Provided is a hydraulic driving apparatus including a calculation section calculating a temporary target engine rotation speed corresponding to an engine operation amount, a calculation section calculating a temporary target pump displacement volume based on first-control and second-control target pump displacement volumes corresponding to an actuator operation amount and a pump load pressure, and a command section calculating a final target engine rotation speed and a final target pump displacement volume to output commands. The command section calculates a target pump discharge amount from the temporary target engine rotation speed and the temporary target pump displacement volume, sets the final target pump displacement volume to one larger than the temporary target pump displacement volume, and sets the final target engine rotation speed to one being lower than the temporary target engine rotation speed and allowing a pump discharge amount equivalent to the target pump discharge amount to be obtained.

Provided is a hydraulic driving apparatus including a calculation section calculating a temporary target engine rotation speed corresponding to an engine operation amount, a calculation section calculating a temporary target pump displacement volume based on first-control and second-control target pump displacement volumes corresponding to an actuator operation amount and a pump load pressure, and a command section calculating a final target engine rotation speed and a final target pump displacement volume to output commands. The command section calculates a target pump discharge amount from the temporary target engine rotation speed and the temporary target pump displacement volume, sets the final target pump displacement volume to one larger than the temporary target pump displacement volume, and sets the final target engine rotation speed to one being lower than the temporary target engine rotation speed and allowing a pump discharge amount equivalent to the target pump discharge amount to be obtained.

Provided is a hybrid work machine in which a hybrid system and a downsized engine are used. The hybrid work machine improves fuel consumption, improves exhaust characteristics, and reduces noise. The hybrid work machine also performs rapid charging of a power storage device while preventing decreases in the output power of a hydraulic pump if the charge amount of the power storage device is extremely insufficient. A vehicle body controller 46 performs engine revolution speed decreasing control in which, if the charge rate of a battery 33 becomes equal to or less than a minimum charge rate, the target revolution speed of an engine 11 is reduced. The vehicle body controller also performs torque reducing control in which the maximum absorption torque of a hydraulic pump 21 is reduced. By performing these control operations, the vehicle body controller coercively generates surplus torque for the engine and operates a generator-motor 31 as a generator with the use of the surplus torque, thereby rapidly charging the battery.

A power transmission includes first and second clutches for switching a transmission path for a driving force. A work vehicle includes a clutch controlling unit and an engine controlling unit. The clutch controlling unit is configured to determine which of first and second modes the transmission path is switched into based on which of a range of greater than or equal to a mode switching threshold and a range of less than or equal to the mode switching threshold a speed ratio parameter falls into, and is configured to output a clutch command signal causing one of the first and second clutches to be engaged corresponding to the determined mode. The engine controlling unit is configured to apply an offset to a rotational speed of an input shaft such that after switching into the determined mode, the speed ratio parameter deviates from the mode switching threshold in the switched mode.

A power transmission includes first and second clutches for switching a transmission path for a driving force. A work vehicle includes a clutch controlling unit and an engine controlling unit. The clutch controlling unit is configured to determine which of first and second modes the transmission path is switched into based on which of a range of greater than or equal to a mode switching threshold and a range of less than or equal to the mode switching threshold a speed ratio parameter falls into, and is configured to output a clutch command signal causing one of the first and second clutches to be engaged corresponding to the determined mode. The engine controlling unit is configured to apply an offset to a rotational speed of an input shaft such that after switching into the determined mode, the speed ratio parameter deviates from the mode switching threshold in the switched mode.

A construction machine includes an engine, a load estimation unit that estimates a pump power absorption, a regeneration/powering power demand calculation unit that calculates a regeneration/powering power demand according to a state of charge in an electrical storage device, an engine power demand calculation unit that calculates an engine power demand based on the power absorption and regeneration/powering power demand, and a motor generator control unit that performs rotational speed control or torque control. The control unit includes a control switching unit that switches the rotational speed and the torque control according to the engine power demand and the rotational speed of the engine. The control switching unit switches from the torque control to the rotational speed control when during performance of the torque control, the engine power demand increases and the rotational speed of the engine becomes lower than a predetermined rotational speed.

A hydraulic pump is driven by an engine. A hydraulic motor is driven by hydraulic fluid discharged from the hydraulic pump thereby causing a vehicle to travel. A controller controls a rotation speed of the engine and a displacement of the hydraulic pump. The controller acquires a tractive force of the vehicle. The controller changes the rotation speed of the engine to a low speed side in accordance with a reduction in the tractive force.

The present invention relates firstly to a method for operating a compressor powered by an internal combustion engine for compressing air. Furthermore, the invention relates to a compressor, which is suitable for executing the method according to the invention. A first turbocharger for supplying pre-compressed air to the internal combustion engine is disposed in an exhaust flow of the internal combustion engine. Furthermore, a second turbocharger for pre-compression of the air to be compressed by the compressor is disposed in the exhaust flow of the internal combustion engine. The method according to the invention first comprises a step in which a monitoring of a pressure of the pre-compressed air generated by the first turbocharger occurs during an operating state of the compressor. In a further step of the method, a termination of the operating state occurs as soon as the monitored pressure falls below a previously determined value.

Provided is a forced-regeneration treatment method for an exhaust-gas aftertreatment device (DPF) and an associated engine-driven compressor. When the amount of particulate matter (PM) deposited in a filter element of a DPF reaches a predetermined amount and a forced-regeneration start command is input, a capacity controlling means of the engine-driven compressor is disabled to close an intake valve and to open the discharge side of a compressor main unit to atmosphere, thereby causing the compressor main unit to achieve a low-load state. The operation mode of the engine is switched to a predetermined forced-regeneration mode to operate the engine at a predetermined speed and to increase the temperature of the gas. The temperature inside the DPF is increased to reach a temperature at which an oxidative catalyst is activated and to a temperature lower than the self-combustion temperature of the PM, thereby forcibly burning the PM.

A prime mover and a plurality of hydraulic actuators, a hydraulic machine having a rotatable shaft in driven engagement with the prime mover and comprising a plurality of working chambers, a hydraulic circuit extending between a group of one or more working chambers of the hydraulic machine and one or more of the hydraulic actuators, each working chamber of the hydraulic machine comprising a low-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a low-pressure manifold and a high-pressure valve which regulates the flow of hydraulic fluid between the working chamber and a high-pressure manifold. The hydraulic machine being configured to actively control at least the low-pressure valves of the group of one or more working chambers to select the net displacement of hydraulic fluid by each working chamber on each cycle of working chamber volume, and thereby the net displacement of hydraulic fluid by the group of one or more working chambers, responsive to a demand signal, wherein the apparatus further comprises a controller configured to calculate the demand signal in response to a measured property of the hydraulic circuit or one or more actuators.