A fluid control valve can suppress heat generation when discharging charges from a piezo actuator for contraction and reduce energy necessary to drive the piezo actuator. The fluid control valve includes a piezo actuator and a drive circuit connected to the piezo actuator is adapted so that the drive circuit includes: a flyback transformer including a primary side coil connected to a DC power supply DV and a secondary side coil connected to the piezo actuator; a charge switch that is connected to the primary side coil and switched from on to off when the piezo actuator charges; a discharge switch that is connected to the secondary side coil and switched from off to on when the piezo actuator discharges; and a regenerative capacitor that is connected to the primary side coil and into which electric energy due to the discharge of the piezo actuator is regenerated.

A method of cooling hydraulic fluid for an aircraft hydraulic system is provided. The method comprises connecting an output side of an external cooling system to a return side of an electric motor driven pump (EMDP) in the hydraulic system and connecting an input side of the external cooling system to a hydraulic fluid reservoir in the hydraulic system. The EMDP pumps hydraulic fluid through the hydraulic system under conditions wherein fuel tanks in the aircraft are empty, and the external cooling system cools the hydraulic fluid as the EMDP pumps the hydraulic fluid, wherein the hydraulic fluid passes from the hydraulic fluid reservoir and through the external cooling system before entering the EMDP.

A hydraulic system for a working machine includes a hydraulic actuator having a first fluid chamber and a second fluid chamber, an accumulator, an outputting fluid tube to output an operation fluid, and a switching valve to be switched between a first position and a second position. The first position allows the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation. The second position allows the first fluid chamber and the accumulator to be communicated with each other, allows the second fluid chamber and the outputting fluid tube to be communicated with each other, and thereby allows an anti-vibration operation.

A vehicle includes a chassis, a controllable vehicle component, a hydraulic circuit, a heater, a temperature sensor, and a controller. The hydraulic circuit includes a reservoir configured to store hydraulic fluid, a pump positioned to drive the hydraulic fluid from the reservoir and throughout the hydraulic circuit, and an actuator positioned to selectively receive the hydraulic fluid from the pump to selectively operate the controllable vehicle component. The heater is positioned to facilitate selectively heating the hydraulic fluid. The temperature sensor is positioned to acquire temperature data indicative of a temperature of the hydraulic fluid. The controller is configured to monitor the temperature of the hydraulic fluid and selectively activate at least one of the heater or the pump to thermally regulate the hydraulic fluid (i) to maintain the hydraulic fluid within a target temperature range and (ii) independent of (a) an operator input and (b) engagement of the actuator.

An air dryer control method may include a cold mode in which a controller performs a winter season condition control in which air temperature is lowered to freezing temperature if an engine starting is detected, and performs a winter season thawing control in which compressed air introduced into a valve control of an air dryer warms a purge valve of the air dryer.

A hydraulic propulsion system converts heat or thermal energy into hydraulic energy, and such hydraulic energy into mechanical work. The hydraulic propulsion system includes a thermal unit, a hydraulic cylinder with pistons and springs mounted therein, one or more hydraulic motors, one or more hydraulic accumulators, and one or more electrical energy generators, as well as a plurality of flow control valves to control the flow of hydraulic fluid between the various components. The hydraulic propulsion system may be enhanced by a sonic transmission unit including a sonic wave generator.

A hydraulic system for a working machine includes a hydraulic actuator having a first fluid chamber and a second fluid chamber, an accumulator, an outputting fluid tube to output an operation fluid, and a switching valve to be switched between a first position and a second position. The first position allows the first fluid chamber and the second fluid chamber to be communicated with the outputting fluid tube and thereby allowing a floating operation. The second position allows the first fluid chamber and the accumulator to be communicated with each other, allows the second fluid chamber and the outputting fluid tube to be communicated with each other, and thereby allows an anti-vibration operation.

A method of flushing a hydraulic system including a fluid circuit and an in-service fluid flowing therein includes fluidly coupling a kidney loop to the fluid circuit such that at least a portion of the in-service fluid may flow therethrough, the kidney loop including a depth media filter and a micro-glass filter arranged in a parallel flow pattern and introducing a solvent cleaner into the in-service fluid at a concentration level between approximately 2.5% and approximately 6%, the solvent cleaner including at least one hydrocarbon group V fluid. The method further includes maintaining a temperature of the in-service fluid between approximately 100 degrees Fahrenheit and approximately 155 degrees Fahrenheit and controlling the flow of the in-service fluid at a flow rate between approximately 3 gallons per minute and approximately 6.8 gallons per minute.

A work machine is provided. The work machine includes a changeover valve capable of disabling area limiting control by bypassing an area limiting control solenoid proportional valve disposed in a pilot line through which pilot pressure generated by a hydraulic pilot type operation device is guided to a directional control valve and the work machine can perform the area limiting control while ensuring response of a work implement. When a first fluid temperature T1 is higher than a first predetermined temperature Ta and a control changeover switch 66 specifies disabling of the area limiting control, a controller brings a plurality of changeover valves into a bypass position. When the first fluid temperature T1 is equal to or lower than the first predetermined temperature Ta, the controller brings the changeover valves into a communication position and places the solenoid proportional valves in a fully open position.

A system and method is provided for monitoring a hydraulic power system having at least one light emitter and a button. The method includes powering on the hydraulic power system, receiving an actuation at the button and detecting a release of the button after a first time interval, and entering a diagnostic state. The method further includes retrieving a code and displaying the code by turning on the emitter in a first pattern. In some embodiments, a system and method is provided for regulating a temperature of a hydraulic power system. In some embodiments, a system and method is provided for controlling operation of a hydraulic torque wrench.