Control means for engine cooling systems

Claim 1

In a vehicle having an internal combustion engine and a cooling system for said engine including means for circulating a coolant through said engine, a radiator operatively connected to said coolant circulating means, a fluid motor driven fan disposed in operative relation with said radiator and an engine driven variable displacement, piston type pump provided with an input shaft, a variable angle yoke mounted on said input shaft, a yoke stroking piston shiftable in a chamber and having an outer end engageable with said variable angle yoke and means for biasing said variable angle yoke against the end portion of said yoke stroking piston, and having a fluid supply line operatively connected to said fluid motor, a means for controlling the operation of said cooling system comprising a first fluid line interconnecting said fluid supply line and said yoke stroking piston chamber of said pump, said first fluid line having a pressure compensating valve operable to open in response to an output pressure of said pump above a first predetermined pressure of said fluid supply line for shifting said stroking piston to vary the angle of said yoke and correspondingly vary the displacement of said pump to provide a pump output pressure corresponding to said first predetermined pressure, a second fluid line intercommunicating said fluid supply line and said stroking piston chamber of said pump, said second fluid line having a pressure compensating valve operable to open in response to a pump output pressure of said valve above a second predetermined pressure for shifting said stroking piston to vary the displacement of said pump and correspondingly provide a pump output pressure corresponding to said second predetermined pressure, and said second fluid line having a cutoff valve normally disposed in a closed condition, operable responsive to a predetermined temperature of said coolant for opening.