BorgWarner Inc.
Valve assembly and system including same for controlling fluid flow to and from a clutch

Abstract:

A system for controlling fluid flow to and from a clutch includes a motor, a pump, and a valve assembly, which includes a housing defining an interior and a first orifice operably coupled to the pump, a second orifice operably coupled to the clutch, and a third orifice fluidly coupled to one of said first and second orifices. A piston is operably coupled to the motor, is disposed within the interior, is movable between a first position for allowing a fluid flow between the first and second orifices, a second position for obstructing the fluid flow between the first and second orifices, and a third position for limiting the fluid flow between the first and second orifices. A biasing member is coupled to the piston, and biases the piston toward the first position when the motor is off. When the pump is activated and a pressure proximate the first orifice is equal to a pressure proximate the second orifice, the motor is energized and moves the piston to the second position. When pressure proximate the second orifice exceeds a predetermined threshold pressure, the energized motor is turned off and the biasing member moves the piston to the first position, or power in the energized motor is reduced and the piston moves to the third position.