Hybrid working machine
AssigneeSumitomo Heavy Industries, Ltd.
InventorKoji Kawashima
Life of this patent
Estimating the term…
Abstract
A hybrid working machine includes an engine, a motor generator connected to the engine, a variable displacement hydraulic pump configured to be driven to rotate with the output of the engine, and a control part configured to control the rotation speed of the engine and the variable displacement hydraulic pump. The control part is configured to determine the target rotation speed of the variable displacement hydraulic pump based on a hydraulic load and control the rotation speed of the engine using the target rotation speed.
Claims9
A hybrid working machine, comprising:
- an engine fed with fuel;
- a motor generator connected to the engine and driven by an inverter to assist the engine and to generate electric power;
- a variable displacement hydraulic pump mechanically connected to the engine and configured to be driven to rotate by the engine;
- and
- a control part configured to control the engine and the variable displacement hydraulic pump,
- wherein the control part is configured to
- estimate a hydraulic load of the variable displacement hydraulic pump based on a discharge pressure, a control current and a rotation speed of the variable displacement hydraulic pump,
- calculate a target discharge flow rate of the variable displacement hydraulic pump based on the estimated hydraulic load,
- calculate a rotation speed command for the engine based on the calculated target discharge flow rate of the variable displacement hydraulic pump and a tilt angle ratio of the variable displacement hydraulic pump, the tilt angle ratio being 90% to 100% of a maximum value of the tilt angle ratio,
- control a rotation speed of the engine based on the calculated rotation speed command for the engine, and
- determine an output of the motor generator based on the calculated rotation speed command for the engine.
A method of controlling a hybrid working machine, the hybrid working machine including an engine fed with fuel, a motor generator connected to the engine and driven by an inverter to assist the engine and to generate electric power, and a variable displacement hydraulic pump mechanically connected to the engine and configured to be driven to rotate by the engine, the method comprising:
- estimating a hydraulic load of the variable displacement hydraulic pump based on a discharge pressure, a control current and a rotation speed of the variable displacement hydraulic pump;
- calculating a target discharge flow rate of the variable displacement hydraulic pump based on the estimated hydraulic load;
- calculating a rotation speed command for the engine based on the calculated target discharge flow rate of the variable displacement hydraulic pump and a tilt angle ratio of the variable displacement hydraulic pump, the tilt angle ratio being 90% to 100% of a maximum value of the tilt angle ratio;
- controlling a rotation speed of the engine based on the calculated rotation speed command for the engine;
- and
- determining an output of the motor generator based on the calculated rotation speed command for the engine.
Dependencies are inferred from the claim text.