Abstract: Direct sensing of rough road conditions are used to modify operation of a wheel slip control system. At least one suspension sensor (139) senses an operating parameter of the suspension system. A road surface classifier is responsive to the suspension sensor (139) for generating a road surface signal representing a roughness of a road surface over which the vehicle travels. A braking system includes a wheel speed sensor and a brake actuator. An active braking control detector wheel slip in response to the wheel speed sensor (108) during at least one of braking or accelerating of the vehicle and modulates the brake actuator in response to the detected wheel slip. The active braking control is responsive to the road surface signal for modifying modulation f the brake actuator as a function of the road surface signal.

Abstract: A manifold for distributing a fluid. The manifold can be used to distribute a fluid to and from a microvalve. The manifold includes a first plate having a groove formed in one face thereof. A second plate is fixed to the first plate so as to cover the groove to form a fluid passage through the groove. First and second bores are formed through at least one of the first plate and the second plate to form an inlet and an outlet, respectively, of the fluid passage. According to a method of manufacturing, etching the first plate forms the groove. Preferably, an etching process also forms the first and second bores. Also, preferably, the first plate is one of a plurality of plates formed from a single sheet of material. Preferably the sheet of material is a standard sized sheet with locating indicia enabling assembly of the manifold with standard pick and place equipment.

Abstract: A test apparatus which having a window comparitor circuit which includes a coil. The coil is placed over a solenoid valve cartridge and switched on and off. The on time of the window comparitor circuit is measured to verify correct assembly of the solenoid valve cartridge.

Abstract: The present invention provides a proportional microvalve having a first, second and third layer, and having high aspect ratio geometries. The first layer defines a cavity with inlet and outlet ports. The second layer, doped to have a low resistively and bonded between the first and third layers, defines a cavity having a flow area to permit fluid flow between the inlet and outlet ports. The second layer further defines an actuatable displaceable member, and one or more thermal actuators for actuating the displaceable member to a position between and including an open and a closed position to permit or occlude fluid flow. The third layer provides one wall of the cavity and provides electrical contacts for electrically heating the thermally expandable actuators. The thermal actuators and the displaceable member have high aspect ratios and are formed by deep reactive ion etching such that they are displaceable in the plane of the second layer while being very stiff out of the plane.

Abstract: A piston pump comprises cylinder attached within a cavity of a pump housing. An outlet check valve seat is defined about an outlet of the cylinder. A piston is slidably received in a bore of the cylinder and has a first passageway formed therein. A cylinder head encloses the outlet of the cylinder and defines a second passageway therein. The first passageway has an inlet in fluid communication with the cavity of the pump housing, and an outlet in fluid communication with a pumping chamber defined in the pump housing. A first spring retains the piston to the cylinder. A first check valve member is a ball retained near a valve seat formed in the first passageway of the piston by a disk spring, and allows fluid to flow only from the inlet to the outlet of the piston.

Abstract: Hydraulic or electro-hydraulic braking systems which include at least one wheel braking device and micro-machined technology, such as microvalves, are described herein. The use of the microvalves helps to eliminate audible noise produced in the hydraulic systems as well as allows for reduced package size of the system. In particular, many of the braking systems described herein have Anti-lock Braking System (ABS) capabilities, and as such employ apply microvalves, dump microvalves and changeover microvalves. The microvalves may be digitally or proportionally controlled for selectively controlling the pressure supplied to the wheel brake cylinders.

Abstract: Disclosed is a microvalve suitable for use in high pressure applications such as refriigeration. The microvalve has a displaceable member that slides across an inlet port, thereby creating an orifice. A pressure-equalizing contour is positioned beneath the displaceable member and is in fluid contact with the inlet port. The pressure on the displaceable member from the inlet port is equalized by the pressure from the pressure-equalizing contour. Consequently, the microvalve can be configured with its inlet port and outlet port on opposite sides of the microvalve. Pressures in the x and y direction are also equalized because of recesses that permit fluid from the inlet to contact all faces of the displaceable member.

Abstract: A method and apparatus for information embedding modulation and information extraction demodulation are presented which use analysis and/or synthesis filter banks. Spectral control of the form of the composite signals arising from the embedding of digital embedded information signals into digital host signals is provided. Various implementations, including cable head-end and user-end systems using such modulators are presented. One aspect of the modulator allows for reduced noise spillover into adjacent communication channels in a multi-channel communication system. In some implementations the analysis and the synthesis filter banks form perfect reconstruction filter sets. In other implementations, block transforms are used as the filter banks.

Abstract: A fluid control valve assembly including a microvalve for controlling fluid flow in a fluid circuit having a relatively high fluid pressure requirement, such as vehicular brake system, is fixed to an associated fluid distributing substrate with a high-pressure fluid connection. The fluid distributing substrate is provided with fluid passages adapted for connection to a fluid source to provide communication between the fluid source and the microvalve device. The connection between the microvalve and the fluid distributing substrate may include metallic connections forming electrical current paths between the microvalve and the substrate; solder joints forming part of the pressure boundary of the high-pressure fluid connection; underfill formed of elastomeric or other adhesive; and bonding between the substrate and the microvalves in only selected portions of the surface of the microvalve.

Abstract: The present invention provides a proportional microvalve having a first, second and third layer, and having high aspect ratio geometries. The first layer defines a cavity with inlet and outlet ports. The second layer, doped to have a low resistivity and bonded between the first and third layers, defines a cavity having a flow area to permit fluid flow between the inlet and outlet ports. The second layer further defines an actuatable displaceable member, and one or more thermal actuators for actuating the displaceable member to a position between and including an open and a closed position to permit or occlude fluid flow. The third layer provides one wall of the cavity and provides electrical contacts for electrically heating the thermally expandable actuators. The thermal actuators and the displaceable member have high aspect ratios and are formed by deep reactive ion etching such that they are displaceable in the plane of the second layer while being very stiff out of the plane.

Abstract: A vehicle hydraulic system is disclosed comprising a hydraulic fluid reservoir; a pressure force supplying pressurized hydraulic fluid to a discharge header; a fluid conduit between the discharge header and the reservoir; a back pressure valve operative in the fluid conduit to maintain a desired pressure in the discharge header; and a vehicle braking system having a hydraulically operated boost piston assembly for supplementing a force exerted by a vehicle operator to operate brakes of the vehicle braking system. The system further includes a boost pressure control valve responsive to an input from the vehicle operator for selectively directing pressured hydraulic fluid from the discharge header to the boost piston assembly and venting hydraulic fluid from the boost piston assembly to the reservoir.

Abstract: A vehicle hydraulic system is disclosed comprising a pressure source supplying pressurized hydraulic fluid to a discharge header, a vehicle braking system having a hydraulically operated boost piston assembly for supplementing a force exerted by a vehicle operator to operate brakes of the vehicle braking system; a boost pressure control valve for selectively directing pressurized hydraulic fluid from the discharge header to boost piston assembly and venting hydraulic fluid from the boost piston assembly; and a sensor for receiving an input from a vehicle operator and supplying an electrical signal to the boost pressure control valve to control the operation thereof.

Abstract: Hydraulic or electro-hydraulic braking systems which include at least one wheel braking device and micro-machined technology, such as microvalves, are described herein. The use of the microvalves helps to eliminate audible noise produced in the hydraulic systems as well as allows for reduced package size of the system. In particular, many of the braking systems described herein have Anti-lock Braking System (ABS) capabilities, and as such employ apply microvalves, dump microvalves and changeover microvalves. The microvalves may be digitally or proportionally controlled for selectively controlling the pressure supplied to the wheel brake cylinders.

Abstract: A method of controlling the operation of an electrohydraulic brake booster to achieve a desired pedal feel. The method includes sensing brake pedal movement from a fully retracted rest position before a significant resistance to travel of the brake pedal is developed. The method further includes generating a command pulse that results in application of pressurized hydraulic fluid to the boost piston assembly sufficient to overcome preloaded spring forces and seal friction in the boost piston assembly that would otherwise tend to resist further brake pedal travel. The method further includes providing a control signal override when a brake pedal "bounce" condition is detected to avoid undesired vehicle braking. A brake pedal bounce condition may occur if the brake pedal is released suddenly so that the brake pedal returns to the fully retracted rest position rapidly enough to bounce off of a mechanical stop at that position and move in the brake apply direction.

Abstract: A brake booster for a brake system of a vehicle, wherein the brake booster is in fluid communication with a source of pressurized fluid. The brake booster includes a housing having a bore formed therein and a conduit formed therein being in fluid communication with the bore and the source of pressurized fluid. The brake booster includes first and second pistons slidably disposed within the bore of the housing. The bore, the first piston, and the second piston define a fluid chamber in fluid communication with the conduit formed in the housing, wherein the volume of the chamber is defined by the position of the first piston relative to the second piston. The brake booster further includes a valve selectively preventing fluid flow in a direction from the chamber to the source of pressurized fluid via the conduit.

Abstract: An improvement in a mounting system for mounting a thrust generating engine to an aircraft wherein force generating means are operatively connected to a casing surrounding and supporting the engine for applying a variable force to the casing for maintaining the engine in a predetermined position relative to said aircraft.