Glow plug arranged for measuring the ionization current of an engine, and method for manufacturing the same

摘要

A glow plug (10) that includes a metal tubular body (12), a metal sheath (24) carried by the tubular body, a heating resistor (33) located inside the sheath, first and second electrical terminals (30,32), and a layer (36) of insulating material applied on a portion of the outer surface of the sheath. The first terminal (30) is electrically connected to the heating resistor (33) and the second terminal (32) is electrically connected to the sheath (24). The layer (36) of insulating material is located on the sheath (24) between the sheath and tubular body (12) to thereby electrically insulate the metal sheath from the metal tubular body. The layer (36) of insulating material can be applied by plasma deposition which enables the sheath (24) to be attached to the tubular body (12) by an interference fit of the sheath within a cavity (16) in the tubular portion. Also disclosed is a method of fabricating the glow plug (10).