JPS6137820Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ignition device for an internal combustion engine, and more particularly to a power supply circuit for a capacitor charge/discharge type ignition device.

[Conventional technology]

Conventionally, capacitor charging/discharging type ignition devices used in motorcycles or outboard motors, etc.
It is known from Publication No. 45129, Utility Model Application Publication No. 55-71072, etc.

[Problem that the invention attempts to solve]

However, in the ignition device shown in the above-mentioned Japanese Patent Application Laid-Open No. 50-45129, as shown in FIG. Current flows through 3→primary winding 41 of ignition coil 4→diode 5→ignition power supply coil 1, and capacitor 3 is charged.

On the other hand, when voltage is generated in the direction shown by the broken line, it passes through diode 6, capacitor 7, resistor 8,
Power is supplied to a power supply circuit for driving a control circuit 11 formed to be smoothed by a smoothing circuit composed of a capacitor 9 and clamped to a constant voltage by a Zener diode 10, and then passed through a diode 12 to the ignition power supply coil 1. A closed circuit is formed to return.

Next, an ignition signal is generated in the pulsar coil 13 and inputted to the control circuit 11, and when the output processed based on the control contents set in advance is applied to the gate of the thyristor 14, the thyristor 14 becomes conductive and is stored in the capacitor 3. The electric charge passes through the closed circuit of the thyristor 14 → the primary winding 41 of the ignition coil 4 → the capacitor 3, and is instantly discharged, generating a high voltage in the secondary winding 42 of the ignition coil 4, which sparks the spark plug 15 and fires the ignition system. functions as

However, as the rotation of the internal combustion engine increases, the power generated in the ignition power supply coil 1 increases and the power borne by the Zener diode 10 also increases, so internal heat generation increases and the temperature of the Zener diode 10 rises. When the temperature of the Zener diode 10 rises, as shown in FIGS. 3 and 4, the Zener voltage changes, the power supply of the control circuit 11 fluctuates, and the control content changes.

SUMMARY OF THE INVENTION An object of the present invention was to provide a power supply circuit for a capacitor charge/discharge type ignition device in which the supply voltage does not fluctuate due to self-heating of the Zener diode or changes in environmental temperature.

[Means for solving problems]

According to the present invention, in the power supply circuit of a capacitor charge/discharge type ignition device, two stabilizing circuits connected in series and each having a positive and negative temperature coefficient are inserted into a smoothing circuit consisting of a capacitor and a resistor. It is.

[Effect]

This invention connects a Zener diode with a positive temperature coefficient and a Zener diode with a negative temperature coefficient in series, and their mutual action prevents the voltage from changing even if self-heating occurs or the environmental temperature changes. It is.

〔Example〕

Fig. 2 shows an embodiment of a capacitive discharge type ignition device using a magnet generator as a power source, which adopts the present invention.The operation is the same as the conventional example shown in Fig. 1, and the same reference numerals are used. It has a function.

Here, select a Zener diode 16 with a positive temperature coefficient that increases the Zener voltage as the temperature rises as shown in Figure 3, and choose a Zener diode 17 with a positive temperature coefficient that increases the Zener voltage as the temperature increases as shown in Figure 4. By connecting the Zener diode 16 and the Zener diode 17 in series, the input voltage to the control circuit 11 can be reduced because fluctuations in the Zener voltage due to changes in the temperature of the Zener diode 16 and Zener diode 17 cancel each other out. is kept constant and stable control is performed.

By the way, when controlling the power supply voltage to 8V, (1) When using one Hitachi AW01-08 type Zener diode, if the temperature coefficient changes by 100℃ at 0.045%/℃, the fluctuation will be 8×0.045×100÷100=0.36V do.

(2) When Hitachi AW01-06 type and AW03-02 type are used in series, the temperature coefficient of each is 0.025%/℃, -
Calculating the overall temperature coefficient due to power sharing at 0.09%/℃ is (0.025×6−0.09×2)÷8 = −0.00375%/℃, and if it changes by 100℃, −0.00375×8×100÷100=− The amount of variation can be made as small as 0.03V, which is almost negligible.

[Effect of idea]

According to the present invention, it is possible to provide a power supply circuit that is inexpensive and has a simple configuration, with little voltage fluctuation even when the Zener diode self-heats or the environmental temperature changes.

Further, although an embodiment using a magnet generator as a power source has been described, it is of course also effective for an embodiment using a battery or other power source.

[Brief explanation of the drawing]

Figure 1 is a conventional circuit diagram of a capacitive discharge type ignition device using a magnet generator as a power source, Figure 2 is a circuit diagram of an embodiment to which the present invention is applied, and Figures 3 and 4 are temperature characteristics of a Zener diode. FIG. 1...Ignition power supply coil, 2...Diode, 3
... Capacitor, 4 ... Ignition coil, 41 ... Primary winding, 42 ... Secondary winding, 5 ... Diode,
6... Diode, 7... Capacitor, 8... Resistor, 9... Capacitor, 10... Zener diode, 11... Control circuit, 12... Diode, 1
3... Pulsa coil, 14... Thyristor, 15
... Spark plug, 16 ... Zena diode, 1
7...Zena diode.

Claims (1)

[Scope of utility model registration request] an ignition power supply coil, a means connected to the ignition power supply coil to rectify its alternating current output, a capacitor charged by the output of one polarity of the coil output rectified by the rectification means, and a capacitor synchronized with the rotation of the engine. a pulsar coil that generates an ignition reference signal; a control circuit that generates an ignition control signal based on the output signal from the pulsar coil; A thyristor constituting a discharge circuit, and an ignition coil connected in series to the discharge circuit constituted by the thyristor and a capacitor to generate an ignition high voltage by discharging the capacitor, further rectified by the rectifier. and a circuit for supplying constant voltage power to the control circuit by the output of the other polarity of the AC output, and the constant voltage circuit includes a smoothing circuit consisting of a capacitor and a resistor, and a circuit connected in parallel to the smoothing circuit. 1. A power supply circuit for a capacitor charge/discharge type ignition device, comprising a stabilizing circuit consisting of series-connected Zener diodes, each having a positive and a negative temperature coefficient.