Hybrid Construction Machinery

摘要

The purpose of the present invention is to operate an engine in a proper operation state while keeping the remaining amount in an electrical storage apparatus within a proper range. Hybrid construction machinery according to the present invention is provided with a controller for controlling an engine according to a governor characteristic having a predetermined inclination that defines a relationship between load torque and rotational speed so that the rotational speed decreases with an increase in the load torque. In the controller, a target engine power calculating unit (2-5) calculates a first target engine power that increases and decreases according to increases and decreases in output values of a load power calculating unit (2-1) and a charge/discharge request calculating unit (2-3), and a target rotational speed calculating unit (2-6) calculates, as a command value for a target rotational speed of a motor generator, a rotational speed at the intersection point of a governor characteristic line changed by a governor characteristic changing unit (2-4) and an equal power line dependent on the first target engine power on a rotating speed-torque characteristic line diagram.

主权项

1. Hybrid construction machinery, comprising:
an engine (1-1); a hydraulic pump (1-3) that is driven by the engine (1-1); a hydraulic working unit (16-3, 4, 5) that is driven by pressure oil discharged from the hydraulic pump (1-3); a motor generator (1-2) that transmits torque between the engine (1-1); an electrical storage apparatus (1-19) that feeds electric power to the motor generator (1-2); and a controller (1-8) that controls the engine (1-1) with a governor characteristic in which the relation between load torque and rotational speed has such predetermined inclination that the rotational speed reduces as the load torque increases, wherein the controller (1-8) includes: a governor characteristic changing unit (2-4) that changes setting of the governor characteristic; a load power calculating unit (2-1) that calculates load power on an engine shaft; an electrical storage remaining amount calculating unit (2-2) that calculates a remaining amount of the electrical storage apparatus (1-19); a charge/discharge request calculating unit (2-3) that calculates a charge/discharge request required for keeping electric power of the electrical storage apparatus (1-19) in a proper range based on an output of the electrical storage remaining amount calculating unit (2-2); a target engine power calculating unit (2-5) that calculates target power of the engine (1-1); a target rotational speed calculating unit (2-6) that calculates a target rotational speed command of the motor generator (1-2); and a motor generator control unit (2-7) that controls the motor generator (1-2) according to a target rotational speed command value calculated by the target rotational speed calculating unit (2-6), wherein the target engine power calculating unit (2-5) calculates first target engine power that increases and decreases according to increase and decrease of an output value from the load power calculating unit (2-1) and the charge/discharge request calculating unit (2-3), and wherein the target rotational speed calculating unit (2-6) calculates rotational speed of an intersection point of a governor characteristic line changed by the governor characteristic changing unit (2-4) and an equal power line dependent on the first target engine power on a rotational speed-torque characteristic diagram as a target rotational speed command value of the motor generator (1-2).