Spark plug and engine

Abstract

The invention provides a spark plug. The spark plug comprises a cylindrical insulator, an axial hole formed in the center of the insulator in the axis direction and a central electrode arranged in the axial hole; a precious metal end is welded to the end of the central electrode; a fusion area is formed at a welding position; and the fusion area coincides with the radial projection of the insulator. Since the fusion area and the projection of the insulator has an overlapping area, so that fuel oil sprayed out at high pressure can be prevented from directly acting on the fusion area, the fusion area on the central electrode is prevented from forming holes after being repeatedly scoured by the high-pressure fuel oil, and the corrosion resistance is improved.

Description

technical field

[0001] The invention relates to a spark plug, in particular to a spark plug for a high-pressure fuel injection engine; the invention also relates to a high-pressure fuel injection engine. Background technique

[0002] In recent years, with the increasingly stringent emission regulations, in order to achieve higher thermal efficiency, engines have adopted technologies such as high tumble flow, high-energy ignition, high-pressure fuel injection, and direct injection in cylinders, which have brought higher challenges to spark plugs. On the one hand, the operating voltage of the spark plug has increased by nearly 10KV compared with the previous engine. On the other hand, the durability of the spark plug has been challenged, which has caused concerns about the life of the spark plug. In traditional engines using this type of technology, precious metal spark plugs are often used. For example, the ignition end of the center electrode is laser-welded with an Ir alloy...

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