Patent ID: 6688262
Filing Date: 2004-02-10
Classification: F01P,F02B,F02M

Abstract:
An engine cooling system which cools an engine by circulating cooling water in a circulation passage and controls a cooling degree of the engine according to an operating condition of the engine, the system including:a flow rate regulating valve for regulating a circulation flow rate of the cooling water, which is selectively opened and closed at a variable opening and closing speed; water temperature detection means for detecting a temperature of the cooling water circulating in the circulation passage; target water temperature calculation means for calculating a target water temperature according to the operating condition of the engine; control region setting means for setting a first temperature range centering on the calculated target water temperature as a non-control region and a second temperature range centering on the target water temperature and being larger than the first temperature range, excluding the non-control region, as a control region; opening and closing speed control means for controlling the opening and closing speed of the flow rate regulating valve according to a deviation of the cooling water temperature from the target water temperature to allow the cooling water temperature, when the detected cooling water temperature is in the set control region, to approach the non-control region; and opening degree holding means for holding the flow rate regulating valve at a current opening degree when the detected cooling water temperature is in the set non-control region.