Working fluid cooling control system for construction machine

a A working fluid cooling control system has a controller that receives inputs signals from a traveling motor speed pickup , a pressure sensor , a signal receiving line of an option selecting switch and a temperature sensor . The controller performs predetermined arithmetic processing and controls proportional solenoid valves and . The pressures controlled by the solenoid valves are compared with positive control command pressures in shuttle valves and . In this way, in the case of an operation pattern corresponding to a rise in temperature of the working fluid, minimum tilting angles of hydraulic pumps and are increased to increase an average flow rate of the working fluid passing through an oil cooler , thereby increasing an average heat discharge amount and reducing an equilibrium temperature of the working fluid.