Patent ID: 8646264

Claim:
A cooling system comprising: a heat radiator; a fan for forcing cooling fluid across said heat radiator; a hydraulically driven motor for driving said fan; a hydraulic pump having a working cycle and configured to be driven by an off-center cam arrangement, and the hydraulic pump configured to provide pressurized hydraulic fluid to power said motor during said working cycle, said pump having at least one outlet valve comprising a normally closed pressure opened valve and at least one inlet valve comprising a normally closed solenoid opened valve; a pump shaft speed sensor for indicating a speed of said pump shaft; one or more sensors for sensing one or more parameters to alter a rate of cooling induced by the fan; and a hydraulic fluid delivery controller, responsive to said pump shaft speed sensor indication and operably connected to said at least one inlet valve, for initiating control of said at least one inlet valve on a stroke by stroke basis thereby to supply fluid in discrete volumes to drive said motor and for altering a frequency of the supply of the discrete volumes fluid to said motor dependent upon a desired motor speed and the speed of the pump shaft.