Self temperature control type glow plug

摘要

A self-regulating temperature controlled glow plug has a hollow metal holder, a rod-like ceramic heater and a power control heater. The ceramic heater extends from one end of the holder and has embedded therein a first resistor of tungsten alloyed with rhenium or molybdenum. The power control heater includes a second resistor embedded in a dense mass of powdered insulation material filling a tubular metallic sheath. The sheath is positioned in the holder with its central portion held in spaced relationship thereto by a thermally insulating spacer at least one end thereof. The second resistor is made of tungsten, iron or nickel, has a positive temperature coefficient of resistance at least equal to and a heating capacity greater than the first resistor, and is connected in series with the first resistor.