Fuel injection spark plug

A fuel injection spark plug assembly comprising, an elongated insulating body having an electrode extending axially therethrough and projecting from each end of the insulating body;

• a circumferential shoulder formed on said insulating body in proximity to one end thereof, said end of the insulating body being tapered from the shoulder to adjacent the projecting end of said electrode;
• a metallic shell having a hollow threaded end for securing said spark plug in a combustion chamber opening, said shell adapted to receive and envelop the shoulder, a portion of the insulating body adjacent the shoulder and the tapered end of the insulating body, said metallic shell defining an annular space between the metallic shell and said insulating body adjacent the shoulder on a side of the shoulder away from the tapered end of the insulating body;
• a plurality of substantially longitudinal equispaced slots formed across the shoulder defining with the metallic shell passages to permit a gaseous fuel to flow from said annular space along the tapered end of the insulating body through the hollow threaded end of the shell;
• said metallic shell having a peripheral plenum in communication in the annular space for supplying gaseous fuel to the annular space;
• a conduit for supplying a gaseous fuel under pressure to said plenum;
• and valve means provided in said conduit remote from said spark plug for permitting the flow of a gaseous fuel towards said spark plug while preventing the flow of gaseous combustion products in a direction away from the spark plug.