A hydraulic module with a switch valve for controlling a flow of a hydraulic fluid in a connecting rod for an internal combustion engine with variable compression with an eccentric element adjustment arrangement for adjusting an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes a first cylinder and a second cylinder configured as hydraulic chambers, wherein a first inlet is provided for feeding the hydraulic fluid into the first cylinder and a second inlet is provided for feeding the hydraulic fluid into the second cylinder, wherein a first outlet is provided for draining the hydraulic fluid from the first cylinder and a second outlet is provided for draining the hydraulic fluid from the second cylinder wherein a first check valve is associated with the first cylinder and a second check valve is associated with the second cylinder.

A multi-actuation system includes a first electrohydraulic servo valve and a first actuator. A first fluid line fluidically connects the first electrohydraulic servo valve to the first actuator. The multi-actuation system also includes a second electrohydraulic servo valve and a second actuator. A second fluid line fluidically connects the second electrohydraulic servo valve to the second actuator. A ring fluidically connects the first fluid line with the second fluid line.

A hydraulic valve assembly includes a first spool valve and a first selector valve for actuating a first hydraulic consumer port or a second hydraulic consumer port, and a second spool valve and a second selector valve for actuating a third hydraulic consumer port or a fourth hydraulic consumer port. A shut-off valve is arranged in a common pressure channel. A branch channel with first and second pressure branch channels branches off the pressure channel upstream of the shut-off valve. The first selector valve connects the first pressure branch channel to a first connection line in a first switching position and connects the second pressure branch channel to a second connection line in a second switching position. The second selector valve, in a first switching position, connects the first connection line to the control channel and, in a second switching position, connects the second connection line to the control channel.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

When hydraulic fluid discharged from a hydraulic actuator is to be recovered for driving a different hydraulic actuator, the recovery frequency is increased to achieve further energy saving. To this end, a pressure increasing circuit 36 is provided in which a communication pressure increasing valve 12 is disposed in a communication passage 26 that connects a bottom side line 23 of and a rod side line 24 a boom cylinder 4. A recovery control valve 11 is controlled such that, when a first operation unit 5 is operated in a boom lowering direction (own weight falling direction of the boom) and a second operation unit 6 is operated simultaneously, only if the pressure at the bottom side of the boom cylinder 4 is higher than the pressure at the arm cylinder side that is a recovery destination of hydraulic fluid, the recovery control valve 11 is opened to recover the flow rate discharged from the bottom side of the boom cylinder 4 to the arm cylinder side.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

A multi-actuation system includes a first electrohydraulic servo valve and a first actuator. A first fluid line fluidically connects the first electrohydraulic servo valve to the first actuator. The multi-actuation system also includes a second electrohydraulic servo valve and a second actuator. A second fluid line fluidically connects the second electrohydraulic servo valve to the second actuator. A ring fluidically connects the first fluid line with the second fluid line.

To provide a hydraulic drive system for a work machine capable of securing a favorable operability in the case where hydraulic fluid discharged from a hydraulic actuator is regenerated for driving other hydraulic actuator. The hydraulic drive system for a work machine includes: a regeneration line that connects a bottom-side hydraulic chamber of a hydraulic cylinder to a portion between a hydraulic pump and a second hydraulic actuator; a regeneration flow rate adjustment device that supplies at least part of the hydraulic fluid discharged from the bottom-side hydraulic chamber to a portion between the hydraulic pump and the second hydraulic actuator through the regeneration line; a differential pressure calculating section that reads a pressure in the bottom-side hydraulic chamber of the hydraulic cylinder detected by a first pressure sensor and a pressure between the hydraulic pump and the second hydraulic actuator detected by a second pressure sensor, and calculates a differential pressure, or a differential pressure sensor; and a control unit that controls the regeneration flow rate adjustment device such as to gradually increase the flow rate of the hydraulic fluid flowing through the regeneration line according to an increase in the differential pressure calculated by the differential pressure calculation section or in the differential pressure detected by the differential pressure sensor.

A hydraulic module with a switch valve for controlling a flow of a hydraulic fluid in a connecting rod for an internal combustion engine with variable compression with an eccentric element adjustment arrangement for adjusting an effective connecting rod length, wherein the eccentrical element adjustment arrangement includes a first cylinder and a second cylinder configured as hydraulic chambers, wherein a first inlet is provided for feeding the hydraulic fluid into the first cylinder and a second inlet is provided for feeding the hydraulic fluid into the second cylinder, wherein a first outlet is provided for draining the hydraulic fluid from the first cylinder and a second outlet is provided for draining the hydraulic fluid from the second cylinder wherein a first check valve is associated with the first cylinder and a second check valve is associated with the second cylinder.

A dual mode control system for a work vehicle includes a hydraulic system configured to drive a loader assembly and a dozer assembly coupled to the work vehicle. The hydraulic system includes a fluid delivery system comprising a plurality of flow paths fluidly coupled to a hydraulic pump. The hydraulic system includes a valve assembly configured to regulate diversion of fluid into a first and a second hydraulic cylinders coupled to the fluid delivery system to adjust the loader assembly, or into a third cylinder coupled to the fluid delivery system to adjust the dozer assembly. The dual mode control system also includes a controller operably coupled to the valve assembly, and one or more user interfaces coupled to the controller to enable an operator to provide inputs to cause the controller to adjust the valve assembly, and to thereby adjust the loader assembly or the dozer assembly.