Patent ID: 7893604

Claim:
A spark plug for an internal combustion engine comprising: a hollow cylindrical metal housing which has an open top end portion to be exposed to a combustion chamber of an internal combustion engine; a ground electrode joined to said metal housing; a center electrode disposed in said metal housing to define a spark gap between itself and said ground electrode; a porcelain insulator disposed in said metal housing to electrically insulate between said metal housing and said center electrode; and a stream shaper geometrically formed on the top end portion of said metal housing to shape tumble vortexes of air-fuel mixture into vortex streams oriented toward a central portion of the combustion chamber, wherein the open top end portion of the housing has an annular top surface at an axial end of the open top end portion, said stream shaper being formed on a portion of the top end portion of said metal housing which is located inwardly of the annular top surface in a radial direction of said metal housing, the annular top surface extending continuously in a circumferential direction of said metal housing.