| 摘要 |
The present invention relates to a failure judgment device for a thermostat (16) that is arranged in a circulation passage (13) of cooling water (12) for an engine (1). The failure judgment device comprises: a water temperature sensor (18) which can detect the temperature of the cooling water (12) that has passed through the engine (1); and a control unit (19) which inputs a detection signal (18a) from the water temperature sensor (18) to monitor the increase in temperature of the cooling water (12) at the time of the initiation of cooling, calculates a predicted water temperature of the engine (1) from the engine start, and judges that the thermostat (16) is failed when the temperature of the cooling water (12) at the time at which the predicted water temperature reaches the valve opening temperature of the thermostat (16) is lower than a threshold value. |
