JPH0763147A - Ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an ignition device for an internal combustion engine whereby startability of the engine can be improved by decreasing a rotational speed where ignition action is started. CONSTITUTION:A bias giving diode 16 is connected in series to a pulsar coil 15b of generating a signal for determining an ignition position of an engine, to flow a current in the diode 16 from a power supply circuit 14. Forward direction voltage, generated across both ends of the diode 16, is applied as bias voltage Vb to signal voltage Vso2 induced in the pulsar coil 15b, and sum voltage of the bias voltage Vb and the signal voltage Vso2 is input as a control signal Vs to an ignition circuit 10.

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 which controls ignition timing by a control signal generated from a pulsar coil of a signal generator which rotates in synchronization with the internal combustion engine to induce a high voltage for ignition. is there.

[0002]

2. Description of the Related Art As an ignition device for an internal combustion engine, a signal generator having a pulser coil for generating a pulse-like signal including rotation information (rotation angle information and rotation speed information) of the engine in synchronization with rotation of the engine, An ignition circuit that widely changes the primary current of the ignition coil and generates a high voltage for ignition in the secondary coil of the ignition coil at the ignition position determined based on the rotation information obtained from this signal is widely used. Has been done.

FIG. 7 shows a conventional example of this kind of internal combustion engine ignition device. In the figure, the ignition coil 1, the diodes 3 and 9, the ignition energy storage capacitor 4, the thyristor 5 serving as a switch element, and the resistor 6 constitute a capacitor discharge type ignition circuit 10, and an ignition energy storage capacitor 4 is provided. Is charged to the polarity shown by a DC voltage obtained by rectifying the AC output of the exciter coil 11 with the diode 12. Reference numeral 15 denotes a reluctor 15a that rotates synchronously with the engine, and the reluctor 15a.
Is a signal generator having a pulser coil 15b that generates a pulsed signal voltage by changing the magnetic flux due to the rotation of the. When the signal voltage Vs generated in the pulsar coil 15b at the ignition position of the engine is input to the ignition circuit 10 as a control signal and the thyristor 5 is triggered by the control signal, the charge of the ignition energy storage capacitor 4 passes through the thyristor 5 and the ignition coil is charged. Is discharged through the primary coil 1a, and a high voltage for ignition is generated in the secondary coil 1b. Since this high voltage is applied to the spark plug 2, a spark is generated in the spark plug 2 and the engine is ignited.

[0004]

In the above conventional ignition device, the magnitude of the control signal Vs generated from the pulsar coil 15b in synchronism with the rotation of the engine is substantially proportional to the number of revolutions of the engine, and the magnitude of the control signal Vs is large. However, as shown by the solid line in FIG. 8, at a rotational speed that is equal to or higher than the trigger level Vt of the switch element 5 that controls the primary current of the ignition coil 1, the switch element 5 is triggered to ignite from the ignition circuit. High voltage is generated. However, the rotation speed is low and the control signal is
When the trigger level Vt of the switch element 5 is not reached as indicated by the waveform Vs' indicated by the broken line in FIG.
Is not triggered, the ignition circuit 10 cannot generate a high voltage for ignition.

In an internal combustion engine, such as an internal combustion engine for a two-wheeled vehicle, when the engine is started by kick start, the number of revolutions at the time of starting reaches about 500 to 700 [rpm], but when the engine is started by a starter motor. In some cases, the number of revolutions at the time of starting may be as low as about 100 to 200 rpm. Therefore, the control signal may not reach the trigger level of the switch element, which may make it difficult to start the engine. Therefore, in this type of ignition device, it is required that the minimum value of the number of revolutions at which the ignition operation is possible (the number of revolutions at which the ignition operation starts) be made as low as possible.

An object of the present invention is to provide an ignition device for an internal combustion engine, which is capable of lowering the starting speed of ignition operation with a simple structure and lowering the startable speed of the engine. It is in.

[0007]

As shown in FIG. 1 which shows the structure of the present invention, a pulsed signal voltage (Vso1 and Vso) containing engine rotation information in synchronization with the rotation of an internal combustion engine.
2) having a pulse generator coil 15b for generating a pulse generator, and a control signal input terminal S to which one end of the pulser coil 15b is connected. From the control signal Vs input between the control signal input terminal S and ground. In an ignition device for an internal combustion engine that includes an ignition circuit 10 that generates a high voltage for ignition at an ignition position determined based on the obtained rotation information, it is possible to reduce the ignition operation start rotation speed with a simple configuration. It is the one.

Therefore, in the present invention, the other end of the pulsar coil 15b is grounded through at least one bias applying diode 16 whose anode is directed to the pulsar coil side, and the bias applying diode 16 is connected between the other end of the pulsar coil 15b and the ground. A diode 17 for forming a signal supply circuit in the opposite direction is connected. The connection point between the bias applying diode 16 and the pulsar coil 15b is connected to the power supply circuit 14 that causes a forward current to flow in the bias applying diode via the current control element 18.

The ignition circuit uses the rotation information itself included in the control signal Vs to determine the ignition position (for example, the position where the level of the control signal Vs reaches a predetermined level at a predetermined rotation angle position is defined as the ignition position). Circuit),
It may be a circuit that calculates the ignition position based on the rotation information included in the control signal Vs and performs the ignition operation at the calculated ignition position.

In the present invention, "ground" means a ground potential portion common to the ignition circuit and the pulser coil. It is optional whether or not the "ground" is connected to the ground potential portion (engine case, vehicle chassis, etc.).

The power supply circuit may use a power generation coil in a power generator driven by an engine, such as a magnet generator, or a battery.

[0012]

In the above structure, when the current is flowing from the power supply circuit 14 to the bias adding diode 16 through the current limiting element 18, the bias adding diode 16 is connected between the other end of the pulsar coil 15b and the ground. A bias voltage Vb is generated by the directional voltage drop. When a positive pulsed signal voltage Vso2 in the direction of the arrow in the figure is generated in the pulsar coil 15b in this state, a voltage Vso2 generated by the pulsar coil is generated as a control signal Vs between the control signal input terminal S of the ignition circuit 10 and the ground. A voltage (Vso2 + Vb) obtained by adding the bias voltage Vb is input to. Therefore, even when the engine speed is low and the generated voltage Vso2 of the pulsar coil alone does not reach a value that can trigger the primary current control switch element of the ignition circuit 10, the control signal Vs to which the bias voltage Vb is added is used as a switch signal. The ignition circuit can be operated above a value that can trigger the element.

A current limiting element 1 in which two or more bias applying diodes 16 are connected in series or which is composed of a resistor
By reducing the resistance value of 8, the bias voltage Vb
The value of can be increased. If the value of the bias voltage Vb is selected to be a value slightly lower than the trigger level of the switching element for controlling the primary current, the ignition circuit 10 can be operated even when the engine speed is very low.

Further, even if a failure occurs in which the forward current does not flow in the bias applying diode 16 during operation of the engine and the bias voltage does not occur, the pulsar coil 15 passes through the signal supply circuit forming diode 17.
Since the signal voltage generated in b is supplied to the ignition circuit as a control signal, the ignition operation does not stop.

[0015]

FIG. 2 shows an embodiment of the present invention. In FIG. 2, 1 is an ignition coil having a primary coil 1a and a secondary coil 1b whose one ends are grounded, and 2 is a cylinder of an engine (not shown). The spark plug is attached and connected to the secondary coil 1b of the ignition coil 1. A diode 3 having a cathode directed to the ground side is connected between both ends of the primary coil 1a. One end of the ignition energy storage capacitor 4 is connected to the non-grounded terminal of the primary coil 1a, and the other end of the capacitor 4 is connected to the anode of the primary current control thyristor 5 whose cathode is grounded. . A resistor 6 is connected between the gate and cathode of the thyristor 5. The gate of the thyristor 5 is also connected to one end of a parallel circuit of the capacitor 7 and the resistor 8, and the cathode of the diode 9 is connected to the other end of the parallel circuit. The ignition coil 1, the capacitor 4 for storing the ignition energy, the thyristor 5, the diodes 3 and 9, the capacitor 7, and the resistors 6 and 8 constitute a capacitor discharge type ignition circuit 10, and the anode of the diode 9 controls the ignition circuit 10. It is connected to the signal input terminal S.

Numeral 11 is an exciter coil which is arranged in a magnet generator attached to the engine and induces an AC voltage Ve as shown in FIG. 3A in synchronization with the rotation of the engine.
One end of the exciter coil 11 is grounded and the other end is connected to the respective anodes of the diodes 12 and 13. The cathode of the diode 12 is connected to the other end of the ignition energy storage capacitor 4 of the ignition circuit 10, and the cathode of the diode 13 is connected to one end of the current limiting element of the bias circuit 19 described later. Exciter coil 11
A power supply circuit 14 for outputting a direct current is constituted by the diodes 12 and 13 and the voltage in the direction of the arrow induced in the exciter coil 11 causes a capacitor 4 for ignition energy storage through the diodes 12 and 13 respectively.
Also, a DC current having a half-wave rectified waveform is supplied to the bias circuit 19.

A signal generator 15 is provided to obtain a signal for determining the ignition position of the ignition circuit 10. The signal generator 15 is a reluctor 1 that rotates in synchronization with the engine.
5a and a pulser coil 15b for generating a pulse-shaped first signal Vso1 and a second signal Vso2 having different polarities as shown in FIG. 3B due to a change in magnetic flux caused by the rotation of the reluctor 15a. Is equipped with. Reluctor 15a
The rotation angle position of and the relative position of the pulsar coil 15b are
The pulsar coil 15b is set so as to induce the positive second signal Vso2 in the direction of the solid arrow shown in the figure while the voltage in the direction of the arrow shown in the exciter coil 11 is being induced. One end of the pulser coil 15b is connected to the control signal input terminal S of the ignition circuit 10.

The other end of the pulsar coil 15b has a bias-applying diode 1 whose anode side faces the pulsar coil side.
It is grounded through 6. Between the other end of the pulsar coil 15b and the ground, a diode 17 for forming a signal supply circuit, which is directed in the opposite direction to the diode 16, is connected. The connection point between the diode 16 and the pulser coil 15b is connected to the cathode of the diode 13 of the power supply circuit 14 via the resistor 18 as a current limiting element. A bias circuit 19 is configured by the bias applying diode 16, the signal supply circuit forming diode 17, and the resistor (current limiting element) 18.

In the circuit shown in FIG. 2, when the exciter coil 11 generates a voltage of a half cycle in the direction of the arrow shown in the figure, the voltage charges the ignition energy storage capacitor 4 through the diodes 12 and 3 to the polarity shown in the figure.
At the same time, a forward current flows through the diode 13 and the resistor 18 to the bias applying diode 16, and a bias voltage Vb is generated between the anode of the diode 16 and the ground due to the forward voltage drop of the diode 16. Next, when the second signal Vso2 in the direction of the solid arrow shown in the pulsar coil 15b is generated at the angular position θ2, this signal Vso2 is superimposed on the bias voltage Vb as shown in FIG. 3C, and the ignition circuit 10 is controlled. A signal of Vs = Vb + Vso2 is input as a control signal between the signal input terminal and the ground. The magnitude of the bias voltage Vb is set to a value slightly lower than the value of the trigger level Vt required to trigger the thyristor 5 of the ignition circuit 10. This bias voltage Vb
Can be adjusted by the resistance value of the resistor 18. If necessary, the bias voltage Vs can also be adjusted by forming the bias applying diode 16 by a plurality of diodes connected in series and appropriately selecting the number of the diodes.

The control signal Vs input between the control signal input terminal S and the ground is applied between the gate and cathode of the thyristor 5 through a noise removing circuit formed of a parallel circuit of the capacitor 7 and the resistor 8. As a result, when the thyristor 5 becomes conductive, the charge of the ignition energy storage capacitor 4 is discharged to the primary coil 1a of the ignition coil 1 through the thyristor 5, and at that time, a high voltage for ignition is induced in the secondary coil 1b. A spark is generated in the spark plug 2 and the engine is ignited.

In this embodiment, the pulsar coil 15b has a second
The angular position θ2 at which the signal Vso2 is generated becomes the ignition position of the engine, and the control signal Vs for triggering the thyristor 5 at this ignition position is the bias voltage Vb and the pulser coil 1
Since the second signal Vso2 induced in 5b is a superimposed voltage, only the signal Vso2 induced in the pulsar coil 15b due to the low engine speed when the engine is started is enough to trigger the thyristor 5. Even when Vt is not reached, the control signal Vs can be set to the trigger level Vt or higher. Therefore, the ignition operation start rotation speed can be lowered. Further, if a failure occurs in which the forward current of the bias applying diode 16 stops flowing during the operation of the engine, a control signal is supplied through the signal supply circuit forming diode 17, so that the ignition operation is stopped. There is nothing to do.

FIG. 4 shows another embodiment of the present invention. In this embodiment, the starting speed of the ignition operation is lowered and the ignition position of the engine is set to the minimum advance position according to the engine speed. An ignition position control circuit that controls the maximum advance position is provided. In the figure, the same parts as those of the circuit in FIG. 2 are designated by the same reference numerals as those in FIG.

In FIG. 4, the ungrounded terminals of the exciter coil 11 are connected to the anodes of the diodes 12 and 13 and the cathode of the diode 20 whose anode is grounded. The cathode of the diode 13 is connected via the resistor 21 to the power supply capacitor. It is connected to one end of 22. The other end of the power supply capacitor 22 is grounded, and a zener diode 23 with its anode facing the ground side is connected in parallel between both ends of the capacitor 22. In this embodiment, the exciter coil 1
1, a power supply circuit 1 including diodes 12, 13 and 20, a resistor 21, a capacitor 22 and a zener diode 23.
4, the capacitor 22 is charged to the Zener voltage of the Zener diode 23 with the polarity shown by the induced voltage of the exciter coil 11 in the direction of the arrow shown in the figure. The output terminal t1 is derived from the non-grounded side terminal of the power supply capacitor 22, and the DC voltage V1 obtained at the output terminal t1 is applied to the bias circuit 19 and the power supply terminal t2 of the integrating circuit described later.

In this embodiment, as shown in FIG. 5A, the pulser coil 15b of the signal generator 15 has pulses of different polarities at the maximum advance position θ1 and the minimum advance position θ2 of the ignition position of the engine. -Shaped first and second signal voltages Vso
1 and Vso2 are generated. Further, in the bias applying diode 16, a forward current flows through the resistor 18 as a current limiting element due to the terminal voltage V1 of the power supply capacitor 22, and a substantially constant bias voltage Vb is generated across the diode 16. Therefore, between the control signal input terminal S of the ignition circuit 10 and the ground, as shown in FIG. 5B, the pulse-shaped first and second signal voltages at the maximum advance position θ1 and the minimum advance position θ2. Bias voltage Vb is applied to Vso1 and Vso2
Are added to the first and second control signals Vs1 and Vs2.

The ignition circuit 10 includes a first integrator circuit 24, a second integrator circuit 25, which are surrounded by a chain line, respectively.
A publicly known (actual fair 4-22063) composed of a low speed signal supply circuit 26, a switch element 27 and a resistor 28.
No.) ignition timing control circuit is provided.

The first integrating circuit 24 includes a first integrating capacitor 29, transistors 30 to 32, and a diode 3.
3, capacitors 34 and 35, and resistors 36 to 41
It consists of When the negative first control signal Vs1 is input to the control signal input terminal S, a base current flows through the transistor 30 and the transistor 30 becomes conductive, whereby a base current flows through the transistor 31 and the transistor 31 becomes conductive. To do. When the transistor 31 becomes conductive, the capacitor 35 is instantly charged to the power supply voltage V1 with the polarity shown. Since the terminal voltage of the capacitor 35 is applied to both ends of the series circuit of the resistors 39 and 40, a base current flows through the transistor 32 to make the transistor 32 conductive, and
The integrating capacitor 29 of is instantly charged to a constant voltage V2 determined by the resistors 39 and 40. After that, the capacitor 29 is additionally charged by the charge of the capacitor 35 through the resistor 41 with a constant time constant. Therefore, the voltage Vc1 having an integrated waveform as shown in FIG. 5C is obtained across the capacitor 29.

The second integrating circuit 25 includes a second integrating capacitor 42, a transistor 43, and diodes 44 to 4.
6 and resistors 47 to 50. When the positive second control signal Vs2 is input to the control signal input terminal S, a base current flows through the transistor 43 and the transistor 43 becomes conductive, and the capacitor 42 is instantly discharged. When the control signal Vs2 disappears, the transistor 43 is turned off, so that the capacitor 42 is charged by the power supply voltage V1 through the resistor 49 with a constant time constant. Therefore, the voltage Vc2 having an integral waveform as shown in FIG. 5D is obtained across the capacitor 42.

The switch element 27 comprises a programmable unijunction transistor (hereinafter referred to as PUT), and the cathode of the PUT 27 is connected to the cathode of the primary current controlling thyristor 5 through the resistor 28. P
The terminal voltage of the first integrating capacitor 29 is applied between the anode of the UT 27 and the cathode of the thyristor 5,
The second between the gate of T27 and the cathode of thyristor 5
The terminal voltage of the integrating capacitor 42 is applied.

The low speed signal supply circuit 26 comprises a series circuit of a noise removing circuit composed of a parallel circuit of a capacitor 7 and a resistor 8 and a diode 9. The second control signal Vs2 is the low speed signal supply circuit 26. Is directly applied to the gate of the primary current controlling thyristor 5.

In the above circuit, when the engine speed is less than the advance start rotation speed, the second advance is made to the minimum advance position θ2.
Since the terminal voltage Vc2 of the integrating capacitor 42 exceeds the terminal voltage Vc1 of the first integrating capacitor 29, the PUT 27 does not conduct until the minimum advance position. The second integration capacitor 42 at the minimum advance position θ2
The PUT 27 is triggered at the moment when the terminal voltage of the PUT becomes zero, and the first integrating capacitor 29 is driven by the PU at the minimum advance position.
It discharges through T27 and the gate of the thyristor 5 for primary current control. As a result, the thyristor 5 is conducted and the ignition operation is performed. Therefore, in the region where the engine speed is less than the advancing start speed, the ignition position becomes the minimum advancing position θ2,
The ignition position is constant.

First and second integrating capacitors 29 and 4
Since the time for charging 2 decreases as the engine speed increases, the terminal voltage of both capacitors decreases as the engine speed increases, but the first integrating capacitor 29
Is instantly charged to a constant voltage V2 at the start of charging, so that as the charging time of both capacitors shortens as the engine speed increases, the terminal voltage Vc1 of the first integrating capacitor 29 will eventually be reached. The terminal voltage Vc2 of the second integrating capacitor 42 is exceeded. When the engine speed exceeds the advance start speed, the terminal voltage Vc1 of the first integrating capacitor becomes the second value at the position θ3 where the phase advances from the minimum advance position θ2 as shown in FIG. 5 (E). The terminal voltage Vc2 of the integration capacitor is exceeded, and at this position θ3, the PUT 27
Becomes conductive and supplies an ignition signal to the thyristor 25. As a result, a high voltage Vh for ignition is obtained on the secondary side of the ignition coil 1 as shown in FIG. Since the position where the terminal voltage Vc1 of the first integrating capacitor 29 exceeds the terminal voltage Vc2 of the second integrating capacitor 42 advances as the engine speed increases, the ignition position θ3 of the engine increases the engine speed. The angle is advancing accordingly. After the ignition position of the engine is advanced to the maximum advance position θ1, the first integrating capacitor 29 is instantaneously charged to the constant voltage V2 at the maximum advance position θ1, and at the same time, the PUT 27 becomes conductive and the maximum advance angle is increased. The ignition operation is performed at the position.

In the circuit of FIG. 4, the charge of the capacitor 35 causes the first through the transistor 32 and the resistor 41.
Integration capacitor 29 is charged. However, a series circuit of resistors 39 and 40 is connected to both ends of the capacitor 35, and the charge of the capacitor 35 is applied to the resistors 39 and 40.
Therefore, if the rotation speed of the engine decreases and the charging interval of the capacitor 35 becomes longer, the capacitor 3 is discharged.
The discharge amount of 5 increases, and the charge of the capacitor 29 becomes insufficient. Therefore, when the low speed signal supply circuit 26 is not provided, it becomes difficult to supply the ignition signal to the thyristor 5 through the PUT 27 when the engine speed decreases to some extent, and the ignition operation start speed increases. However, in this embodiment, the low speed signal supply circuit 26 is provided, and when the second control signal Vs2 is input to the control signal input terminal S when the engine is low speed, the signal Vs2 is supplied to the low speed signal. An ignition signal is supplied to the primary current control thyristor 5 through the circuit 26. Moreover, in the present invention,
Since the signal obtained by adding the bias voltage Vb to the second signal voltage Vso2 induced in the pulsar coil 15b of the signal generator 15 is input as the second control signal Vs2, the rotation speed of the engine is low, and the second induced voltage in the pulsar coil 15b is induced. Even when the signal voltage Vso2 of 2 is small, it is possible to supply a sufficiently large ignition signal to the thyristor 5. Therefore, in the present embodiment, it is possible to advance the ignition position as the engine speed increases and to lower the ignition operation start speed to improve the engine startability.

In the above embodiment, the DC voltage for charging the ignition energy storage capacitor 4 of the capacitor discharge type ignition circuit and the DC voltage for supplying the current to the bias addition diode 16 and the ignition timing control circuit. As the power supply circuit 14 for outputting the above, a circuit for rectifying the AC output of the exciter coil 11 arranged in the magnet generator driven by the engine by the diodes 12 and 13 to obtain a DC voltage is used. For example, as shown in FIG. 6, a circuit including a battery can be used.

In the power supply circuit 14 shown in FIG. 6, a surge absorbing capacitor 63, a known constant voltage circuit 64, and a DC voltage are provided at both ends of the battery 61 via key switches 62.
-The input side of the DC converter 65 is connected. The constant voltage V1 obtained at the output terminal t1 of the constant voltage circuit 64 is input to the bias circuit 19 (see FIGS. 2 and 4) and the power supply terminal t2 (see FIG. 4) of the ignition timing control circuit of the ignition circuit 10, and DC The boosted DC voltage obtained at the output terminal of the DC converter 65 is the ignition energy storage capacitor 4
(See FIGS. 2 and 4).

[0035]

As described above, according to the present invention, one end of the pulsar coil that generates a pulse-shaped control signal including engine rotation information in synchronization with the rotation of the internal combustion engine is connected to the control signal input terminal of the ignition circuit. Along with the connection, a bias applying diode with the anode facing the pulsar coil side is connected between the other end of the pulsar coil and ground, and the connection point between the bias applying diode and the pulsar coil is connected to the power supply circuit via the current limiting element. Since a forward current is made to flow from the power supply circuit to the bias addition diode, the signal generated by adding the bias voltage generated across the bias addition diode to the signal generated in the pulsar coil is input to the ignition circuit as a control signal. be able to. Therefore, the ignition operation can be performed even in the starting rotation region of the engine in which the magnitude of the signal generated in the pulsar coil is small, and the ignition operation start rotation speed can be reduced by adding a circuit having a simple configuration. There is an advantage that the startability can be improved.

Further, according to the present invention, since the bias supply diode and the diode for forming the signal supply circuit in the reverse direction are connected between the other end of the pulsar coil and the ground, a failure occurs in which no forward current flows through the bias addition diode. Even if it occurs, the control signal can be supplied through the diode for forming the signal supply circuit to perform the ignition operation, and the reliability is not deteriorated.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing an embodiment of the present invention.

FIG. 3 is a waveform diagram showing voltage waveforms of respective parts of FIG.

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

FIG. 5 is a waveform diagram showing signals of respective parts in FIG.

FIG. 6 is a circuit diagram showing another configuration example of the power supply circuit used in the present invention by using a partial block diagram.

FIG. 7 is a circuit diagram showing a conventional example.

FIG. 8 is a waveform diagram showing control signals in FIG.

[Explanation of symbols]

 10 Ignition Circuit 14 Power Supply Circuit 15 Signal Generator 15b Pulser Coil 16 Bias Addition Diode 17 Signal Supply Circuit Forming Diode 18 Resistance (Current Control Element)

Claims (1)

[Claims] 1. A signal generator having a pulser coil that generates a pulse-shaped control signal including rotation information of the engine in synchronization with the rotation of the internal combustion engine, and a control signal input terminal to which one end of the pulser coil is connected. And an ignition circuit for generating an ignition high voltage at an ignition position determined based on rotation information obtained from the control signal input between the control signal input terminal and ground. The other end of the pulsar coil is grounded through at least one bias applying diode with the anode side facing the pulsar coil side, and a signal supply circuit in the opposite direction to the bias applying diode is formed between the other end of the pulsar coil and the ground. Diode is connected, and the connection point between the bias applying diode and the pulsar coil is biased via a current control element. Ignition system for an internal combustion engine, characterized in that it is connected to a power supply circuit for supplying a forward current to the diode.