Study On Power Matching Of Hydraulic Excavators

Power system is an important part of the hydraulic excavators, with the development of diesel fuel injection technology, new energy-saving hydraulic circuit and hybrid systems, the traditional hydraulic excavator power matching method can not meet the new technical requirements.Beacuse of these,a new subject about the hydraulic excavator powertrain architecture and matching method has raised.Researchs of the excavator power system matching are usually worked by differential equations and transfer functions in some softwares, it is brings some deficiencies.the first,the calculation complexity, poor portability, debugging problems; the second, different software interface differences, resulting in the form of data conversion problems and error-prone; the third, can not reflect the dynamic matching process. All of those, it is necessary to find a new power system matching methodology.This paper started in the power system matching of23tons hybrid system hydraulic excavator.The electronically controlled diesel engine model, LUDV hydraulic control system model, hydraulic excavators mechanical structure model and system control unit integrated in the same simulation platform by the software named AMESim, the hydraulic excavator’s power system simulation matches do. Main works as below.(1) A dynamic model of the Cummins QSB6.7engine was built by AMESim, It can calculate indicators of engine power and economic, what’s more, it is able to reflect the dynamics of the engines work.Analyse and calculate the additional charge pump flow required in the conditions of high impact load or long pipe.(2) Based on the combination valve of Rexroth and typical23-ton hydraulic excavator mechanical structure, the machine’s load model has Established. This model is effectively two-dimensional hydraulic system and mechanical movement. It can reflect typical control characteristics of LUDV also can simulate a variety excavator working conditions.(3) Based on parallel hybrid system,the total model of parallel hybrid system hydraulic excavator has bulit up.At the same time, based on the division of state-based integrated control strategy has gave, the strategy division of the status of both control and fuzzy to control, and has a battery management and protection.Calculations show that each sub-model established right, at the same time, it can meet the needs of simulation and realistic conditions. The total model of parallel hybrid system hydraulic excavator can simulate a variety of excavators work and results consistent with the actual situation.Tthe control strategy proposed in the model has been well represented and achieved the desired dynamic indicators and economic indicators. Through analysis, with this program the system can reach the highest fuel efficiency of17.1%.All of those provide a reference for the hybrid excavator power Matching.