Igniter plug particularly for use in very low temperature liquid fuel

摘要

An igniter plug is provided with a metallic shell, an insulator located within the metallic shell and a center electrode within the inner bore of the insulator. The front end of the electrode extends outside beyond the front end of the insulator. The insulator is made from sintered ceramic material which includes silicon nitride in an amount in the range 85-99% by weight. The front end of the insulator is axially retracted interiorally from the front end of the metallic shell from about 1.5 to about 2.5 mm.