Patent attributes
When a temperature of cooling water detected by a water temperature sensor is, for instance, higher than, or equal to degrees, and is smaller than degrees, an abnormal state judging unit judges that an engine is under semiwarming-up condition, and then forcibly drives an electric motor fan so as to forcibly cool cooling water contained in a radiator. After the abnormal state judging unit has forcibly driven the electric motor fan, this abnormal state judging unit calculates a difference between the cooling water temperature detected by the water temperature sensor and a predicted cooling water temperature. When the calculated temperature difference is smaller than a predetermined abnormal state judging value, the abnormal state judging unit judges that a thermostat provided in a cooling water circulating path is brought into an abnormal valve opening state.
