摘要 |
In a malfunction detecting system of an engine cooling apparatus constituted as a radiator having a thermostat that opens/closes a communicating passage between the engine and the radiator, estimated coolant temperature is calculated using a thermal load parameter correlated to rise in the coolant temperature after engine starting, whilst an engine standing time period is detected. Then, the detected engine standing time period is compared with a predetermined value and based on a result of comparison, one of preset threshold values including a malfunction discrimination threshold value and a malfunction discrimination execute threshold value is selected. The selected threshold value is then compared with the estimated coolant temperature or a difference between the estimated coolant temperature and the detected coolant temperature, and it is discriminated that the cooling apparatus has malfunctioned, when the estimated coolant temperature or the difference exceeds the malfunction discrimination threshold value. With this, the malfunction can be detected with high accuracy.
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