ignition signal Vt is bypassed from the ignition circuit 1 while the signal Vj is being generated, the ignition position is the position θi 'at which the trigger signal Vj disappears. Since the position at which the trigger signal Vj disappears is delayed as the rotation speed increases, the ignition position θi 'is retarded as the rotation speed increases. Therefore, an increase in the rotation speed of the engine is suppressed.

[0009]

In the conventional ignition device for an internal combustion engine, the signal generator controls the integral operation of the speed limiting circuit by the second pulse signal generated at the minimum advance position. The extinguishing position of the trigger signal Vj for triggering the limiting switch circuit (i.e., the ignition position at the time of the overspeed prevention operation) .theta.i 'can be retarded only to the minimum advance position .theta. It could not be prevented from being applied to the ignition circuit as a timing signal. Therefore, in the conventional ignition device, the engine cannot be misfired finally in a region where the engine speed exceeds the set value, and depending on the load condition, the engine speed may exceed the limit value and increase. It was not desirable. An object of the present invention is to provide an overspeed prevention function that can finally prevent the engine from misfiring when the engine speed exceeds a limit value, thereby reliably preventing an excessive increase in the speed. And an ignition device for an internal combustion engine.

[0010]

According to the present invention, there is provided an ignition circuit for generating a high voltage for ignition when an ignition timing signal is given, and a maximum advance position and a minimum advance position of the internal combustion engine, respectively. A signal generator for generating the first and second pulse signals, and between the maximum advance position and the minimum advance position in accordance with a change in the rotation speed of the internal combustion engine, controlled by the first and second pulse signals. An ignition position calculation circuit for generating an ignition signal for advancing, the generation position of which changes at the same time, an ignition signal generating circuit for a startup for generating an ignition signal for a startup while the second pulse signal is generated, and an advance angle An ignition timing signal supply circuit for providing the ignition signal for ignition and the ignition signal for starting as an ignition timing signal to the ignition circuit; a speed limiting switch circuit provided to bypass the ignition timing signal from the ignition circuit when the ignition circuit is turned on; , Internal combustion Those related to internal combustion engine ignition device and a speed limiting switch trigger circuit providing a trigger signal to the switching circuit for speed limit when the rotational speed of the function exceeds a preset value.

In the first aspect of the present invention, the second
And a pulse generating circuit for generating a third pulse signal when the pulse signal disappears, and a period integration capacitor from the generation of the third pulse signal to the generation of the first pulse signal, with a constant time constant. Charging, maintaining a voltage between both ends of the integration capacitor during a period from generation of the first pulse signal to generation of the third pulse signal, and charging of the integration capacitor when the third pulse signal is generated. A speed limiting integration circuit for performing an integration operation for discharging the current almost instantaneously, and an integrated voltage obtained at both ends of an integration capacitor of the speed limiting integration circuit are compared with a fixed level reference voltage, and the integrated voltage is compared with the reference voltage. The speed limiting switch trigger circuit is constituted by a comparison circuit that generates a trigger signal during a period when the speed is low.

According to a second aspect of the present invention, the configuration of the speed limiting integration circuit is different from that of the first aspect of the present invention. In this invention, the integration capacitor is charged with a constant time constant, and The speed limiting integration circuit is configured to perform an integration operation of discharging the charge of the integration capacitor almost instantaneously every time the pulse signal 3 is generated.

[0013]

As described above, the third pulse signal is generated when the second pulse signal generated at the minimum advance position disappears, and the next third pulse is generated from the position where each third pulse signal is generated. If an integrated voltage is created by using the section up to the signal generation position as an integration section, and the integrated voltage is compared with a reference voltage to generate a trigger signal, the second
Since the trigger signal can be continued until the pulse signal disappears (the ignition signal for start-up disappears), the rotation speed of the engine becomes a predetermined limit value (the disappearance position of the trigger signal becomes the disappearance of the second pulse signal). (Engine speed corresponding to the position), the engine can be misfired.

As described above, according to the present invention, the engine can be misfired when the rotation speed of the engine exceeds the limit value, so that the rotation speed can be reliably prevented from excessively increasing. it can.

In the speed limiting integration circuit, the integration capacitor is charged from the position where the third pulse signal is generated to the position where the first pulse signal is generated. When the voltage at both ends of the integration capacitor is held from the occurrence position of the third pulse signal to the occurrence position of the third pulse signal, the rotation speed of the engine becomes equal to the set value (the rotation speed at which the disappearance position of the trigger signal matches the maximum advance position) ), The trigger signal extinction position is retarded to the second pulse signal extinction position, so that the engine can be immediately set to the misfire state when the engine speed exceeds the set value. Therefore, according to the first aspect of the invention, it is possible to obtain a characteristic that when the rotation speed of the engine reaches the set value, the rotation speed sharply decreases.

In the case where the integration capacitor is continuously charged from the position where each third pulse signal is generated to the position where the next third pulse signal is generated, as in the second aspect of the present invention, When the rotation speed of the engine exceeds the set value, first, the ignition position is retarded as the rotation speed increases, and finally, when the ignition position is retarded to the position where the second pulse signal disappears. The engine is misfired. Therefore, according to the invention described in claim 2, it is possible to obtain the characteristic that the rotation speed gradually decreases when the rotation speed of the engine exceeds the set value.

[0017]

【Example】

(1) Overall Configuration of Embodiment FIG. 1 shows an embodiment of the present invention.
A signal generator which is mounted on the internal combustion engine and generates a first pulse signal Vs1 and a second pulse signal Vs2 at the maximum advance position and the minimum advance position of the engine, respectively.
3 is controlled by the first and second pulse signals Vs1 and Vs2 generated by the signal generator 2 to generate a position between a maximum advance position and a minimum advance position with a change in the rotation speed of the internal combustion engine. The ignition position calculation circuit 4 generates the ignition signal Vtn for the advance angle, and the ignition signal generation circuit 4 for the start generates the ignition signal Vts for the start while the second pulse signal Vs2 is generated. An ignition timing signal supply circuit for providing an ignition timing signal Vt to the ignition circuit 1 with an ignition signal for advancing and an ignition signal for starting, Le is an exciter coil provided in a magnet generator mounted on the internal combustion engine. The main part of the device is configured.

Reference numeral 6 denotes a speed limiting circuit. This speed limiting circuit is a speed limiting switch circuit 7 for bypassing the ignition timing signal Vt from the ignition circuit 1, and a rotational speed of the internal combustion engine exceeds a set value. Sometimes speed limit switch circuit 7
And a speed-limiting switch trigger circuit 8 for giving a trigger signal Vj to the switch.

Reference numeral 13 denotes a power supply circuit. This power supply circuit controls a circuit for charging a power supply capacitor (not shown) with the output of the negative half cycle of the exciter coil Le, and controls the voltage across the power supply capacitor to a constant value. Control circuit. A constant DC voltage E is supplied from the power supply circuit 13 to the ignition position calculation circuit 3 and the speed limit circuit 5.

(2) Configuration and Operation of Ignition Circuit The ignition circuit 1 includes an ignition coil IG, an ignition energy storage capacitor Ca, and a diode Da for applying the positive half cycle output voltage of the exciter coil Le to the capacitor Ca. And the electric charge of the capacitor Ca is transferred to the ignition coil IG.
A thyristor Th for discharging the secondary coil and a resistor R
and a well-known capacitor discharge type circuit comprising:

In this ignition circuit, the capacitor Ca is charged to the polarity shown through the diode Da by the voltage of the positive half cycle in the direction shown by the solid line arrow generated by the exciter coil Le. When the ignition timing signal Vt is given to the gate of the thyristor Th, the thyristor T
h is conducted, the electric charge of the capacitor Ca is discharged through the thyristor Th and the primary coil of the ignition coil IG,
A high voltage is induced in the secondary coil of the ignition coil. Since this high voltage is applied to a spark plug P attached to a cylinder of the engine, a spark is generated in the spark plug and the engine is ignited.

(3) Configuration and Operation of Ignition Position Calculation Circuit The ignition position calculation circuit 3 compares the control signal generation circuit 3A, the reset circuit 3B, the first integration circuit 3C, and the second integration circuit 3D with each other. And a device CP1.

In this embodiment, as shown in FIG. 2A, the signal generator 2 generates a negative first pulse signal Vs1 at the maximum advance position θ1 of the engine, and generates the minimum advance position. θ2
Generates a second pulse signal Vs2 of positive polarity. These signals are generated at positions where the respective signals reach a predetermined threshold level Vo. The threshold level Vo is determined by the trigger levels of the transistors TR1 and TR3.

When the signal generator 2 generates the first pulse signal Vs1 at the maximum advance position θ1, a base current is applied to the transistor TR1 through a bias circuit comprising the resistors Ro and Co during the generation of the pulse signal Vs1. The transistor TR1 is turned on, and the transistor T1 is turned on.
Transistor R1 turns on transistor TR2. Therefore, when the first pulse signal Vs1 is generated, the capacitor C1 is charged to the illustrated polarity from the power supply circuit 13 through the transistor TR2 and the diode D1. When the first pulse signal Vs1 disappears, the transistors TR1 and TR2 are turned off, so that the charging of the capacitor C1 is stopped. When the charging of the capacitor C1 is stopped, the charge decreases with the charging of the integrating capacitor of the second integrating circuit 3C, which will be described later. Therefore, after the disappearance of the first pulse signal, the voltage across the capacitor C1 gradually increases. Going down.

When the signal generator 2 generates the second pulse signal Vs2 at the minimum advance position θ2, the transistor TR3 is passed through the bias circuit consisting of a parallel circuit of the resistor R2 of the reset circuit 3B and the capacitor C2, the diode D2 and the resistor R3. , The transistor TR3 conducts while the second pulse signal Vs2 is being generated (while the second pulse signal Vs2 is at or above the threshold level Vo). When the transistor TR3 conducts, the capacitor C1 is discharged instantaneously through the diode D3 and the transistor TR3. Therefore, both ends of the capacitor C1 are
As shown in (B), a control signal Vq having a waveform that maintains a constant voltage for a short time after rising at the maximum advance position θ1 and then gradually decreases and returns to zero at the minimum advance position θ2 is obtained.

The first integrating circuit 3C includes a variable resistor VR1
And a first integration capacitor Ci1.
, The first integrating capacitor Ci1 is charged with a constant time constant through the variable resistor VR1. When the second pulse signal Vs2 is generated and the transistor TR3 of the reset circuit becomes conductive, the first integrating capacitor Ci1 is discharged almost instantaneously through the diode D4. Therefore, as shown by a broken line in FIG. 2 (C), both ends of the first integration capacitor Ci1 have a first rising waveform having a constant slope from the minimum advance position θ2 to the next minimum advance position θ2. Is obtained. The slope of the first integrated voltage can be adjusted by the variable resistor VR1.

In the second integrating circuit 3D, when the control signal Vq is generated, the control signal Vq is applied to the resistors R4 and R4.
The transistor TR is divided by a voltage dividing circuit consisting of
4 is applied between the base and the emitter. As a result, the transistor TR4 is turned on, and the second integration capacitor Ci2 is initially charged through the transistor TR4 by the control signal Vq. When the voltage across the second integrating capacitor Ci2 reaches an initial value Vco equal to the divided value of the control signal Vq (the voltage across the resistor R5), the transistor TR4 is turned off. After the transistor TR4 is turned off, the capacitor Ci2 is charged with a constant time constant through the variable resistor VR2 by the control signal Vq. When the second pulse signal Vs2 is generated at the minimum advance position θ2 and the transistor TR3 of the reset circuit 3B is turned on, the electric charge of the second integration capacitor Ci2 is discharged instantaneously through the diode D5 and the transistor TR3. Therefore, the second integration capacitor C
At both ends of i2, as shown by the solid line in FIG. 2 (C), it instantaneously rises to the initial value Vco at the maximum advance position θ1, rises at a predetermined inclination, and reaches zero at the minimum advance position θ2. A second integrated voltage Vc2 having a returning waveform is obtained. This second integrated voltage Vc2
Can be appropriately set by adjusting the resistance values of the resistors R4 and R5.
The slope of c2 can be adjusted by the variable resistor VR2.

The first integrated voltage Vc1 and the second integrated voltage Vc2 are input to an inverting input terminal and a non-inverting input terminal of the comparator CP1, respectively. When the second integrated voltage Vc2 exceeds the first integrated voltage Vc1, the comparator CP1 operates as shown in FIG.
As shown in (D), an ignition signal for advance angle Vtn is generated. The ignition timing signal Vtn is supplied to the gate of the thyristor Th1 of the ignition circuit 1 through the diodes D6 and D7 of the ignition timing signal supply circuit 5, and the ignition timing signal Vtn is supplied to the ignition timing signal Vtn.
supplied as t.

First and second integrating capacitors Ci1 and C1
Since the time for charging i2 becomes shorter as the engine speed increases, the peak values of the first and second integrated voltages Vc1 and Vc2 obtained at both ends of both capacitors increase as the engine speed increases. However, when the rate of decrease of the two integrated voltages with the increase in the rotation speed is compared, the first integrated voltage V obtained at both ends of the first integration capacitor Ci1 having a longer charging section is obtained.
Since the rate of decrease of c1 is greater than the rate of decrease of second integrated voltage Vc2, the position where second integrated voltage Vc2 exceeds first integrated voltage Vc1 proceeds with an increase in engine speed. The generation position (ignition position) of the advance ignition signal Vtn advances as the engine speed increases. Therefore, this ignition signal Vtn is used as an ignition timing signal Vt as the ignition circuit 1
, The ignition position of the engine advances as the rotational speed increases.

The starting ignition signal generating circuit 4 includes a signal generator 2 and a diode D8 whose anode is connected to one output terminal of the signal generator 2 through a bias circuit comprising a parallel circuit of a resistor R2 and a capacitor C2. One end of the resistor R6 is connected to the cathode of the diode. The other end of the resistor R6 is connected to the cathode of the diode D6 of the ignition timing signal supply circuit 5. When the signal generator 2 generates the second pulse signal Vs2 at the minimum advance position θ2 at the time of starting or at a low speed of an engine in which the ignition calculation circuit cannot calculate the ignition position, the ignition signal for starting is generated. The circuit 4 generates a starting ignition signal Vts (FIG. 2J),
This ignition signal Vts is given to the ignition circuit 1 as an ignition timing signal Vt.

(4) Structure and Operation of Speed Limiting Circuit The speed limiting circuit 6 comprises a speed limiting switch circuit 7 and a speed limiting switch trigger circuit 8.

The speed limiting switch circuit 7 includes a transistor T in which the collector is connected to the cathode of the diode D6 of the ignition timing signal supply circuit 5 and the emitter is grounded.
R5 and an attached resistor and capacitor. When a predetermined base current is applied to the transistor TR5, the transistor TR5 conducts, and the ignition timing signal Vt
Is bypassed from the ignition circuit 1.

The speed limit switch trigger circuit 8 is provided with a second
, A pulse generating circuit 9 for generating a third pulse signal Vp when the pulse signal disappears, a speed limiting integration circuit 10 controlled by the third pulse signal Vp, a reference voltage generating circuit 11, a comparing circuit It consists of 12.

The pulse generation circuit 9 includes a differentiation capacitor C
d, a Zener diode ZD connected between one end of the capacitor Cd and the ground, a diode D9 connected between the other end of the capacitor Cd and the ground, and a resistor R7 connected at one end to the other end of the capacitor Cd. The capacitor Cd is charged to the polarity shown in FIG. The charging voltage of the capacitor Cd is the Zener diode Z.
Therefore, when the transistor TR3 of the reset circuit 3B is not conducting, the potential Vd at one end of the capacitor Cd becomes equal to the Zener voltage of the Zener diode ZD as shown in FIG. I have.
When the signal generator 2 generates the second pulse signal Vs2 and the transistor TR3 of the reset circuit 3B conducts, the electric charge of the capacitor Cd is changed to the diode D10 and the transistor TR3.
Discharges instantly through While the second pulse signal Vs2 is being generated, the transistor TR3 is kept conductive, so that the potential at one end of the capacitor Cd is kept at zero.
When the second pulse signal Vs2 disappears (below the threshold level Vo) at a position θ3 further delayed from the minimum advance position θ2, the transistor TR3 of the reset circuit 3B is turned off, so that the capacitor Cd is rapidly applied. Charging current flows into the At this time, the capacitor Cd performs a differential operation,
As shown in FIG. 2F, the potential at the other end changes in a pulsed manner. This change in potential is used as the third pulse signal Vp. The third pulse signal Vp is applied to the speed limiting integration circuit 10.

The integrating circuit 10 includes an integrating main circuit 10A.
, Reset circuit 10B, control signal shaping circuit 10C
And an integration operation stop circuit 10D.

The integration main circuit 10A includes an integration capacitor Ci3
, A diode D11, and a variable resistor VR3. The integration capacitor Ci3 is charged with a constant time constant from the power supply circuit 13 through the variable resistor VR3 and the diode D11.

The reset circuit 10B includes a transistor TR
6, the collector of the transistor TR6 is connected to the non-ground terminal of the integrating capacitor Ci3 through the diode D12.
The third pulse signal Vp is applied to the base of the transistor TR6.
When the pulse signal Vp is generated, the transistor TR6 is turned on to discharge the charge of the integrating capacitor Ci3 almost instantaneously.

The control signal shaping circuit 10C includes a capacitor C
3 and diodes D13 and D14. The capacitor C3 is connected through a diode D14 to the collector of the transistor TR2 of the control signal generating circuit 3A of the ignition position calculation circuit, and is connected through a diode D13 to the collector of the transistor TR6 of the reset circuit 10B. When the first pulse signal Vs1 is generated and the transistor TR2 is turned on, the capacitor C3 is charged almost instantaneously from the power supply circuit 13 through the transistor TR2 and the diode D14. The electric charge of the capacitor C3 is gradually discharged through the integration operation stop circuit 10C. At the position θ3 where the second pulse signal Vs2 has disappeared, the third pulse signal V
When p occurs and the transistor TR6 conducts, the electric charge of the capacitor C3 is transferred to the diode D13 and the transistor TR6.
Discharges almost instantaneously through. Therefore, the capacitor C3
2 (G), the maximum advance position θ
A control signal Vq 'having a waveform which rises at 1 and maintains a constant value while the first pulse signal Vs1 is generated, then gradually falls and returns to zero at the third pulse signal generation position θ3. can get.

The control signal Vq 'is supplied to the integration operation stop circuit 10
D has been entered. The integration operation stop circuit 10D includes a transistor TR7. When the control signal Vq 'is generated, the transistor TR7 is turned on, and the charging current of the integration capacitor Ci3 supplied from the power supply circuit through the variable resistor VR3 is supplied from the integration capacitor. Bypass. Therefore, while the control signal Vq 'is being generated, the integration capacitor Ci3
Is stopped, and the voltage across the integration capacitor is kept constant.

Therefore, both ends of the integrating capacitor Ci3 are
As shown in FIG. 2H, the third pulse signal Vp rises at a predetermined inclination from the generation position (the extinction position of the ignition signal Vts for starting) θ3 from the maximum advance position θ1 to the next first pulse position V1. 3 is maintained at a constant value up to the generation position θ3 of the pulse signal Vp.
At the generation position θ3 of the third pulse signal, a speed limiting integrated voltage Vc3 having a waveform returning to zero is obtained.

The reference voltage generation circuit 11 includes resistors R11 and R11 constituting a voltage dividing circuit for dividing the output voltage of the power supply circuit 13.
And outputs a constant reference voltage Vr across the resistor R12.

The speed limiting integrated voltage Vc3 and the reference voltage Vr
Are input to the inverting input terminal and the non-inverting input terminal of the comparison circuit 12, respectively. As shown in FIG. 2 (I), the comparison circuit 12 determines that the speed limiting integrated voltage Vc3 is equal to the reference voltage Vr.
A high-level trigger signal Vj is generated during a period in which the trigger signal Vj is lower than the threshold value. While the trigger signal Vj is being generated, the transistor TR5 of the speed limiting switch circuit 7 becomes conductive,
While the trigger signal Vj is being generated, the application of the ignition timing signal Vt to the ignition circuit 1 is prevented. Since the charging time of the integration capacitor Ci3 decreases as the rotation speed increases, the speed limiting integrated voltage Vc3 decreases as the rotation speed increases. Therefore, the trigger signal V
The disappearance position θi of j is delayed as the engine speed increases. In this embodiment, the integration constant of the integration main circuit 10A and the reference voltage Vr are set so that the trigger signal Vj disappears at the maximum advance position θ1 when the rotation speed of the engine reaches the set value.
The level has been adjusted.

In the present embodiment, the third advance from the maximum advance position θ 1
Until the pulse signal Vp is generated at the position θ3.
Is maintained constant, the integrated voltage Vc3 is maintained at a value lower than the reference voltage Vr during the entire period when the engine speed exceeds the set value, as shown by the broken line in FIG. At the same time, the trigger signal Vj maintains the high level state during the entire period. Therefore, when the rotational speed of the engine exceeds the set value, the transistor TR5 of the speed limiting switch circuit 7 is kept conductive for the entire period, and the supply of the ignition timing signal to the ignition circuit 1 is completely blocked. You.

In this embodiment, when the rotational speed of the engine is lower than the set value, the trigger signal Vj changes to the maximum advance position θ1.
The speed limit circuit 6 has no influence on the ignition operation since the light is extinguished at a position further advanced. In this state, the ignition timing signal Vt is given to the ignition circuit 1 when either the ignition signal Vts for starting or the ignition signal Vtn for advance is generated, and the ignition operation is performed at the regular ignition position at each rotational speed. Will be

When the rotation speed of the engine exceeds the set value, the trigger signal Vj is constantly generated, so that the ignition timing signal Vt is prevented from being given by the advance ignition signal Vtn. The ignition timing signal Vt is also prevented from being given by the starting ignition signal Vts. Therefore, when the rotation speed of the engine exceeds the set value, the ignition operation is not performed at all and the engine is misfired, and the rotation speed of the engine is forcibly reduced.

As described above, in the present invention, the third pulse signal Vp is generated at the position where the second pulse signal Vs2 disappears (the position where the ignition signal Vts for start-up disappears) in the speed limiting circuit. By generating a speed limiting integrated voltage Vc3 that continues from the position where the third pulse signal is generated to the position where the next third pulse signal is generated, and comparing the integrated voltage Vc3 with the reference voltage Vr, the speed limiting switch circuit is generated. Since the trigger signal of No. 7 is obtained, when the rotation speed of the engine exceeds the set value, the ignition operation by the starting ignition signal Vts can be prevented, and the engine can be set in a misfire state. Therefore,
It is possible to reliably prevent the rotational speed of the engine from excessively increasing.

(5) Other Embodiments In the speed limiting circuit of the above embodiment, the control signal shaping circuit 10C and the integrating operation stopping circuit 10D can be omitted. When these circuits are omitted, the integrating capacitor Ci3 is continuously provided from the maximum advance position θ1 to the position where the third pulse signal is generated (the position where the ignition signal for starting is extinguished) θ3.
Is charged, the waveform of the speed limiting integrated voltage Vc3 is
The waveform continuously rises at a predetermined inclination from the generation position θ3 of each third pulse signal to the generation position θ3 of the next third pulse signal. The speed limiting integrated voltage V having such a waveform
When c3 is compared with the reference voltage Vr to obtain the trigger signal Vj,
The disappearance position θi 'of the trigger signal Vj is continuously retarded as the engine speed increases. Therefore, in this case, when the rotation speed of the engine exceeds the set value, the ignition position is initially continuously retarded at first to suppress the increase in the rotation speed,
When the rotational speed of the engine reaches the limit value and the position where the trigger signal disappears reaches the position θ3 where the third pulse signal is generated, the engine can be set to the misfire state. That is, in the case of such a configuration, the rotation speed of the engine can be gradually reduced when the rotation speed of the engine exceeds the set value.
It is possible to prevent the rotation speed from suddenly decreasing during the overspeed prevention operation and giving the driver an uncomfortable feeling. Further, when the rotation speed cannot be reduced due to the load condition, the engine can be finally shifted to the misfire state, so that the rotation speed of the engine can be reliably prevented from excessively increasing.

In the above embodiment, the advance ignition signal is obtained by comparing the first and second integrated voltages Vc1 and Vc2 having the waveforms shown in FIG. 2C. In the present invention, the arithmetic method for obtaining the advance ignition signal is arbitrary, and an ignition position arithmetic circuit for obtaining the advance ignition signal by various arithmetic methods employed in the electronic advance type ignition device is provided. Can be used.

[0049]

As described above, according to the present invention, when the second pulse signal generated at the minimum advance position disappears, the third pulse signal is generated in the speed limiting circuit, and the third pulse signal is generated. An integral voltage is generated using an interval from the position where the pulse signal is generated to the position where the next third pulse signal is generated as an integration period, and the integrated voltage is compared with a reference voltage to make the speed limiting switch circuit conductive. Trigger signal is generated, so that the trigger signal can be finally continued to the position where the ignition signal for starting disappears. Therefore, when the rotation speed of the engine exceeds a predetermined limit value,
Eventually, the engine can be shifted to the misfire state, and the rotation speed can be reliably prevented from excessively increasing.

According to the first aspect of the present invention, in the speed limiting integration circuit, the integration capacitor is charged from the position where the third pulse signal is generated to the position where the first pulse signal is generated, and the first pulse is charged. Since the voltage at both ends of the integrating capacitor is maintained at a constant value from the position where the signal is generated to the position where the third pulse signal is generated, the trigger signal disappears at the moment when the engine speed exceeds the set value. Can be retarded to the disappearance position of the second pulse signal, and the engine can be immediately set to a misfire state when the rotation speed of the engine exceeds a set value. Therefore, according to the first aspect of the invention, it is possible to obtain a characteristic that when the rotation speed of the engine reaches the set value, the rotation speed sharply decreases.

According to the second aspect of the present invention, the integration capacitor is continuously charged from the position where each third pulse signal is generated to the position where the next third pulse signal is generated, so that the engine can be charged. When the rotation speed exceeds the set value, the ignition position is first retarded with the increase in the rotation speed, and finally, when the ignition position is retarded to the position where the second pulse signal disappears, the engine is started. Since the misfire state is set, the rotation speed of the engine can be gradually reduced when the rotation speed of the engine exceeds a set value. Also in this case, if the rotational speed does not decrease due to the load condition, the engine can be set to the misfire state, so that the rotational speed of the engine can be reliably prevented from excessively increasing.

[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 signal waveforms at various parts in FIG.

FIG. 3 is a block diagram showing a configuration of a conventional internal combustion engine ignition device.

FIG. 4 is a waveform chart showing signal waveforms of various parts of the ignition device of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition circuit 2 Signal generator 3 Ignition position calculation circuit 4 Ignition signal generation circuit for starting 5 Ignition timing signal supply circuit 6 Speed limit circuit 7 Speed limit switch circuit 8 Speed limit switch trigger circuit 9 Pulse generation circuit 10 Speed limit Integration circuit for integration 10A Integral main circuit 10B Reset circuit 10C Control signal shaping circuit 10D Integral operation stop circuit 11 Reference voltage generation circuit 12 Comparison circuit

Continuation of the front page (56) References JP-A-5-1651 (JP, A) JP-A-60-256562 (JP, A) JP-A-1-240772 (JP, A) JP-A-3-23664 (JP) , U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02P 11/02 301 F02D 45/00 345

Claims (2)

(57) [Claims] 1. An ignition circuit for generating a high voltage for ignition when an ignition timing signal is given, and a first and a second pulse signal at a maximum advance position and a minimum advance position of an internal combustion engine, respectively. A signal generator that is generated, and a lead that is controlled by the first and second pulse signals to change a generated position between a maximum advanced position and a minimum advanced position with a change in the rotation speed of the internal combustion engine. An ignition position calculation circuit for generating an angle ignition signal; a start-time ignition signal generation circuit for generating a start-time ignition signal while the second pulse signal is being generated; An ignition timing signal supply circuit for providing a time ignition signal to the ignition circuit as an ignition timing signal; a speed limiting switch circuit provided to bypass the ignition timing signal from the ignition circuit when the ignition circuit is turned on; of A speed limiting switch trigger circuit for providing a trigger signal to the speed limiting switch circuit when the rotation speed exceeds a set value, wherein the speed limiting switch trigger circuit comprises: A pulse generation circuit for generating a third pulse signal when the second pulse signal is extinguished, and a constant integration capacitor for a period from the generation of the third pulse signal to the generation of the first pulse signal. The battery is charged with a time constant, and the voltage between both ends of the integrating capacitor is held during a period from the generation of the first pulse signal to the generation of the third pulse signal, and the integration is performed when the third pulse signal is generated. A speed limiting integration circuit for performing an integration operation for discharging the charge of the capacitor almost instantaneously; An ignition circuit for an internal combustion engine with an overspeed prevention function, comprising: a comparison circuit that generates the trigger signal during a period in which the integrated voltage is lower than a reference voltage. 2. An ignition circuit for generating a high voltage for ignition when an ignition timing signal is given, and first and second pulse signals at a maximum advance position and a minimum advance position of the internal combustion engine, respectively. A signal generator that is generated, and a lead that is controlled by the first and second pulse signals to change a generated position between a maximum advanced position and a minimum advanced position with a change in the rotation speed of the internal combustion engine. An ignition position calculation circuit for generating an angle ignition signal; a start-time ignition signal generation circuit for generating a start-time ignition signal while the second pulse signal is being generated; An ignition timing signal supply circuit for providing a time ignition signal to the ignition circuit as an ignition timing signal; a speed limiting switch circuit provided to bypass the ignition timing signal from the ignition circuit when the ignition circuit is turned on; of A speed limit switch trigger circuit for providing a trigger signal to the speed limit switch circuit when the rotational speed exceeds a set value, wherein the ignition timing signal is ignited when the internal combustion engine is turned on. An ignition for an internal combustion engine, comprising: a speed limiting switch circuit provided to bypass the circuit; and a speed limiting switch trigger circuit for providing a trigger signal to the speed limiting switch circuit in accordance with the rotation speed of the internal combustion engine. An apparatus, wherein the speed-limiting switch trigger circuit comprises: a pulse generation circuit that generates a third pulse signal when the magnitude of the second pulse signal has disappeared; and an integration capacitor that is charged with a constant time constant. A speed limiting integration circuit for performing an integration operation of discharging the charge of the integration capacitor almost instantaneously each time each third pulse signal is generated; A comparison circuit that compares an integrated voltage obtained at both ends of an integration capacitor of the integration circuit with a reference voltage of a fixed level and generates the trigger signal during a period when the integrated voltage is lower than the reference voltage. An ignition device for an internal combustion engine having an overspeed prevention function, characterized in that: