Automotive fluid control system with pressure balanced solenoid valve

A solenoid exhaust gas recirculation valve, comprising:

• a valve body having a central chamber, an exhaust inlet passage, an outlet passage, and a moveable valve member in said central chamber controlling the flow between said inlet passage and said outlet passage, said valve member including a valve stem and a valve head;
• a solenoid assembly for reciprocating the moveable valve member between an open position and a closed position, wherein in said closed position said valve head contacts a valve seat located at the inlet of said exhaust gas inlet passage, said solenoid assembly including a wound coil, a bobbin in contact with one surface of said wound coil, and a flux tube in contact with a surface of said bobbin;
• the valve member being subjected to exhaust gas in said closed position that produces a force tending to move the moveable poppet away from said closed position, said valve member including an armature attached to and encapsulating a portion thereof;
• an expandable device which produces a force responsive to said exhaust gas pressure for generally equalizing the force tending to move the moveable valve member away from the closed position and maintaining the moveable valve member in said closed position;
• said expandable device including an expandable chamber that is in fluid communication with the exhaust inlet passage when said valve member is closed;
• and
• said valve being configured such that a radial gap exists between said solenoid assembly and said armature for equalizing pressure in the solenoid.

A method of constructing and calibrating a solenoid valve assembly comprising:

• slidably mounting an armature, including a wound coil, and poppet within a housing to form a solenoid subassembly;
• mounting a position sensor within the housing;
• placing the subassembly in a test chamber;
• calibrating the position sensor to sense the position of the poppet by
• (a) energizing the coil to the maximum required poppet stoke and ensuring that the poppet is in a fully open position;
• and
• (b) deenergizing the coil to a no poppet stoke condition and ensuring that the poppet is in a closed position abutting the valve seat;
• and
• attaching the calibrated subassembly to a base valve housing which is configured to mount an engine.

A solenoid operated exhaust gas recirculation valve for an internal combustion engine, comprising:

• a valve housing having a central chamber, an exhaust gas inlet passage having an inlet opening and an outlet passage both of said passages in fluid communication with said central chamber;
• a valve member positioned in and moveable within said central chamber, said valve member having a valve stem and a valve head said valve stem including a passageway having an opening in communication with said exhaust gas inlet passageway;
• a solenoid assembly for reciprocating said moveable valve member between a closed position wherein said valve head engages a valve seat located at said exhaust gas inlet passage into said central chamber and a fully open position wherein said valve head is displaced from said valve seat allowing exhaust gas to flow from said exhaust gas inlet passage into said central chamber;
• said valve member being subjected to an initial pressure in said closed position which produces a force tending to move the moveable valve member away from said closed position;
• an expandable device that produces a force responsive to said initial pressure to produce a force tending to urge said valve head away from the closed position said expandable device further having a pressure exerted thereon by said exhaust gas from said valve stem passageway to counteract the pressure exerted by the exhaust gas on said valve head, whereby at all positions of the valve member between the closed and fully open positions, the pressures acting on the valve member and the expandable device are equal so that the valve member remains in the desired position to allow the appropriate amount of exhaust gas to enter said central chamber;
• and
• a sensor housing attached to said solenoid housing and including a position sensor to monitor the position of said valve member, said position sensor being in communication with an engine controller which controls the movement of said valve member in response to operating conditions of said engine.