Abstract: A coaxial transmission line system includes a coaxial transmission line having a center conductor and an outer conductor, and an rf generator. A stub antenna is coupled to the generator, and extends radially into the transmission line between the outer and center conductors for capacitively coupling rf energy from the generator to the center conductor. Input impedance of the coaxial transmission line is matched to the impedance of the antenna and generator by means of a pair of tuning screws that extend radially into the transmission line between the outer and center conductors adjacent to the antenna. The tuning screws are adjustably positionable radially of the center conductor and are spaced from each other lengthwise of the transmission line.

Abstract: A bidirectional check valve that includes a housing having an internal cavity with fluid openings at axially opposed ends. A first valve element comprises a cup-shaped sleeve having a base adjacent to one axial end of the cavity and a sidewall axially slidably embraced by the housing within the cavity. A first fluid passage extends through the base of the sleeve adjacent to one of the cavity openings. A second valve element comprises a spool telescopically slidably received within the sidewall of the sleeve. A second fluid passage extends through the spool end from adjacent the second end of the housing cavity to internally adjacent the sidewall of the sleeve. A fluid passage is formed between the radially opposed surfaces of the sleeve and the spool for passing fluid therethrough as a function of axial position of the sleeve and spool with respect to each other.

Abstract: A hydraulic control system that comprises a hydraulic pressure line, a hydraulic fluid control mechanism and a lag network coupling the pressure line to the control mechanism for restricting flow of hydraulic flow therethrough, and thereby delaying and damping response of the control mechanism to fluid pressure fluctuations at the hydraulic line. The lag network comprises check valve that includes a flow passages interconnecting the hydraulic line and the control mechanism, a valve element, and a spring resiliently urging the valve element to close the passage, such that resistance to fluid flow increases as fluid flow decreases between the hydraulic pressure line and the control mechanism. Preferably, a pair of such check valves are connected in parallel between the hydraulic pressure line and the control mechanism for controllably restricting fluid flow in both directions.

Abstract: An electrohydraulic control system includes an actuator having a cylinder and a piston variably positionable therewithin. An electrohydaulic valve is responsive to valve control signals for coupling the actuator to a source of hydraulic fluid. A coaxial transmission line extends through the actuator, and includes an outer conductor formed by the actuator cylinder and a center conductor operatively coupled to the piston, such that length of the coaxial transmission line is effectively directly determined by position of the piston within the cylinder. An rf generator is coupled to the coaxial transmission line for launching rf energy therewithin, and valve control electronics is responsive to rf energy reflected by the coaxial transmission line for indicating position of the piston within the cylinder and generating electronic control signals to the valve. A second coaxial transmission line of fixed length is connected the valve and actuator so that the hydraulic fluid flows therethrough.

Abstract: An electrohydraulic control system includes an actuator having a cylinder and a piston variably positionable therewithin. An electrohydraulic valve is responsive to valve control signals for coupling the actuator to a source of hydraulic fluid. A coaxial transmission line extends through the actuator, and includes an outer conductor formed by the actuator cylinder and a center conductor operatively coupled to the piston such that length of the coaxial transmission line is effectively directly determined by position of the piston within the cylinder. An rf generator is coupled by an antenna to the coaxial transmission line for launching rf energy therewithin, and valve control electronics is responsive to rf energy reflected by the coaxial transmission line for indicating position of the piston within the cylinder and generating electronic control signals to the valve.

Abstract: An electrohydraulic servo system which includes an actuator having a cylinder and a piston variably positioned therewithin, a servo valve responsive to valve control signals for coupling the actuator to a source of hydraulic fluid, and control electronics responsive to piston position for generating the valve control signals. A variable frequency rf generator is coupled through associated directional couplers to a pair of antennas which are positioned within the actuator cylinder and physically spaced from each other in the direction of piston motion by an odd multiple of quarter-wavelengths at a nominal generator output frequency.

Abstract: An electrohydraulic servo system which includes a linear actuator having a cylinder and a piston variably positioned therewithin, a servo valve responsive to valve control signals for coupling the actuator to a source of hydraulic fluid, and control electronics responsive to piston position for generating the valve control signals. A coaxial transmission line is formed within the linear actuator to include a center conductor coaxial with the actuator and an outer conductor. A bead of ferrite or other suitable magnetically permeable material is coupled to the piston and surrounds the center conductor of the transmission line for altering impedance characteristics of the transmission line as a function of position of the piston within the cylinder.

Abstract: A variable displacement pump system including a pressure compensator for operating a pump adjusting mechanism to vary the displacement by applying hydraulic fluid to the pump adjusting mechanism and a spring biased piston applying a yielding force to the pump adjusting mechanism opposing the pressure compensator. A load sensing valve senses the pressure of the load to which fluid is supplied from the pump through a system valve and applies this load pressure to work in unison with the spring biased piston for purposes of urging the pump towards its maximum displacement.

Abstract: An electro-hydraulic servo control system which has N dynamic state variables and includes a servo actuator adapted to variably position a load mass. An actuator control system includes sensors coupled to the actuator for providing indications of X measured state variables, such as actuator position and/or velocity, and a digital observer responsive to the X measured actuator variables for estimating the remaining N-X variables at the actuator such as velocity and/or acceleration. Signals indicative of measured and estimated state variables are fed to a comparator together with a state command signal, for obtaining a difference or error signal to provide a control input to the actuator. The observer electronics include digital computation means suitably programmed to estimate N state variables as solutions to N linear equations for N unknowns.

Abstract: A stabilizing system for a wheeled vehicle having a movable mass on the vehicle, an actuator mounted on the vehicle connected to the mass for moving the mass, a sensor mounted on the vehicle for sensing movement of the vehicle about an axis to be stabilized, and a controller responsive to the sensor for controlling the actuator to cause movement of the movable mass in the same direction about the axis to be stabilized as the direction which the sensor is sensing movement of the vehicle and, in turn, the mass.

Abstract: An electro-hydraulic servo control system which includes a servo actuator adapted to variably position a load mass, and an actuator control system which includes a sensor coupled to the actuator for providing an indication of measured actuator position and a digital observer responsive to measured actuator position for estimating velocity and acceleration at the actuator. Signals indicative of measured actuator position, estimated velocity and estimated acceleration are fed to a comparator, together with a position command signal, for obtaining a difference or error signal to provide a control input to the actuator. The observer electronics includes digital computation means suitably programmed to estimate position, velocity and acceleration as solutions to three linear equations with three unknowns. Equation constants, which are functions of actuator and driven mass physical characteristics, are entered through operator-adjustable resistors.

Abstract: A fuel system for a diesel engine incorporating a distributor pump for controlling the operation of a plurality of fuel injectors. Each injector comprising a housing having situated therein an intensifier piston. The housing and intensifier piston cooperate to create a plurality of variable volume chambers including an upper, middle and metering chamber. The fuel injector incorporates a means entrapping a quantity of fuel during the injection mode of operation means for forming a vacuum pressure within the middle chamber to reduce the trapped fuel to its vapor pressure after the metering mode of operation has begun to ensure that the actual pressure intensification is nearly equal to the theoretical intensification ratio by minimizing unnecessary losses.

Abstract: An electro-hydraulic servo valve system comprising a two-stage spool type servo valve including a first stage comprising an electrical force motor and a second stage including a spool for controlling flow to an actuator. The force motor is operable upon receipt of a command electrical signal to move the spool. A first feedback is operable to cause the force motor to stop the movement of the spool. A second feedback is also operable to stop the movement of the spool at a predetermined position. The second feedback has a greater gain than said first feedback so that it normally dominates in the system. The second feedback comprises a pair of identical electrical sensors connected in parallel, and operable by movement of the spool.

Abstract: A fuel injection system for a diesel engine having injection and metering modes of operation for delivering fuel to an engine comprising a plurality of fuel injectors wherein each of said fuel injectors comprise a first port, a second port and a metering chamber for storing a premetered quantity of fuel, during the metering mode of operation, prior to the injection of said premetered quantity of fuel into the engine during the injection mode of operation.

Abstract: A fuel delivery system for a diesel engine for controlling the propagation of unwanted pressure waves including a fuel pump for sequentially delivering fuel from a fuel tank to a plurality of fuel injectors through a plurality of injection lines. The system further includes a drain line, one associated with each fuel injector, that is connected a pressure source, wherein the impedance of each drain line is equal to the impedance of its corresponding injection line. Each drain line further includes a flow restriction having an impedance equal to the impedance of its corresponding drain line and a valve, connected across the flow restriction for diverting flow around the flow restriction during intervals of time when fuel is flowing from the pressure source towards a particular one of the fuel injectors.

Abstract: The present invention is directed to an integrating angular accelerometer ich has a neutrally buoyant mass, thereby eliminating the detrimental effect of high shock and vibration loads. The accelerometer includes a housing and an inertial mass positioned in the housing, arranged for relative rotation with respect to the housing. An annular channel is provided between the housing and the inertial mass, located about the acceleration sensitive axis and dimensioned to cause fluid flow upon relative rotation of the housing and inertial mass in the direction of relative rotation. The fluid contained within the channel is a viscous fluid having a density equal to that of the inertial mass so as to achieve a neutral buoyancy of the inertial mass. A splitter for blocking fluid flow in the channel is provided so as to produce a differential pressure which corresponds to the relative angular rotation of the inertial mass and housing.

Abstract: An open loop adaptive control system for improving the driveability of a vehicle having at least one air supply modulator such as a throttle. The control system generating a correction signal supplied to the air supply modulator wherein the correction signal when added to the operator commanded signal input to the air supply modulator is such as to cancel the speed and pressure variability of the engine and vehicle dynamics and substitute for these dynamics determinable vehicle control dynamics therein improving the driveability of the vehicle by establishing uniform performance.

Abstract: An open loop adaptive control system for improving the driveability of a vehicle having at least one air supply modulator such as a throttle. The control system generating a correction signal supplied to the air supply modulator wherein the correction signal when added to the operator commanded signal input to the air supply modulator is such as to cancel the speed and pressure variability of the engine and vehicle dynamics and substitute for these dynamics determinable vehicle control dynamics therein improving the driveability of the vehicle by establishing uniform performance.

Abstract: A fuel injector, especially adapted for diesel engines, produces a fuel injection pulse having a predetermined time-variable flow rate. Preferably the injection pulse is ramp-shaped which approximates a linear function of time. A pressure chamber receives fuel at a substantially constant flow rate and an injection valve connected therewith opens in response to the pressure in the pressure chamber for delivering a fuel injection pulse to the combustion chamber. Means for absorbing a fluid pulse, in the form of an absorption chamber and flow restrictor, is connected with the pressure chamber to accept a ramp-shaped absorption pulse which is inversely related to the injection pulse.

Abstract: Means for controlling the quantities of the constituents of the combustion charge for an internal combustion engine wherein the controlled quantity is varied at a comparatively high frequency by a relatively small percentage of the presumedly correct quantity. Such variation causes an oscillation of the same relatively high frequency to appear in the output of an oxygen sensor exposed to the engine exhaust. Such sensor oscillations are detected and compared as to proportion with the percentage variation in the controlled quantity. The difference in proportion serves as an error signal to adjust the controlled quantity.