Patent ID: 8278808
Filing Date: 2012-10-02
Classification: H01T

Abstract:
1. A spark plug for a spark-ignited internal combustion engine, said spark plug comprising: a generally tubular ceramic insulator comprising a single piece of insulating material extending continuously along a length and having an outer surface and an inner surface along said length; a metallic shell disposed about said outer surface of said ceramic insulator, said shell including at least one ground electrode; a center electrode disposed in said ceramic insulator in registry with said inner surface thereof, said center electrode having an upper terminal end and a lower sparking end in opposing relation to said ground electrode with a spark gap defining the space therebetween; and said ceramic insulator including an outer metallic film disposed over said outer surface in electrical contact with said shell, and an inner metallic film disposed over said inner surface in electrical contact with said center electrode, said inner and outer metallic films electrically separated from one another by said ceramic insulator and operative to store a charge of electrical energy therebetween in response to an electrical potential between said center electrode and said shell and wherein said inner and outer metallic films extend over only a portion of said length of said ceramic insulator and, wherein said inner and outer metallic films are coextensive in length.