Abstract: A pilot-operated spool valve includes a body defining a bore. A supply port and a load port are in fluid communication with the bore. A spool is disposed in the longitudinal bore, and the spool and the body cooperate to define a command chamber at a first end of the spool, which command chamber is adapted to receive fluid at a command pressure supplied to the body. The spool is movable in the bore to control fluid communication between the supply port and the load port. A pressure space is defined in at least one of the body and the spool between the command chamber and both of the supply port and the load port in all operative positions of the spool. The pressure space is supplied with pressurized fluid such that leakage from the command chamber is minimized or eliminated.

Abstract: A pilot-operated spool valve includes a body defining a bore. A supply port and a load port are in fluid communication with the bore. A spool is disposed in the longitudinal bore, and the spool and the body cooperate to define a command chamber at a first end of the spool, which command chamber is adapted to receive fluid at a command pressure supplied to the body. The spool is movable in the bore to control fluid communication between the supply port and the load port. A pressure space is defined in at least one of the body and the spool between the command chamber and both of the supply port and the load port in all operative positions of the spool. The pressure space is supplied with pressurized fluid such that leakage from the command chamber is minimized or eliminated.

Abstract: A microvalve device includes a body, a valve element supported for movement relative to the body, and an actuator operatively coupled to the valve element for moving the valve element in a normal range of travel. A travel limiting structure operatively cooperates with at least one of the valve element and the actuator to effectively limit the magnitude of movement of the valve element or the actuator outside the normal range of travel to prevent failure of the body, the valve element, or the actuator due to exceeding failure stress limits. A method of forming a microvalve with such a travel limiting structure is also disclosed.

Abstract: A device has been disclosed that may include a spool valve including a body having a first connector and a second connector and a spool movable relative to the body for controlling flow between the first connector and the second connector. The reversible flow control assembly further may include a pilot valve device developing a single pressure command in the form of a fluid at a command pressure. The spool valve may be responsive to the single pressure command developed in said pilot valve device to control flow between the first connector and the second connector without regard to the direction of flow. The majority of axial forces acting on the spool to position the spool relative to the body when fluid is flowing through the valve may be fluid forces.

Abstract: The microvalve device includes a pilot microvalve and a pilot operated spool valve. The pilot microvalve includes a pilot input orifice; a pilot output orifice, at least one of the pilot input orifice and the pilot output orifice having a cross-section flow area that changes as the pilot microvalve is actuated; and a passageway providing fluid communication between the pilot input orifice and the pilot output orifice. The pilot operated spool valve includes a spool having a surface in fluid communication with the passageway; a spool input port; and a spool output port, at least one of the spool input port and the spool output port having a cross-section flow area that changes as the spool is actuated. The spool valve is operable by the pilot microvalve such that a ratio of the cross-sectional flow area of the spool input port to the spool output port will substantially equal to a ratio of the cross-sectional flow area of the pilot input orifice to the pilot output orifice.

Abstract: A spool valve assembly includes a spool that is moveable by differential pressure across the spool.

Abstract: The invention relates to an active chassis stabilization system including a hydraulic pressure supply unit, a hydraulic stabilizer assembly which is associated with a front axle, a hydraulic stabilizer assembly which is associated with a rear axle, and a control unit. The active chassis stabilization system is a two-channel system.

Abstract: A microvalve device is disclosed for controlling fluid flow in a fluid circuit. The microvalve device comprises a body having a bore formed therein. A pilot-operated main valve spool supported by the body is movably disposed in the bore for opening and closing ports formed in the body. A pilot microvalve is operable for controlling movement of the pilot-operated main valve. The pilot microvalve may include a movable valve element that controls the cross-sectional area of two variable orifices in series. When the pilot microvalve is at rest, one orifice is closed and the other is open. Upon actuating the pilot microvalve, the closed orifice may begin to open and the open orifice may begin to close. Pressure between the orifices is used as a command pressure, which is utilized to position the pressure control valve to control load pressure. A method of operating a microvalve device is also disclosed.

Abstract: A microvalve device for controlling the supply of pressurized fluid to a load in a fluid circuit, and having multiple internal fluid conduits for providing pressure feedback.

Abstract: A device has been disclosed that may include a spool valve including a body having a first connector and a second connector and a spool movable relative to the body for controlling flow between the first connector and the second connector. The reversible flow control assembly further may include a pilot valve device developing a single pressure command in the form of a fluid at a command pressure. The spool valve may be responsive to the single pressure command developed in said pilot valve device to control flow between the first connector and the second connector without regard to the direction of flow. The majority of axial forces acting on the spool to position the spool relative to the body when fluid is flowing through the valve may be fluid forces.

Abstract: A MEMS device is disclosed having a single microvalve actuator for controlling multiple microvalves. Exemplary embodiments include a MEMS device including two microvalves formed on a beam positioned by an actuator, the two microvalves controlling separate flow paths between two separate pairs of ports; a device with a two-way pilot operated microvalve and a four-way pilot microvalve for controlling the two-way pilot operated microvalve; a device with two three-way microvalves actuated by a common microvalve actuator; and a two-way microvalve with a moveable microvalve element and a feedback port formed in the moveable element operable to regulate the pressure on an end of the moveable element relative to the movement of the moveable element between the first position and the second position. Also disclosed is a MEMS device including a beam with a plurality of apertures formed therein, resulting in a mass reduction of at least 10 percent.

Abstract: A hydraulic control system for high flow applications in motor vehicles, in particular for active wheel suspensions and active steering arrangements, includes at least one passive high flow valve which is controlled hydraulically by at least one low flow valve.

Abstract: A microvalve device includes a body, a valve element supported for movement relative to the body, and an actuator operatively coupled to the valve element for moving the valve element in a normal range of travel. A travel limiting structure operatively cooperates with at least one of the valve element and the actuator to effectively limit the magnitude of movement of the valve element or the actuator outside the normal range of travel to prevent failure of the body, the valve element, or the actuator due to exceeding failure stress limits. A method of forming a microvalve with such a travel limiting structure is also disclosed.

Abstract: A pilot-control valve assembly for a roll control system for a vehicle defines a pressure control valve assembly and includes a main stage valve and a pilot stage valve. A body of the main stage valve is press fit to a body of the pilot stage valve.

Abstract: A spool valve assembly includes a spool that is moveable by differential pressure across the spool.

Abstract: A microvalve device for controlling the supply of pressurized fluid to a load in a fluid circuit, and having multiple internal fluid conduits for providing pressure feedback.

Abstract: The microvalve device includes a pilot microvalve and a pilot operated spool valve. The pilot microvalve includes a pilot input orifice; a pilot output orifice, at least one of the pilot input orifice and the pilot output orifice having a cross-section flow area that changes as the pilot microvalve is actuated; and a passageway providing fluid communication between the pilot input orifice and the pilot output orifice. The pilot operated spool valve includes a spool having a surface in fluid communication with the passageway; a spool input port; and a spool output port, at least one of the spool input port and the spool output port having a cross-section flow area that changes as the spool is actuated. The spool valve is operable by the pilot microvalve such that a ratio of the cross-sectional flow area of the spool input port to the spool output port will substantially equal to a ratio of the cross-sectional flow area of the pilot input orifice to the pilot output orifice.

Abstract: The invention relates to an active chassis stabilization system including a hydraulic pressure supply unit, a hydraulic stabilizer assembly which is associated with a front axle, a hydraulic stabilizer assembly which is associated with a rear axle, and a control unit. The active chassis stabilization system is a two-channel system.

Abstract: A vehicle Active Roll Control System having a two stage spool valve that provides hydraulic fluid at different pressures to front and rear actuators for varying the torque applied to associated roll bars.

Abstract: A hydraulic control system for high flow applications in motor vehicles, in particular for active wheel suspensions and active steering arrangements, includes at least one passive high flow valve which is controlled hydraulically by at least one low flow valve.