摘要 |
A glow plug includes a metallic sleeve 1; a cylindrical metallic shell 2, which holds the metallic sleeve 1; a terminal electrode 3, which is attached into the cylindrical metallic shell 2 while being insulated therefrom; a ceramic heating member 4, which is fitted into the metallic sleeve 1; and a glass coating layer 5. In the glow plug, a portion of an ion detection electrode 411 is exposed at the surface of an insulator 44 of the ceramic heating member 4. The exposed portion is coated with a glass coating layer 5, which is formed in such a manner as to extend all around the insulator 44 of the ceramic heating member 4 and has a thickness of 10-200 mum and a softening point of not lower than 600° C.
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