A construction machine, comprising a hydraulic pump, a swing hydraulic motor, a swing electric motor, a delivery capacity regulating device, and a control unit which controls the driving/braking of the swing structure, is configured to comprise an operation amount detection device for detecting the operation amount of the swing control lever and a speed detection device for detecting the speed of the swing electric motor. The control unit includes a hydraulic pump output reduction control unit which takes in an operation amount signal representing the operation amount of the swing control lever detected by the operation amount detection device and a speed signal representing the speed of the swing electric motor detected by the speed detection device and controls the delivery capacity regulating device by calculating a reduction rate of the output of the hydraulic pump based on the detection signals.

A motor generator (27) is connected mechanically to an engine (21) and a hydraulic pump (23). The hydraulic pump (23) delivers pressurized oil to cylinders (11D) to (11F) in a working mechanism (11), a traveling hydraulic motor (25) and a revolving hydraulic motor (26). The revolving hydraulic motor (26) drives a revolving device (3) in cooperation with a revolving electric motor (33). The motor generator (27) and the revolving electric motor (33) are connected electrically to an electricity storage device (31). An HCU (36) sets a target electricity storage rate (SOC0) of the electricity storage device (31) and a pump output limit (POL0) of the hydraulic pump (23) corresponding to a mode selected by a mode selection device (38). The HCU (36) controls the engine (21), the motor generator (27), the revolving electric motor (33) and the electricity storage device (31) corresponding to the target electricity storage rate (SOC0) and the pump output limit (POL0).

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.

Construction machine including: an inverter; a battery; a battery controller; a main controller controlling the inverter based on limited power modes prescribed; and a display device displaying a remaining battery electric power. The main controller calculates open circuit voltage and battery resistance values of the battery at the state of energy of the battery based on the specification information about the battery and state of energy of the battery which are input from the battery controller, calculates an amount of electric power stored in the battery in each of the limited power modes based on the open circuit voltage value and battery resistance value of the battery as well as limited power and operating voltage prescribed for each of the limited power modes, and outputs a display signal for displaying the amount of electric power stored in the battery in each of the limited power.

The hybrid construction machine includes an engine 11, an electric motor/generator 14, a hydraulic pump unit 17, an electricity storage device 16, an inverter 15, a temperature regulator (16D or 16E), and a hybrid control unit 22. The hybrid control unit 22 executes at least one of first control for controlling a warming-up battery temperature regulator 16D so that it increases a temperature of the electricity storage device 16, second control for controlling the inverter 15 so that it reduces the power output from the inverter 15, and third control for controlling a pump capacity control unit 21 so that it reduces the flow rate of a hydraulic fluid delivered from the hydraulic pump unit 17, according to a charge/discharge history of the electricity storage device 16.

A cylinder has a piston part, a cylinder part, and a pipe section connected to the piston or cylinder parts. A portion of the pipe section encloses a pressure compartment which receives a fluid to apply a pressure on a pressure surface so the piston part is displaced in a first stroke direction. A first return pressure compartment receives a fluid to apply a pressure on a first return pressure surface so that the piston part is displaced in a second return stroke direction. The first return pressure compartment is positioned on the outside of the pipe section, and the area of the first return pressure surface is substantially equal to the area of the return pressure surface so that a volume-neutral operation of the cylinder is provided. Also described is a hydraulic system, an excavator comprising the cylinder and a procedure for operation of the cylinder.

The power-transmission device has an input shaft, an output shaft, a gear mechanism, and a motor. The gear mechanism includes a plurality of planetary gear mechanisms and a mode-switching mechanism, and transmits the rotations of the input shaft to the output shaft. The mode-switching mechanism selectively switches the drive-power transmission path of the power-transmission device between a plurality of modes. The motor is connected to the rotating elements of the planetary gear mechanisms. A target-input-torque determination unit determines the target input torque, which is a target value for the torque to be inputted to the power-transmission device. The target-output-torque determination unit determines the target output torque, which is a target value for the torque to be outputted from the power-transmission device. The command-torque determination unit uses the torque balance information to determine torque commands to the motor from the target input torque and the target output torque.

There are provided an electric motor (12) that is driven by an engine (8) to generate electric power or assists in a drive of the engine (8) by supply of electric power thereto, a heat exchanger (13) to which cooling air is supplied by a cooling fan (8A), a heat exchanger upstream room (28) that is positioned upstream of the heat exchanger (13) in a flow direction of the cooling air supplied to the heat exchanger (13), and an electricity storage device (30) that stores or discharges electric power. In addition, a radiator (42) for electricity storage device, a cooling pump (43) for electricity storage device and a cooling line (44) for electricity storage device configure a cooling system (41) for electricity storage device that independently cools the electricity storage device (30) aside from the inverter device (34), and the cooling system (41) for electricity storage device is arranged in the heat exchanger upstream room (28).

A machine control system controls operation of any one of a plurality of interchangeable power sources mounted on a machine. The machine includes an undercarriage supporting ground engagement members that propel the machine and an upper structure rotatably supported on the undercarriage. The upper structure includes a swing frame that supports an operator cab, an interchangeable power source, hydraulic components, and electrical components. The machine control system includes a processor configured to receive variables, control parameters, and standards associated with operation of each of the plurality of power sources from one or more of sensors, input devices, output devices, and memory communicatively coupled to the processor, utilize control logic, machine operational inputs and outputs, sensed and processed signals associated with position, movement, and operation of the machine, and one or more of stored, sensed, and processed data, variables, control parameters, and standards to process outputs and operating characteristics specific to each of the plurality of power sources, and standardize the power output by each of the power sources to provide a normalized, consistent control and operation of systems of the machine regardless of which of the power sources is mounted on the machine.

A hybrid-type construction machine includes: a motor generator system connected to an internal combustion engine and performing a motor generator operation; an electric power accumulation system connected to the motor generator system; a load drive system connected to the electric power accumulation system and being driven electrically; an abnormality detection part equipped to the motor generator system, the electric power accumulation system and the load drive system; and a main control part determining whether an abnormality has occurred based on a detection value of the abnormality detection part. When the abnormality determination part determines that an abnormality has occurred, the main control part stops a drive of a drive system in which the abnormality is detected in the load drive system.