LT5131B - Spark plug - Google Patents

Abstract

The invention relates to a spark plug having a body with a side electrode, an insulator with a central electrode. A spark gap is formed between the side electrode and the central electrode. An area around the spark gap is located inside internal conical surface expanding outward that is secured on a jacket with a channel for the central electrode. The jacket is made of an alloy possessing a catalyst property.

Description

The invention relates to the field of electrical engineering and motors.

Devices are known to ignite the air-fuel mixture in light-fueled combustion engines. These are spark plugs. The vast majority of them are, by their very nature, passive ignitors. The spark plug exerts high voltage from the outside of the engine into the combustion chamber and generates a high voltage spark discharge in the compressed air-fuel mixture. The spark has a high temperature so it ignites a flammable mixture. However, such passive ignition at the combustion chamber wall causes an asymmetric combustion of the mixture along an extended trajectory. This significantly reduces torque at high loads and high revs, resulting in reduced engine performance.

This can be remedied by burning the air-fuel mixture in the center of the combustion chamber. However, this can only be done with a spark plug with a flare effect.

Known pre-chamber spark plugs described in RU 2118026.

The spark plug has an insulator housing and a central electrode. At the rear of the housing, the incoming tanning chamber has an opening which, together with the central electrode, forms a coaxial spark gap and a nozzle for creating a torch. Inside the case is a cavity that acts as a pre-chamber. However, such pre-chamber spark plugs have a small pre-chamber volume, poor ventilation, and high thermal energy loss, resulting in unstable operation and short torque duration.

The use of a conical surface mounted around the spark gap in the spark plug (Authorization No. 1720115) is significantly more promising. Increases cartridge volume and improves ventilation. However, even in this case, significant thermal losses remain in the structural parts of the spark plug.

The prototype of the invention is patent RU 2185015. The spark plug has a side electrode housing, an insulator and a central electrode with a lateral electrode spark around which area is enclosed by an inner, expanding outwardly tapered surface. The tapered surface is mounted on a socket with a channel for a lateral electrode, which is mounted in a housing and is made of a material having low thermal conductivity and expansion coefficients.

The low thermal conductivity of the sleeve reduced the heat loss of the spark plug and increased its efficiency. Due to the low thermal expansion coefficient of the coupling material, the mechanical stress at the coupling points to the housing during thermal cycling is reduced.

However, the spark plug's efficiency and reliability have not reached their limits. The thick-walled sleeve cannot heat up to high temperatures because of its thermal inertia and relatively high heat transfer. In addition, during thermal cycling, the thick-walled sleeve causes significant mechanical stresses at the points of connection of the sleeve to the housing.

The object of the present invention is to eliminate the above mentioned disadvantages and to increase the efficiency and reliability of the spark plug.

this object is accomplished by the spark plug having a side electrode housing, an insulator and a central electrode forming a spark gap at its end with a lateral electrode, the area around which is surrounded by an internal, expanding outwardly tapered surface mounted on a duct with a channel for the lateral electrode to the housing, the sleeve is made of a thin-walled heat-resistant alloy with catalytic properties and is attached to the outside of the housing.

The wall thickness of the cap may be in the range of 0.1 to 0.5 mm.

The cap is fixed to the body by spot welding.

Fig. 1 is a sectional view of a spark plug of the present invention. The spark plug has a housing 1 with a lateral electrode 2, an insulator 3, a central electrode 4 forming a spark gap 5 with a lateral electrode 2 surrounded by an inwardly extending outwardly tapered surface 6 mounted on a thin wall sleeve 7 with a channel 8 for the lateral electrode 2 and mounted on the outside of the housing 1 9.

The sleeve is made of a heat-resistant alloy with catalytic properties, such as stainless steel, rich in nickel and chromium. The angle α at the apex of the conical surface is 40-60 °. The recommended wall thickness is 0.3-0.4 mm.

The spark plug operates in this way: when a high voltage is applied to the central electrode 4 and when the puncture voltage is reached, a gap channel is formed in the gap 5, which gradually passes into the plasma ball. It is reliably protected from the air-fuel mixture vortex impeller 7, so that combustion occurs only in the cavity formed by the conical mouth 7, the housing 1, and the insulator 3. When fully charged, this limited amount of air-fuel mixture charge fires the spark plug along its axis. When the torch reaches the center of the combustion chamber, the air-fuel mixture burns symmetrically and about three times faster than a conventional spark plug.

Because the sleeve 7 is a thin wall, it heats up to a minimum with minimal heat loss. In addition, the sleeve does not create significant mechanical stresses at the points of connection to the housing. The material of the plug 7 provides high heat resistance and prevents incendiary ignition. Clamps 7 The anchorage on the outside of the housing 1 9 ensures maximum bonding due to the transverse forces. Spot welding compensates for the increasing 7 dimensions of the hot bush in the spaces between the joints.

The high efficiency and reliability of the spark plug of the present invention has been proven by multiple tests.

Claims (3)

DEFINITION OF INVENTION 1. A spark plug having a side electrode housing, a central electrode insulator forming a spark gap with a lateral electrode, the area of which is surrounded by an internal, expanding outwardly tapered surface mounted on a duct with a central electrode, that the sleeve is made of a thin-walled heat-resistant alloy with catalytic properties and is attached to the outside of the housing. 2. A spark plug according to claim 1, wherein the sleeve wall has a thickness in the range of 0.1 to 0.5 mm. 3. The spark plug according to claim 1, characterized in that the cap is secured by spot welding.