Patent ID: 7973459

Claim:
A spark plug for use in an internal combustion engine, comprising: a shell having an axial bore and a thread diameter (A); an insulator having an axial bore and a nose portion with an axial length (C), said insulator being located within said shell axial bore such that an outer surface of said nose portion is spaced from an inner surface of said shell axial bore by a radial distance (B) and said nose portion extends beyond said shell by a distance (D); a center electrode being at least partially located within said insulator axial bore and having a main shank portion that includes a lower axial end extending out of said insulator axial bore; a noble metal tip having a sparking surface, and; a ground electrode attached to said shell; wherein said noble metal tip is attached to said lower axial end such that said noble metal tip sparking surface is spaced beyond said insulator by a distance (M) and; wherein: 10 mm≦A≦14 mm; 8 mm≦C≦20 mm; 0 mm≦B≦3 mm; 0 mm≦D≦6 mm; and 1.5 mm≦M≦3.5 mm.