| 摘要 |
A ceramic insulator (17) containing a substantial proportion of silicon nitride is disposed annularly within the shell (13) of the igniter so that spark discharge occurs along a surface of the silicon nitride insulator (17) adjacent the spark gap between a center electrode (14) and a ground electrode (18). An igniter having such a silicon nitride insulator is particularly adapted for service under conditions of severe thermal, mechanical, and electrical stress, in an engine having a high voltage, (e.g., 10,000 volts or more), high energy (e.g., up to 20 joules) ignition system. Use of silicon nitride as an insulating material in such igniters eliminates health hazards associated with toxic beryllium oxide insulators previously used, while producing an insulating surface far more durable than one made of alumina. <IMAGE> |
