A hydraulic system for a mobile work vehicle is configurable in a hybrid mode and a hydrostatic mode. The hydraulic system includes a pump/motor, a propel circuit, a pump, a hydraulic accumulator, and an accessory circuit. The pump/motor is adapted to exchange power with a drive train of the mobile work vehicle. The propel circuit is adapted to exchange hydraulic fluid power with the pump/motor. The pump is adapted to transfer power from a prime mover of the mobile work vehicle to the propel circuit. The hydraulic accumulator is adapted to exchange hydraulic fluid power via an accumulator isolation valve with the propel circuit when the hydraulic system is configured in the hybrid mode. The accessory circuit is adapted to receive hydraulic fluid power from the hydraulic accumulator, at least when the hydraulic system is configured in the hydrostatic mode and the accumulator isolation valve is closed.

To provide a construction machine that appropriately sets the magnitude of an engine output for each work mode. A construction machine according to the present invention includes: an engine (22); a generator-motor (23) configured to generate electric power by the engine; a hydraulic pump (41) configured to be driven by the engine and the generator-motor; a hydraulic actuator (32, 34, 36) that drives and operates a working device (30) with the power of the hydraulic pump; an electric storage device (24) for supplying electric power to drive the generator-motor and charging the electric power generated by the generator-motor; a work-mode selecting device (45, 46) that selects a work mode corresponding to operation of an operator; and an engine-output setting unit (403, 405, 407) that sets the magnitude of the output of the engine corresponding to the work mode selected by the work-mode selecting device.

A transmission assembly for a work vehicle having an engine includes a variator operably connected to the engine, a gear arrangement configured to provide a selective gear reduction for transmission of output power from the variator to an output shaft, and an electrical machine unit. The electrical machine unit further includes a main shaft operably connected to the variator, a first rotor configured to rotatably drive a first shaft, a second rotor configured to rotatably drive a second shaft, and a clutch configured to selectively couple the first shaft or the second shaft, or both the first shaft and the second shaft, to the main shaft. The clutch, the first rotor, and the second rotor are operable to control a speed and rotational direction of the main shaft in providing rotational power to the variator.

A hybrid power train system for a tractor scraper is provided. The hybrid power train system may include a primary power source coupled to a first set of traction devices, a generator coupled to the primary power source, a first electric motor coupled to a second set of traction devices, an inverter circuit coupled to the generator and the first electric motor, an energy storage device coupled to the inverter circuit, and a controller operatively coupled to the inverter circuit. The controller may be configured to engage a first operation mode enabling electrical energy, supplied by the generator and the first electric motor, to be stored in the energy storage device, and engage a second operation mode enabling electrical energy, stored in the energy storage device, to be supplied to the first electric motor to drive the second set of traction devices.

A power transmission device includes an input shaft, an output shaft, a gear mechanism, an energy-generating motor, a first clutch, and a locking device. The energy storage unit is configured to store the energy generated by the energy-generating motor. The gear mechanism includes a planetary gear mechanism, which includes a first rotation element, a second rotation element, and a third rotation element, which are mutually different. The first clutch is provided in the power transmission route between the engine and the first rotation element. The locking device locks or releases the second rotation element. The energy-generating motor is connected to the third rotation element. A controller locks the second rotation element, converges the rotation speeds of two rotation shafts in the first clutch to cause the first clutch to engage, and rotates the energy-generating motor using drive power from the engine to thereby accumulate energy in the energy storage unit.

Provided is hybrid construction machine that can charge/discharge an electrical storage device appropriately and can suppress stop of an engine accompanying sharp increase of a load. The present invention includes a hybrid controller 22 that controls power of a hydraulic pump 17 and electric power of an inverter 15 in response to storage battery characteristics of the electrical storage device 16, and an output command unit 22F of the hybrid controller 22 is configured to control at least either one of the power of the hydraulic pump 17 and the electric power of the inverter 15 on the basis of at least either one of electric current or voltage of the storage battery characteristics and at least either one of temperature or a state of charge of the storage battery characteristics.

A shovel includes an attachment including a working assembly, a diesel engine provided with a supercharger, an oil hydraulic pump connected to the diesel engine provided with the supercharger, and a controller that executes a preload boost function, wherein the preload boost function is for increasing boost pressure of the supercharger prior to increasing a hydraulic pressure load on the oil hydraulic pump, wherein a range accessible by a predetermined part of the attachment includes a partial range at which, upon the working assembly being operated, the preload boost function is to be executed and a partial range at which, upon the working assembly being operated, the preload boost function is not to be executed.

The present disclosure relates to a power supply device for hybrid construction machinery, and more particularly, to a power supply device for hybrid construction machinery, which is capable of reducing engine loads and facilitating improvement of engine efficiency by excluding a starting motor used in general hybrid construction machinery and an alternator for charging a battery from hybrid construction machinery, such as a hybrid excavator or vehicle, which commonly uses an engine and an electric motor as a power source and includes an electric energy storage device, and a method for the same.

At the time of starting up an engine (9) using an assist motor generator (10), a main controller (28) lowers a lower limit value in a charge/discharge range of an electricity storage device (19) from a first lower limit value (min1) to a second lower limit value (min2) through an energy management control part (28B). The main controller (28) heightens the lower limit value in the charge/discharge range of an electricity storage device (19) from the second lower limit value (min2) to the first lower limit value (min1) when the start of the engine (9) is completed. Further, the main controller (28) displays engine stop prohibition information on a display device (30) when the start of the engine (9) is completed and when an SOC of the electricity storage device (19) falls below the first lower limit value (min1).

The object of the present invention is to provide a hybrid construction machine that can quickly warm up an electrical storage device and can improve the service life of the electrical storage device. This hybrid construction machine is equipped with: a prime mover (1); an electric motor that supplements the power of the prime mover (1) and generates electric power; an electrical storage device (8) that transmits power to and receives power from the electric motor; a warm-up circuit (25) that circulates a heating medium heated by waste heat from the prime mover (1) or the electric motor, or by a heater (40), to the vicinity of the electrical storage device (8); a control device that controls charging/discharging of the electrical storage device (8) and circulation of the heating medium of the warm-up circuit (25); and an outside air temperature measurement device that measures the outside air temperature. The control device executes warm-up operation by means of the heating medium, determines whether or not to execute charging/discharging of the electrical storage device (8) for the purpose of the warm-up operation in response to the outside air temperature measured by the outside air temperature measurement device, and conducts warm-up operation in which the warm-up operation by charging/discharging of the electrical storage device (8) is effected simultaneously.