A study on an energy saving electro-hydraulic excavator

Nowadays with the high fuel prices, the demands for energy saving and green emission of construction machinery, without sacrifice of working performance, safety and reliability, especially hydraulic excavators, has been highly increased. As a result, electro-hydraulic hybrid system, which are promoted and successfully applied to automobile industry, is recently introduced to hydraulic excavators. The aim of this paper is to propose a new energy saving hybrid excavator using an electro-hydraulic circuit design driven by an electric motor/generator for the generation of potential energy. Consequently, a 5 ton class hybrid excavator is analyzed, developed with the boom arm for the evaluation of the designed system. The hardware implementation is also present in this paper. A control strategy for the hybrid excavator is built to operate the machine with a highest efficiency. The energy saving capacity of the proposed excavator is clearly verified through simulation results in a comparison with a conventional hydraulic excavator.