A pilot pressure supply solenoid valve (36) is disposed in a flow path connecting an inlet port (16) and a pilot chamber (48), and a pilot pressure discharge solenoid valve (38) is disposed in a flow path through which a pressure fluid in the pilot chamber is discharged to the exterior. A flow path, through which the pressure fluid that has passed through a supply valve (26) is discharged to the exterior, is not provided.

A hydraulic system (600) and method for reducing boom dynamics of a boom (30), while providing counter-balance valve protection, includes a hydraulic actuator (110), first and second counter-balance valves (300, 400), first and second independent control valves (700, 800), and first and second blocking valves (350, 450). The actuator includes first and second corresponding chambers. In a first mode, the second counter-balance valve is opened by the first control valve, and the first counter-balance valve is opened by the second control valve. In a second mode, at least one of the counter-balance valves is closed. A meter-out control valve (800, 700) may be operated in a flow control mode, and/or a meter-in control valve (700, 800) may be operated in a pressure control mode. Boom dynamics reduction may occur while the boom is in motion (e.g., about a worksite). By opening the counter-balance valves, sensors at the control valves may be used to characterize external loads. The control valves may respond to the external loads and at least partially cancel unwanted boom dynamics. The system may further detecting faults in actuators with counter-balance valves and prevent any single point fault from causing a boom falling event and/or mitigate such faults.

The present disclosure relates to diagnosing and locating fluid leakage within a pneumatic system (5) using a minimal amount of pressure sensors (55, 75, 89). In general, each branch (51, 71, 85) of a pneumatic system (5) includes an associated pressure sensor (55, 75, 89) and in accordance with how the pneumatic components (57, 59, 61, 77, 91, 93, 95) associated with the pneumatic branch (51, 71, 85) are toggled and monitored, leaks can be detected and located within the branch (51, 71, 85) using a minimal amount of pressure sensors (55, 75, 89). More specifically, pressure and pressure decay may be measured by the sensors (55, 75, 89) within a branch (51, 71, 85) while the pneumatic components (57, 59, 61, 77, 91, 93, 95) are in a particular configuration. The configuration is thereafter changed, and pressure and pressure decay are again measured by the sensors (55, 75, 89). The results of these two measurements may enable the pneumatic system (5) to derive the presence and location of a leak.

An object of the present invention is to provide a construction machine that allows easy and accurate calibration of a pressure sensor and enables accurate control of hydraulic actuators. A controller increases the delivery pressure of a hydraulic pump in a state in which first and second meter-out valves and a second meter-in valve are closed and in which a first meter-in valve is opened, and calibrates a first pressure-calculation map such that a pressure calculated on the basis of the first pressure-calculation map matches a pressure calculated on the basis of a supply-pressure-calculation map, and increases the delivery pressure of the hydraulic pump in a state in which the first and second meter-out valves and the first meter-in valve are closed and in which the second meter-in valve is opened, and calibrates a second pressure-calculation map such that a pressure calculated on the basis of the second pressure-calculation map matches the pressure calculated on the basis of the supply-pressure-calculation map.

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 method is provided for the simultaneous detection, localization, and quantification of leaks and obstructions in a gas network under pressure or vacuum. The gas network includes: one or more sources of compressed gas or vacuum; one or more consumers or consumer areas of compressed gas or vacuum applications; pipelines or a network of pipelines to transport the compressed gas or vacuum from the sources to the consumers, consumer areas or applications; a plurality of sensors providing one or more physical parameters of the gas at different times and locations within the gas network. The gas network is further provided with controllable or adjustable relief valves, controllable or adjustable throttle valves and possibly one or a plurality of sensors capable of monitoring the status or state of the relief valves and/or throttle valves.

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.

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.

A pedal travel simulator for a hydraulic powered vehicle braking system. In order to realize a “jump-in,” a first piston spring is provided that, after a first displacement path, loads a simulator piston of the pedal travel simulator with a spring force that is higher by a multiple than that of a second piston spring that loads the simulator piston during the first displacement path.

A hydraulic system includes: a solenoid valve that includes a valve spool configured to slide within a housing, and moves the valve spool to a position corresponding to an operation command input to the solenoid valve; and a control device that outputs the operation command to the solenoid valve. When a predetermined condition is satisfied, the control device outputs a continuously or intermittently changing operation command to the solenoid valve to reciprocate the valve spool from a full open position or a full closed position.