JPS632030B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition system for an internal combustion engine, and more particularly to an ignition system for an internal combustion engine that has an advance characteristic that advances the ignition position in a medium to high speed rotation range.

In general, internal combustion engines are often required to have advance angle characteristics as shown in FIG. In other words, from idling speed No. (rpm) to a certain set speed
In the low speed rotation range up to N ₁ , ignition is performed at a substantially constant ignition position θ ₂ close to top dead center TDC, and the rotation speed N ₁
It is required to advance the ignition position from θ _{2 to} θ ₁ toward the bottom dead center BTDC in the medium to high speed rotation range from θ to the set rotation speed N 2. As a conventional ignition device having such advance angle characteristics, the one shown in FIG.
An ignition coil having a primary coil 1b, 2 a spark plug connected to the secondary coil 1b, and 3 a thyristor connected in series to the primary coil 1a and having a cathode grounded. An exciter coil 4 disposed in a magnetic AC generator (not shown) driven by the engine is connected in parallel to both ends of the series circuit of the primary coil 1a and the thyristor 3, and emitters are grounded at both ends of the exciter coil. transistor 5
The collector-emitter circuits are connected in parallel via a diode 6. The anode of the thyristor 3 is connected to the base of the transistor 5 via a diode 7, and a resistor 8 is connected in parallel between the gate and cathode of the thyristor 3. The above-mentioned parts constitute an ignition circuit that controls the primary current of the ignition coil 1 to generate a spark in the ignition plug 2. In order to supply an ignition timing signal to this ignition circuit, a first signal coil 11 for low speed and a second signal coil 12' for high speed are provided, and the outputs of these signal coils are connected to diodes 13 and 14, respectively. The voltage is applied between the gate and cathode of the thyristor 3 via the thyristor 3.

In the ignition system shown in FIG. 2, the signal coils 11 and 12' each have a
The signal coil 12' generates a signal whose phase is more advanced than that of the signal coil 11. In addition, in the low speed rotation region of the engine (N ₀ ≦N < N ₁ ), only the output of the first signal coil 11 is output from the thyristor 3.
The second trigger level is reached only in the medium and high speed rotation range.
The number of turns of the first signal coil 11 is greater than the number of turns of the second signal coil 12' so that the output of the signal coil 12' reaches the trigger level of the thyristor 3. In this ignition device, when the exciter coil 4 generates a half-cycle output voltage in the direction of the arrow shown in the figure, a base current flows to the transistor 5 through the primary coil 1a and the diode 7, making the transistor 5 conductive, and the exciter coil 4 A short-circuit current flows from the diode 6 through the collector-emitter circuit of the transistor 5. When this current reaches a sufficient level, the signal coil 1
An ignition signal is applied to the thyristor 3 from 1 or 12', and the thyristor 3 becomes conductive. Thyristor 3
When conductive, the base current of the transistor 5 becomes zero, so the transistor 5 is cut off, and the current flowing through the exciter coil 4 is cut off. This induces a high voltage in the exciter coil 4, which is boosted by the ignition coil 1 and applied to the spark plug 2. Therefore, a spark is generated in the spark plug 2, and ignition is performed. In the low speed rotation region of the engine, the output signal of the first signal coil 11 reaches the trigger level of the thyristor 3 at an angle θ ₂ to perform the ignition operation, and in the medium and high speed rotation region, the output signal of the second signal coil 12' reaches the trigger level of the thyristor 3 at an angle θ 2 The signal reaches the trigger level of the thyristor 3 earlier than the output signal of the first signal coil 11, causing the ignition operation to be performed. Second
Since the peak value of the output of the second signal coil 12' increases as the rotational speed of the engine increases, the phase at which the output signal of the second signal coil 12' reaches the trigger level of the thyristor 3 advances, and as shown in FIG. The ignition position advances as shown.

As mentioned above, according to the ignition system shown in FIG. 2, the ignition position can be kept approximately constant in the low speed rotation range of the engine, and can be advanced in the medium and high speed rotation range, but the advance angle characteristic is Since the output characteristics of the second signal coil 12' are determined only by the output characteristics of the second signal coil 12', it is very difficult to set the output characteristics of the second signal coil 12'. Especially the set rotation speed N ₂ in the high speed rotation area
It is not easy to determine the ignition position θ ₁ in the above case, and if the output characteristics of the second signal coil 12' are not appropriate, there is a risk that the ignition position will be advanced too much even if the set rotational speed is N ₂ or higher. It was hot.
In addition, in the case of a four-stroke engine, ignition needs to be performed only once per cylinder during one rotation of the engine, so if a multi-pole magnet generator is used as the magnet generator attached to the engine, The first and second signal coils could not be placed inside the magnet generator, and a special signal generator with two signal coils had to be prepared separately.

An object of the present invention is to supply an ignition timing signal from a second signal source for medium and high speeds only during a negative half cycle in which the first signal source that determines the ignition position in the low speed rotation region does not supply the ignition timing signal. This makes it possible to clearly set the advance angle width by the period of the negative half cycle of the output of the first signal source, and even if a second signal source that generates multiple signals per revolution is used, An object of the present invention is to provide an ignition device for an internal combustion engine that can perform one ignition operation per engine. In order to solve the above problems, in the ignition device for an internal combustion engine of the present invention,
In particular, the first signal source is provided to generate an output of a positive half cycle only once for one cylinder per revolution of the internal combustion engine, and when activated, the output of the second signal source is connected to the ignition circuit. A control switch circuit is provided to prevent the power from being supplied. The control switch circuit is inhibited from operating during a period in which the output of the first signal source is in a negative half cycle, and in a period in which the output of the first signal source is zero or in a positive half cycle. The device is configured to be controlled by the outputs of the first and second signal sources so as to operate when the second signal source outputs a signal of positive polarity.

The terms "low-speed rotation region" and "medium-high speed rotation region" used in this specification are relative terms, and the range of rotational speed (rpm) specifically meant by each rotation region differs depending on the engine. Also, the terms "positive" and "negative" indicating the polarity of a signal are also relative, and in this specification, the polarity that serves as the ignition timing signal is referred to as "positive."

DESCRIPTION OF THE PREFERRED EMBODIMENTS The ignition device of the present invention will be explained in detail below with reference to the illustrated embodiments.

FIG. 3 shows an embodiment of the present invention, in which the same parts as in FIG. 2 are denoted by the same reference numerals. 4A to 4C show operating waveforms of various parts when the exciter coil 4 is placed in a four-pole magnetic AC generator attached to the crankshaft of the engine. In Figure 3, 11 is the second
A first signal source consisting of a signal coil similar to that shown in the figure, which has an output u ₁ for the negative half cycle followed by an output for the positive half cycle as shown in Figure 4B.
A one-cycle output signal u in which u ₂ appears is generated once per revolution of the engine crankshaft, and a positive half-cycle output u ₂ provides an ignition timing signal. The signal coil constituting this first signal source is a signal generator provided separately from a magnetic alternator that incorporates an exciter coil, for example, a part of the magnetic pole of a flywheel magnet rotor of a magnetic alternator. A signal generator with a signal rotor magnetic pole led out to the outer circumference of the flywheel, and a magnetic alternator with a built-in exciter coil are installed coaxially.
It can be installed in a known signal generator, such as a pole magnet rotating signal generator. This first ignition source 11
is the low speed rotation region of the engine (N ₀ ≦N<N ₁ in Figure 1)
It is configured to generate an output that reaches the trigger level of the thyristor 3 or higher.

12 is the medium-high speed rotation region of the engine (N ₁ ≦ in Figure 1)
N) is a second signal source that generates an output higher than the trigger level of the thyristor 3; in this embodiment, this second signal source is arranged together with the exciter coil in a magnetic alternator having a built-in exciter coil 4. It consists of a signal coil. Since the magnetic alternator is configured with four poles, the second signal source 12 produces an output of two cycles per revolution of the engine.

The output of the first signal source 11 is applied between the gate and cathode of the thyristor 3 via a diode 13, and the output of the second signal source 12 is applied between the gate and cathode of the thyristor 3 through a series circuit of a resistor 15 and a diode 14. is being applied. 16 is an NPN transistor that constitutes a control switch circuit, and the collector of this transistor is connected to the second transistor through a resistor 15.
The emitter is connected to one end of the signal source 12 of the second
is grounded together with the other end of the signal source 12. Therefore, the collector-emitter circuit of the transistor 16 is connected in parallel to the second signal source 12 and the ignition timing signal input terminal of the ignition circuit (in this embodiment, between the gate and cathode of the thyristor 3). When the transistor 16 becomes conductive, the output of the second signal source 12 is bypassed from the gate-cathode circuit of the thyristor 3. A capacitor 17 and a diode 18 whose anode is grounded are connected in parallel between the base and emitter of the transistor 16, and a resistor 1 is connected between the base of the transistor 16 and the non-ground terminal of the second signal source 12.
9 is connected. The base of the transistor 16 is also connected to the non-ground terminal of the first signal source 11 through a resistor 20. Therefore, when the positive half-cycle output u ₁ is generated in the first signal source 11, the transistor 16 becomes conductive, thereby blocking the supply of the output of the second signal source 12 to the thyristor 3. . Further, when the negative half-cycle output u ₂ is generated in the first signal source 11, the conduction of the transistor 16 is blocked and the second signal source 12
is allowed to be supplied to the thyristor 3. Furthermore, the transistor 16 is conductive when the output of the first signal source 11 is zero and the output of the second signal source 12 is in a positive half cycle, thereby causing the output of the second signal source 12 to be in a positive half cycle. Of the outputs of the thyristor 3, the output of the half cycle that is not used as the ignition timing signal is prevented from being supplied to the thyristor 3.

In the ignition system shown in Fig. 3, the exciter coil 4 is arranged in a four-pole magnet generator, so the exciter coil 4 is located at one of the crankshafts of the engine.
Two cycles of output voltage are induced per revolution, and the transistor 5 becomes conductive in the half cycle when the output of the exciter coil 4 has the polarity in the direction of the arrow shown. FIG. 4A shows the waveform of the collector current i _c of this transistor 5 at the rotational speed N ₀ to N ₃ shown in FIG. 1.
is shown for parameters. The first signal source 11 generates a signal u of one cycle per revolution (see FIG. 4B) as described above, and the second signal source 12 generates a signal u of two cycles per revolution like the exciter coil 4. Induces a signal υ. FIG. 4C shows only the positive half cycle of this signal υ used as the ignition timing signal.

Now, when a negative half-cycle output u ₁ is generated from the first signal source 11 at an angle θ ₁ , the signal coil 11
Current flows from the transistor 18 through the resistor 20, and the base-emitter of the transistor 16 of the control switch circuit is reverse biased due to the voltage drop across the diode 18.
6 is locked in the cut-off state. This state has an angle θ ₂
continues until the output u ₁ of the negative half cycle of the first signal source 11 becomes zero. In this way, during the period θ ₁ to _{θ 2} of the negative half cycle of the output of the first signal source 11, the transistor 16 is in the cut-off state, so the positive output of the second signal source 12 is transmitted through the diode 14 to the thyristor 3. Supplied to the gate. Positive half-cycle output u ₂ of the first signal source 11 at angle θ ₂
When this occurs, the transistor 16 becomes conductive, so the output υ of the second signal source 12 is short-circuited by the transistor 16 and is no longer supplied to the thyristor 3. Further, when only the second signal source 12 outputs a positive polarity signal υ at a position leading from the angle θ ₂ and a position behind the angle θ ₀ ' in FIG. 4C, the transistor 16 becomes conductive. This second signal source 12
is prevented from being supplied to the thyristor 3. Therefore, the ignition signal is supplied to the thyristor 3 only during the period when the output signal u of the first signal source 11 is generated, and when the second signal source 12 is
Even if multiple signals are generated per revolution, one ignition operation is performed per revolution.

In the low speed rotation region of the engine, the output υ of the second signal source 12 does not reach the trigger level e _t of the thyristor 3, and only the output u ₂ of the first signal source 11 reaches the trigger level e _t . Therefore, ignition is performed at an angle θ ₂ or at an angle slightly later than the angle θ ₂ . The ignition position in this low speed region advances slightly as the output u ₂ of the first signal source 11 increases as the rotation speed increases, but it is sufficient to cover the width of the output u ₂ of the positive half cycle of the first signal source 11. By narrowing the range, the advance of the ignition position can be suppressed to a small range, and the ignition position in the low speed region (N ₁ >N) can be maintained at a substantially constant position θ ₂ . Next, when the engine speed reaches N ₁ , the second signal source 1 is activated near the angle θ ₂ .
The output υ of the second signal source υ reaches the trigger level e _t , and the output υ of this second signal source provides an ignition signal to the thyristor 3 through the diode 4 . When the rotational speed increases from N ₁ to N ₂ , the peak value of the output signal υ of the second signal source 12 increases, so the phase at which the signal υ reaches the trigger level e _t advances, and the ignition position advances. When the rotational speed reaches N ₂ , the signal υ reaches the trigger level e _t at the angle θ ₁ . When the rotational speed further increases, the peak value of the signal υ increases, and the phase at which the signal υ reaches the trigger level e _t further advances, but at a position that has advanced beyond the angle θ ₁ , the transistor 16 becomes conductive as described above, and the signal υ reaches the trigger level e t. Since the output of the signal source 12 of 2 is prevented from being supplied to the thyristor 3, the signal υ is at the trigger level e _t
No matter how far the phase advances, the ignition signal is given to the thyristor 3 at the angle θ ₁ , and the angle does not advance further than this angle θ ₁ . Therefore, in the region where the rotational speed is higher than N ₂ , the constant position θ ₁
The ignition takes place. In this way, the advance angle characteristics shown in FIG. 1 can be obtained.

FIG. 5 shows an embodiment in which the present invention is applied to a capacitor discharge type ignition device. In this case, one end of a capacitor 21 is connected to one end of the non-grounded side of the primary coil 1a of the ignition coil 1. 21
A thyristor 22 is connected between the other end and ground with its cathode on the ground side. Capacitors 21 and 1
A diode 2 is connected to both ends of the series circuit with the next coil 1a.
The output of an exciter coil 4 is applied via 3. A resistor 8 is connected in parallel between the gate and cathode of the thyristor 22, and a third
The outputs of the first and second signal sources 11 and 12 are applied by a circuit having exactly the same configuration as shown in the figure. In this ignition system, the output of the exciter coil 4 for half a cycle in the direction of the arrow in the figure causes the diode 2
3 and the primary coil 1a, the capacitor 21 is charged to the polarity shown in the figure, and when an ignition timing signal higher than the trigger level is input to the gate of the thyristor 22 at the ignition position, the thyristor 22 becomes conductive to discharge the charge in the capacitor 21. . This causes a sudden large current to flow through the primary coil 1a,
This current change induces a high voltage for ignition in the secondary coil 1b. The advance angle operation of this ignition device is the third
It is exactly the same as the embodiment shown in the figure.

In each of the above embodiments, an exciter coil and a separate signal coil are used as the second signal source.
It is also possible to share the exciter coil as a second signal source. FIG. 6 shows an embodiment in which the signal coil used as the second signal source 12 in the embodiment of FIG. 5 is omitted, and the exciter coil 4 is also used as the second signal source. be. In this embodiment, one end of the ground side of the exciter coil 4 is grounded via a diode 24 whose anode is grounded, and the connection point between the exciter coil 4 and the diode 24 is connected to the connection point between the resistors 15 and 19. Further, a diode 25 whose anode is grounded is connected in parallel to both ends of the series circuit of the exciter coil 4 and the diode 24. In other respects, the structure is exactly the same as the embodiment shown in FIG. The operation of the embodiment shown in FIG. 6 is such that the capacitor 21 is charged by the output of the exciter coil 4 in the direction of the solid arrow, and the output in the direction of the dashed arrow is used as the output of the second signal source for advancing the angle. This is the same as the case shown in FIG. 5 except for this point.

When a current cutoff type circuit as shown in Fig. 3 is used as the ignition circuit, the voltage drop across the current control switch (transistor 5) connected in parallel with the exciter coil 4 is It can be used as the output of a signal source. FIG. 7 shows such an embodiment, in which the same parts as those in FIG. 3 are denoted by the same reference numerals. In order to detect the voltage drop across the collector-emitter circuit of transistor 5 and the series circuit of diode 6, a voltage divider circuit consisting of a series circuit of resistors 26 and 27 is installed between the anode of diode 6 and the emitter of transistor 5. connected,
The voltage across the resistor 27 is the voltage across the transistors 28, 2.
9, resistors 15 and 30, and a diode 31. In other words, the voltage across the resistor 27 is the same as that of the transistor 2 whose emitter is grounded.
The collector of transistor 28 is connected to the base of transistor 29 whose emitter is grounded. In addition, the collectors of transistors 28 and 29 are each connected to a resistor 30.
and 15 to the connection point between the anode of the thyristor 3 and the primary coil 1a, so that collector current is supplied from the exciter coil 4 to the transistors 28 and 29 through the primary coil 1a. The output of the second signal source is amplified and obtained between the collector and emitter of the transistor 29, and this output is applied between the base and cathode of the thyristor 3 through the diode 14. In addition, in order to supply base current to the transistor 16 constituting the control switch circuit with the output of the second signal source, a resistor 19 connects the base of the transistor 16 and the thyristor 3.
is connected between the anode and the anode. Furthermore, in this embodiment, the anode of a diode 7 that causes a base current to flow through the transistor 5 is connected through a small resistor 32 to the connection point between the anode of the thyristor 3 and the primary coil 1a. The other points are constructed in the same manner as in FIG. 3.

Transistor 5 in the embodiment shown in FIG.
The waveforms of the collector current i _c , the output signal u of the first signal source 11, and the potential υ at the connection point a between the resistors 26 and 27 (output of the second signal source) are shown in FIGS. 8A, B, and 8, respectively. As shown in Figure C, a signal voltage with a waveform similar to the output voltage υ of the second signal source in the embodiment of Figure 3 is obtained, and the same operation as in Figure 3 is performed. can be set.

In the embodiment shown in FIG. 7, the circuit that performs the advance angle operation and the circuit that performs the ignition operation once per revolution are separated by an amplifying circuit including transistors 28 and 29, but it is particularly important to provide an amplifying circuit. In the embodiment of FIG. 3, the second signal source 1
Even if the signal coil constituting transistor 2 is removed and the connection point between resistors 15 and 19 is connected to the anode of diode 6, the voltage across the series circuit between the collector-emitter circuit of transistor 5 and diode 6 ( A similar operation can be performed using (the voltage across the exciter coil) as a second signal source.

FIG. 9 shows still another embodiment of the present invention in which a part of the embodiment shown in FIG. 7 is modified, and in this figure, the same parts as those in FIG. be. In this embodiment, the voltage divider circuit that divides the voltage drop of the collector-emitter circuit of the transistor 5 is composed of a series circuit of a variable resistor 26 and resistors 27a and 27b. The collector of the transistor 16 is connected to the point). The first signal source 11 is connected in parallel between the base and emitter of the transistor 16 via a series circuit of a Zener diode 33 and a diode 34, and the non-grounded terminal of the first signal source 11 is connected in parallel as in the case of FIG. It is connected to the gate of the thyristor 3 via the diode 13. A resistor 27b constituting a part of the voltage dividing circuit is connected in parallel between the gate and cathode of the thyristor 3, and a thyristor 35 is connected to the connection point between the resistor 27b and the gate of the thyristor 3.
The cathode of is connected. The anode of the thyristor 35 is connected to the connection point between the primary coil 1a and the anode of the thyristor 3 via a resistor 36, and the resistor 27 is connected between the gate and cathode of the thyristor 35.
a are connected in parallel. The resistor 19 that supplies the base current to the transistor 16 is connected to the transistor 16.
and the anode of the thyristor 35, and a diode 18 is connected in parallel between the base and emitter of the transistor 16 with its anode being on the ground side. Further, in this embodiment, a resistor 37 is connected in parallel between the base and emitter of the transistor 5, and the base of the transistor 5 is connected only through a diode 7 to a connection point between the primary coil 1a and the anode of the thyristor 3.

In the embodiment of FIG. 9, during the negative half cycle of the first signal source 11, current flows from the first signal source 11 through the diode 18, the Zener diode 33, and the diode 34, so that the base-emitter voltage of the transistor 16 is Transistor 16 is reverse biased due to the voltage drop across diode 18.
is maintained in a blocked state. During this time, when the voltage divided by the voltage divider circuit consisting of the resistor 26 and the series circuit of resistors 27a and 27b reaches a predetermined level, the thyristor 35 becomes conductive, and the primary coil 1a is connected to the resistor 3.
A gate signal is applied to the thyristor 3 through the thyristor 6 and the thyristor 35. In the positive half cycle of the first signal source 11, a gate signal source is provided from the first signal source 11 to the thyristor 3 through the diode 13. When the engine is running at low speed, the collector-emitter voltage of the transistor 5 is low, and the voltage from the exciter coil 4 to the primary coil 1a and the resistor 3 is low.
Since the gate signal applied to the thyristor 3 through the thyristor 6 and the thyristor 35 does not reach the trigger level of the thyristor 3, the thyristor 3 is triggered by the positive half cycle output of the first signal source 11, and the ignition position is almost constant. . When the rotational speed of the engine increases, the gate signal applied from the exciter coil 4 side through the primary coil 1a, the resistor 36, and the thyristor 35 reaches the trigger level of the thyristor 3 during the negative half cycle of the first signal source 11. Therefore, the thyristor 3 is triggered by this gate signal, and the ignition position advances as the rotational speed of the engine increases. Further, when the output of the first signal source 11 is zero or in a positive half cycle and the voltage across the exciter coil 4 has the polarity in the direction of the arrow shown in the figure, the voltage is applied to the base of the transistor 16 through the primary coil 1a, the resistors 36 and 19. Since current flows and the transistor 16 becomes conductive, the thyristor 35
is not given a firing signal. Therefore, the ignition timing signal is given by the voltage across the exciter coil 4 at a position other than the ignition position, and there is no risk of unnecessary fire flying into the engine.

In the embodiment of FIG. 9, the Zener diode 3
The series circuit of 3 and diode 34 can be replaced by a resistor sufficient to prevent the positive half-cycle output of first signal source 11 from being taken to the base of transistor 16 at low engine speeds.

As described above, according to the present invention, in an ignition system for an internal combustion engine, an ignition timing signal is supplied by a first signal source in a low speed rotation region of the engine and by a second signal source in a region where the engine speed is higher than the low speed rotation region. , a control switch circuit is provided for supplying the output of the second signal source to the ignition circuit during a period in the negative half cycle in which the output of the first signal source does not supply the ignition timing signal; Since the advance angle width is regulated by the signal width of the negative half cycle of , it is possible to prevent the ignition position from advancing too far when the engine rotates at high speed. Therefore, according to the present invention, it is possible to obtain an advance angle characteristic in which the ignition position is approximately constant in the low-speed rotation region of the engine, the ignition position advances in the medium-high rotation speed region, and the ignition position is approximately constant in the high-speed rotation region. . Further, the lead angle width is determined by the negative half cycle output of the first signal source, and the output characteristics of the second signal source are unrelated to the lead angle width, so the second signal source is An appropriate portion of the output waveform of the signal source can be selected and used, and the degree of freedom in design can be increased compared to the conventional method. Furthermore, since we used a source that generates a positive half-cycle output only once per cylinder per rotation of the internal combustion engine as the first signal source, it is possible to use multiple signals per rotation as the second signal source. Even if the signal generator is used, it is possible to perform one ignition operation per revolution, and only the first signal source needs to be placed in the signal generator, which simplifies the structure of the signal generator. Can be done.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of advance angle characteristics required for an engine, Fig. 2 is a connection diagram showing a conventional example, Fig. 3 is a connection diagram showing an embodiment of the present invention, and Figs. C
5 is a diagram showing the signal waveform of each part of the embodiment in FIG. 3 with respect to the rotation angle of the generator or crankshaft.
7 to 7 are connection diagrams showing other different embodiments of the present invention, FIGS. 8A to 8C are diagrams showing signal waveforms of each part of the embodiment of FIG. 7 with respect to rotation angle, FIG. 9 is a connection diagram showing still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Ignition coil, 2... Spark plug, 3... Thyristor, 4... Exciter coil, 5... Transistor, 11... First signal source, 12... Second signal source,
13, 14... Diode, 16... Transistor (control switch circuit), 15, 19, 20... Resistor,
18...Diode, 21...Capacitor, 22...Thyristor, 28,29...Transistor, 30,3
1...Resistance.

Claims (1)

[Claims] 1 An ignition circuit that outputs a high voltage to produce a spark in the spark plug when an ignition timing signal is supplied, and a negative half cycle followed by a positive half cycle that synchronizes the output with the rotation of the internal combustion engine. a first signal source that generates the ignition timing signal during the positive half cycle; and a first signal source that generates the ignition timing signal during the positive half cycle; a second signal source that outputs a positive polarity signal for supplying a signal, and in a low speed region of the engine, the first signal source is used, and in a region where the engine speed is higher than the low speed region, the second signal source is used. The ignition device for an internal combustion engine that supplies the ignition timing signal includes a control switch circuit configured to prevent the output of the second signal source from being supplied to the ignition circuit when activated; The first signal source is provided to generate the positive half-cycle output only once for one cylinder per revolution of the internal combustion engine,
The control switch circuit is inhibited from operating during a period when the output of the first signal source is in a negative half cycle, and is configured to switch the control switch circuit from the second signal source during a period when the output of the first signal source is zero or a positive half cycle. An ignition device for an internal combustion engine, characterized in that the ignition device is controlled by the outputs of the first and second signal sources so as to operate when the signal source outputs a signal of positive polarity.