Ignition plug and method of manufacture

A method of sealing a multi-part electrode assembly of an igniter plug within a passage of a surrounding insulator to provide a fluid-tight seal there between, said method including:

• providing a pair of sealing shoulders on said insulator within said passage in spaced relation to axially opposite ends of said insulator;
• disposing a pair of sealing washers against said sealing shoulders of said insulator;
• disposing an expansion sleeve of the multi-part electrode assembly about a first electrode of the assembly and extending said sleeve and said first electrode into said passage from one end thereof such that an end sealing surface of said expansion sleeve confronts one of said sealing washers;
• disposing a second electrode of the assembly into the passage such that said second electrode confronts the other washer;
• forcing said electrodes axially into confronting engagement with one another placing the washers in axial compression;
• and
• while supporting the confronting electrodes in axial compression, joining the electrodes together by a resistance weld to permanently maintain the washers under axial compression thereby perfecting a fluid-tight seal between the electrode assembly and the insulator.

An igniter construction for igniting combustion gases in an internal combustion engine comprising:

• a tubular insulator having axially opposite ends and a passage therein extending between said ends;
• said insulator having upper and lower sealing shoulders provided within said passage spaced axially inwardly from said ends of said insulator and facing generally axially outwardly toward said ends;
• a multi-part electrode assembly disposed within said passage including an upper electrode having a sealing surface and a lower electrode having a sealing surface;
• a resistance weld joint securing said upper electrode to said lower electrode disposing said sealing surfaces of said electrodes in axially spaced, axially inwardly facing relation adjacent said sealing shoulders of said insulator;
• and
• upper and lower sealing gaskets disposed in constant axial compression between said sealing shoulders of said insulator and said sealing surfaces of said electrode assembly as a result of the joining of said electrodes by said resistance weld joint to provide a gas-tight seal between said electrode assembly and said insulator to prevent the leakage of combustion gases therebetween.