Patent ID: 6794803
Filing Date: 2004-09-21
Classification: H01T

Abstract:
A spark plug for an internal combustion engine comprising:an insulator; a center electrode fixed to a leg portion of said insulator which is exposed to a combustion chamber of an internal combustion engine; a metal housing firmly surrounding an outer surface of said insulator; and a ground electrode fixed to an end of said metal housing so as to form a spark discharge gap between said center electrode and said ground electrode, wherein at least one of said center electrode and said ground electrode is a Ni-base alloy containing, in weight percentage, 0.5Ëœ2.5% Si, 0.1Ëœ1.2% Mn, 3.2Ëœ5.0% Al, 0.9Ëœ2.8% Cr, 0.001Ëœ0.025% C in addition to Ni and unavoidable impurities, and a value S/V is in a range from 1.7 mmâˆ’1 to 3.9 mmâˆ’1 when â€˜Sâ€™ represents a surface area of said ground electrode and â€˜Vâ€™ represents a volume of said ground electrode.