System Description

DESCRIPTION

In this system, the cooling fan ECU controls the hydraulic pressure acting on the hydraulic motor, thus controlling the speed of the cooling fan steplessly in response to the condition of the engine and air conditioning.





OPERATION
The hydraulic pump is driven by a drive belt. The solenoid valve adjusts the volume of oil sent from the hydraulic pump to the hydraulic motor which drives the fan directly, thereby controlling the fan speed.

Oil which has passed through the hydraulic motor is cooled by the oil cooler before returning to the reservoir tank.

The solenoid valve is controlled by the cooling fan ECU in accordance with the engine rpm, water temp. and A/C signals.