JPH0697628B2 - Ignition device with series gap - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ignition device with a series gap suitable for an ignition device with a series gap such as an automobile engine.

[Problems to be Solved by Prior Art and Invention]

Conventionally, a pair of electrodes facing each other is sealed in a sealing tube,
As a discharge device in which an inert gas is sealed in the sealed tube,
So-called discharge tubes are known.

FIG. 4 shows a discharge tube 1 used, for example, in a lightning arrester of various electric devices, in which both end openings of an insulating tube 2 as a sealing tube made of ceramics or the like have discharge electrode portions 3 facing each other. , Is sealed with a pair of electrode plates 4, 4 having
The insulating tube 2 is filled with a predetermined inert gas. Then, when an abnormal voltage due to lightning or the like enters, a discharge is generated between the discharge electrode portions 3 and 3, the discharge tube 1 is temporarily brought into a conductive state, and an abnormal current is discharged to the ground side.

By the way, since the discharge tube 1 is arranged and connected on a predetermined electric circuit such as a lightning arrester, an electric element having a predetermined potential or a metal or the like at a ground potential is arranged immediately behind the discharge tube 1. Sometimes. Then, when the discharge tube 1 and the electric element or the like are disposed so close to each other in this positional manner, the electric field formed around the electric element or the like affects the discharge tube 1 and the discharge voltage of the discharge tube 1 is increased. There is a problem that the characteristics change.

Further, in recent years, as shown in FIG. 5, an automobile in which a so-called series gap S is provided in series with the spark plug 5 to prevent smoldering of the spark plug 5 due to adhesion of carbon or the like and keep the ignition timing constant An ignition device C for an engine or the like is known (see Japanese Patent Publication No. 51-32180), and it is considered that the series gap S is formed by the discharge tube 1 having the above-described configuration.

As shown in FIG. 6, the ignition device C with a series gap has a plug gap 7 which is detachably fitted to the ignition plug 5 at the tip of a high voltage cable 6 communicating with the power supply side.
Is attached to the inside of the plug cap 7,
A connection terminal 9 engageable with the terminal 8 of the spark plug 5 and a power supply terminal 10 connected to the end of the high-voltage cable 6 are arranged so as to face each other, and the discharge electrode section 3 described above is provided between the terminals 9 and 10. , 3
The discharge tube 1 having the above is mounted. The ignition device C having the above-described structure is provided with a recess formed in the cylinder head of the engine or the cylinder head cover 11.
Spark plug 5 embedded in 12 and screwed to the engine side
It is designed to be fitted into. In addition, reference numeral 13 in the drawing
Is a metal pipe for guiding the ignition device C and at the same time protecting the ignition device C from contamination by engine oil.

However, the discharge tube 1 has the ignition device C as described above.
Built in the cylinder head or cylinder head cover
Since it is embedded in 11, the metal pipe 13 for guiding the ignition device C is located immediately behind it,
Moreover, since the metal pipe 13 is at the same potential as the ground potential of the cylinder head or the cylinder head cover 11, the presence of the metal pipe 13 at this ground potential changes the electric field strength around the discharge tube 1 and the discharge tube 1 The discharge voltage characteristics of may change. When the discharge voltage characteristic changes in this way, the timing of the spark plug 5 is entirely displaced, and the timing of the spark plug is controlled more precisely to obtain high performance in an automobile engine or the like. There is a problem that the performance of is not obtained.

The present invention has been made in view of the above points, and provides an ignition device with a series gap, which can prevent the influence of an electric field of electric elements and the like arranged around and can improve the performance of an engine. The purpose is to do.

[Means for Solving the Problems]

In order to achieve the above object, the ignition device with a series gap according to the present invention forms a series gap in which one end is connected to the center electrode side of the spark plug and the other end is connected to the high voltage cable side extending from the power supply side. In a series gap ignition device incorporating a discharge device that
In the plug cap of the ignition device incorporating the discharge device, a conductive member surrounding a cathode side portion of the incorporated discharge device is provided.

Also, preferably, the conductive member is electrically connected to the high-voltage cable side.

[Action]

According to the ignition device with a series gap according to the present invention, in the plug cap of the ignition device incorporating the discharge device as the series gap, the conductive member surrounding the cathode side portion of the incorporated discharge device is provided. The influence of the surrounding electric field can be prevented to stabilize the electric field in the vicinity of the cathode side inside the discharge device, and by eliminating the change in the discharge voltage characteristic of the discharge device, it is possible to prevent the overall deviation of the ignition timing. It is possible to achieve higher performance.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 3, and the same reference numerals will be used for the same portions as those in the related art.

FIG. 1 shows a first embodiment of an ignition device C with a series gap according to the present invention. The inner peripheral surface of a plug cap 7 embedded in a metal pipe 13 provided in the cylinder head or the cylinder head cover 11 is shown. One of the conventional discharge tubes 1 as shown in FIG. 4 mounted in the plug cap 7 at the side of the power supply terminal 10 connected to the high voltage cable 6 extending from the high voltage coil for generating a negative voltage. A strip-shaped conductive member 27 is provided so as to cover the electrode portions 4a, 3a. The conductive member 27 is connected to the power supply terminal 10 with a wire or the like, and has the same potential as the power supply terminal 10 side.

Therefore, in the plug cap 7, the side of the power supply terminal 10 to which a negative voltage is applied is the cathode, and the side of the connection terminal 9 connected to the center electrode of the spark plug is the anode.

When the discharge tube 1 is mounted in such a plug cap 7, one of the electrode portions 4a, 3a of the discharge tube 1 which is connected to the power supply terminal 10 and becomes the cathode side and the conductive member 27 have the same potential. Even when a predetermined electric field is formed around the discharge tube 1 due to the presence of the metal pipe 13 at the ground potential, the vicinity of the cathode side inside the discharge tube 1 is not disturbed, and the discharge electrode portion 3a is , Discharge electrode parts facing each other
A stable electric field is formed with 3b.

Therefore, the discharge tube 1 is not affected by the change in the electric field strength due to the metal pipe 13 at the ground potential that guides and protects the plug cap 7, stabilizes the discharge voltage characteristic, and prevents the overall shift of the ignition timing. It is possible,
This makes it possible to improve the performance of the engine.

The reference numeral 28 in the figure indicates that the discharge tube 1 has the plug cap 7
Retained in, is an electrically insulating mold material such as a resin for fixing, the conductive member 27 may be a plurality of cut, not a series as described above,
A coil spring-shaped metal wire 29 may be used as in the second embodiment shown in FIG.

Further, as described above, the conductive member 27 is connected to the power supply terminal.
It is possible to sufficiently prevent the influence of the surrounding electric field without electrically connecting with 10, and the conductive member 27 can be formed of various materials such as a metal foil, a metal mesh, and a conductive paint. It is a thing.

Furthermore, as shown in the third embodiment of FIG. 3, even if the conductive member 27 is embedded inside the wall of the plug cap 7, the same effect can be obtained.

The high-voltage coils provided in the circuit of each series gap ignition device described above all generate negative high-voltage pulses, and in this case, the remarkable effect of the conductive member 27 as the back electrode is obtained. However, in the circuit as described above, when the high voltage coil generates a positive high voltage pulse, the effect of the conductive member 27 as the back electrode described above cannot be obtained, but there is no particular problem. .

In the circuit as described above, the high-voltage coil generates a positive high-voltage pulse, the side without the back electrode is connected to the high-voltage cable side to become the anode, and the side with the back electrode is the center electrode of the spark plug. In the case where it is connected to the cathode side to serve as a cathode, as in each of the above-described embodiments, the remarkable effect as in the case where a high voltage negative voltage acts on the back electrode side cannot be obtained, but some effect cannot be obtained. The obtained discharge voltage characteristics can be stabilized to some extent.

In addition, in Table 1 below, as experimental data showing the effect of the series gap igniter C having the conductive member, a case where the conductive member 27 of the first embodiment is electrically connected to the cathode side of the discharge tube 1 is shown. The discharge start voltage values of the assembly main body when not electrically connected and the discharge start voltage value when the earth body approaches them are shown in comparison with the conventional example shown in FIG.

[Advantages of the Invention] As described above, the ignition device with a series gap according to the present invention includes a conductive member that surrounds the cathode side portion of the discharge device to be incorporated in the plug cap of the ignition device that incorporates the discharge device as the series gap. Since it is provided, the conductive member can prevent the influence of the surrounding electric field and stabilize the electric field near the cathode side inside the discharge device, and by eliminating the change in the discharge voltage characteristic of the discharge device, the overall ignition timing can be improved. It is possible to prevent deviation and to achieve higher engine performance.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a first embodiment of a series gap ignition device according to the present invention, and FIG. 2 is a main part sectional view showing a second embodiment of the series gap ignition device according to the present invention. FIG. 4 is a sectional view of an essential part of a third embodiment of the ignition device with a series gap, FIG. 4 is a sectional view showing a conventional discharge tube, FIG. 5 is a circuit diagram of the ignition device with a series gap, and FIG. FIG. 3 is a sectional view showing the ignition device with a series gap. DESCRIPTION OF SYMBOLS 1 ... Discharge tube, 2 ... Insulation tube, 3 ... Discharge electrode part, 3a ... Cathode side discharge electrode part, 3b ... Anode side discharge electrode part, 4 ... Electrode plate, 4a ... Cathode side electrode plate, 4b ... Anode side electrode plate 5,
... spark plug, 6 ... high-voltage cable, 7 ... plug cap, 13 ... metal pipe, 26, 27, 29 ... conductive member, 28 ... electrically insulating material.

Continuation of front page (56) Reference JP-A-59-108290 (JP, A) US Pat. No. 4631453 (US, A) US Pat. No. 4475055 (US, A)

Claims (2)

[Claims] 1. A igniter with a series gap, which comprises a discharge device having one end connected to a center electrode side of an ignition plug and the other end connected to a high-voltage cable side extending from a power supply side to form a series gap. An ignition device with a series gap, wherein a conductive member surrounding a cathode side portion of the discharge device to be incorporated is provided in a plug cap of the ignition device incorporating the discharge device. 2. The ignition device with a series gap according to claim 2, wherein the conductive member is electrically connected to the high-voltage cable side.