| 摘要 |
A system is provided wherein temperature conduction upon the changing of temperature of cooling water in an engine is forecast, and achievement of a cooling control system with an improved life and reliability and a reduction in cost results therefrom. A butterfly valve for regulating the flow of cooling water is rotatably controlled through a DC motor, a clutch mechanism 33 and a deceleration mechanism 33 so as to cool the engine at an appropriate temperature. A PWM signal generated by a quick response control and a PI control on the basis of at least load information of the engine is supplied to the DC motor 31 from ECU, whereby the butterfly valve 34b is rotatably controlled. A butterfly valve adjusting the flow of cooling water is controlled with the degree of valve opening by a thermo-element enclosing a thermal expansive body such as wax. A PTC heater is placed in proximity with the thermo-element, and supplied with current for heating on the basis of operation parameters of an engine to control the cooling efficiency of the cooling water. As a consequence, the characteristics of the butterfly valve which is capable of extremely decreasing rotation torque for adjusting the flow of the cooling water is used, so that mechanical stress can be reduced, resulting in improved life and reliability.
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