Patent ID: 6215233
Filing Date: 2001-04-10
Classification: H01T

Abstract:
A spark plug comprising, in combination; a tapered insulator having a tip end and a diameter that decreases toward said tip end;a center electrode held by said insulator;a metallic shell having a terraced interior portion, an open end and a tip end, said metallic shell fixedly supporting said tapered insulator such that a portion of said tip end of said tapered insulator projects from said metallic shell and said insulator abuts said terraced portion of said metallic shell;a ground electrode provided at said tip end of said metallic shell, said center electrode and said ground electrode defining a main gap;an inwardly projecting ledge formed at said open end of said metallic shell; andsaid metallic shell having a tapered inner wall surface extending from said terraced portion toward said inwardly projecting ledge such that the diameter of said tapered inner wall surface decreases toward said inwardly projecting ledge.