Patent ID: 8428817

Claim:
A vehicle cooling fan control system, comprising: a cooling fan including a fan motor and configured to cool a condenser by an air blowing from a rotation of said fan motor, said condenser being configured for cooling down a refrigerant delivered from a compressor in a refrigeration cycle of an air conditioner; an evaporator in a refrigeration cycle of the air conditioner; a temperature sensor for detecting an actual outlet temperature of said evaporator; a setting section for setting a target outlet temperature of said evaporator; a compressor control section for controlling a discharge pressure of said compressor via a compressor ON request signal so that the actual outlet temperature of said evaporator as detected by said temperature sensor approaches the target outlet temperature set by said setting section; and a fan motor control section for receiving the compressor ON request signal from the compressor control section to control said fan motor of said cooling fan so as to maintain a cooling performance of said condenser, said fan motor control section being configured to: determine whether or not at least one of a vehicle speed and an engine rotation speed is lower than a predetermined speed; decide whether or not the air conditioner is in operation; start counting a predetermined time upon satisfaction of a stoppage condition for the air conditioner and upon determining that at least one of the vehicle speed and the engine rotation speed is lower than the predetermined speed; control said fan motor to keep operating at a predetermined rotation speed while receiving the compressor ON request signal even when the stoppage condition is satisfied, and to stop operating when the predetermined time has elapsed; and when the stoppage condition is satisfied, change a difference between the set target outlet temperature and the actual outlet temperature of said evaporator detected by said temperature sensor to a zero value without canceling the compressor ON request signal so as to make the compressor stop or operate at a minimal level.