Hybrid construction machine

摘要

The present charging rate of a battery is accurately calculated. The calculation mode of the present charging rate is switched to a current integration mode during operation of a generator motor while the mode is switched to a voltage reference mode at a predetermined switchover timing. In the current integration mode, charge current of the battery is integrated and added to the initial charging rate and an integrated discharge current value is subtracted from the initial charging rate of the battery to calculate the present charging rate. In the voltage reference mode, the present charging rate is calculated based on a predetermined map and detected voltage of the battery. After calculation of the present charging rate according to the voltage reference mode, the calculation mode is restored from the voltage reference mode to the current integration mode and the suspension of operating the generator motor is cancelled.

主权项

1. A hybrid construction machine, comprising:
a hydraulic actuator; a battery; an engine as a power source; a hydraulic pump which is connected to the engine as a hydraulic source for the hydraulic actuator; a generator motor which is connected to the engine, charges the battery by acting as a generator by power from the engine and assists the engine by acting as an electric motor by electric power from the battery; a voltage detector which detects terminal voltage of the battery; a current detector which detects charge current and discharge current of the battery; a work electric motor electrically connected to the battery and the generator motor; an operating member which is operated to drive the work electric motor; an operation detector which detects operation to the operating member; and a controller which calculates a present charging rate as a currently remaining charged amount of the battery, wherein the controller (A) can switch over a calculation mode of calculating the present charging rate between a current integration mode, in which the charge current and the discharge current of the battery detected by the current detector are integrated and the integrated value of the charge current is added to an initial charging rate of the battery as well as the integrated value of the discharge current is subtracted from the initial charging rate of the battery to calculate the present charging rate, and a voltage reference mode in which the present charging rate is determined based on a predefined relation between terminal voltage and charging rate of the battery and terminal voltage of the battery detected by the voltage detector; (B) calculates, during operation of the generator motor, the present charging rate according to the current integration mode, forces the generator motor to suspend operation in a case that the operation detector detects that there is no operation for driving the work electric motor after a switchover time is determined to arrive at a predetermined switchover timing, and calculates the present charging rate according to the voltage reference mode; and (C) after calculation of the present charging rate according to the voltage reference mode, restores the calculation mode back to the current integration mode from the voltage reference mode and cancels the suspension of operating the generator motor, and wherein the predetermined switchover timing is set such that a degree of accumulated error in the current integration mode is not excessive or beyond a certain amount.