JPS6244133Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a capacitor discharge type ignition device that ignites by discharging a capacitor, and then turns on the current flowing intermittently through the primary side of the ignition coil for a desired period of time.
This relates to an ignition device, primarily for internal combustion engines, that produces multiple sparks when turned off, extending the duration of the discharge.

Conventional capacitor discharge type ignition systems have the advantage of fast secondary voltage rise and little output drop in the high rotation range, but have the disadvantage of extremely short discharge duration, which makes them difficult to use. At present, it is hardly used in wheeled vehicles.

Therefore, the present invention solves the above-mentioned drawbacks by extending the discharge duration of the capacitor discharge type ignition device, and the capacitor discharge circuit is configured with a series circuit of the primary coil of the ignition coil and the first switching element. In the capacitor discharge type ignition system, a second switching element for current interrupting is connected in series to the primary coil of the ignition coil, and the primary coil of the ignition coil is connected for an arbitrary period of time after ignition due to discharge of the capacitor at the engine ignition timing. It is characterized in that the current flowing to the side is intermittently turned on and off by the second switching element.

Hereinafter, the present invention will be explained with reference to an illustrated embodiment.

Output terminal 2a of a DC high voltage power supply circuit (DC-DC converter) 2 that boosts the DC voltage of the power supply battery 1
The series circuit of the energy storage capacitor 3 and the primary winding 17a of the ignition coil 17 and the thyristor 4 are connected in parallel between (+ side) and 2b (- side), and one end of the energy storage capacitor 3 and the anode of the thyristor are connected to the above DC current. The cathode of a diode 5 is connected to the gate of the thyristor 4, and the secondary winding of a pulse transformer 6 is connected between the anode of the diode 5 and the cathode of the thyristor 4. One end of the primary winding 6a of the pulse transformer 6 is connected to the power supply battery 1 via a resistor 9, and the other end is connected to an interrupter 10 which is opened and closed in synchronization with the rotation of the engine. Furthermore, a resistor 7 is connected between the gate and cathode of the thyristor 4.
A capacitive discharge circuit is constructed by connecting a parallel circuit of capacitor 8 and capacitor 8.

The base of a control transistor 12 is connected to the interrupter 10, the collector of this transistor is connected to the power battery 1 via resistors 13 and 14, and the emitter of the PNP transistor 15 is connected to the power battery 1, and the base of the control transistor 12 is connected to the interrupter 10. are connected to the contacts of the resistors 13 and 14, their collectors are connected to the power supply line of the oscillation circuit 16, and the output of the oscillation circuit 16 is connected to the base of the current cutoff transistor 18 via the resistor 20 to form a current cutoff circuit. The collector of this current interrupting transistor 18 is connected to the ignition coil 1.
7's primary winding 17a.

When the interrupter 10 is closed, the energy storage capacitor 3 is charged by the DC high voltage power supply circuit 2 with the polarity shown. The engine then rotates and interrupter 1
When 0 opens, a voltage is generated in the secondary winding 6b of the pulse transformer 6, and voltage is applied to the gate of the thyristor 4, and the thyristor 4 is turned on, so that the charge in the energy storage capacitor 3 is transferred to the ignition coil. 17 primary winding 17a, and its secondary winding 1
A high voltage is generated at 7b, causing a spark to fly to the spark plug 19.

In this case, at the same time as the interrupter 10 opens, the transistors 12 and 15 are turned on and the power supply voltage is supplied to the oscillation circuit 16, so that a continuous rectangular wave is applied from the oscillator output to the base of the current interrupting transistor 18, and the ignition coil The current flowing through the primary winding 17a of the coil 17 is intermittently turned on and off. Therefore,
As shown in FIG. 2D, the spark plug emits sparks intermittently after the sparks fly due to the discharge of the energy storage capacitor.

Then, when the interrupter 10 closes, the oscillation circuit 16 is cut off from the power supply voltage, and therefore stops oscillating, and the current cutoff transistor 18 is also turned off.

In this way, while the discharge duration of a normal capacitor discharge type ignition device is about 200 μs,
According to the present invention, it is also possible to increase the discharge duration to 5 ms or more. Furthermore, it is possible to provide an ideal ignition device that has a high voltage that rises quickly due to the discharge of the capacitor and a very long discharge duration due to the intermittent discharge that follows, and also to control the operating time of the oscillator 16. The discharge duration can be freely adjusted.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the same operation. 10 is an interrupter,
17a is the primary coil of the ignition coil, 18
shows a current interrupting transistor exemplified as a second switching element.

Claims (1)

[Claims for Utility Model Registration] In a capacitor discharge type ignition device in which a capacitor discharge circuit is configured by a series circuit of a primary coil of an ignition coil and a first switching element, Two switching elements are connected in series, and after ignition due to capacitor discharge at the engine ignition timing,
A capacitor discharge type ignition device characterized in that the current flowing through the primary side of the ignition coil is turned on and off by the second switching element at a given time.