摘要 |
A spark plug includes a metal shell, an insulator, a center electrode, a ground electrode, a first noble metal chip, and a second noble metal chip. The metal shell has a threaded portion with an outer diameter of equal to or less than 14 mm for installing the spark plug to an internal combustion engine. The parameters in the structure of the spark plug, such as an end surface area S of the first noble metal chip, a length A of the first noble metal chip, an end surface area Q of the second noble metal chip, a length B of the second noble metal chip, an air pocket size L, a space G of a spark gap, a ratio L/G, and a thickness T of the insulator, have suitable dimensional ranges determined through experimental investigation. The structure ensures high performance and a long service life for the spark plug.
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