Patent ID: 6834661
Filing Date: 2004-12-28
Classification: F15B,F16K,Y10T

Abstract:
A control valve system comprising:a housing having an inlet port, a first output port, a second output port, and a valve chamber; a primary spool having first and second longitudinal ends with respective working surface areas being substantially equal, wherein said primary spool is slidable in said valve chamber to a first position where fluid communication is established between said inlet port and said first output port, a second position where fluid communication is established between said inlet port and said second output port, and an intermediate third position where fluid communication is generally prevented between said inlet port and both of said first and second output ports; a secondary spool independently slidable in said valve chamber, said secondary spool having a first end for abutting against said second end of said primary spool and having a second end with a working surface area greater than either of said working surface areas of said primary spool; a solenoid valve assembly coupled in fluid communication with said inlet port, wherein said solenoid valve assembly is positionable in a first position for providing fluid communication from said inlet port to said second end of said secondary spool to move said primary spool from said first position to said second position, and wherein said solenoid valve assembly is positionable in a second position to isolate said inlet port from said second end of said secondary spool; a biaser providing a biasing force to said primary spool in a direction toward said first position, said biasing force having a predetermined magnitude when said primary spool is in said third position; and a first fluid passage through said primary spool providing fluid communication between said first output port and said second end of said primary spool for displacing said primary spool relative to said secondary spool in an energy saving mode when said solenoid valve is in said second position, thereby regulating a pressure at said first output relative to said predetermined magnitude of said biasing force.