JPH0676916A - Ignition plug - Google Patents

Abstract

PURPOSE: To prolong a service life and to improve starting characteristics in cold weather by forming a plug body electrode from a Ag-Ni-fiber composite member in forming a composite material from a Ag matrix with a Ni fiber inserted thereinto, and by forming a central electrode from the same kind of composite material. CONSTITUTION: An ignition plug is centrally provided with an insulator 1 having a central electrode 3, and the electrode 3 is fixed through a glass fusion-sealed body 4. A plug body 2 is provided on the outside of an insulator 1, and a plug body electrode 5 is attached to the plug body 2. The electrodes 3 and 5 form a plug spacing 9. The electrode 5 is made of Ag-Ni-fiber composite material, which is formed of a Ag matrix with a Ni fiber inserted thereinto and which contains 20 to 80% of Ni fiber having 100 to 6000 lines per square millimeter. Also, the central electrode 3 using Ag-Ni-fiber composite is shaped in the form of, for example, a Ag-Ni insertion body 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises an insulator, a center electrode provided inside the insulator, a plug body outside the insulator, and a plug body electrode (outer electrode) provided on the plug body. The present invention relates to a spark plug having.

[0002]

2. Description of the Prior Art In a conventional spark plug of this type, the center electrode and the plug body electrode (outer electrode) are usually made of binary-nickel-copper, pure silver or nickel alloy.

[0003] From German Patent Publication No. 2 508 490 is further known a silver-nickel-fiber composite material, which is made of a silver matrix with nickel fibers embedded therein, and a similar electrode. It can also be used as a material for manufacturing.

For applications in modern internal combustion engines of motor vehicles, spark plugs with a lifespan as long as possible are required, for example for vehicle running capacities of approximately 100,000 km.
Such a spark plug does not contact, for example, a fuel that does not burn with a catalyst for purifying the exhaust gas, does not damage the catalyst, or the exhaust gas does not violate legal regulations, and does not interfere with the internal combustion engine. It should operate at a predetermined ignition condition without being ignited so that the output reduction does not occur. Furthermore, good cold start characteristics are required.

The spark plugs known to date are not sufficient for these requirements.

Particularly with regard to burn-off strength, this strength was only obtained with platinum metal, which has a high cost. On the other hand, if the electrode material is burned down over the transit time, the plug gap (electrode gap) becomes larger. Since the spark plug discharge voltage increases in proportion to the compression pressure and the plug gap, the voltage demand exceeds the supply of the ignition voltage, especially in the case of an internal combustion engine with high compressibility, and this supply voltage is usually the case in continuous ignition. Is 33 kV, or 40 kV in the case of condenser ignition for gas engines. Small plug gaps, on the other hand, will worsen the exhaust gas value.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is therefore to say that it has a long service life, so that, for example, a vehicle equipped with a spark plug of this kind can achieve a mileage of 100,000 km. Other types of spark plugs.

[0008]

According to the present invention, a plug body electrode is formed from a silver-nickel-fiber composite material into which a nickel fiber or a nickel alloy fiber is inserted. It is solved by being made of a silver matrix that is

That is, the spark plug of the present invention has an insulator, a center electrode provided in the insulator, a plug body outside the insulator, and a plug body electrode provided on the plug body. In claim 1, the plug body electrode is formed of a silver-nickel-fiber composite material, the fiber composite material being made of a silver matrix having nickel fibers or nickel alloy fibers inserted therein. It is a plug.

Spark plugs whose plug body electrodes are formed from such a silver-nickel-fiber composite material have a long service life, which means that in particular, together with the plug body electrodes, the center electrode is formed from this material. Sometimes it applies.

In contrast to the known spark plugs with conventional electrodes, the electrode edges are not particularly strongly burned off, but the burn-off is distributed almost uniformly over the facing electrode surfaces. . After a short time, the sharp nickel peaks give a low discharge voltage (response voltage: Anpreschspanungung) over a long operating time. The good heat dissipation of the silver matrix results in a particularly good cooling of the nickel or nickel alloy fibers, so that such an electrode burns down significantly more than the known binary-nickel-copper-electrodes. The speed is low.
The plug gap can be chosen to be larger for the same ignition conditions, which may result in thinner fuel, for example in a gas engine (Abmagerungsmogl).
ichkeiten) becomes larger. This results in good efficiency, low consumption and greater sales opportunities for gas engines with such spark plugs. The same applies to low fuel-internal combustion engines of the Otto cycle engine type.

The spark plug according to the present invention has improved cold start characteristics. Because the lower discharge voltage until ignition causes some energy to flow through some shunts.

The spark plug according to the invention is also suitable for high-pressure compressed methanol engines, where a larger plug gap can be selected for the same discharge voltage. This is more insensitive to shunts than other common materials, allows even colder start even with extended discharge life at low discharge voltage, and has a large burnout reserve. It is possible.

The spark plug according to the invention can therefore be applied as a long-life spark plug for stationary and running engines, for example for Otto engines for private cars and motorcycles, for 2-stroke engines and 4-stroke engines, It can be applied to single-cylinder and multi-cylinder rotary piston engines, Otto fuel, methanol, ethanol, etc., gas-powered engines such as natural gas, hydrogen, biogas, and highly compressible methanol engine. . Spark plugs may or may not have mechanical distributors, individual ignition coils and electronic distributors, as well as pre-ignition spark ignition, e.g.
It is suitable for conventional igniters such as SZ- and / or HKZ-igniters. Due to its particularly low discharge voltage, this kind of spark plug is also suitable for model engines. In the case of work machines and lawn mowers that are handled by hand, a low discharge voltage has a good starting characteristic, which allows a simpler and cheaper plug. If the discharge voltage is low, it results in lowering the cost of removing radio interference.

Particularly advantageous embodiments and developments of the spark plug according to the invention are the subject of claims 2 to 13.

To reduce the burning of the spark plug electrode,
In particular obtained by using a silver-nickel-fiber composite material for the center electrode and the plug body electrode, which material contains from 100 to 6000 fibers of nickel per mm ² or eg silicon, magnesium, chromium. It contains 20 to 80% of nickel alloy. The plug body electrode is then a side electrode (Seitenelektr).
den) or roof electrode (Dachelektrod)
en) selectively welded to the plug body in an annular shape or for example with a collar on the plug body (ein
The plug body electrode is also provided with a binary-nickel-copper, complete silver,
A conventional center electrode made of silver or nickel alloy with a copper core can be placed opposite. On nickel surfaces, this center electrode may also be platinum-plated, that is to say it may be provided with platinum or gold-palladium-platinum alloy inserts or protrusions.

When the electrodes burn out, the silver burns first, leaving the sharpness of the nickel fibers cooled by the silver. Tip action (Spitgenwirku
ng) lowers the discharge voltage, which is particularly preferred when both electrodes are made of the fiber composite material. This material undergoes a nearly uniform burnout across the entire ignition surface, which causes additional electric field distortion due to the roughened and nickel-tipped surface, which is non-magnetic in silver and magnetic in nickel. Some are additionally preferred. Sliding spark gap (Gleitfunken) on insulator leg
If there is a "strecke", the discharge voltage further decreases. Additives on the semiconductor substrate in the electrode material have the further function of lowering the discharge voltage.

The electrodes should be as short as possible to reduce the electrode temperature. Lateral electrodes are shorter than roof electrodes,
Therefore, the temperature is lower. The silver matrix produces a particularly favorable heat dissipation and it is also possible to lengthen the insulator legs when the plug body electrode is cold in order to achieve the same burning ignition state. Longer insulation means less sensitive to residue formation on the insulation, which means more cold and cold start is possible.

The number of plug body electrodes is not limited to one. Two to four plug body electrodes (side electrodes) can be provided, but this has proved to be particularly good in practice.

The spark plug according to the invention can also be produced in a mass production process. This is because the silver-nickel-fiber composite material as the center electrode can be glass-sealed, and the plug-body electrode made of this fiber composite material can be welded to meet the requirement of bending around. .

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS In the following, a particularly advantageous embodiment of the spark plug according to the invention will be explained in more detail with reference to the accompanying drawings.

The first embodiment of the spark plug according to the invention shown in FIG. 1 comprises an insulator 1 with a central electrode 3 provided in the center of the insulator 1 as usual. 3 is fixed there via a glass melt seal 4. A plug body 2 is provided outside the insulator, and a plug body electrode 5 is attached to the plug body 2. The electrodes 3 and 5 form a plug gap 9.

The insulator 1 including the glass seal 4 and the center electrode 3 may be provided with a flange on the plug body 2.
The plug body electrode 5 is particularly preferably welded to the plug body, which can also be flanged on the plug body. The electrode 5 is made of a silver-nickel-fiber composite material, where the silver component can be made of an oxygen-impermeable silver alloy in order to protect the nickel component from chemistry in the combustion chamber. If necessary, additional measures may be taken to reduce the discharge voltage. Common spark plug nickel alloys as nickel constituents, particularly preferably nickel alloys containing 0.3% magnesium and 1 to 4% silicon, come into consideration.

In the first embodiment shown in FIG. 1 of the present invention, the center electrode is made of binary-nickel-copper or complete silver or nickel alloy. The plug body electrode is in the form of a roof electrode and is made of a silver-nickel-fiber composite material.

In the second embodiment of the spark plug according to the invention shown in FIG. 2, the center electrode 3 is also formed of a silver-nickel-fiber composite material, for example in the form of a silver-nickel-insert 12. Has been done. The two side electrodes 5 are also silver-
It is made of nickel-fiber composite material.

Clean room (Reinigungscamme
r) 7 produces an additional clean spray on the insulator 1. The insulator leg is at its natural combustion temperature, ie about 55
Purified by itself with a recent unleaded fuel at 0 ° C. This temperature is not available at cold start. The residue may include a conductive constituent material, and in some cases, the conductivity may significantly affect the applied voltage. The resulting shunts rob energy, thus making it difficult to reach the required flashover voltage when not at all impossible. The clean room is additionally cleaned by blowing air on the insulator 1. The part of the insulator located in the spark passage is cleaned by the spark, while the electrodes 3, 5
The metal of is attached. The plug gap, which grows over operating time due to burnout of the electrodes, is then partially bridged by this electrically conductive section, so that the discharge voltage remains low over a long operating time.

In the third embodiment of the spark plug according to the present invention shown in FIG. 3, the center electrode 3 is formed using a silver-nickel-fiber composite material, and three center electrodes 3 of silver-nickel-fiber composite material are formed. Lateral electrodes 5 are provided on the insulator together with the slide spark gap. An insulator sharp 11 is located in the plug gap, that is, in the spark passage.

FIG. 4 shows a square lightning rod (hornerable).
It shows the embodiment of the present invention having a spark plug according to the present invention, in which the center electrode and the plug body electrode are formed from a silver-nickel-fiber composite material, or only the center electrode or the plug body electrode, respectively. The same material is formed in a single arrangement or a plurality of arrangements. Slide spark spark plug (Gleitfunken
Zundkerzen) tends to fill the medium with the ceramic surface of the insulator. The purpose of the device shown in FIG. 4 is to start the spark through an insulator when pressure is high, but then by a special electrode device the spark is lifted from this surface in the direction of the combustion chamber. It is to let it be pulled forward (square lightning rod). Thus the load on the insulator is essentially reduced and a longer life is ensured.

In the embodiment shown in FIG. 5 of the present invention, an ignition plate of silver-nickel-fiber composite material is provided as the plug body electrode 5. This kind of ignition plate is integrally formed in a substantially star shape and is welded to the plug body at three points. Above the center electrode 3, a combination of three star-shaped radial members (Strahlen) forms a unique ignition plate. It is also possible to adopt three or more radial stars, or to provide some holes at the center of the star or eccentrically.

The embodiment of the spark plug according to the invention shown in FIG. 6 has a center electrode 3 with a silver-nickel-protrusion or insert 12 on the end face on the ignition side and a corresponding silver-nickel-protrusion or And a plug body electrode 5 with an insert 13.

As mentioned above, the spark plug according to the present invention comprises a single electrode composed of a silver-nickel-fiber composite material.
A plug body electrode in the form of a double electrode is welded to the spark plug body. However, the plug body electrode may also be, for example, a disk (ein) with a collar on the plug body.
It can also be provided in the form of a Gebordelten Scheive). This plug-body electrode consists of a center electrode of the same composite material as well as electrodes of known materials such as nickel alloys (complete silver-center electrode, platinum-mounted center electrode, nickel-copper-binary center electrode, silver). -Copper-binary center electrode). The plug body electrode can, of course, also be provided in the form of an ignition plate made of a silver-nickel-fiber composite material. Spark plugs of this kind can be formed on glass substrates or on loosely incorporated resistors, for example wound wires, with or without burnout or (radio) obstruction removal resistors, or additionally. Slide spark involvement (Gleitfunkenant
eil) (Air Spark Gap (Luftfunkens
(a combination of a trecke) and a slide spark gap) may be provided.

In the special electrode device of the spark plug, the spark runs through the air when the compression pressure is low, and increases through the slide gap (square lightning rod-electrode type) when the pressure rises. The ventilation space of the plug body can be provided with an additional clean room into which hot combustion gases are sent in order to dry the insulation rapidly or to clean the soot, which combustion gases then It emerges after a delay in the outflow stroke, grabbing the side of the insulator, heating it and removing it with the vaporized components. The shape of the electrode made of fiber composite material (Masseelektrode) can be different from the usual shape with a natural edge (Naturkanten). This shape may be formed, for example, in the form of a U-shaped contour or in the form of a trapezoidal cross-section, the center electrode should then be as large as possible, and at the best also appoint the sharps.

When the plug body electrode is made of nickel alloy or nickel-copper-binary, fine pieces made of silver-nickel-fiber composite material may be attached and joined by welding, for example. The center electrode and plug body electrode with attached or incorporated micropieces of silver-nickel-fiber composite can be provided in combination with conventional electrode base materials.

Another advantage of applying the silver-nickel-fiber composite material is that it is a mechanically and thermally stable electrode material as compared to perfect silver. No large annular gap is required, and the gap prevents thermal degradation at the silver electrode. The larger electrode diameter results in a larger burnout surface, which is a prerequisite for the spark plug to have a high operating power.

[Brief description of drawings]

1 is a partial cross-sectional view of a first embodiment of a spark plug according to the present invention.

2A is a partial cross-sectional view of a second embodiment of the spark plug according to the present invention, and FIG. 2B is a bottom view of the spark plug of FIG.

3A is a partial cross-sectional view of a third embodiment of the spark plug according to the present invention, and FIG. 3B is a bottom view of the spark plug of FIG.

FIG. 4 is a partial sectional view of a fourth embodiment of a spark plug according to the present invention.

5A is a partial cross-sectional view of a fifth embodiment of the spark plug according to the present invention, and FIG. 5B is a bottom view of the spark plug of FIG.

FIG. 6 is a partial sectional view of a sixth embodiment of a spark plug according to the present invention.

[Explanation of symbols]

 1 Insulator 2 Plug Body 3 Center Electrode 4 Glass Sealing Body 5 Plug Body Electrode 7 Clean Room 9 Plug Gap 11 Tip of Insulator 12 Silver-Nickel-Fiber Composite Protrusion or Insert 13 Silver-Nickel-Fiber Composite protrusion or insert

Claims (14)

[Claims] A spark plug having an insulator, a center electrode provided inside the insulator, a plug body outside the insulator, and a plug body electrode provided on the plug body, wherein the plug body electrode is silver. A spark plug formed of a nickel-fiber composite material, the fiber composite material being made of a silver matrix having nickel fibers or nickel alloy fibers inserted therein. 2. The center electrode is formed of a silver-nickel-fiber composite material, the fiber composite material being made of a silver matrix having nickel fibers inserted therein. Spark plug described in. 03. The fiber composite material is 100 per 1 mm ^2.
The spark plug according to claim 1 or 2, characterized in that it comprises 20 to 80% of nickel of from 6000 fibers. 4. The spark plug according to claim 1, wherein the silver matrix is made of an oxygen impermeable silver alloy. 5. The spark plug according to claim 1, wherein the nickel fiber is made of a nickel alloy containing a magnesium component and a silicon component. 6. The spark plug according to claim 1, wherein the plug body electrode is formed in the shape of a disk having a flange on the plug body. 07. The plug body electrode is silver-nickel-
6. The spark plug according to claim 1, further comprising an ignition plate made of a fiber composite material. 08. The center electrode and / or the plug body electrode is formed of a nickel alloy or a nickel-copper-binary component, into which a fine piece made of a silver-nickel-fiber composite material is inserted or attached. The spark plug according to any one of claims 1 to 5. 9. The spark plug according to claim 1, wherein a clean room is formed in the ventilation space of the plug body. 10. The spark plug according to claim 1, wherein the slide spark gap is provided on the insulator. 11. The spark plug according to claim 1, wherein a plurality of plug body electrodes are provided. 12. The spark plug according to claim 1, wherein the plug body electrode is formed in the shape of a rectangular lightning rod. 13. The spark plug according to claim 1, wherein the electrode having a nickel surface is provided with a silver-nickel-adduct or an insert in advance. 14. The center electrode is formed of a silver coating and a copper core material, and the center electrode is formed of a silver coating and a copper core material.
The spark plug according to item 1.