A method for driving a transmission mechanism output power in response to an anticipated fluid-pressure gradient field is provided. The method includes sensing the change of direction of pressure gradient field at a desired location from the different area of the transmission mechanism within fluid. The method further includes constructing fluid-pressure gradient field based upon isolation-fluid apparatus or low-density fluid space installed on a transmission mechanism within fluid.

A method for driving a transmission mechanism output power in response to an anticipated fluid-pressure gradient field is provided. The method includes sensing the change of direction of pressure gradient field at a desired location from the different area of the transmission mechanism within fluid. The method further includes constructing fluid-pressure gradient field based upon isolation-fluid apparatus or low-density fluid space installed on a transmission mechanism within fluid.

When the driving force between a driven wheel of a wheel and the surface on which the vehicle is travelling exceeds the available traction, wheel slippage may occur. Wheel slippage may result in a loss of control of the vehicle. The present disclosure may facilitate the control of drive power sent to a driven wheel of a vehicle from consideration of a torque setting and a speed of the vehicle.

When the driving force between a driven wheel of a wheel and the surface on which the vehicle is travelling exceeds the available traction, wheel slippage may occur. Wheel slippage may result in a loss of control of the vehicle. The present disclosure may facilitate the control of drive power sent to a driven wheel of a vehicle from consideration of a torque setting and a speed of the vehicle.

An industrial vehicle includes a hydraulic mechanism, an operation lever, and a pump, a hydraulic control valve unit, a lever operation detector, an internal combustion engine controller, and a valve controller that controls the hydraulic control valve unit. When the lever operation detector detects the operation of the operation lever under a situation in which a speed of the internal combustion engine is less than or equal to a predetermined speed, the valve controller operates the hydraulic control valve unit to discharge the hydraulic oil without supplying the hydraulic oil to the hydraulic mechanism and instructs the internal combustion engine controller to increase the speed of the internal combustion engine, and subsequently operates the hydraulic control valve unit to supply the hydraulic mechanism with the hydraulic oil.

An industrial vehicle includes a hydraulic mechanism, an operation lever, and a pump, a hydraulic control valve unit, a lever operation detector, an internal combustion engine controller, and a valve controller that controls the hydraulic control valve unit. When the lever operation detector detects the operation of the operation lever under a situation in which a speed of the internal combustion engine is less than or equal to a predetermined speed, the valve controller operates the hydraulic control valve unit to discharge the hydraulic oil without supplying the hydraulic oil to the hydraulic mechanism and instructs the internal combustion engine controller to increase the speed of the internal combustion engine, and subsequently operates the hydraulic control valve unit to supply the hydraulic mechanism with the hydraulic oil.

Method for deceleration of a hydrostatic transmission 3 driven by a drive motor 2 comprising a closed hydraulic fluid circuit, in which a hydraulic pump 4 coupled mechanically with the drive motor 2 and a hydraulic motor 5 are arranged. Two hydraulic lines 6, 7 connect the hydraulic pump 4 and the hydraulic motor 5 and constitute for the hydraulic motor 5 according to the drive direction of the hydrostatic transmission 3 a supply line 6 and a return line 7. In at least one of the two hydraulic lines 6, 7 a throttle valve 16 is arranged being adjustable in its throttle cross section which, if the corresponding hydraulic line 7 is a return line 7 for hydraulic fluid under high pressure towards the hydraulic pump 4 is being adaptable in its throttle cross section dynamically such that the adjustable hydraulic power in return line 7 downstream of throttle valve 16 at any time during a coasting mode corresponds to the maximum power being supportable at the drive motor 2 in consideration of the power consumption of auxiliary consumers 100 and power losses.

Method for deceleration of a hydrostatic transmission 3 driven by a drive motor 2 comprising a closed hydraulic fluid circuit, in which a hydraulic pump 4 coupled mechanically with the drive motor 2 and a hydraulic motor 5 are arranged. Two hydraulic lines 6, 7 connect the hydraulic pump 4 and the hydraulic motor 5 and constitute for the hydraulic motor 5 according to the drive direction of the hydrostatic transmission 3 a supply line 6 and a return line 7. In at least one of the two hydraulic lines 6, 7 a throttle valve 16 is arranged being adjustable in its throttle cross section which, if the corresponding hydraulic line 7 is a return line 7 for hydraulic fluid under high pressure towards the hydraulic pump 4 is being adaptable in its throttle cross section dynamically such that the adjustable hydraulic power in return line 7 downstream of throttle valve 16 at any time during a coasting mode corresponds to the maximum power being supportable at the drive motor 2 in consideration of the power consumption of auxiliary consumers 100 and power losses.

The invention provides a construction machine in which the load torque at the time of engine start-up can be reduced even when the engine stops against the will of the operator. A hydraulic excavator includes a control device (35) having a pump displacement control section (37) and an unload control section (38). The pump displacement control section (37) makes the displacement of a hydraulic pump (16) variable to a minimum displacement by controlling a regulator device (20) when the speed of an engine (14) detected by a speed sensor (41) becomes equal to or less than a preset low speed N3 at the time of driving of the engine (14). The unload control section (40) controls an unloading valve (24) to the open position at the time of start-up of the engine (14).

Hydrostatic adjusting device of a hydraulic machine, the swept volume of which can be adjusted by way of a servo adjusting unit, having a control unit which has a control cylinder which has at least one inlet for pressurized hydraulic fluid, at least one servo connector for a connecting line to the servo adjusting unit, and at least one outlet to a hydraulic fluid collecting region. A control piston is arranged in the control cylinder, which control piston can be displaced by means of at least one control piston actuator and has control edges. In interaction with control edges which are configured in the control cylinder, the inlet or the outlet can be alternately connected hydraulically to the connecting line, whereby the pressure which prevails in the connecting line can be returned hydraulically via a control line to at least one end side of the control piston.