Glow plug for internal combustion engines - using resistance heater coil packed in insulating powder with good thermal conductivity

摘要

Glow plug for internal combustion engines, using a metal housing with a longitudinal bore contg. a scale-resistant glow tube, in which a resistance heating element made of metal with a high m.pt. is embedded in a compacted powde. The powder is a hard material which is a good heat conductor but has a specific electrical resistance (SER) of min. 108 ohm.mm2/m. Metal is pref. Mo, Nb, Ta, or W; and powder is Pref. AlN, BN, SiC, or B4C. The plug only requires a short preheating time of below 15 secs, and contains no toxic BeO which is sometimes used as a packing in conventional glow plugs.