Patent ID: 7082903

Claim:
A temperature-responsive control valve for use in an engine cooling system, the engine cooling system having a primary cooling circuit having a pump to circulate liquid coolant through an engine, the coolant being returned to the pump via a radiator and a bypass arranged in parallel, the control valve controlling flow as between said radiator and the bypass, said control valve comprising: a housing defining: a first or hot inlet which in use is connected to the bypass; a second or cold inlet which in use is connected to the radiator; and a valve chamber; a first valve member disposed in said valve chamber movable between first and second limits to control the flow of coolant from said hot inlet to said outlet; a second valve member disposed in said valve chamber movable between first and second limits to control coolant flow from said cold inlet to said outlet; and a temperature-responsive actuator to move said first and second valve members; wherein the control valve is operable: to substantially prevent coolant flow from said hot and cold inlets to said outlet when a temperature of the coolant sensed by said temperature-responsive actuator is below a first predetermined temperature; to permit coolant flow only from said hot inlet to said outlet when said sensed temperature is between said first predetermined temperature and a second higher predetermined temperature; to permit coolant flow from both of said inlets to said outlet when said sensed temperature is between said second predetermined temperature and a third higher predetermined temperature; and to permit coolant flow only from said cold inlet to said outlet when said sensed temperature exceeds said third predetermined temperature.