JPH0319912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition device for an internal combustion engine that induces a high voltage for ignition by controlling the primary current of an ignition coil using a semiconductor switch.

[Prior Art] As an ignition device for an internal combustion engine, an electronically controlled ignition device that obtains an advance characteristic using an electronic circuit including an integrating circuit, a comparison circuit, etc. is known. In the conventional ignition system of this type, a signal coil is provided that generates a first signal and a second signal at the minimum advance position of the engine, respectively, and the output of the signal coil triggers a flip-flop circuit. , an ignition operation permissible section detection signal that lasts during the ignition operation permissible section corresponding to the section from the maximum advance angle position to the minimum advance angle position, and an ignition operation permissible section detection signal that lasts for the ignition operation permissible section corresponding to the section from the minimum advance angle position to the next maximum advance angle position. An ignition operation prohibition section detection signal that continues during the operation prohibition section is generated. Then, with these section detection signals, the first and second
By controlling the integral circuit of The first integral voltage of the waveform increases linearly during the period of time and returns to the initial voltage at the minimum advance position, and increases at a constant slope during the ignition operation prohibition period from the minimum advance position to the maximum advance position and reaches the maximum. A second integrated voltage having a waveform that maintains a constant value during the ignition operation permissible interval from the advance angle position to the minimum advance angle position and returns to zero at the minimum advance angle position, and The integrated voltages are compared by a comparison circuit, and when the first integrated voltage exceeds the second integrated voltage in the ignition operation permissible interval, the primary current control switch is cut off to perform the ignition operation.

According to the electronically controlled ignition system as described above,
It is possible to accurately determine the advance angle width, the advance angle start rotational speed, and the advance angle end rotational speed.

However, in this type of ignition system, the primary current control switch is made conductive at the same time as the ignition operation permissible range detection signal rises to cause the primary current to flow through the ignition coil, so the period during which the primary current flows is limited. The problem was that the length was too long, resulting in high losses and a rapid rise in temperature of the ignition coil and switch element.

Therefore, the present applicant previously proposed an electronically controlled ignition system for internal combustion engines in which the timing at which the primary current control switch is turned on can be arbitrarily set in Japanese Patent Application No. 59-201451. did.

According to the ignition system proposed earlier, by appropriately setting the conduction period of the primary current control switch, it is possible to prevent the conduction period from becoming too long when the engine is running at low speed. This can prevent an increase in the temperature of the ignition coil and the temperature of the ignition coil and elements.

However, in the device proposed earlier, 1
The period (angle) during which the next current control switch conducts is approximately constant over the entire rotational speed range of the engine, so when the engine is running at high speeds, the energization time becomes shorter, the current cut-off value decreases, and ignition performance deteriorates. It became clear that there was a problem.

Therefore, in order to solve this problem, the applicant
The timing of the rise of the integral voltage used to determine when the primary current control switch starts conducting is changed according to the engine rotational speed, and the timing when the primary current control switch starts conducting is changed according to the engine rotational speed. By doing so, the conduction period of the primary current control switch is prevented from becoming too long when the engine is running at low speed, thereby reducing loss, and at the same time, the conduction period of the primary current control switch is shortened when the engine is at high speed. proposed an ignition system for internal combustion engines (Patent Application No. 60-30057) that prevents overflow and deterioration of ignition performance. In this ignition system, the first integrated voltage increases to a certain voltage at the maximum advance position and then increases at a constant gradient from the maximum advance position to the minimum advance position, and The second integrated voltage increases at a constant gradient to the next minimum advance position, and a signal indicating the next maximum advance position is generated after a certain period of time has elapsed after the signal indicating the maximum advance position is generated. A third integral voltage that rises at a constant gradient until a time when When the integrated voltage exceeds the second integrated voltage, the primary current control switch is cut off to perform the ignition operation.

[Problems to be solved by the invention] Previously proposed ignition device (Patent Application No. 60-30057)
According to the invention, it is possible to prevent the period in which the primary current control switch is conductive when the engine is running at low speed from becoming longer than necessary, thereby increasing loss and preventing the temperature of the switch element from increasing significantly. Further, since the rising position of the third integrated voltage is delayed as the rotational speed of the engine increases, the magnitude of the third integrated voltage decreases as the rotational speed increases. Therefore, the position where the second integrated voltage exceeds the third integrated voltage advances as the rotational speed of the engine increases,
Since the conduction start position of the primary current control switch advances as the engine rotation speed increases, it is possible to prevent the current cutoff value from becoming low and ignition performance from deteriorating when the engine rotates at high speed. .

However, with the device proposed earlier, if the power switch was accidentally left closed while the engine was stopped, it became clear that the ignition would occur spontaneously after a few minutes and sparks would fly into the engine's cylinders. Summer.

If spontaneous combustion occurs in this manner, an explosion may occur within the cylinder and damage the engine if a mixture of fuel and air remains within the cylinder.

An object of the present invention is to provide an electronically controlled ignition device for an internal combustion engine that solves the above problems.

[Means for Solving the Problems] As shown in FIG. 1 showing an embodiment of the present invention, an ignition coil 1 and one of the ignition coils are
A primary current control switch 3 provided on the next side,
and a control circuit that controls the primary current control switch from a conductive state to a cutoff state at the ignition timing of the internal combustion engine, and the primary current of the ignition coil is suddenly changed by cutting off the primary current control switch. The target is an ignition system for an internal combustion engine that obtains high voltage for ignition.

In the present invention, the control circuit is constituted by the following elements.

(b) Output first and second signals Vs ₁ and Vs ₂ that are equal to or higher than the threshold level at the maximum and minimum advance positions of the ignition timing of the engine in synchronization with the rotation of the internal combustion engine. Signal coil 4.

(b) A first pulse shaping circuit that shapes the first signal into a pulse shape and generates a first pulse signal that rises at the maximum advance angle position.

(c) A waveform shaping switch is provided between the collector and emitter of the waveform shaping switch that maintains the cutoff state during the period when the second signal is above the threshold level and maintains the conduction state during the other periods. a second pulse shaping circuit for obtaining a second pulse signal;

(d) The signal storage capacitor 7g conducts when the first pulse signal is generated, and the charge control transistor switch instantly charges the signal storage capacitor 7g, and the transistor switch conducts when the second pulse signal occurs. and a discharge control transistor switch that instantly discharges the signal storage capacitor 7g, and obtains an ignition operation permissible range detection signal Vg that lasts from the maximum advance position to the minimum advance position at both ends of the signal storage capacitor 7g. Operation permissible section detection signal generation circuit 7.

(E) Voltage Vq across the first integrating capacitor 8d and the signal storage capacitor 7g at the maximum advance position
At the same time as rising, the signal storage capacitor 7
a first integral capacitor charging circuit that instantaneously charges the first integral capacitor to a constant voltage using a terminal voltage of g; and an additional charging circuit that additionally charges the first integral capacitor at a constant time constant. First integration circuit.

(F) A reset circuit 9 that instantly discharges the first integrating capacitor when the second pulse signal _Vp2 is generated.

(G) A second integrating capacitor 10a, a second integrating capacitor charging circuit that charges the second integrating capacitor 10a at a constant time constant, and a collector-emitter circuit are connected to the second integrating capacitor 10a. a second integrating capacitor discharging transistor switch connected in parallel and made conductive by the second pulse signal; A second integrating circuit 1 that performs an integrating operation of charging an integrating capacitor with a constant time constant and instantly discharging the second integrating capacitor at the minimum advance angle position.
0.

(H) A third integrating capacitor charging circuit that charges the third integrating capacitor 11a with a voltage across the signal storage capacitor through a reverse blocking diode and a current limiting resistor at a constant time constant. , a differentiating circuit 11g that differentiates the rising edge of the first pulse signal Vp ₁ or the rising edge of the ignition operation permissible interval detection signal Vq, and a collector-emitter circuit connected in parallel to the third integrating capacitor to form a differentiating circuit. A third integral capacitor discharging transistor switch that is triggered by the output of )
a third integrating circuit that performs an integral operation of charging the third integrating capacitor with a constant time constant from to the next maximum advance position and instantaneously discharging the third integrating capacitor at the maximum advance position; 11.

(li) Spontaneous ignition prevention that combines the third integrating capacitor and the waveform shaping switch to form a discharge circuit that discharges the charge of the third integrating capacitor through the waveform shaping switch of the second pulse shaping circuit. Resistance 14.

(J) The output terminal is connected to the control signal input terminal of the primary current control switch, and the second integrating capacitor 1
By inputting the second integrated voltage Vc ₂ obtained across 0a and the third integrated voltage Vc ₃ obtained across the third integrating capacitor 11a, the second integrated voltage becomes equal to or lower than the third integrated voltage. a first comparator circuit 12 that prevents conduction of the primary current control switch when the second integrated voltage exceeds the third integrated voltage;

(l) The output terminal is coupled to the control signal input terminal of the primary current control switch, and the first integral voltage Vc 1 is obtained across the first integrating capacitor 8d and the first integral voltage Vc ₁ is obtained across the second integrating capacitor 10a. The first comparator circuit inputs the second integrated voltage Vc ₂ and controls the primary current while allowing the primary current control switch to conduct and the first integrated voltage is equal to or less than the second integrated voltage. 1 when the first integral voltage exceeds the second integral voltage.
A second comparator circuit 13 that shuts off the next current control switch.

The ignition device previously proposed in the present invention (patent application
60-30057) is that the third integrating capacitor and the waveform shaping switch are connected to form a discharge circuit that discharges the charge of the third integrating capacitor through the waveform shaping switch of the second pulse shaping circuit. The point is that a spontaneous ignition prevention resistor 14 is provided which connects the two.

[Operation of the Invention] In the above configuration, the position where the ignition operation is performed is the position where the first integrated voltage exceeds the second integrated voltage. Since the position where the first integrated voltage exceeds the second integrated voltage advances as the rotational speed of the engine increases, the ignition timing of the engine advances as the rotational speed increases.

Also in the present invention, the second integrated voltage increases at a constant gradient from the position immediately after each minimum advance position to the next minimum advance position, and the second integral voltage increases from a position delayed by a predetermined angle from each maximum advance position. The primary current control switch is activated when the second integrated voltage exceeds the third integrated voltage by comparing the voltage with the third integrated voltage that increases at a constant gradient up to the angular position or the next maximum advance position. This prevents the period during which the primary current control switch is conductive during low engine speeds from becoming unnecessarily long, increasing losses and causing a significant temperature rise in the switch element. .

In addition, since the transistor switch for discharging the second integral capacitor is triggered by the output pulse of the differentiating circuit with a constant time width, the charging start position (angle) of the third integral capacitor changes as the engine speed increases. I'm getting late. Therefore, as the rotational speed of the engine increases, the charging time of the third integral capacitor becomes shorter, so the magnitude of the third integral voltage decreases as the rotational speed of the engine increases. Therefore, the position where the second integrated voltage exceeds the third integrated voltage advances as the engine rotational speed increases, and the conduction start position of the primary current control switch advances as the engine rotational speed increases. (the conduction angle of the primary current becomes longer). Therefore, it is possible to prevent the current cutoff value from becoming low when the engine rotates at high speed.
It is possible to prevent the ignition performance from deteriorating at high speeds.

Assuming that there is no self-ignition prevention resistor in the above configuration, when the power switch is closed with the engine stopped, the input bias current of the first comparator circuit flows from the input terminal of the comparator circuit to the third integrating capacitor. It flows out to the side. As a result, the third integral capacitor is charged, so that the third integral voltage Vc ₃ rises at a constant gradient as time t passes, as shown in FIG. Furthermore, since the second integral capacitor is charged by the current supplied from the power supply, the second integral voltage Vc ₂ also increases with the passage of time. Initially, the second integrated voltage Vc ₂ is larger than the third integrated voltage Vc ₃ , so the primary current control switch is in a conductive state, but after a certain period of time (several minutes) has passed after the power switch is closed, , 4th
As shown in the figure, the third integrated voltage Vc ₃ exceeds the second integrated voltage Vc ₂ , and the primary current control switch is turned off. When this primary current control switch is shut off, a high voltage is induced in the ignition coil, resulting in spontaneous ignition, which may cause an explosion within the cylinders of the engine.

In contrast, in the present invention, since a resistor for preventing spontaneous ignition is added, when the power switch is closed when the internal combustion engine is stopped, the resistor for preventing spontaneous ignition is connected to the waveform shaping switch that is in conduction state. The third integrating capacitor can be discharged. Therefore, even if the power switch is left closed while the internal combustion engine is stopped, the second integrated voltage will not exceed the third integrated voltage, and ignition operation will be prevented. can.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

Configuration of Embodiment FIG. 1 shows an embodiment of the present invention. In the figure, 1 is an ignition coil having a primary coil 1a and a secondary coil 1b with one end commonly connected;
A spark plug 2 is attached to a cylinder of an engine (not shown) and connected to a non-ground terminal of a secondary coil of an ignition coil via a high voltage cord. One end of the primary coil and the secondary coil of the ignition coil 1 are connected to the collector of the transistor 3 whose emitter is grounded, and the other end _1a1 of the primary coil is connected to the positive terminal of a battery (not shown) whose negative terminal is grounded. ing. Note that a Darlington-connected composite transistor is used as the transistor 3 in this example.

The transistor 3 constitutes a switch for controlling the primary current, and is made conductive by a control circuit to be described later when the phase is advanced from the ignition timing of the engine.
It is controlled to be in a cut-off state at the ignition timing.
When the transistor 3 is cut off, the primary current that had been flowing between the primary coil 1a of the ignition coil and the collector-emitter of the transistor 3 is cut off. A high voltage is induced in the direction of continuing to flow.
At this point, a large magnetic flux change occurs in the iron core of the ignition coil, and this magnetic flux change induces a high voltage in the secondary coil. Since this high voltage is applied to the spark plug 2, a spark discharge occurs in the spark plug, and the engine is ignited.

The above transistor (primary current control switch)
A control circuit that controls the signal coil 4 and the first
and a waveform shaping circuit consisting of second pulse shaping circuits 5 and 6, an ignition operation permissible interval detection signal generation circuit 7, a first integration circuit 8, and a reset circuit 9.
a second integrating circuit 10, a third integrating circuit 11,
It consists of first and second comparison circuits 12 and 13.

The signal coil 4 is disposed in a signal generator that rotates in synchronization with the rotation of the engine, _and as shown in _FIG . signal Vs ₁ and 2nd
generates a signal Vs ₂ . One end of this signal coil 4 is grounded. In this type of ignition system, when the engine rotational speed is extremely low, the second signal Vs ₂ is set to be larger than the first signal Vs 1, and when the engine starting operation is performed, the second signal Vs ₂ is set to be larger than the first signal Vs 1. The second signal rises above the threshold level before the first signal.

The first pulse shaping circuit 5 includes a diode 5 whose anode is connected to the non-ground terminal of the signal coil 4.
a, a capacitor 5b and a resistor 5c, one end of which is connected to the cathode of the diode 5a, and the other end of which is commonly connected.

The second pulse shaping circuit 6 includes a diode 6 whose cathode is connected to the non-ground terminal of the signal coil 4.
a, a capacitor 6b and a resistor 6c with one end connected to the anode of the diode 6a and the other end commonly connected, and a waveform in which the base is connected to the common connection point of the other end of the capacitor 6b and the resistor 6c and the emitter is grounded. An NPN transistor 6d as a shaping switch, a diode 6e connected between the base of the transistor 6d and ground with its anode facing the ground, and resistors 6f and 6g connected at one end to the base and collector of the transistor 6d, respectively.
It is made up of.

The ignition operation permissible interval detection signal generation circuit 7 includes an NPN transistor 7 whose base is connected to the common connection point of the capacitor 5b and the resistor 5c of the first pulse shaping circuit 5 via a resistor 7a, and whose emitter is grounded.
b, a resistor 7c connected between the base and emitter of the transistor 7b, and a PNP whose base is connected to the collector of the transistor 7b via a resistor 7d.
A transistor 7e, a resistor 7f connected between the emitter and the base of the transistor 7e, a signal storage capacitor 7g connected between the collector of the transistor 7e and ground, and a collector connected to the non-ground terminal of the capacitor 7g, NPN transistor 7h whose emitter is grounded and transistor 7
The terminal _7e1 connected to the emitter of the transistor 7e is connected to the output terminal of a constant voltage circuit (not shown) whose power source is a battery. In this embodiment, transistors 7b, 7e and resistors 7a, 7
c, 7d, and 7f constitute a charging control transistor switch, and transistor 7h and resistor 7
i constitutes a discharge control transistor switch.

As described above, in the present invention, since the ignition operation permissible interval detection signal generation circuit 7 is configured by the signal storage capacitor and the transistor switch that controls charging and discharging of the capacitor, a flip-flop circuit using many logic elements can be used. The configuration can be simplified compared to the case where the capacitor 7e is used, and malfunctions due to noise can be prevented by appropriately setting the trigger level of the transistor switch that controls charging and discharging of the capacitor 7e.

Next, the first integrating circuit 8 includes a resistive voltage dividing circuit consisting of a series circuit of resistors 8a and 8b connected in parallel to both ends of the signal storage capacitor 7g, and a base connected to the voltage dividing point of the resistive voltage dividing circuit. A first integrating circuit transistor (NPN transistor) 8c whose collector is connected to the non-ground terminal of the signal storage capacitor 7g, and a first integrating capacitor 8d and the transistor connected between the emitter of the transistor 8c and the ground. A speed up capacitor 8e connected between the base and emitter of transistor 8c and a resistor 8f connected between the collector and emitter of transistor 8c.
It is made up of.

The reset circuit 9 includes a reset transistor (NPN) whose emitter is grounded and whose collector is connected to the non-grounded terminal of the first integrating capacitor 8d.
A resistor 9b has one end connected to the base of the transistor 9a and the other end connected to the collector of the waveform shaping transistor 6d.

The second integrator circuit 10 includes a second integrator circuit 10 whose one end is grounded.
A discharging transistor (NPN transistor) 10b whose collector is connected to the non-grounded terminal of the capacitor 10a and whose emitter is grounded is connected between the base of the transistor 10b and the collector of the waveform shaping transistor 6d. The resistor 10d has one end connected to the collector of the transistor 10b, and the other end _10d1 of the resistor 10d is connected to an output terminal of a constant voltage circuit (not shown).

The third integrator circuit 11 includes a third integrator circuit 11 whose one end is grounded.
an integrating capacitor 11a, a discharge transistor (NPN transistor) 11b whose collector is connected to the non-grounded terminal of the capacitor 11a and whose emitter is grounded, a resistor 11c whose one end is connected to the base of the transistor 11b, and the transistor 11.
A resistor 11d connected between the base and emitter of b
and a capacitor 11e connected between the other end of the resistor 11c and the non-grounded terminal of the signal storage capacitor 7g of the ignition operation permissible section detection signal generation circuit 7.
, a resistor 11h whose one end is connected to the non-grounded terminal of the third integrating capacitor 11a, and a diode whose cathode is connected to the other end of the resistor 11h and whose anode is connected to the non-grounded terminal of the signal storage capacitor 7g. 11i.

In this embodiment, a differential circuit 11g is composed of resistors 11c and 11d and a capacitor 11e. This differentiating circuit 11g generates a pulse by differentiating the rising edge of the ignition operation permissible interval detection signal Vq obtained across the signal storage capacitor 7g, and while the pulse is being generated, the transistor 11b is made conductive and the third The integrating capacitor 11a is discharged.

The first comparison circuit 12 includes a voltage comparator 12a made of an IC, and an external resistor 12b connected between the output terminal of the comparator 12a and a power supply terminal.
The output terminal of the comparator 12a is connected to the base (control signal input terminal) of the transistor 3. The third integrated voltage Vc 3 obtained across the third integrating capacitor 11a is input to the negative phase input terminal of the comparator 12a, and the second integrated voltage Vc ₃ is input to the positive phase input terminal of the comparator 12a.
A second integrated voltage Vc ₂ obtained across the integrating capacitor 10a is inputted.

The second comparison circuit 13 includes a voltage comparator 13a made of an IC, and an external resistor 13b connected between the output terminal of the comparator 13a and a power supply terminal.
The output terminal of comparator 13a is connected to the base of transistor 3. The first integrated voltage Vc ₁ obtained across the first integrating capacitor 8d is input to the negative phase input terminal of the comparator 13a.
A second integrating capacitor 10a is connected to the positive phase input terminal of
A second integrated voltage Vc ₂ obtained across the terminals is inputted.

In this embodiment, the third integrating circuit 1
A spontaneous ignition prevention resistor 14 is connected between the connection point between the resistor 11h of No. 1 and the diode 11i and the collector of the transistor 6d as a waveform shaping switch of the pulse shaping circuit 6. When conducting, the resistors 11h and 1 are connected from the third integrating capacitor 11a.
The circuit leading to the transistor 6d via the transistor 4 constitutes a discharge circuit for the capacitor 11a. The resistance value of the resistor 14 is set to a sufficiently large value so that normal charging of the third integrating capacitor 11a is not hindered during steady operation.

Operation of the embodiment Next, the operation of the above embodiment will be explained. Figure 2 shows the signal waveforms of each part of the above embodiment.
Figure A shows the waveforms of the first and second signals Vs ₁ and Vs ₂ obtained at the signal coil 4. FIG. 2B shows the ignition operation permissible interval detection signal Vq obtained at both ends of the signal storage capacitor, and FIG. 2C shows the waveforms of the first and second pulse signals Vp ₁ and Vp ₂ . In addition, Fig. 2 D to I are respectively integrated voltages.
Vc ₁ , Vc ₂ , voltage Vb of the 13 output terminals of the second comparison circuit, integrated voltage Vc ₂ , Vc ₃ , first comparison circuit 12
Voltage Vd at the output terminal of , base-emitter voltage Vbe of transistor 3, and primary current I ₁ of the ignition coil.
The waveform of In each of these figures, the solid line shows the waveform when the engine speed is extremely low, and the broken line shows the waveform when the engine rotational speed increases to a certain extent. The horizontal axis in Figure 2 shows the rotation angle θ of the engine, and each angle is measured from the top dead center of the engine TDC.

First, consider the case where the engine is started immediately after the power switch is closed.

When the engine is started, the signal coil 4 outputs first and second signals. When the engine is running at an extremely low speed, the first signal Vs ₁ does not exceed the threshold level, and only the second signal Vs ₂ exceeds the threshold level. Therefore, when the engine speed is extremely low, the first pulse shaping circuit 5
cannot generate the first pulse signal Vp ₁ having a magnitude sufficient to trigger the transistor 7b of the ignition operation permissible interval detection signal generation circuit 7.

In the second pulse shaping circuit 6, a base current flows from a power supply (not shown) to the transistor 6d through the resistor 6f, so that the transistor 6d is conductive. When the second signal Vs ₂ is generated, a current flows through the diode 6e, resistor 6c, capacitor 6b, and diode 6a of the second pulse shaping circuit 6, and the voltage across the diode 6e reaches a predetermined value at the minimum advance position θ ₂ . (when the second signal Vs ₂ becomes equal to or higher than the threshold level Vt), the base-emitter of the transistor 6d is reverse biased, and the transistor 6d is turned off. second signal
When Vs ₂ falls below the threshold level, transistor 6d becomes conductive again. Therefore, a second signal is present between the collector and emitter of the transistor 6d.
A second pulse signal Vp ₂ is obtained with a pulse width corresponding to the period during which Vs ₂ is equal to or higher than the threshold level.

In this way, when the engine speed is extremely low, only the second pulse signal Vp ₂ is generated, and the first pulse signal Vp ₁ that can operate the ignition operation permissible interval detection circuit 7 is not generated. Therefore, the ignition operation permissible range detection signal Vq
is not output, and the first integrating capacitor 8d and the third integrating capacitor 11a are not charged by the ignition operation permissible section detection signal Vq.

In the second integrating circuit, the second integrating capacitor 10a is charged from the power supply through the resistor 10d to the polarity shown in the figure, and when the transistor 10b is turned on by the second pulse signal Vp ₂ , the second integrating capacitor 1
0a discharges. Therefore the second integrating capacitor 1
At both ends of 0a, as shown in _FIG .
An integrated voltage Vc ₂ is obtained.

As mentioned above, at extremely low speeds, the third integrating capacitor 11a is not charged by the ignition operation permissible interval detection signal Vq, but the second integrating capacitor 11a is charged during the period when the second signal Vs ₂ is above the threshold level. When the transistor 6d of the pulse shaping circuit 6 is cut off, the resistor 6g and the resistors 14 and 1 are connected to the power supply (not shown).
1h, a charging current flows to the third integrating capacitor 11a. Therefore, the third integrating capacitor is slightly charged while the second signal Vs ₂ is above the threshold level, and its terminal voltage Vc ₃
increases slightly as shown by the chain line in FIG. 2F.

The first comparison circuit 12 compares this voltage Vc ₃ with the second integrated voltage Vc ₂ . When the voltage Vc ₂ becomes larger than the voltage Vc ₃ , the comparator circuit 1 as shown in FIG.
The output voltage Vd of No. 2 becomes high level. Furthermore, since the first integrated voltage Vc ₁ is not generated, the output voltage Vb of the second comparator circuit 13 remains at a high level, as shown by the solid line in FIG. 2E. Therefore, when the output voltage Vd of the first comparison circuit 12 becomes high level, the base-emitter voltage Vbe of the transistor 3 becomes high level as shown by the solid line in FIG. 2H. As a result, a base current flows through the transistor 3, making the transistor 3 conductive, and the primary current flows through the ignition coil 1.
I ₁ flows. Next, the second integrated voltage is applied at the minimum advance position.
When Vc ₂ becomes zero, the potential of the output terminal of the first comparison circuit 12 becomes the ground level, so the transistor 3 is cut off and the primary current I ₁ is suddenly cut off. This causes a large magnetic flux change in the iron core of the ignition coil, and a spark is generated in the ignition plug 2. In this way, in the present invention, the ignition operation is performed at the minimum advance angle position θ ₂ even at extremely low speeds of the engine where the first signal Vs ₁ does not exceed the threshold level, which improves engine startability. be able to.

When the rotational speed increases to a certain extent by starting the engine, the first signal Vs ₁ increases as shown by the broken line in Figure 2.
is also above the threshold level. At this time the first
The pulse shaping circuit 5 differentiates the first signal Vs ₁ and generates a first pulse signal Vp ₁ of sufficient magnitude at the maximum advance angle position θ ₁ as shown by the broken line in FIG. 2C.

When the first pulse signal Vp ₁ is generated at the maximum advance angle position θ ₁ , the transistor 7b becomes conductive and the transistor 7e becomes conductive. As a result, the signal storage capacitor 7g is instantly charged to a constant voltage Vqm as shown in FIG. 2B. Next, when the second pulse signal Vp ₂ is generated at the minimum advance angle position θ ₂ (the transistor 6d is cut off), the base current flows to the transistor 7h through the resistor 6g, making the transistor 7h conductive, and the signal storage capacitor 7g
is instantly discharged. Therefore, the ignition operation permissible range detection signal Vq that lasts from the maximum advance angle position θ ₁ to the minimum advance angle position θ ₂ is present at both ends of the signal storage capacitor 7g.
(Figure 2B) is obtained.

When the ignition operation permissible interval detection signal Vq is generated, the first integrating circuit transistor 8c becomes conductive, and the first integrating capacitor 8d of the first integrating circuit 8 becomes conductive.
is from the output voltage of the resistor voltage divider circuit to the transistor 8c.
It is instantly charged to the initial voltage V ₀ , which is equal to the base-emitter voltage of . When the signal storage capacitor 8d is charged to the initial voltage _V0 , the first integrating circuit transistor 8c is cut off (base current no longer flows to the transistor 8c). Additional charging is performed at a constant time constant through a charging resistor 8f connected between the collector and emitter of the integrating circuit transistor 8c. Therefore, the waveform of the first integrated voltage _Vc1 obtained across the first integrating capacitor 8d instantly rises to the initial voltage _V0 at the maximum advance position _θ1 , as shown in Figure 2D. After that, the waveform becomes even higher.

In the second integrating circuit 10, a second integrated voltage Vc ₂ as shown in FIGS. 2D and F is obtained across the second integrating capacitor 10a by the operation already described.

In the third integrating circuit 11, the output voltage Vf of the differentiating circuit 11g that differentiates the rise of the ignition operation permissible interval detection signal Vq disappears and the third integrating circuit 11 moves from the position where the transistor 11b is cut off to the next maximum advance angle position θ ₁ . Integrating capacitor 11a is charged with a constant time constant,
Ignition operation permissible zone detection signal Vq at maximum advance angle position θ ₁
rises and the differentiating circuit 11g outputs a pulse Vf, the transistor 11b becomes conductive and the capacitor 1
1a is discharged. Therefore, as shown in FIG. 2F, at both ends of _{the third integrating capacitor 11a, a voltage rises at a constant gradient from a position θ 3 delayed} by an angle α from each maximum advance angle position θ 1 to a minimum advance angle position θ ₂ . the third integral voltage that maintains that voltage until the next maximum advance position θ ₁
Vc ₃ is obtained.

The second integrated voltage Vc ₂ and the third integrated voltage Vc ₃
is input to the first comparison circuit 12. In the first comparator circuit 12, when the second integrated voltage Vc ₂ is lower than the third integrated voltage Vc ₃ , the output stage of the comparator 12a becomes conductive, and the ground voltage Vd at its output terminal becomes zero (ground level). )become. Also, the second integrated voltage Vc ₂
exceeds the third integrated voltage _Vc3 , the output stage of the comparator 12a is cut off, and the comparator circuit 1
The potential Vd of the output terminal No. 2 becomes high level. Therefore, the waveform of the voltage Vd at the output terminal of the first comparison circuit 12 is as shown by the broken line in FIG. 2G, and the voltage Vbe between the base and emitter of the transistor 3 is as shown by the broken line in FIG. 2H. Become. That is, during the period when the output voltage Vd of the first comparator circuit 12 is zero, the potential of the base of the transistor 3 is kept at the ground level and conduction of the transistor 3 is prohibited, and only during the period when the voltage Vd is at a high level, the transistor 3 is turned on. conduction is allowed.

The first integrated voltage Vc ₁ and the second integrated voltage
Vc ₂ is input to the second comparison circuit 13. In the second comparator circuit, when the first integrated voltage Vc ₁ is less than or equal to the second integrated voltage Vc ₂ , the output stage of the comparator 13a is in a cutoff state, and the first integrated voltage Vc ₁ is lower than the second integrated voltage Vc 2 .
When the integrated voltage Vc ₂ is exceeded, the output stage of the comparator 13a is cut off. Therefore, as shown in FIG. 2E or M, when the first integrated voltage Vc ₁ is less than the second integrated voltage Vc ₂ , the output terminal of the second comparison circuit 13 indicates that the ground voltage Vb is at a high level. Therefore, while the first integrated voltage Vc ₁ exceeds the second integrated voltage Vc ₂ , the ground voltage at the output terminal of the second comparison circuit 13 becomes zero. Therefore, the second integrated voltage Vc ₂ exceeds the third integrated voltage Vc ₃ (conduction of transistor 3 is allowed), and the first integrated voltage Vc ₁ is less than or equal to the second integrated voltage Vc ₂ . In this case, the second comparator circuit 13 allows the base current to flow through the transistor 3 as a primary current control switch, making the transistor 3 conductive, and the ignition coil is turned on as shown by the broken line in FIG. 2I. A primary current I ₁ is applied to the Angle θi
, the first integrated voltage Vc ₁ becomes the second integrated voltage
When it exceeds Vc ₂ , the output voltage of the second comparator circuit 13
Transistor 3 because Vb becomes zero (ground potential)
becomes blocked. When the transistor 3 changes from the conductive state to the cut-off state in this way, the ignition coil 1
Because the next current I ₁ changes rapidly, the ignition coil 2
A high voltage is induced in the next coil 1b. This causes a spark discharge to occur in the spark plug 2 attached to the cylinder of the engine, and the engine is ignited.

The angle θi at which the first integral voltage Vc ₁ exceeds the second integral voltage Vc ₂ advances as the engine rotational speed increases, so the engine ignition timing (θi) advances as the engine rotational speed increases. Turn around and go.

As described above, if the transistor 3 (primary current control switch) is made conductive when the second integrated voltage Vc ₂ exceeds the third integrated voltage Vc ₃ , the constant of the differentiating circuit 11g (the resistor 11c , 11d
and the time constant determined by the capacitor 11e) and the integration constant of the third integrating circuit 11 (the time constant determined by the capacitor 11a)
By appropriately setting the time constant determined by the resistor 11d and the time constant determined by the resistor 11d, it is possible to arbitrarily set the timing at which the primary current control switch starts conducting. Therefore, by setting the integration constant of the third integration circuit so that the period during which the primary current of the ignition coil is energized is the minimum necessary when the engine is running at low speed, the loss can be minimized. It is possible to suppress the temperature rise of the switch elements constituting the next current control switch. Furthermore, the position θ ₃ at which charging of the third integral capacitor starts is delayed as the engine rotational speed increases, and the position where the second integral voltage exceeds the third integral voltage is determined by the engine rotational speed. As the rotational speed of the engine increases, the primary current energization time becomes longer.
Therefore, by preventing the breaking current value from becoming low when the engine is running at high speed, it is possible to prevent the ignition performance from decreasing at high speed.

Next, consider the case where the power switch is held closed while the engine is stopped.

Since the signal coil 4 does not output the first and second signals Vs ₁ and Vs ₂ when the engine is stopped,
The first and second pulse signals Vp ₁ and Vp ₂ are also not generated, and the ignition operation permissible section detection signal Vq is not obtained at both ends of the signal storage capacitor 7g. Therefore, the first and third
Integrating capacitors 8d and 11a are never charged. However, since the second integrating capacitor 10a is charged from a power supply (not shown) through the resistor 10d, its terminal voltage _Vc2 rises at a predetermined slope as shown in FIG. 4, and eventually becomes saturated. Since the voltage at the terminal of this second integrating capacitor increases the potential at the output terminal of the first comparison circuit 12,
A base current is supplied to the transistor 3, the transistor 3 becomes conductive, and a primary current flows through the ignition coil 1.

At this time, in the second comparison circuit 12, a weak current flows from the power supply through the inside of the comparator 12a and from the negative phase input terminal and the positive phase input terminal of the comparator.

Now, in FIG. 1, if there is no self-ignition prevention resistor 14, the third integrating capacitor 11 is caused by a weak current flowing from the negative phase input terminal of the comparator 12a.
a is charged, the third integrating capacitor 11
The terminal voltage Vc ₃ of a increases as shown in FIG. 4, and eventually this third integrating capacitor 11a
terminal voltage Vc ₃ exceeds the second integrated voltage Vc ₂ . In this way, the third integrated voltage Vc ₃ is
When the integrated voltage Vc exceeds ₂ , the first comparator circuit 1
Since the output terminal of transistor 2 is at ground potential, transistor 3 is cut off, and the primary current I ₁ is cut off.
Therefore, a large magnetic flux change occurs in the iron core of the ignition coil 1, and a high voltage is induced in the secondary coil of the ignition coil. Since this high voltage is applied to the ignition plug 2, a spark is generated in the ignition plug, resulting in so-called spontaneous ignition.

On the other hand, if the spontaneous combustion prevention resistor 14 is provided as in the present invention, when the power switch is held in the closed state while the engine is stopped, the spontaneous combustion prevention resistor 11h Since the third integrating capacitor 11a is discharged through the resistor 14 and the waveform shaping switch (transistor 6d in the example of FIG. 1) of the second pulse shaping circuit 6 which is in a conductive state, the terminal voltage of the third integrating capacitor 11a is discharged. is prevented from rising and spontaneous combustion is prevented from occurring.

For reference, FIG. 3 shows signal waveforms at various parts when the spontaneous combustion prevention resistor 14 in FIG. 1 is not provided. The waveforms shown by solid lines in FIGS. 3A to 3I show the waveforms when the rotational speed of the engine is extremely low and only the second signal Vs ₂ is above the threshold level, and the waveforms shown by broken lines are The waveforms are shown when both the first and second signals Vs ₁ and Vs ₂ are at or above the threshold level.

In order to prevent spontaneous combustion in the device of the embodiment shown in FIG. 1, a resistor 15 is connected in parallel to both ends of the third integrating capacitor 11a as shown in FIG. It is also possible to prevent the capacitor 11a from being charged by the flowing current. However, with this configuration, when the engine is started, the first signal
The third integrating capacitor 1 at the point when Vs ₁ does not occur
1a cannot be charged, the ignition operation cannot be performed at extremely low rotational speeds where only the second signal _Vs2 exceeds the threshold level as in the present invention, and the starting rotational speed of the engine is low. It is unavoidable that the engine's startability will deteriorate as the engine temperature increases.

In the above embodiment, the transistor 3 as a primary current control switch is connected in series with the primary coil 1a of the ignition coil, but it is possible to change the primary current control switch from a conductive state to a cutoff state. Another type of current interrupter type ignition device that interrupts the current to perform the ignition operation, for example, a known current interrupter type ignition device in which a primary current control switch is provided in parallel to the primary coil of the ignition coil. The present invention can also be applied to devices. In this case, the collector-emitter circuit of the transistor 3 is connected in parallel to the primary coil 1a of the ignition coil 1,
An exciter coil (a power generation coil provided in a generator driven by the engine) is connected in parallel to the collector-emitter circuit of the transistor 3.

Other Modifications In the above embodiment, the differentiation circuit 11g of the third integration circuit differentiates the rise of the ignition operation permissible interval detection signal Vq, thereby generating a pulse with a constant time width.
However, if it is possible to obtain a waveform with a sufficiently fast rise as the first pulse signal Vp ₁ , the rise of the first pulse signal Vp 1 is differentiated by the differentiating circuit 11g and the pulse signal Vp ₁ is differentiated over a certain period of time. width pulse
It is also possible to obtain Vf.

In the above embodiment, a switch consisting of a transistor 6d is used as the waveform shaping switch of the second pulse shaping circuit 6, but the elements constituting this switch are used when the second signal Vs ₂ becomes equal to or higher than the threshold level. For example, an inverter IC whose output stage becomes conductive when the second signal Vs ₂ is input can be used as the waveform shaping switch.

In the above embodiment, the spontaneous ignition prevention resistor 1
One end of 4 is connected to the connection point between the resistor 11h and the diode 11i, and this resistor 14 is a waveform shaping switch (transistor 6d in the example of FIG. 1).
In addition, it is sufficient to provide a discharge circuit for discharging the third integrating capacitor, and one end of the resistor 14 may be connected to the non-ground terminal of the third integrating capacitor 11a.

[Effects of the Invention] As described above, according to the present invention, the spontaneous ignition prevention resistor is provided so as to constitute the discharge circuit of the third integrating capacitor together with the waveform shaping switch of the second pulse shaping circuit. When the power switch is closed when the internal combustion engine is stopped, the third integrating capacitor can be discharged through the spontaneous ignition prevention resistor and the waveform shaping switch which is in conduction. Therefore, even if the power switch is left closed while the internal combustion engine is stopped, the second integrated voltage will not exceed the third integrated voltage, and ignition operation will be prevented. can.

In addition, the structure is the same as the invention of the previously proposed application except for the provision of a resistor to prevent spontaneous combustion.
Similar to the invention of the previous application, this invention has the effect of preventing the period in which the primary current control switch is conductive when the engine is running at low speeds from becoming longer than necessary and increasing losses, and the current cutoff value is low when the engine is running at high speeds. It is possible to obtain the effect of preventing this from occurring.

Therefore, according to the present invention, it is possible to obtain an ignition device for an internal combustion engine that has good engine startability, does not cause spontaneous combustion, has small loss at low engine speeds, and has good ignition performance at high speeds. There is an advantage that it can be done.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram showing signal waveforms of each part of FIG. 1,
Fig. 3 is a waveform diagram showing the signal waveforms of each part in the case where there is no spontaneous ignition prevention resistor in the embodiment shown in Fig. 1, and Fig. 4 is a waveform diagram showing the signal waveform of each part when there is no spontaneous ignition prevention resistor. FIG. 5 is a diagram illustrating the operation when left as it is, and a circuit diagram showing an alternative spontaneous combustion prevention means. 1...Ignition coil, 2...Spark plug, 3...
Transistor (primary current control switch), 4...
...Signal coil, 5...First pulse shaping circuit, 6
...Second pulse shaping circuit, 7...Ignition operation permissible interval detection signal generation circuit, 8...First integrating circuit,
9...Reset circuit, 10...Second integration circuit,
DESCRIPTION OF SYMBOLS 11... Third integrating circuit, 11a... Third integrating capacitor, 11b... Third integrating capacitor discharging transistor switch, 11g... Differentiating circuit, 12... First comparing circuit, 13... Third integrating circuit. Comparison circuit 2, 14... Resistor for preventing spontaneous combustion.

Claims (1)

[Scope of Claims] 1. An ignition coil, a primary current control switch provided on the primary side of the ignition coil, and a switch that changes the primary current control switch from a conductive state to a cutoff state at the ignition timing of an internal combustion engine. In the ignition device for an internal combustion engine, the ignition device for an internal combustion engine obtains a high voltage for ignition by abruptly changing the primary current of the ignition coil by interrupting the primary current control switch, the control circuit comprising: , a signal coil that outputs first and second signals that are equal to or higher than a threshold level at a maximum advance position and a minimum advance position of the ignition timing of the engine in synchronization with the rotation of the internal combustion engine; A first pulse signal that shapes the signal into a pulse and generates a first pulse signal that rises at the maximum advance angle position.
a pulse shaping circuit, and a waveform shaping switch that maintains a cut-off state during a period when the second signal is above a threshold level and maintains a conductive state during other periods, and a waveform shaping switch that is connected to both ends of the waveform shaping switch. a second pulse shaping circuit that obtains a second pulse signal; a signal storage capacitor; and a charging control transistor switch that becomes conductive when the first pulse signal is generated and instantly charges the signal storage capacitor. , a discharge control transistor switch that becomes conductive when the second pulse signal is generated to instantly discharge the signal storage capacitor; an ignition operation permissible interval detection signal generation circuit that obtains an ignition operation permissible interval detection signal that lasts up to 100 seconds; a first integrating capacitor; and a first integrating capacitor; a first integrating capacitor charging circuit that instantaneously charges the first integrating capacitor to a certain voltage using the terminal voltage of the storage capacitor; and an additional charging circuit that additionally charges the first integrating capacitor at a certain time constant. a first integrator circuit comprising: a first integrator circuit comprising a
a reset circuit that instantly discharges the integrating capacitor; a second integrating capacitor; a second integrating capacitor charging circuit that charges the second integrating capacitor with a constant time constant; a second integrating capacitor discharging transistor switch connected in parallel to the second integrating capacitor and conducting when triggered by the second pulse signal; and a third integrating capacitor; , a third integrating capacitor discharging circuit that charges the third integrating capacitor with a voltage across the signal storage capacitor through a reverse current blocking diode and a current limiting resistor at a constant time constant; a differentiating circuit for differentiating the rising edge or the rising edge of the ignition operation permissible interval detection signal, and a collector-emitter circuit connected in parallel to the third integrating capacitor, and being triggered by the output of the differentiating circuit to conduct. a third integrating circuit comprising a transistor switch for discharging the third integrating capacitor; a self-ignition prevention resistor coupled to the waveform shaping switch; and a second integrated voltage obtained across the second integrating capacitor whose output terminal is coupled to the control signal input terminal of the primary current control switch. Vc ₂ and the third integrated voltage Vc ₃ obtained across the third integrating capacitor as input, and when the second integrated voltage is equal to or less than the third integrated voltage, the primary current control a first comparator circuit that prevents conduction of the switch and allows conduction of the primary current control switch while the second integrated voltage exceeds the third integrated voltage; A first integrated voltage Vc 1 coupled to a control signal input terminal _{of a control switch and obtained across the first integrating capacitor, and a second integrated voltage Vc 2 obtained} across the second integrating capacitor. As an input, the first comparator circuit allows the primary current control switch to conduct and conducts the primary current control switch while the first integrated voltage is equal to or lower than the second integrated voltage. and a second comparison circuit that shuts off the primary current control switch when the first integrated voltage exceeds the second integrated voltage.