| 摘要 |
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. |
| 主权项 |
1. A construction machine provided with:
an engine, a motor generator that performs a power assist to the engine and electricity generation, an electrical storage device that performs a transfer of electric power with the motor generator, a hydraulic pump that is driven by the engine and motor generator, a rotational speed sensing device that detects an actual rotational speed of the engine, an engine controller that performs, based on the actual rotational speed of the engine as detected by the rotational speed sensing device and a target rotational speed for the engine, control to produce a torque from the engine, and a vehicle body controller that controls an operation of a vehicle body, wherein: the vehicle body controller includes: a load estimation unit that estimates a power absorption by the hydraulic pump, a regeneration/powering power demand calculation unit that according to a state of charge in the electrical storage device, calculates a power demand for a regenerative operation or powering operation of the motor generator, an engine power demand calculation unit that calculates a power demand to the engine based on the power absorption estimated by the load estimation unit and the power calculated by the regeneration/powering power demand calculation unit, and a motor generator control unit configured to perform rotational speed control, which makes the motor generator generate a torque based on a target rotational speed for the motor generator, or torque control, which makes the motor generator generate a torque based on a target torque for the motor generator; the motor generator control unit has a control switching unit configured to switch the rotational speed control and the torque control according to the power calculated by the engine power demand calculation unit and the actual rotational speed of the engine as detected by the rotational speed sensing device; and the control switching unit is configured to switch from the torque control to the rotational speed control when during the performance of the torque control, the power demand to the engine increases and the actual rotational speed of the engine becomes lower than a predetermined first rotational speed. |
