PURPOSE: To improve the reliability of a glow plug having a self-temperatur saturation type rod-like ceramic heater by a method wherein an electrical conductive ceramic resistor is helically wound around the outer circumference of a cylindrical ceramic insulator to construct the heater.
CONSTITUTION: A first and a second helical resistors 21 and 22 composed of electrical conductive ceramic material to be connected to (+) side and (-) side are wound around the outer circumference of an insulation ceramic rod-like insulator 20, and the extremity ends are connected to each other to form a series of resistors and to construct a rod-like ceramic heater 11. This holder 11 is held at the extremity end of the holder (not shown). With this arrangement, it is possible to provide a glow plug having rapid heating characteristic, self- temperature saturation characteristic and improved heat-resistant strength.
MARUTA KENJI
SUWABE HIROHISA
HITACHI METALS LTD