Patent ID: 8047450

Claim:
A temperature responsive control valve for use in an engine cooling system in which a pump circulates liquid coolant to an engine, coolant from the engine is returned to the pump through a radiator and a bypass arranged in parallel and the control valve controls flow as between the radiator and the bypass, the control valve comprising: a housing defining a hot inlet which in use is connected to the bypass, a cold inlet which in use is connected to the radiator, an outlet which in use is connected to the pump, a first valve member to control the flow of coolant from the hot inlet to the outlet, a second valve member to control coolant flow from the cold inlet to the outlet and a temperature responsive actuator to move the first and second valve members, wherein the control valve is operable to substantially prevent coolant flow from the hot and cold inlets to the outlet when the temperature of the coolant sensed by the temperature responsive actuator is below a first predetermined temperature, to permit coolant flow only from the hot inlet to the outlet when the sensed temperature is between the first predetermined temperature and a second higher predetermined temperature and to permit coolant flow from both of the inlets to the outlet when the sensed temperature is above the second temperature, wherein the second valve member is spring biased onto a seat in the housing to prevent coolant flow from the cold inlet to the outlet when the temperature of the coolant sensed by the temperature responsive actuator is below the second predetermined temperature and is lifted from the seat by the first valve member when the temperature of the coolant sensed by the temperature responsive actuator exceeds the second predetermined temperature.