| 摘要 |
PROBLEM TO BE SOLVED: To suppress problems caused by fluctuation (variation) of a radiator flow channel closing position of a flow rate control valve for adjusting a cooling water flow rate of a radiator flow channel and the like.SOLUTION: Cooling water is circulated to a radiator flow channel 16, and lowering of outlet water temperature and inlet water temperature of an engine 11 is started, when a valve rotation angle of a flow rate control valve 15 is over a radiator flow channel closing position in changing the valve rotation angle of the flow rate control valve 15 to an opening direction of the radiator flow channel 16 from a state that the radiator flow channel 16 is closed. By taking a note of such a characteristic, the valve rotation angle of the flow rate control valve 15 just before the start of the lowering of the outlet water temperature detected by an outlet water temperature sensor 22 (or inlet water temperature detected by inlet water temperature sensor 23) in changing the valve in the opening direction of the radiator flow channel 16 from the state that the radiator flow channel 16 is closed, is learned as the radiator flow channel closing position. |
