| 摘要 |
2063435 9118245 PCTABS00008 The service life of conventional glow plugs is extremely short when they are continuously energized at an elevated temperature during engine operation in order to assist ignition of non-autoignitable fuels. Such glow plugs typically fail due to thermal stresses and/or oxidation and corrosion. Herein is disclosed an improved heating element assembly (10, 10', 10'') adapted for incorporation in a glow plug (12). The heating element assembly (10, 10', 10'') includes a monolithic sheath (24) having a relatively-thin and generally annular wall (30) defining a blind bore (34). The heating element assembly (10, 10', 10'') further includes a heating device (26, 26', 26'') positioned in the blind bore (34) and adapted to emit heat, and a heat transfer device (28) adapted to transfer heat from the heating means (26, 26', 26'') to the sheath (24). The heating device (26, 26', 26'') is protected by the sheath (24) formed of a preselected material which is chosen and configured so as to minimize failure of the heating element assembly (10, 10', 10'') caused by thermal stresses, oxidation and/or corrosion.
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