| 摘要 |
A valve assembly comprises a chamber (26, Fig 2) within a housing (22, 24 Fig 1) into which housing connects a radiator port 32 extending from a radiator into the end wall 28 of the chamber, a bypass port 38 extending between an outlet from the engine and the chamber, and an engine port 36 extending between the chamber and the engine inlet. A main valve 40 is slidably received within the chamber for movement in and out of engagement with the end wall 28 of the chamber in communication with the radiator port. A secondary valve 50 is slidably received within the chamber for movement with the main valve in and out of engagement with the end wall 28 for opening and closing fluid flow between the bypass port and the chamber. A linear actuator is coupled between the secondary valve 50 and a central control for opening and closing the main and secondary valves in response to changes in the fluid temperature within a preselected temperature range. Preferably the valve assembly also includes a failsafe mechanism in the form of a wax motor (90, Fig 2) disposed between the radiator port and the main valve, the wax motor expanding if the drive assembly fails in order to continue regulating the transfer of coolant between the radiator and engine. The failsafe wax motor may be secured within a central cavity of the main valve 40 at one end, where the other end 92 engages with a locator port (96, Fig 6) formed in the radiator port.
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