A work vehicle includes an engine, a variable displacement hydraulic pump, a hydraulic motor, an exhaust treatment device, and a controller. The engine drives the variable displacement hydraulic pump. The variable displacement hydraulic pump is able configured to change the discharge direction of the hydraulic fluid. Depending on the discharge direction of the hydraulic oil from the variable displacement hydraulic pump, the hydraulic motor is configured to change the driving direction to the forward direction or the reverse direction. The exhaust treatment device is configured to treat the exhaust from the engine. The controller is configured to increase the speed of the engine to a predetermined first speed or greater and to change the discharge direction of the variable displacement hydraulic pump to a neutral state during regeneration of the exhaust treatment device.

A work vehicle includes an engine, a variable displacement hydraulic pump, a hydraulic motor, an exhaust treatment device, and a controller. The engine drives the variable displacement hydraulic pump. The variable displacement hydraulic pump is able configured to change the discharge direction of the hydraulic fluid. Depending on the discharge direction of the hydraulic oil from the variable displacement hydraulic pump, the hydraulic motor is configured to change the driving direction to the forward direction or the reverse direction. The exhaust treatment device is configured to treat the exhaust from the engine. The controller is configured to increase the speed of the engine to a predetermined first speed or greater and to change the discharge direction of the variable displacement hydraulic pump to a neutral state during regeneration of the exhaust treatment device.

A hydraulic system powered by a shaft of an engine to control a plurality of hydraulic cylinders including at least one boom lift hydraulic cylinder coupled to a boom to pivot the boom about a horizontal axis, wherein a first variable displacement pump/motor and a second variable displacement pump/motor can be connected to provide a higher flow to the at least one boom lift hydraulic cylinder than a flow achieved by one of the first variable displacement pump/motor or the second variable displacement pump/motor, and a high-pressure accumulator and the first variable displacement pump/motor and the second variable displacement pump/motor can add power back to the engine shaft.

A hydraulic system powered by a shaft of an engine to control a plurality of hydraulic cylinders including at least one boom lift hydraulic cylinder coupled to a boom to pivot the boom about a horizontal axis, wherein a first variable displacement pump/motor and a second variable displacement pump/motor can be connected to provide a higher flow to the at least one boom lift hydraulic cylinder than a flow achieved by one of the first variable displacement pump/motor or the second variable displacement pump/motor, and a high-pressure accumulator and the first variable displacement pump/motor and the second variable displacement pump/motor can add power back to the engine shaft.

The invention relates to a displacement unit (1) of a hydraulic machine, for which the hysteresis is reduced. For this purpose, in the control spool (3) and/or at the control spool (3) a mass body (16) and a spring (17) are arranged, which are excited to resonance vibrations. The vibrations are self-excited and sustained by a partial flow rate of the hydraulic fluid which is modulated periodically. The high frequent vibrations are transmitted over the spring (17) onto the associated control spool (3), thereby reducing the friction and hence the hysteresis.

The invention relates to a displacement unit (1) of a hydraulic machine, for which the hysteresis is reduced. For this purpose, in the control spool (3) and/or at the control spool (3) a mass body (16) and a spring (17) are arranged, which are excited to resonance vibrations. The vibrations are self-excited and sustained by a partial flow rate of the hydraulic fluid which is modulated periodically. The high frequent vibrations are transmitted over the spring (17) onto the associated control spool (3), thereby reducing the friction and hence the hysteresis.

Controlling a hydraulic drive for a hydraulic consumer alternately pressurized in opposite directions, the hydraulic drive comprising a hydraulic machine driven by an electric machine and featuring variable displacement adjustable through zero, wherein a rotational speed of the hydraulic machine controlled by the electric machine, includes varying displacement so that conveying direction of hydraulic fluid is alternated using a cyclically varying volumetric flow specification, to perform direction reversals. After direction reversal during a first change time period, the rotational speed is increased from a first rotational speed set at the end of the direction reversal to a second rotational speed, and within a second change time period after the first change time period, the rotational speed is decreased until the first rotational speed is reached. The displacement is varied during the change time periods depending on the rotational speed and volumetric flow specification to comply with the volumetric flow specification.

Controlling a hydraulic drive for a hydraulic consumer alternately pressurized in opposite directions, the hydraulic drive comprising a hydraulic machine driven by an electric machine and featuring variable displacement adjustable through zero, wherein a rotational speed of the hydraulic machine controlled by the electric machine, includes varying displacement so that conveying direction of hydraulic fluid is alternated using a cyclically varying volumetric flow specification, to perform direction reversals. After direction reversal during a first change time period, the rotational speed is increased from a first rotational speed set at the end of the direction reversal to a second rotational speed, and within a second change time period after the first change time period, the rotational speed is decreased until the first rotational speed is reached. The displacement is varied during the change time periods depending on the rotational speed and volumetric flow specification to comply with the volumetric flow specification.

A system is provided for determining piston position and for monitoring and maintaining stroke rate in a hydraulic lift system comprising a lift cylinder, a reversible hydraulic pump, a motor and a flywheel. A method is further provided for managing energy requirements of a hydraulic lift system comprising a lift cylinder, a reversible hydraulic pump, a motor and a flywheel.

A system is provided for determining piston position and for monitoring and maintaining stroke rate in a hydraulic lift system comprising a lift cylinder, a reversible hydraulic pump, a motor and a flywheel. A method is further provided for managing energy requirements of a hydraulic lift system comprising a lift cylinder, a reversible hydraulic pump, a motor and a flywheel.