Corona ignition device with improved electrical performance

摘要

A corona igniter (20) comprises a central electrode (22) surrounded by an insulator (26), which is surrounded by a conductive component. The conductive component includes a shell (34) and an intermediate part (36) both formed of an electrically conductive material. The intermediate part (36) is typically attached to a lower ledge (52) of the insulator outer surface (50) prior to inserting the insulator (26) into the shell (34). The shell firing end (56) is typically aligned with the lower edge and the intermediate firing end. The conductive inner diameter (Dg) is less than an insulator outer diameter (Dio) directly below the lower ledge (52) such the insulator thickness (ti) increases toward the electrode firing end (40).

主权项

1. A corona igniter for emitting a radio frequency electric field to ionize a fuel-air mixture and provide a corona discharge, comprising:
a central electrode formed of an electrically conductive material for receiving a high radio frequency voltage and emitting the radio frequency electric field; an insulator formed of an electrically insulating material surrounding said central electrode and extending longitudinally along a center axis from an insulator upper end to an insulator nose end; said insulator including an insulator outer surface extending from said insulator upper end to said insulator nose end; said insulator outer surface presenting an insulator outer diameter extending across and perpendicular to said center axis; said insulator including an insulator body region and an insulator nose region; said insulator outer surface including a lower ledge extending outwardly away from and transverse to said center axis between said insulator body region and said insulator nose region; said lower ledge presenting an increase in said insulator outer diameter; a conductive component surrounding at least a portion of said insulator body region such that said insulator nose region extends outwardly of said conductive component; said conductive component including a shell surrounding at least a portion of said insulator body region and extending from a shell upper end to a shell firing end; said shell presenting a shell inner surface facing said center axis and extending along said insulator outer surface from said shell upper end to said shell firing end; said conductive component including an intermediate part formed of an electrically conductive material and surrounding a portion of said insulator body region and extending longitudinally from an intermediate upper end to an intermediate firing end; said intermediate part including an intermediate inner surface facing said center axis and extending longitudinally along said insulator surface said from said intermediate upper end to said intermediate firing end; said intermediate inner surface presenting a conductive inner diameter extending across and perpendicular to said center axis; said conductive inner diameter being less than said insulator outer diameter below said lower ledge of said insulator; and said intermediate firing end engaging said lower ledge of said insulator.