Patent ID: 6199398
Filing Date: 2001-03-13
Classification: F01P,F04D

Abstract:
A vehicle cooling system for cooling water flowing through an engine radiator and refrigerant flowing through an air-conditioning condenser, comprising:a cooling fan for cooling the water flowing through the radiator and the refrigerant flowing through the condenser;an electric motor that has an associated rated input power and that drives the cooling fan; anda controller operative to generate and output control signals having a calculated duty ratio to drive the motor when a temperature of the water is less than or equal to a predetermined temperature, at an input power lower than the rated input power of the motor;the controller being operative to determine a first target duty ratio based on the water temperature, and a second target duty ratio based on the refrigerant pressure, and to control the electric motor at a final duty ratio that is a larger of the first and second target duty ratios; andthe controller increasing the input power above the rated input power by increasing the final duty ratio if the water temperature reaches the predetermined temperature.