SURFACE-DISCHARGE SPARK PLUG FOR CAPACITIVE IGNITION SYSTEM Russian patent published in 2007 - IPC H01T13/20 F02C7/266 

FIELD: aircraft engine manufacture; devices for kindling gas-turbine engine combustion chambers.

SUBSTANCE: proposed surface-discharge spark plug for low-voltage capacitive ignition system has spark-producing insulator, central electrode with contact, body whose butt-end part forms side electrode, additional insulator, and contact between body side electrode and butt-end surface of spark-producing insulator installed in body. Spark-producing insulator is made of high-alumina ceramics of following composition, %: Al₂O₃ (aluminum oxide), >94.0; SiO₂ (silicon dioxide, 4.3; CaO (calcium oxide), 1.63. Central electrode with contact is disposed in internal duct of spark-producing insulator. Side and central electrodes form annular spark gap on butt-end surface of spark-producing insulator. Additional insulator is disposed in annular gap between spark-producing insulator and body on side opposing working end of spark-gap plug. At least one of electrode contacts is made of enhanced heat resistance alloy that has in its composition 80% of silver and 20% of palladium. Surface layer of spark-producing insulator provided in vicinity of spark gap and where it is mating electrode contacts has in its composition Al₂SiO₃, Ag, CuO, Mn₃O₄, CuMn₂O_4, and CuAl₂O.

EFFECT: enhanced service life and heat resistance of spark plug.

1 cl, 1 dwg