Patent ID: 8853925

Claim:
A high efficiency spark plug comprising, a central electrode imbedded in a high temperature insulator, said insulator having a frusto-conical lower portion extending into a cylindrical cavity located at a lower portion of a metal shell, an annular partition ring mounted in said cylindrical cavity for forming an upper chamber in an upper portion of said cylindrical cavity, a cylindrical sleeve mounted in said cylindrical cavity and located below said annular partition ring, said cylindrical sleeve having an outer diameter equal to the diameter of said cylindrical cavity and a length extending from said annular partition ring to a bottom opening of said cylindrical cavity, said cylindrical sleeve encircling said frusto-conical lower portion of said insulator in a spaced manner, an annular shoulder formed in said cylindrical sleeve, said annular shoulder dividing said cylindrical sleeve into a middle chamber and a lower chamber and having an inner opening with an inner edge located at a predetermined space from a spark tip of said central electrode.