JPS6045312B2 - Ignition device for preventing fouling of creeping plugs - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generates multiple spark discharges in a semi- or full-smooth discharge spark plug (hereinafter referred to as a "smooth plug") installed in an internal combustion engine such as an automobile engine, and This invention relates to an ignition circuit device with improved self-cleaning properties.

Carbon attached to the insulator surface (hereinafter referred to as the smooth surface) in the discharge gap of the smooth plug is removed during operation of the internal combustion engine because it is scattered or burned away by the spark energy of the spark discharge. , this effect is called the electrical self-cleaning property of the smooth plug.

The inventors studied prevention of carbon contamination of smooth surface plugs, and found that carbon adhering to the smooth surface is removed mainly by capacitive discharge energy that flows in the initial stage of a single spark discharge, and that carbon is removed following the capacitive discharge. Inductive discharge energy hardly contributes to electrical self-cleaning because the sparks flow in a space away from the smooth surface, and electrical self-cleaning can be improved by multiplexing sparks and repeatedly supplying capacitive discharge energy to a large number of smooth surfaces. We have found that this can be significantly improved.

The present invention vibrates the multiple spark outputs of an ignition circuit equipped with a multiple spark power source that intermittents current to the primary coil of the ignition coil at times other than the ignition timing, and generates multiple spark voltages in the secondary coil, and further multiplexes the output of the multiple sparks to generate a smooth surface. It is an object of the present invention to provide an ignition device for an internal combustion engine that can generate an extremely large amount of sparks in a plug due to capacitive discharge and can significantly improve electrical self-cleaning performance.

Next, the present invention will be explained with reference to an embodiment shown in the drawings. A is an ignition device according to the present invention, 1 is a battery, and 2 is D
The C-DC converter 3 is an ignition coil in which a capacitor Cl is inserted on the ground side of the secondary coil in series with the secondary coil.

Numeral 4 constitutes a multiple spark circuit together with the DC-DC converter 2, and is a circuit that interrupts the current of the primary coil L at times other than the ignition timing. For example, as shown in FIG. The capacitor C2 is charged with the output of the DC-DC converter 2, which is composed of a thyristor 42, a resistor, . Resistance R.

, 7 to the bidirectional thyristor 42 and breaks down, applying a bias to the gate of the thyristor 41 and making the thyristor 41 conductive. In this way, the interrupter 7
is repeated with a time constant determined by the charging rate of capacitor C2 and the breakdown voltage of bidirectional thyristor 42 until closed, and secondary coil L2 receives multiple high voltages until interrupter 7 is closed again. Occur. 5 is a creepage plug. Next, the operation of the above configuration will be explained.

The output (12V) of the battery 1 is boosted to about several hundred volts by the ■-■ converter 2, and is supplied to the primary coil L1 via the intermittent circuit 4.

As a result, a large number of high voltages are generated in the secondary coil L2 as shown in the time chart shown in FIG.
The current generated by each wave of voltage generated in the secondary coil L2 oscillates in the secondary circuit connecting the capacitor C1, the secondary coil L2, and the creeping plug 5, and generates multiple waves as shown in the time chart shown in Figure 3. The capacitive discharge becomes a pressure waveform, and sparks are generated in the creeping plug 5 due to multiple capacitive discharges. 4-cycle, water-cooled 4-cylinder, 1 equipped with the ignition device A of the present invention
As a result of testing under various driving conditions, using a 600cc internal combustion engine for an automobile, which is easily contaminated, the engine was set to idling or running at low speed, carbon adhering to the creeping surface was removed in a short time, and the electrical self-cleaning performance was superior to that of conventional ignition. It was confirmed that the device is extremely superior compared to other devices.

The present invention has the above configuration, and since a capacitor is connected to the secondary coil of the ignition coil, the multiple sparks in the multiple spark circuit are further multiplexed, and an extremely large number of capacitive discharge sparks can be generated at the creeping plug. The electrical self-cleaning properties of the plug are very good.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit showing an embodiment of the ignition device of the present invention, and FIG. 2 shows the circuit. FIG. 3 is a time chart of the voltage related to the creeping plug, and shows a comparison between the present invention and the conventional example. 1 in the figure. ．． ．． battery, 2. ．． ．． DC-DC converter, 3... Intermittent circuit, 4... Ignition coil, 5● ● Creepage plug, C1●
●Capacitor.

Claims (1)

[Claims] 1. A multiple spark circuit that generates multiple spark voltages in the secondary coil by intermittent current in the primary coil at times other than the ignition timing, an ignition coil in which a capacitor is inserted in series with the secondary coil, and a creeping plug. 1. An ignition device for preventing fouling of a creeping plug, characterized in that the output of the multiple spark circuit is further multiplexed by the ignition coil and applied to the creeping plug.