JPH0811951B2 - Distributor for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributor for an internal combustion engine, and more particularly to a distributor for an internal combustion engine provided with a means for controlling noise radio waves caused by discharge sparks accompanying a distribution operation. Is.

[Conventional technology]

FIG. 6 shows a conventional distributor for an internal combustion engine, in which a distribution electrode (3) is attached to a distribution electron (2) fixed to a rotating shaft (1) which rotates in synchronization with rotation of a crankshaft of the internal combustion engine. A plurality of side electrodes (4) are provided on the rotation locus of the distribution electrode (3) through the discharge gap (g). On the upper surface of the distribution electrode (3), a contact (6) connected to the ignition coil by a conducting wire (5) is pressed.

With the above configuration, the distribution electrode (3) approaches the lateral electrode (4) arranged close to the rotation trajectory of the distribution electrode (3) each time the distribution electrode (3) rotates. , A high voltage is applied by a discharge through the discharge gap (g),
Electric power is sequentially distributed to the ignition plug of each cylinder by the electric discharge generated in the electric discharge gap (g). At this time, noise electric waves are generated by the spark discharge generated in the discharge gap (g) between the distribution electrode (3) and the side electrode (4). This noise radio wave interferes with radio broadcasting, TV broadcasting, various wireless communication devices and electronic devices, and deteriorates the S / N ratio.

As means for suppressing the generation of such noise radio waves, conventionally,
There is one disclosed in Japanese Examined Patent Publication No. 51-38853. As shown in FIG. 7, the high-resistance material layer (7) is formed on the surface of the portion of the electronic distribution electrode (3) near the side electrode (4).

With the above configuration, it is possible to reduce the electric field strength of noise radio waves generated during discharge between the distribution electrode (3) and the side electrodes (4).

[Problems to be Solved by the Invention]

Since the conventional distributor for internal combustion engine as described above is provided with the high-resistance material layer (7) on the distribution electrode, it is equivalent to the peak detection (SAE standard) among the noise radio waves measured by the detection method. The effect can be obtained, but when quasi-peak detection (CISPR standard) is used, a sufficient effect cannot be seen,
Therefore, there is a problem that the interference caused by noise radio waves, especially for FM radio, is still unsolved.

Further, since there is an insulating layer on the front surface of the distribution electrode, there is a problem that discharge is unstable and radio noise becomes large.

The present invention has been made to solve such a problem, and an internal combustion engine arrangement that has a remarkable effect of suppressing noise radio waves even in the measurement result by quasi-peak detection and that can obtain stable discharge in the discharge gap. Aim to get electric appliances.

[Means for solving the problem]

In the distributor for an internal combustion engine according to the present invention, the front surface portion is thin due to the taper and has a serrated shape, the tip end portion is exposed to form a dielectric layer, and the front surface portion is covered with a silicon varnish layer. Equipped with a distribution electrode.

[Action]

In the present invention, the front surface of the distribution electrode is tapered to have a thin and serrated shape, the tip is exposed to form a dielectric layer, and the front surface of the distribution electrode is covered with a silicon varnish layer. By being formed, the discharge is stabilized, and the generation of noise radio waves due to the discharge is suppressed from the start of the distributor.

〔Example〕

The distribution electrode (3) of FIGS. 1 and 2 has a thin front surface which is tapered (3a) and has a serrated shape (3b). Further, a dielectric layer (8) made of Al ₂ O ₃ is formed on the front surface of the distribution electrode with its tip exposed.

As described above, since the front surface of the distribution electrode (3) is thin and has the serrated shape (3b), the concentration of the electric field is suitable and the discharge is stabilized. Furthermore, the dielectric layer (8) suppresses the generation of noise radio waves, and the noise radio wave suppression effect is obtained in both measurement of noise radio waves by peak detection (SAE standard) and measurement of noise radio waves by quasi-peak detection (CISPR standard). It was possible to confirm that it was remarkable.

Moreover, the above effect could be confirmed by the data in the measurement of the noise electric field strength and the auditory judgment for each frequency.

Although the dielectric layer (8) is formed on the upper and lower surfaces of the distribution electrode (3), the dielectric layer (8) may be provided on one of the upper and lower surfaces. Although Al ₂ O ₃ was used as the dielectric, S
iC may be used and the same effect can be obtained.

Further, it is also conceivable to form the dielectric layer by using mica which is known to be less worn against discharge.

3 and 4 show an embodiment of the present invention, in which (10) is the dielectric layer (8) described in FIGS. 1 and 2.
Is a silicon varnish layer formed on the upper surface of the.

FIG. 5 is a diagram showing the relationship between the operating time of the distributor and the noise current (the magnitude of the noise current and the magnitude of the noise radio wave are correlated, and the smaller the noise current, the smaller the generation of the noise radio wave). In the previous examples shown in FIGS. 1 and 2, the front surface of the distribution electrode has a thin and serrated shape, which has the effect of strengthening the electric field concentration at the start of discharge and lowering the discharge start voltage. As can be seen from FIG. 5, the noise current is small compared to the conventional one from the early stage of starting the distributor.

By the way, by applying silicon varnish to the front surface of a flat distribution electrode, there is an effect that discharge is started while breaking the insulating film, and the discharge start voltage is lowered by utilizing the accumulated charge on the dielectric surface. However, at this time, there is a drawback that the discharge breaks the coating film and is generated at a plurality of places to make the discharge unstable, which leads to an increase in ionization. On the other hand, in the case of the embodiment of the present invention shown in FIG. 3 and FIG. 4, a silicon varnish layer (1
The formation of (0) eliminates such instability, minimizes the silicon varnish layer (10) that is destroyed by the discharge, and provides a durable electronic distribution electrode. Oxidation of the silicon varnish layer (10) causes a part of the silicon varnish layer (10) to peel off in the initial stage of power distribution start-up, resulting in a concentrated discharge, which may result in less noise radio waves from the initial stage of power distribution start-up. It can be seen from FIG.

〔The invention's effect〕

As described above, according to the distributor for an internal combustion engine of the present invention, the front surface of the distribution electrode is thin and has a serrated shape, and the tip end is exposed to form the dielectric layer. Since the silicon varnish layer is formed so as to cover it, it is possible to obtain stable discharge, suppress the generation of noise radio waves from the beginning of the power distribution start-up, and obtain a durable distribution electrode that suppresses noise radio waves. There is.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of an essential part of a distribution electrode, FIG. 2 is a side sectional view of FIG. 1, and FIG. 3 is a plan view of an essential part of an embodiment of the present invention. FIG. 6 is a side sectional view of FIG. 3, FIG. 5 is a diagram showing a relationship between operating time of a distributor and noise current, and FIG. 6 is a partially cutaway side sectional view of a conventional internal combustion engine distributor. FIG. 7 is a side sectional view of an essential part of FIG. (1) ... Rotation axis, (2) ... Electron distribution, (3) ... Electron distribution electrode, (4) ... Side electrode, (8) ... Dielectric layer,
(10) …… It is a silicon varnish layer. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A distribution electrode provided on a distribution shaft fixed to a rotating shaft that rotates in synchronization with rotation of a crankshaft,
In a distributor for an internal combustion engine, which comprises a plurality of side electrodes arranged through a discharge gap on a rotation locus of the distribution electrode, a front surface is thin and serrated due to a taper, and a tip portion is A distributor for an internal combustion engine, comprising the distribution electrode which is exposed and has a dielectric layer formed thereon, and which further has a silicon varnish layer formed so as to cover the front surface portion.