A hydraulic valve control unit is for an open center hydraulic system including a pump, a shunt valve and one or more actuator valves coupled to the shunt valve. Each actuator valve controls a corresponding actuator's position. The hydraulic valve control unit has a processor and a memory, containing instructions executable by the processor, and is configured to obtain user input data indicative of a desired actuator's position, determining opening area values of the one or more actuator valves using a predetermined relation dependent on the user input data, determining an opening area value of the shunt valve using the predetermined relation dependent on the user input data, controlling the shunt valve based on the opening area value of the shunt valve, and controlling the one or more actuator valves based on the opening area values of the one or more actuator valves.

A system for operating a work vehicle includes a hydraulic control assembly and a controller. The hydraulic control assembly includes a pump, accumulator, boom hydraulic cylinder, pin hydraulic cylinder, pin control valve, and ride control valve assembly. The boom hydraulic cylinder moves a boom of the work vehicle. The pin hydraulic cylinder moves a pin on the boom. The ride control valve assembly includes a charge valve and discharge valve. The charge valve is in fluid communication with the pump and the accumulator. The discharge valve is in fluid communication with the accumulator and a reservoir. The controller operates the work vehicle in a ride control mode and pin actuation mode. The pin actuation mode includes opening the charge valve with the discharge valve closed, and directing hydraulic fluid through the pin control valve.

A system for operating a work vehicle includes a hydraulic control assembly and a controller. The hydraulic control assembly includes a pump, accumulator, boom hydraulic cylinder, pin hydraulic cylinder, pin control valve, and ride control valve assembly. The boom hydraulic cylinder moves a boom of the work vehicle. The pin hydraulic cylinder moves a pin on the boom. The ride control valve assembly includes a charge valve and discharge valve. The charge valve is in fluid communication with the pump and the accumulator. The discharge valve is in fluid communication with the accumulator and a reservoir. The controller operates the work vehicle in a ride control mode and pin actuation mode. The pin actuation mode includes opening the charge valve with the discharge valve closed, and directing hydraulic fluid through the pin control valve.

A method and system for the hydraulic control of a concrete placing boom (14) comprising a plurality of boom arms (16), wherein hydraulic drive cylinders (18) for the boom arms (16), which are connected to one another in an articulated manner, are controlled by a hydraulic circuit (34), wherein a supply pressure is supplied via a hydraulic pump (32) to the hydraulic circuit (34), and wherein a pressure signal is captured in the drive cylinders (18) by at least one pressure sensor (38) for each cylinder. The maximum pressure in the drive cylinders (18) is determined from the pressure signals and the supply pressure is adjusted by an electronic control unit (36) according to the maximum pressure.

An apparatus comprising a synthetically commutated machine with one or more services, a prime mover coupled to the machine, a hydraulic circuit extending between the services and hydraulic loads to fluidically connect the services to the hydraulic loads such that groups of one or more services are fluidically connected to respective groups of one or more hydraulic loads. The apparatus configured such that the flow of hydraulic fluid to or from a group of services of the machine is controlled responsive to measuring a flow rate and/or pressure requirement of the hydraulic loads which are fluidically connected to the services, or receiving a demand signal indicative of a demanded pressure and/or flow rate based on a pressure and/or flow demand of hydraulic loads which are fluidically connected to the services.

The present invention relates to An open center hydraulic system (100), the open center hydraulic system (100) comprising a tank configured to hold hydraulic fluid, a pump configured to provide pressurized hydraulic fluid from the tank, a shunt valve configured to adapt an first opening area between a first input port and a first output port of the shunt valve dependent on a first control signal, wherein the first input port is coupled to the pump and the first output port is coupled to the tank, a first actuator valve coupled to the first input port and configured to adapt a second opening area of the first actuator valve dependent on a second control signal, a hydraulic valve control unit configured to determine a first opening area value and a second opening area value based on user input data and a predetermined relation dependent on the user input data, sending the first control signal, indicative of the first opening area value and sending the second control signal indicative of the second opening area value.

In a hydraulic drive system for an electrically driven hydraulic work machine that executes flow rate control of a hydraulic pump by controlling a rotation speed of an electric motor to drive a hydraulic pump to supply a hydraulic fluid to a plurality of actuators, and power consumed by the electric motor reliably limited within a range of preset maximum allowable power without unnecessary degradation of responsiveness of the electric motor. To this end, a controller includes a maximum angular acceleration limitation section (allowable rate computation section and rate limitation section), computes hydraulic power consumed by a main pump, computes a maximum angular acceleration allowed for an electric motor on the basis of a magnitude of the hydraulic power and a preset maximum allowable power consumable by the electric motor, and limits an angular acceleration of the electric motor not to exceed the maximum angular acceleration.

A method and system for the hydraulic control of a concrete placing boom (14) comprising a plurality of boom arms (16), wherein hydraulic drive cylinders (18) for the boom arms (16), which are connected to one another in an articulated manner, are controlled by a hydraulic circuit (34), wherein a supply pressure is supplied via a hydraulic pump (32) to the hydraulic circuit (34), and wherein a pressure signal is captured in the drive cylinders (18) by at least one pressure sensor (38) for each cylinder. The maximum pressure in the drive cylinders (18) is determined from the pressure signals and the supply pressure is adjusted by an electronic control unit (36) according to the maximum pressure.

Example aspects of an over-pressure protection system and a method for operating an over-pressure protection system are disclosed. The over-pressure protection system can comprise a main body housing defining a main body chamber; a fluid received in the main body chamber, the fluid defining a fluid pressure; a pressure sensor configured to measure the fluid pressure of the fluid, the pressure sensor configurable in an activated mode and a deactivated mode; and a control system configured to place the pressure sensor in the deactivated mode when the fluid pressure is equal to or above a pre-determined threshold pressure.

The invention relates to a hydraulic machine, in particular to a hydraulic motor with two working lines, from one of which a high pressure line and from the other one a low pressure line is branched off. An electronic control unit and a servo displacement unit are provided to control the displacement of the displacement volume of a drive mechanism of the hydraulic machine, wherein the displacement volume can be determinated by the displacement of a servo piston within the servo displacement unit. For this, the servo piston can be loaded at least on one side via a servo pressure line with hydraulic fluid under servo pressure, wherein the servo pressure level can be adjusted by a control spool arranged moveable within a control valve. For this, hydraulic fluid from the low pressure line or, perhaps, from the high pressure line is guidable via the control valve to the servo pressure line if a suitable control signal is available at a switching valve.