JPH0313579Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ignition device for an internal combustion engine driven by an exciter coil provided in a four-pole magnet generator.

[Conventional technology]

A capacitor discharge type device is known as an ignition device for an internal combustion engine. This type of ignition device includes an exciter coil, an ignition energy storage capacitor provided on the primary side of the ignition coil and charged by the output of the positive half cycle of the exciter coil.
A discharge control thyristor is provided to discharge the charge of the ignition energy storage capacitor to the primary coil of the ignition coil when triggered, and ignition is achieved by triggering the discharge control thyristor at the engine ignition timing. The charge in the energy storage capacitor is discharged through the primary coil of the ignition coil to induce a high voltage for ignition on the secondary side of the ignition coil.

In this type of ignition device, a trigger signal is supplied to a discharge control thyristor using the output of the negative half cycle of the exciter coil. In this way, when a trigger signal (a signal that determines ignition timing) is supplied to the discharge control thyristor using the output of the negative half cycle of the exciter coil, the ignition timing will be adjusted when the engine is running at high speed due to the output characteristics determined by the exciter coil winding specifications. A retarded ignition characteristic can be obtained.

[Problem that the invention attempts to solve]

As mentioned above, when the positive half-cycle output of the exciter coil charges the ignition energy storage capacitor and the negative half-cycle output supplies a trigger signal to the discharge control thyristor, the exciter coil generates electricity using a four-pole magnet. When installed in the machine, two cycles of AC voltage are induced in the exciter coil per engine revolution, resulting in two ignition operations per revolution, which wastes the engine at times other than the ignition timing. There was a problem with the flames flying.

[Means for solving problems]

As shown in FIG. 1 showing an embodiment of the present invention, an exciter coil 1 and an ignition coil 2 are provided in a four-pole magnet generator that induces two cycles of alternating current voltage per revolution of an internal combustion engine. an ignition energy storage capacitor 3 provided on the primary side of the ignition coil and charged to one polarity by the output of the positive half cycle of the exciter coil; 1
Ignition for an internal combustion engine comprising a discharge control thyristor 4 provided to cause discharge through the secondary coil 2a, and a thyristor trigger circuit that provides a trigger signal to the discharge control thyristor 4 with the output of the negative half cycle of the exciter coil 1. The ignition operation is performed only once per rotation in the device.

The present invention includes a signal coil 5 that generates a signal only once per revolution of the internal combustion engine, and an exciter coil short-circuit switch that is triggered by the output of this signal coil and short-circuits the negative half cycle output of the exciter coil 1. 6 is provided. The position where the signal coil 5 triggers the exciter coil short-circuit switch 6 is determined by the angle at which the output of the negative half cycle that the exciter coil generates at a timing different from the ignition timing of the internal engine rises and the negative half cycle of the exciter coil. is set between the angle at which the output reaches the trigger level of the discharge control thyristor 4.

In this specification, of both half cycles of the output of the exciter coil, the half cycle for charging the ignition energy storage capacitor is defined as a positive half cycle, and the half cycle for triggering the discharge control thyristor is defined as a negative half cycle. . In other words, the terms "positive half-cycle output" and "negative half-cycle output" simply refer to the half-cycle output that charges the ignition energy storage capacitor and the half-cycle output that supplies the trigger signal to the discharge control thyristor. It is only used to distinguish between the two, and does not mean the absolute polarity of the output of the exciter coil.

[Effect of invention]

With the above configuration, the output of the negative half cycle of the exciter coil that occurs at a timing different from the ignition timing is short-circuited by the conduction of the exciter coil shorting switch, so that the ignition operation is not performed at a timing other than the ignition timing. This can prevent unnecessary fire from spreading to the engine.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention. In the same figure, an exciter coil 1 is installed in a four-pole magnet generator attached to an internal combustion engine (not shown), and the exciter coil 1 is installed in a four-pole magnet generator attached to an internal combustion engine (not shown). occurs.

The ignition coil 2 includes a primary coil 2a and a secondary coil 2.
b, and has a primary coil 2a and a secondary coil 2b.
One end of is grounded. The non-ground terminal of the secondary coil 2b is connected to the non-ground terminal of a spark plug 7 attached to a cylinder of the engine, and the non-ground terminal of the primary coil 2a is connected to one end of the ignition energy storage capacitor 3. ing. The other end of the ignition energy storage capacitor 3 is connected to the cathode of a diode 8, and the anode of the diode 8 is connected to one end of the exciter coil 1. The anode of a discharge control thyristor 4 is connected to the connection point between the capacitor 3 and the diode 8, and the gate of the thyristor 4 is connected to the anode of a Zener diode 9 whose cathode is connected to the other end of the exciter coil 1. Between the cathode of the Zener diode 9 and the anode of the thyristor 4 is a diode 10 with its cathode facing the anode side of the thyristor 4.
is connected, and a resistor 11 is connected between the cathode of the Zener diode 9 and ground. resistance 11
A diode 12 with an anode facing the ground side is connected in parallel to both ends of the exciter coil 1, and a diode 13 with an anode facing the ground side is connected between the non-ground terminal of the exciter coil 1 and the ground.

The exciter coil short-circuit switch 6 consists of a thyristor inserted between the ground side terminal of the exciter coil 1 and the ground with the cathode facing the ground side, and the signal coil 5 is inserted between the gate cathode of this thyristor.
The output of is applied via the diode 14. Furthermore, a diode 15 with its cathode facing the ground side is connected in parallel to both ends of the primary coil of the ignition coil 2.

The signal coil 5 induces a signal only once per revolution of the internal combustion engine. Such a signal coil may be provided in a signal generator provided separately from the magnet generator, or may be provided in a signal generator incorporated in the magnet generator. For example, when a flywheel magnet generator is used, a signal magnetic pole is formed on the outer periphery of the flywheel, and a signal generator equipped with a signal coil 5 is arranged so as to face the signal magnetic pole. good.

In the above embodiment, the exciter coil 1
→Diode 8 → Capacitor 3 → Diode 15
A circuit of →diode 12 →exciter coil 1 constitutes a capacitor charging circuit that charges the capacitor 3 with the output of the positive half cycle of the exciter coil 1. Also, exciter coil 1→
The circuit of resistor 11→diode 13 constitutes a thyristor trigger circuit that supplies a trigger signal to thyristor 4 by the output of the negative half cycle of exciter coil 1.

Next, the operation of the above embodiment will be explained. An alternating current voltage is induced in the exciter coil 1 for two cycles per rotation as the engine rotates. As shown in FIG. 2A, when the first positive half cycle of the output voltage V1 of the exciter coil 1 rises at the angle α1,
The capacitor 3 is charged from the exciter coil 1 through the diodes 8, 15 and 12 to the polarity shown, and the voltage V2 across the capacitor 3 rises as shown in FIG. 2C.

Next, when the exciter coil 1 generates a negative half-cycle output voltage at the angle α2, a current flows from the exciter coil 1 through the resistor 11 and the diode 13, and a voltage appears across the resistor 11.
When the voltage of the negative half cycle of the exciter coil 1 reaches the trigger level S1 at the angle α4, the voltage across the resistor 11 becomes large enough to conduct the Zener diode 9, and the thyristor 4 is triggered. In this device, as shown in FIG. 2B, the signal coil 5 generates a signal voltage V3 in the interval θ1 from angle α2 to α4, and this signal voltage is applied to the thyristor constituting the exciter coil shorting switch 6 at the angle α3. In order to reach the trigger level S2 of , the exciter coil shorting switch 6 becomes conductive at the position of this angle α3. Therefore, the output of the negative half cycle of the exciter coil 1 is short-circuited through the exciter coil short-circuit switch 6 and the diode 13, and the voltage across the resistor 11 becomes approximately zero at the angle α3. Therefore, the output voltage of the negative half cycle of the exciter coil generated at the angle α2 does not trigger the thyristor 4, and no ignition occurs at the angle α4. When the exciter coil 1 then produces a second positive half-cycle output at angle α5, the capacitor 3 is charged again.

Then, at the angle α6, the exciter coil 1 generates a negative half-cycle output, and when this output reaches the trigger level S1 at the angle α7, the resistor 1
The voltage across the thyristor 4 reaches a level which causes the Zener diode 9 to conduct. Therefore, at the position of this angle α7, the electric charge of the capacitor 3 is discharged through the thyristor 4 and the primary coil 2a of the ignition coil, and a high voltage is induced in the secondary coil 2b. This high voltage generates a spark in the spark plug 7, and the engine is ignited.

As described above, in the present invention, one of the voltages of the negative half cycle of the exciter coil that occurs twice per rotation is short-circuited by the exciter coil short-circuiting switch triggered by the output of the signal coil 6, and the voltage is discharged. Since the trigger signal is supplied to the control thyristor 4 only once per rotation, the trigger signal is sent to the discharge control thyristor by the output of the negative half cycle of the exciter coil installed in the 4-pole magnet generator. The ignition operation can be performed with one ignition per revolution, and unnecessary flames can be prevented from flying into the engine at times other than the ignition timing.

In the above ignition system, the rise of the output during the negative half cycle of the exciter coil 1 tends to be delayed due to the armature reaction caused by the charging current flowing through the capacitor 3 during the positive half cycle of the exciter coil 1. The tendency becomes more pronounced as the engine speed increases. Therefore, if a trigger signal is supplied to the discharge control thyristor by the output of the negative half cycle of the exciter coil as described above, the ignition timing will normally be retarded when the engine is running at high speed, as shown in Figure 3. characteristics can be obtained. In this case, the winding specifications of the exciter coil,
By changing at least one of the capacitance of the capacitor 3 and the resistance value of the resistor 11, the amount of retardation at high speed can be adjusted as appropriate. That is, the larger the inductance of the exciter coil 1, the capacitance of the capacitor 3, and the resistance value of the resistor 11, respectively, the larger the amount of retardation at high speed.

[Effect of idea]

As described above, according to the present invention, the output of the negative half cycle of the exciter coil that occurs at a time different from the ignition timing is short-circuited by the conduction of the exciter coil short-circuiting switch. The ignition operation is performed to prevent unnecessary fire from flying into the engine. Therefore, there is an advantage that it is possible to obtain an ignition device with a simple structure that has ignition characteristics that take advantage of the characteristics of the exciter coil and that performs an ignition operation of one ignition per rotation.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram explaining the operation of the embodiment of FIG. 1, and FIG.
The figure is a diagram showing an example of the ignition characteristics of the ignition device of the present invention. 1... Exciter coil, 2... Ignition coil,
3...Ignition energy storage capacitor, 4...
Discharge control thyristor, 5... Signal coil, 6...
...Exciter coil short circuit switch, 7...Spark plug, 11...Resistor, 12, 13, 14, 15
……diode.

Claims (1)

[Claims for Utility Model Registration] An exciter coil provided in a four-pole magnet generator that induces two cycles of alternating current voltage per revolution of an internal combustion engine, an ignition coil, and an exciter coil provided on the primary side of the ignition coil. an ignition energy storage capacitor that is charged to one polarity by the output of the positive half cycle of the exciter coil; and a capacitor configured to discharge the charge of the capacitor through the primary coil of the ignition coil when triggered. An ignition device for an internal combustion engine comprising a discharge control thyristor and a thyristor trigger circuit that provides a trigger signal to the discharge control thyristor using the output of the negative half cycle of the exciter coil, the ignition device comprising: a signal coil that generates a signal, and an exciter coil short-circuiting switch that is triggered by the output of the signal coil and is provided to short-circuit the output of the negative half cycle of the exciter coil, wherein the signal coil is The position at which the exciter coil short circuit switch is triggered is determined by the angle at which the output of the negative half cycle generated by the exciter coil rises at a timing different from the ignition timing of the internal engine, and the output of the negative half cycle of the exciter coil. An ignition device for an internal combustion engine, characterized in that the ignition device is set between an angle that reaches a trigger level of the discharge control thyristor.