Patent ID: 6858975
Filing Date: 2005-02-22
Classification: H01T

Abstract:
1. A spark plug for an internal combustion engine comprising, in combination, an insulator having an axial bore for holding a terminal electrode at its rear end portion and a center electrode at its front end portion and an intermediate body portion having a surface flanked by a first transition region and a larger body portion proximate said rear end portion and a second transition region and a smaller leg portion proximate said front end portion, a metallic shell having a larger portion for receiving said larger body portion of said insulator and a smaller intermediate hole portion having a surface which integrally secures said intermediate body portion of said insulator, and an oil film on at least one of: a) said surface of said intermediate body portion of said insulator united with said metallic shell; and b) said surface of said intermediate hole portion of said metallic shell that faces said intermediate body portion of said insulator.