Abstract: A hydraulic system for a working machine is a load sensing (LS) system and includes a first hydraulic actuator and a first control valve for controlling the flow of hydraulic fluid from a pump to the first hydraulic actuator and for draining hydraulic fluid from the first hydraulic actuator, respectively and a second hydraulic actuator and a second control valve for controlling the flow of hydraulic fluid from the pump to the second hydraulic actuator and for draining hydraulic fluid from the second hydraulic actuator, respectively. The hydraulic system further includes a first hydraulic circuit for providing an LS pressure for the first actuator and a second hydraulic circuit for providing an LS pressure for the second actuator. At least one of the first and second hydraulic circuits includes an offset valve for changing the LS pressure before providing the LS pressure to the pump.

Abstract: A working machine that includes an internal combustion engine, a generator, an energy storage and an electric motor for driving one or more wheels of the working machine is provided. The internal combustion engine is arranged to drive the generator and the generator is arranged to supply power to the electric motor via the energy storage. The working machine further includes an accelerator for controlling the electric motor, and a hydraulic pump for driving a hydraulic actuator. The hydraulic pump has a drive source different from the electric motor and the accelerator is arranged for controlling the speed of the hydraulic pump.

Abstract: A hydraulic system for a working machine is a load sensing system and includes a hydraulic actuator for movement of an implement and a control valve having an inlet valve and an outlet valve for controlling the flow of hydraulic fluid from a pump to the hydraulic actuator and for draining hydraulic fluid from the hydraulic actuator, respectively. The hydraulic system also includes an arrangement for determining the load on the hydraulic actuator. The hydraulic system further includes a valve for disconnecting the flow of hydraulic fluid from the pump to the hydraulic actuator, while allowing another flow of hydraulic fluid to the hydraulic actuator, provided that the determined load on the hydraulic actuator exceeds a threshold value.

Abstract: A system for a working machine is adapted for springing the movement of a load during transport and includes at least one hydraulic cylinder for operating the load, an accumulator, and a valve adapted to control a flow communication between the hydraulic cylinder and the accumulator. The system includes a first control valve arranged on a conduit connecting to the piston side of the hydraulic cylinder, a second control valve arranged on a conduit connecting to the piston rod side of the hydraulic cylinder, a first pressure sensor for detecting a load pressure of the hydraulic cylinder, a second pressure sensor for detecting a charge pressure of the accumulator, and a control unit adapted to receive signals with information about the pressures detected by the pressure sensors and to generate control signals corresponding to the detected pressures for controlling the springing function.

Abstract: A pilot pressure control system for controlling a pilot signal pressure at a pilot inlet of a control valve includes a pilot outlet adapted to be connected to the pilot inlet. The pilot pressure control assembly further includes a first pilot valve assembly and a second pilot valve assembly. Each one of the first and second pilot valve assemblies are individually controllable so as to selectively provide a first fluid flow direction from a pressure line to the pilot outlet and a second fluid flow direction from the pilot outlet to a drain line. At least the first pilot valve assembly is adapted to assume a maximum pressure supply condition so as to supply a first pilot valve assembly maximum pressure to the pilot outlet. At least the second pilot valve assembly is adapted to provide a pressure drop from the pilot outlet to the drain line via the second pilot valve assembly.

Abstract: A hydraulic fluid tank arrangement for a working machine is provided, the arrangement including a hydraulic fluid tank; an inlet portion for receiving hydraulic fluid into the hydraulic fluid tank; and an oil filter arranged in fluid communication with the inlet portion; wherein the hydraulic fluid tank arrangement further includes a gas removal device arranged in fluid communication with the oil filter downstream the inlet portion and upstream the oil filter for removing gas from the hydraulic fluid before the hydraulic fluid reaches the oil filter. A method for removing gas from hydraulic fluid contained in a hydraulic fluid tank arrangement is also provided.

Abstract: A hydraulic system is provided for a working machine, that includes a hydraulic cylinder for raising and lowering an implement The hydraulic system includes a sensor for measuring a pressure in the hydraulic cylinder; and a control unit for controlling the movement of the hydraulic cylinder; wherein the control unit is configured to compare a pressure value measured by the sensor with a preset target pressure level range and to control the pressure in the hydraulic cylinder to be within the preset target pressure level range by adding or draining hydraulic fluid to/from a pressure side of the hydraulic cylinder for maintaining a substantially constant ground contact force between the implement and the ground.

Abstract: A method is provided for controlling a hydraulic cylinder in a work machine, which hydraulic cylinder is arranged to move an implement that is subjected to a load, with the hydraulic cylinder being controlled by a hydraulic machine. The method includes detecting that a lifting movement of the implement is to be initiated, and attaining a basic speed of the hydraulic machine before lifting takes place.

Abstract: A method is provided for controlling a hydraulic system of a working machine. The hydraulic system includes a hydraulic machine for providing hydraulic fluid to one or more actuators of the working machine. The method includes receiving a signal requesting a pump pressure from the hydraulic machine based on the load pressure of a first actuator of the one or more actuators which first actuator has the highest load pressure of the one or more actuators, discriminating the pressure request from the first actuator provided that the first actuator is stalled due to overload or geometrical limitations, and controlling the hydraulic machine to provide a pump pressure based on the load pressure of a second actuator of the one or more actuators which second actuator is in operation and has the second highest load pressure of the one or more actuators, or, if no actuator in addition to the first actuator is present and in operation, controlling the hydraulic machine to provide a predetermined idle pump pressure.

Abstract: A pilot pressure control system for controlling a pilot signal pressure at a pilot inlet of a control valve includes a pilot outlet adapted to be connected to the pilot inlet. The pilot pressure control assembly further includes a first pilot valve assembly and a second pilot valve assembly. Each one of the first and second pilot valve assemblies are individually controllable so as to selectively provide a first fluid flow direction from a pressure line to the pilot outlet and a second fluid flow direction from the pilot outlet to a drain line. At least the first pilot valve assembly is adapted to assume a maximum pressure supply condition so as to supply a first pilot valve assembly maximum pressure to the pilot outlet. At least the second pilot valve assembly is adapted to provide a pressure drop from the pilot outlet to the drain line via the second pilot valve assembly.

Abstract: A method is provided for recovering energy in a hydraulic system of a working machine. The hydraulic system includes at least one hydraulic cylinder for movement of a load, and a fan driven by a hydraulic motor.

Abstract: A hydraulic system for a work machine including a first and a second hydraulic actuator, and a first and a second hydraulic machine for providing hydraulic fluid to at least one of the first and the second actuator via a first and a second priority valve respectively. The first and second priority valves are controlled by a pressure drop ?P over the inlet valve of the first actuator such that when ?P is lower than a first threshold value T1, a flow of hydraulic fluid is allowed only to the first actuator. The second priority valve allows a flow of hydraulic fluid to both the first and second actuator for a pressure drop higher than T1. The first priority valve is further configured to allow a flow of hydraulic fluid to both of the first and second actuator for a pressure drop higher than a second threshold value T2 which is higher than T1.

Abstract: A method is provided for controlling a hydraulic system of a working machine, which hydraulic system includes a first hydraulic machine for providing hydraulic fluid to a first actuator of the working machine, and a second hydraulic machine for providing hydraulic fluid to a second actuator of the working machine and for providing hydraulic fluid to the first actuator. The method includes using a first control mode, and in the first control mode allowing a flow of hydraulic fluid from the second hydraulic machine to the second actuator, wherein the pump pressure of the second hydraulic machine is selected based on the load pressure of the second actuator independently of the load pressure of the first actuator.

Abstract: A hydraulic system for a working machine includes at least one work function and a control valve unit for controlling hydraulic fluid to and from the work function, and a recovery unit connected to a return port of the control valve unit for recovering energy from the work function. The system further includes an arrangement for limiting the pressure of the hydraulic fluid at the return port, which pressure limiting arrangement has a pilot-operated valve adapted to set a maximum allowable pressure at the return port of the control valve unit. The pressure is variable by controlling the pilot-operated valve by a control unit.

Abstract: A method for controlling lowering of an implement of a working machine is provided. The working machine has a hydraulic system including a hydraulic cylinder for moving the implement and a first control valve for controlling the flow of hydraulic fluid from the piston side of the hydraulic cylinder, and a recovery unit connected to the control valve for recovering energy by receiving a return flow from the piston side of the hydraulic cylinder. The piston side of the hydraulic cylinder and the control valve are connected to each other, and the piston rod side of the hydraulic cylinder is connected to the control valve and to the recovery unit in a point between the control valve and the recovery unit.

Abstract: A load sensing system includes a first assembly of actuators for controlling a first hydraulic function, a pump adapted to supply the actuators with pressurized hydraulic fluid, an electrically controlled valve adapted to control the output pressure of the pump via a hydraulic signal, a first pressure sensor for detecting a load pressure of the first actuator assembly, and a control unit adapted to receive a signal with information about the load pressure detected by the first pressure sensor and to generate a control signal, corresponding to the detected load pressure, to the electrically controlled valve.

Abstract: A system is provided for controlling the tilting of a load-carrying implement of a movable work machine that includes a frame and the implement, pivotally connected to the frame, and a tilting arrangement for tilting the implement in relation to the frame. The system includes a control for controlling the tilting of the implement based upon a sensor-registered movement of the movable work machine, and for controlling the tilting of the implement such that the implement counteracts the inertia of a load carried by the implement.

Abstract: A method is provided for controlling movement of a first vehicle component relative to a second vehicle component, including the steps of determining a deceleration rate of the first vehicle component in order to achieve a predetermined final speed at a final position, determining a starting position for initiating the deceleration on the basis of the predetermined final speed, the final position and the determined deceleration rate and controlling deceleration of the component from the starting position to the final position according to the determined acceleration rate.

Abstract: An arrangement for charging an accumulator with hydraulic fluid is provided. The accumulator is used in a hydraulic boom suspension system for a lift arm of a vehicle and the arrangement includes a first hydraulic pump arranged to supply hydraulic fluid to a hydraulic cylinder system of the lift arm, and a second hydraulic pump arranged to supply hydraulic fluid to a second hydraulic system. The second hydraulic pump is further arranged to supply hydraulic fluid for charging the accumulator.

Abstract: A method is provided for, when necessary, automatically limiting a pressure in a hydraulic system during operation. A system is arranged to deliver pressurized hydraulic fluid to at least one fluid actuated device arranged to perform a work function, where the procedure includes sensing a pressure in at least one position of the system, comparing the detected pressure value, or an associated value, with a first predefined pressure limit, and opening a communication of fluid between the fluid actuated device and a reservoir through a first conduit if the sensed pressure value, or an associated value, exceeds the predefined limit.