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U.S. Department of Energy
Office of Scientific and Technical Information

Method of and system for controlling hydraulic power system

Patent ·
OSTI ID:5147066
A method is described of controlling a hydraulic power system comprising an internal combustion engine receiving a supply of fuel from a fuel injection pump, and at least one variable displacement hydraulic pump driven by the internal combustion engine. The method consists of: (a) obtaining an engine speed deviation from the difference between a target speed set by an accelerator operation of the internal combustion engine and an output speed of the engine; (b) obtaining a fuel injection target value based on at least the engine speed deviation, the fuel injection target value being in predetermined functional relationship to the deviation; (c) controlling a fuel injection rate of the fuel injection pump based on the fuel injection target value; (d) determining, at the same time, a displacement volume target value of the hydraulic pump based on at least the engine speed deviation and an actual discharge pressure of the hydraulic pump in such a manner that an input torque of the hydraulic pump decreases as the engine speed deviation increases; (e) controlling the displacement volume of the hydraulic pump based on the displacement volume target value; and wherein in step (b), the fuel injection target value is in a functional relationship to the engine speed deviation in such manner that the target value increases substantially linearly until the deviation reaches a predetermined value and has a substantially constant maximum value after the deviation has reached the predetermined value.
Assignee:
Hitachi Construction Machinery Co., Ltd., Tokyo
Patent Number(s):
US 4606313
OSTI ID:
5147066
Country of Publication:
United States
Language:
English