Patent ID: 8429911

Claim:
A control system for a turbocharged internal combustion engine having a fan for directing a cooling air stream at an air-cooled intercooler, wherein the fan comprises a fan rotor driven by a drive unit for generating the cooling air stream, and an actuation unit controls the amount of cooling air as a function of a charge air pressure present at the intercooler, characterized in that: the drive unit comprises a hydraulic motor driven by a pressurized hydraulic fluid stream; and the actuation unit includes a pressure-controlled proportional valve which controls the amount of hydraulic fluid provided to the hydraulic motor, the proportional valve being connected in parallel with the hydraulic motor and operates as a bypass valve, the proportional valve having a valve spool which is movable against a resilient member into an open position dependent on the charge air pressure present at a control input of the proportional valve so that the amount of bypassed hydraulic fluid is reduced with increasing charge air pressure.