| 摘要 |
PROBLEM TO BE SOLVED: To provide a failure diagnosing device of a thermal control system for an internal combustion engine, capable of diagnosing the occurrence of abnormality in a heat accumulator and a heat storage water circulating passage. SOLUTION: An amount of cooling water introduced into a radiator by a cooling water passages 2, 4, a two-temperature switching valve 6, a cooling water passage 7 for controlling low water temperatures, a cooling water passage 8 for controlling high water temperatures, an intake air introducing pipe 9, and a thermostat 11 which attain a cooling water temperature control means, is increased and decreased in response to an intake manifold pressure under the operating condition of the combustion engine 1, and a cooling water temperature is controlled to a high water temperature at the time when a low load is applied and is controlled to a low temperature at the time when a high load is applied. When the cooling water temperature does not reach a prescribed high temperature at the time when the low load is applied, or when it does not reach a prescribed low temperature at the time when the high load is applied, it is determined that certain abnormality occurs in the cooling water temperature control means by an ECU 30 attaining this failure diagnostic means. Thereby, failures in the cooling water passages 2, 4, the two-temperature switching valve 6, the cooling water passage 7 for controlling low water temperatures, the cooling water passage 8 for controlling high water temperatures, the intake air introducing pipe 9, and the thermostat 11 can be diagnosed. COPYRIGHT: (C)2008,JPO&INPIT
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