The theory of the excavator’s hydraulic system was elaborated in the paper taking a 20t hybrid hydraulic excavator produced by a domestic company for example. The rotary movement of the hybrid hydraulic excavator was achieved by a newly developed electric motor, fuel consumption could be reduced as the result of the speed inhibition when the excavator standby. The modeling of excavator’s hydraulic system, front-end attachments and revolving frame were built on the AMESim platform according to the installation and actual sizes of the hydraulic components. By setting the parameters of every component in the model, mechanical- electronic- hydraulic integrated simulation was achieved. The paper focused on the solutions of hydraulic system’s pressure fluctuation and poor simulation results of front-end attachments. As a conclusion, appropriate solutions and simulation results were proposed to improve the precision.

Parallel-series is a kind of hybrid configuration which is used in excavator. This configuration can give full contribution to the energy saving potential of hybrid excavator. In the paper, based on the cycle power of excavator, the hybrid power-train’s parameters are matched. Then we analysis the matching results on the software simulation model we have built. The simulation results show that using this method the system can meet the power demand of excavator, and the efficiency of the excavator was improved.

THS II[1-3] is one of the most popular HEV configurations which has three power sources: an engine, an electric motor and a generator. When the engine is started, the dynamic response of engine will cause the vehicle to be power failure or great fluctuation. Therefore, in order to ensure good effect of vehicle dynamic coordination, it is necessary to use the electric motor's torque compensation principle to achieve dynamic coordination control of power sources, during the period of mode switch.