JPS6128054Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ignition device for an internal combustion engine whose power source is an exciter coil that induces an alternating current voltage in synchronization with the rotation of the internal combustion engine.

As a conventional ignition device of this type, one shown in FIG. 1 is known. In the same figure, 1 is an exciter coil arranged in a magnetic alternator driven by an internal combustion engine, and this exciter coil 1
One end is connected to one end of a capacitor 3 through a diode 2. The other end of the capacitor 3 is connected to one end of the primary coil 4a of the ignition coil 4.
The other end of the secondary coil 4a is grounded. The other end of the exciter coil 1 is connected to the cathode of a diode 5 whose anode is grounded, and the output of the exciter coil 1 in one half cycle (hereinafter referred to as a positive half cycle) in the direction of the solid arrow shown in the figure causes the diode to The capacitor 3 is charged to the illustrated polarity through the coils 2 and 5 and the primary coil 4a. One end of the secondary coil 4b of the ignition coil 4 is connected to a non-grounded terminal of a spark plug 6 attached to a cylinder of the engine, and the other end of the secondary coil 4b is grounded. One end of the capacitor 3 that is charged on the positive side is connected to the anode of a thyristor 7 as a semiconductor switch for primary current control whose cathode is grounded. A signal is given. When an ignition signal is applied to the thyristor 7 and the thyristor becomes conductive, the charge in the capacitor 3 is discharged through the thyristor 7 and the primary coil 4a, and this discharge current causes a large change in magnetic flux in the iron core of the ignition coil. This change in magnetic flux induces a high voltage in the secondary coil 4b, producing a spark in the spark plug 6 and igniting the engine. In this way, in this ignition system, the ignition operation is performed by the conduction of the thyristor 7, so by changing the position where the thyristor conducts according to the engine speed (rpm), the advance angle characteristic and the retard angle characteristic can be adjusted. can be obtained. The ignition position control circuit 8 includes a thyristor 7 so that the ignition device has advance characteristics and retard characteristics.
This control circuit 8 is operated by being supplied with a DC voltage from a control power supply circuit 9'. In order to configure the control power supply circuit 9, a diode 1 is connected to the diode 5 side terminal of the exciter coil 1.
A capacitor 11 is connected between the cathode of the diode 10 and ground. The anode of a thyristor 12 whose cathode is grounded is also connected to the diode 5 side terminal of the exciter coil 1, and a Zener diode 13 is connected in parallel between the gate and cathode of the thyristor 12. A cathode of a diode 14 whose anode is grounded is connected to one end of the exciter coil 1 on the diode 2 side, and the diode 10, capacitor 11, thyristor 12, Zener diode 13, and diode 14 connect the exciter coil 1 in the direction of the dashed arrow shown in the figure. the other half cycle (hereinafter this half cycle will be referred to as the negative half cycle)
A control power supply circuit 9' is configured to supply power for operating the ignition position control circuit 8 with the output of the ignition position control circuit 8. In this power supply circuit 9', the negative half cycle output of the exciter coil 1 causes the diode 1 to
0, current flows through capacitors 11 and 14, and capacitor 11 is charged to the polarity shown. When the terminal voltage of this capacitor 11 reaches the set value, the Zener diode 13 becomes conductive and the thyristor 1
Since the ignition signal is input to 2, this thyristor becomes conductive. When the thyristor 12 becomes conductive, the negative direction output of the exciter coil 1 is short-circuited through the thyristor 12 and the diode 14, so that the capacitor 11
is always charged to a substantially constant voltage. A substantially constant voltage across the capacitor 11 is applied between the power supply terminal 8a of the ignition position control circuit 8 and ground.

According to the above circuit, power can be supplied to the control circuit with the output of the exciter coil 1 without using a battery, so it can be applied to engines such as vehicles that are not equipped with a battery. 1 must be lifted from the ground, so if the part surrounded by chain lines in the figure is configured as an igniter unit, it is necessary to draw out four terminals t ₁ to t ₄ in addition to the ground terminal from the unit. In addition, the exciter coil 1 also requires two ungrounded terminals, which has the disadvantage that the overall wiring becomes extremely complicated.

An object of the present invention is to provide an ignition device for an internal combustion engine that reduces the number of terminals in the ignition circuit and allows one end of the exciter coil to be grounded to simplify wiring.

Hereinafter, the present invention will be explained in detail together with its embodiments with reference to FIG.

FIG. 2 shows an embodiment of the present invention. In the figure, the same parts as those in FIG. 4 constitutes a capacitor discharge type ignition control circuit.
One end of the exciter coil 1 is grounded, and the other end is connected to one end of a capacitor 3 through a diode 2.

A thyristor 20 is connected in parallel to both ends of the exciter coil 1 in such a direction that it can conduct at the negative cycle output of the coil (with its anode grounded). At both ends of the exciter coil 1, there is also a series circuit consisting of a diode 21, a first capacitor 22 whose one end is connected to the cathode of the diode 21, and a diode 23 whose anode is connected to the other end of the capacitor 22. The first capacitor 22 is connected in parallel with its anode being grounded, and charges the first capacitor 22 to one polarity with the output of the negative half cycle of the exciter coil 1 through the series circuit.
A charging circuit is configured. The anode of the diode 24 is connected to the connection point between the first capacitor 22 and the diode 21, and the second capacitor 25 is connected between the cathode of the diode 24 and ground. Further, a resistor 26 is connected between the connection point between the first capacitor 22 and the diode 23 and the ground, and the diode 24 and the resistor 26 cause the terminal voltage of the first capacitor 22 to be applied to the second capacitor 25.
A second charging circuit is configured to charge the battery. Zener diode 2 is installed at the gate of thyristor 20.
7 is connected, and the cathode of this Zener diode is connected to the cathode of a diode 28 whose anode is grounded. These Zener diode 27 and diode 28 constitute a trigger circuit that provides an ignition signal to the thyristor 20 when the terminal voltage of the first capacitor 22 reaches a set value.

Although the configuration of the ignition position control circuit 8 is not particularly shown, this control circuit controls the position where the ignition signal is supplied to the thyristor 7 according to the engine speed, thereby controlling the advance or retard characteristic or It has characteristics such as advancing the rotation speed up to a set rotation speed and retarding the rotation speed above the set rotation speed, and includes an electronic circuit driven by a DC power source. For example, this control circuit includes a signal coil that generates an advance width setting signal having a width corresponding to the advance width in synchronization with engine rotation, and a signal coil that generates an advance width setting signal having a width corresponding to the advance width, and During the first period (until the next ignition) when the advance width setting signal is not generated, the battery is charged with a constant current, and during the second period when the advance width setting signal is generated, the battery is discharged with a constant current. The capacitor is reset at the end of the second period, and the voltage of the capacitor is compared with the reference voltage, and when the voltage at the time of discharge of the capacitor falls to the reference voltage, the semiconductor switch of the ignition control circuit (in the above example) In this case, it is constituted by a comparator circuit etc. that allows a trigger signal to be applied to the thyristor 7).

In the above embodiment, when a voltage v ₁ is induced in the exciter coil 1 as shown in FIG. When the terminal voltage v ₂ reaches the set value, the thyristor 20 becomes conductive and short-circuits the voltage of the negative half cycle of the exciter coil 1. At this time, a current i ₁ flows through the thyristor 20 as shown in FIG. 3B. The thyristor 20 is cut off when the voltage of the positive half cycle of the exciter coil 1 rises. On the other hand, the electric charge of the first capacitor 22 is transferred to the diode 24, the second capacitor 25, and the resistor 26.
Since the terminal voltage v ₂ of the first capacitor 22 changes as shown in FIG. 3C, the voltage at the terminal of the first capacitor 22 changes as shown in FIG. Since the second capacitor 25 is charged by the discharge current of the first capacitor 22 and discharged to the ignition position control circuit 8 side, the terminal voltage v ₃ of the second capacitor 25 is as shown in FIG. 3D. This results in a waveform that repeats charging and discharging with a small fluctuation range. The charging voltage of this second capacitor 25 can be adjusted by the resistance value of the resistor 26. In other words, if the resistance value of resistor 26 is reduced, capacitor 2
If the charging voltage of the capacitor 25 increases, and conversely the resistance value of the resistor 26 increases, the charging voltage of the capacitor 25 decreases.

If configured as in the above embodiment, if the circuit portion surrounded by _the chain line in _FIG . The number of terminals can be significantly reduced compared to the case shown in FIG. 1, in which as many as four terminals had to be drawn out outside the ground terminal. Further, since one end of the exciter coil 1 can be grounded to the iron core of the generator, only one terminal is required to be drawn out from the exciter coil 1, and the wiring as a whole can be significantly simplified.

When configured as in the above embodiment, all the current when the voltage of the negative half cycle of the exciter coil 1 is short-circuited flows through the thyristor 20.
Unlike the circuit shown in the figure, there is no need for a large-capacity diode 14 through which a short-circuit current flows.

In FIG. 2, if the ignition position control circuit 8 requires a signal coil, a terminal for connecting the signal coil is drawn out.

In the above embodiment, a capacitor discharge type ignition control circuit was used, and this ignition control circuit uses the output of one half cycle of the exciter coil as the ignition energy source, and rapidly changes the primary current of the ignition coil by operating a semiconductor switch. Any other type of ignition control circuit may be used as long as it causes the ignition operation to be performed by the ignition control circuit.

As described above, according to the present invention, one end of the exciter coil can be grounded, and the number of terminals drawn out from the ignition device can be significantly reduced, simplifying wiring and preventing incorrect wiring. The number of assembly steps can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a connection diagram showing a conventional example, Fig. 2 is a connection diagram showing an embodiment of the present invention, and Figs. 3 A to D are connection diagrams showing a conventional example.
FIG. 3 is a diagram showing voltage and current waveforms at various parts of the figure with respect to the rotation angle of the engine. 1...exciter coil, 3...capacitor,
4... Ignition coil, 7... Thyristor (semiconductor switch), 8... Ignition position control circuit, 9... Control power supply circuit, 20... Thyristor, 21, 23, 2
4, 28...diode, 22... first capacitor, 25... second capacitor, 27... Zener diode.

Claims (1)

[Scope of utility model registration request] An exciter coil induces an alternating current voltage in synchronization with the rotation of the internal combustion engine, and the output of one half cycle of the exciter coil is used as the ignition energy source, and the primary current of the ignition coil is suddenly changed by the operation of a semiconductor switch to generate the ignition coil. an ignition control circuit that induces a high voltage for ignition in the secondary coil of the exciter coil; an ignition position control circuit that controls the operating position of the semiconductor switch to control the ignition position; and an output of the other half cycle of the exciter coil. and a control power supply circuit for supplying electric power for operating the ignition position control circuit, wherein the control power supply circuit is oriented so as to be conductive during the other half cycle of the exciter coil. a thyristor connected in parallel to both ends of the exciter coil, first and second capacitors, and a first capacitor that charges the first capacitor to one polarity with the output of the other half cycle of the exciter coil.
a second charging circuit that charges the second capacitor to one polarity with the terminal voltage of the first capacitor; and a second charging circuit that charges the second capacitor to one polarity with the terminal voltage of the first capacitor; 1. An ignition device for an internal combustion engine, comprising: a trigger circuit for giving an ignition signal to a thyristor; and a voltage across the second capacitor is applied to a power supply terminal of the ignition position control circuit.