Patent ID: 8839753

Claim:
A corona igniter for providing a corona discharge, comprising: a central electrode formed of an electrically conductive material for receiving a high radio frequency voltage and emitting a radio frequency electric field to ionize a fuel-air mixture and provide a corona discharge, said central electrode extending from an electrode terminal end for receiving the high radio frequency voltage to an electrode firing end for emitting the radio frequency electric field, said central electrode extending along an electrode center axis and having an electrode surface facing away from said electrode center axis, an insulator formed of an electrically insulating material disposed around said central electrode and extending longitudinally from an insulator upper end past said electrode terminal end to an insulator nose end, said insulator including a plurality of regions between said insulator upper end and said insulator nose end, said insulator presenting an insulator inner surface facing said electrode surface and an oppositely facing insulator outer surface extending between said insulator ends, said insulator inner surface being spaced from at least a portion of said electrode surface to present an electrode gap therebetween, a shell formed of an electrically conductive metal material disposed around said insulator and extending longitudinally from a shell upper end to a shell lower end, said shell presenting a shell inner surface facing said insulator outer surface and extending between said shell ends, said shell inner surface being spaced from at least a portion of said insulator outer surface to present a shell gap therebetween, an electrically conductive coating disposed along at least one of said gaps on said insulator surface, said electrically conductive coating on said insulator surface being spaced radially from said facing surface across said gap, said electrically conductive coating including a plurality of materials, and wherein the material of said electrically conductive coating along one of said regions of said insulator is different from the material of said electrically conductive coating along another one of said regions of said insulator.