An active accumulator system which automatically adjusts or adapts the charge pressure or volume of an accumulator to maintain an optimal charge pressure or volume of the accumulator may provide optimal operation of a pump. An active accumulator system may comprise a flow line coupled to a pump, wherein a fluid flows through the flow line to the pump, an accumulator coupled to the flow line, a transducer coupled to the pump, wherein the transducer detects a parameter of the pump at an inlet of the pump, and a controller coupled to the transducer and the accumulator, wherein the controller receives the parameter, and wherein the controller regulates air flow to the accumulator such that the accumulator is adjusted to an optimal charge pressure based at least in part on the parameter.

A fluid pressure circuit includes a directional switching valve arranged between a fixed displacement pump and a fluid pressure actuator and configured to switch a flow passage for a pressurized fluid, an accumulator arranged in a branch flow passage branched from a connection flow passage that connects the fluid pressure actuator and the directional switching valve, an accumulator flow control valve arranged between the connection flow passage and the accumulator, and a pump flow control valve arranged between the fluid pressure actuator and the fixed displacement pump and configured to variably divert a flow rate of the pressurized fluid discharged from the fixed displacement pump into a first system including the tank and a second system including the fluid pressure actuator.

A fluid circuit includes a pressure fluid source configured to supply pressure fluid, multiple actuators connected to the pressure fluid source, a direction switching valve configured to switch a supply destination of the pressure fluid supplied from the pressure fluid source, and a discharge amount control mechanism configured to control the output pressure of the pressure fluid source such that a pressure difference ΔP between the output pressure of the pressure fluid source and the maximum load pressure of the load pressures of the multiple actuators reaches a target value ΔPt. The fluid circuit further includes an accumulator configured to accumulate part of return fluid from the actuators.

A device for maintaining a hydraulic supply of a utility vehicle includes a hydraulic pump, which is adjustable in terms of its delivery volume via a pressure control inlet, for feeding hydraulic fluid to a hydraulic circuit, a pressure accumulator that can be charged from the hydraulic circuit via a check valve, a pressure connection between the hydraulic circuit and the pressure control inlet of the hydraulic pump being producible via a sensor line by means of a charging valve, and a supply connection between the pressure accumulator and the hydraulic circuit being producible by means of a discharging valve, by virtue of the check valve being bypassed.

A system for automatically actuating a hydraulic accumulator—useful for oil collection systems—capable of operation while maintaining a zero or near zero draw of electrical energy.

Various embodiments of the present disclosure provide a rotorcraft-assisted system and method for launching and retrieving a fixed-wing aircraft into and from free flight. The launch and retrieval system includes a modular multicopter, a storage and launch system, an anchor system, a flexible capture member, and an aircraft-landing structure. The multicopter is attachable to the fixed-wing aircraft to facilitate launching the fixed-wing aircraft into free, wing-borne flight. The storage and launch system is usable to store the multicopter (when disassembled) and to act as a launch mount for the fixed-wing aircraft by retaining the fixed-wing aircraft in a desired launch orientation. The anchor system is usable with the multicopter, the flexible capture member, and the aircraft-landing structure to retrieve the fixed-wing aircraft from free, wing-borne flight.

A hydraulic system for an automatic transmission of a motor vehicle, including a high pressure circuit in which a pressure accumulator, at least one clutch and a gear selector are connected, and comprising a low pressure circuit for cooling the clutch, wherein the high pressure circuit and the low pressure circuit have at least one hydraulic pump that can be driven by an electric motor, and including a control unit that actuates the electric motor of the hydraulic pump when a pressure accumulator charging requirement is detected, wherein the high and low pressure circuits are connected via a bypass line to an integrated accumulator charging valve.

A liftgate assembly, such as a for a delivery vehicle, includes a liftgate that is movable by hydraulic power between a raised position and a lowered position. The hydraulic power unit includes an energy-recovery mechanism that stores energy while the liftgate is being lowered under load. Energy stored by the energy-recovery mechanism, such as in an accumulator, may be used to raise the liftgate. The hydraulic power unit includes a pump that pumps hydraulic fluid for providing hydraulic pressure. The liftgate assembly thereby uses energy more efficiently, enabling repurposing part of the energy from lowering the liftgate (and any cargo thereupon) in raising the liftgate.

A method is provided for determining a gas charge pressure P.sub.calcGC of a hydraulic accumulator within a hydraulic fluid system. The method includes receiving pressure decay data representing the pressure decay within a self-pressurizing hydraulic reservoir of the hydraulic fluid system as the self-pressurizing hydraulic reservoir depressurizes from an operating pressure of the self-pressurizing hydraulic reservoir towards atmospheric pressure. The method also includes calculating the gas charge pressure P.sub.calcGC of the hydraulic accumulator using the received pressure decay data of the self-pressurizing hydraulic reservoir.

A hydraulic system for an automatic transmission of a motor vehicle. A high-pressure circuit, in which a pressure accumulator, at least one clutch, and gear selectors and a hydraulic pump, which can be operated by an electronic control unit and by which the accumulator pressure in the high-pressure circuit can be increased in charging operation. A clutch valve that can be operated by the control unit is arranged in a clutch path between the pressure accumulator and a clutch hydraulic cylinder of the clutch, using which clutch valve a hydraulic pressure applied to the clutch hydraulic cylinder can be adjusted, and a safety valve that can be operated by the control unit is arranged upstream of the clutch valve.