Ignitor assembly including arcing reduction features
AssigneeFederal-Mogul Ignition Company
InventorsJames Lykowski, Keith Hampton
Life of this patent
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Abstract
A corona igniter (20) includes a metal shell (32) with a corona reducing lip (38) spaced from an insulator (26) and being free of sharp edges (40) to prevent arcing (42) in a rollover region and concentrate the electrical field at an electrode firing end (48). The corona reducing lip (38) includes lip outer surfaces (88) being round, convex, concave, or curving continuously with smooth transitions (90) therebetween. The corona reducing lip (38) includes lip outer surfaces (88) presenting spherical lip radii (rl) being at least 0.004 inches. The corona igniter (20) also includes shell inner surfaces (104) and insulator outer surfaces (75) facing one another being free of sharp edges (40).
Claims14
A method of forming a corona igniter operative to ionize a mixture of fuel and air of an internal combustion engine comprising the steps of:
- providing a shell extending longitudinally from an upper shell end to a lower shell end;
- disposing an insulator in the shell;
- disposing an electrode in the insulator including an electrode body portion extending longitudinally from an upper electrode terminal end to a lower electrode firing end which projects below said insulator and below said shell;
- disposing a corona enhancing tip on the lower electrode firing end, the corona enhancing tip including a plurality of branches;
- and
- forming a corona reducing lip at the upper shell end, the corona reducing lip including a lip surface having a plurality of spherical lip radii, and each spherical lip radii of the lip surface of the corona reducing lip being at least 0.004 inches.
Dependencies are inferred from the claim text.