JPS5838548Y2 - Internal combustion engine ignition system - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ignition device for an internal combustion engine installed in an automobile or the like.

In recent years, automobile engines have been required to recirculate a large amount of exhaust gas or operate with a lean air-fuel mixture ratio in order to reduce harmful components in the exhaust gas. In order to ensure reliable ignition, there is a trend toward installing ignition devices that combine a spark plug with a wide discharge gap and a high-energy power source.

Semi-creeping discharge plugs, which have a wide discharge gap and excellent self-cleaning properties, are extremely advantageous as spark plugs used in such cases, but because the power source used is high energy, the insulator surface that makes up the creepage gap is A groove is dug along the path of the discharge spark, which tends to cause so-called channeling discharge destruction.

When this discharge breakdown occurs, the discharge sparks pass through the grooves, resulting in poor ignition performance, and furthermore, as the grooves become deeper, the insulator is damaged.

The inventors discovered that the main cause of channeling at the tip of the insulator of a semi-creeping discharge plug is the capacitive discharge current flowing through the plug, and that the channeling can be effectively prevented.
It is an object of the present invention to provide an ignition device for an internal combustion engine having a semi-creeping discharge plug having a wide discharge gap and excellent durability.

The present invention uses a high energy power source of 100 to 200 millijoules and 1.2 to 3. This device is characterized by having a wide discharge gap of Qmm and having 2 resistors inserted between 5 and 35 in series with the discharge gap.Next, the present invention will be explained based on an embodiment shown in the figure. .

1 is a power supply installed in the engine such as a generator or storage battery, and 2 is a boost and distribution circuit device consisting of an ignition coil, a power distributor, a transistor eveninger, etc., and its output energy is set to be 100 to 200 millijoules. has been done.

3 is a semi-creeping discharge plug, which includes a ceramic insulator 32 in which a center electrode 33 is inserted inside a mounting bracket 31;
are fitted, and the inner wall of the mounting bracket tip 31A and the center electrode tip 33A are formed by a creeping gap 4 and an air gap 5, which are the surfaces of the insulator tip 32A. A semi-creeping discharge gap A of Qmm is formed, and a resistor 6 of Q is inserted between 5 and 35 between the center electrode 31 in the insulator.

Note that the resistor 6 can be formed in a plug cap inserted in series with the discharge gap A or in a high voltage cord.

In the above ignition device, a high-energy spark discharge is made in the semi-creeping discharge gap A, but the resistor 6 reduces the pinic value of the capacitive discharge flow during discharge, so a groove-shaped discharge breakage occurs on the surface of the insulator tip 32A. This prevents so-called channeling from occurring.

Note that the lower limit of resistance is 5Kg, and the upper limit is 35K! Q is the reason why the channeling prevention effect is small when the resistor 6 is less than 5KQ, and it is most effective in preventing channeling in the range of 7KQ to 30KQ, and when it is over 35KQ, the spark energy decreases. This is because the ignitability decreases and it is not practical.

In the structure shown in FIG. 2, the creepage gap 4 is 0.8 mm, the air gap 5 is 1.2 mm, and the length B of the insulator tip protruding from the mounting bracket is 1.8 mm. Qmm semi-creeping discharge plug (
b) When no resistor is inserted.

(b) When a 5 kg resistor 6 is inserted.

(c)7K,! When each resistor 6 of Ω is inserted in Q, 10, KQ, and 30.

A discharge test was conducted on each of the batteries at 40 kg/mm2 in the atmosphere at room temperature by applying a voltage of 25 KV at a frequency of 200 Hz using a transistor power supply of 130 mJ.

As a result, if (a) the resistor was not inserted, channeling would occur at the tip of the insulator after 6 hours, and (b) 5KJ7
Channeling occurred after 20 hours in the case of using a resistance of (c), and no channeling occurred even after 100 hours in the cases of (c) using a resistance of 7 KJ7.10 KJ7.30 KQ.

This discharge test confirmed that the ignition system for an internal combustion engine of the present invention has good durability as a semi-creeping discharge plug.

As described above, the ignition system for an internal combustion engine according to the present invention uses a semi-creeping discharge plug with a discharge gap of 1.2 to 3.0 mm and a resistance of 5 to 35 KJ7 inserted, so it has excellent durability and ignition. Gender is not lost.

[Brief explanation of drawings]

FIG. 1 shows the components of the ignition device according to the present invention, and FIG. 2 shows a partially cutaway diagram of a semi-creeping discharge plug. In the diagram: 1...Power supply, 2...Step-up and power distribution electric circuit, 3...Semi-creeping discharge plug, 6
...Resistance, A...Discharge gap.

Claims (1)

[Scope of utility model registration request] A high energy power source of 100 to 200 millijoules and 1
．． 2-3. An ignition device for an internal combustion engine, characterized in that a semi-creeping discharge plug having a wide discharge gap of Qmm and a resistor of 5 to 35 KQ are inserted in series with the discharge gap.