Electro-Hydrostatic Actuator System With Separate Design to Improve Efficiency for Working Function of Electric Wheel Loader

Abstract Powertrain electrification is an effective solution to reducing emissions of construction machinery. However, working function of current electric wheel loaders still employs electric motors paired with centralized load-sensing system. The system suffers from low energy efficiency because of valve throttling losses. The electro-hydrostatic actuator (EHA) emerges as an efficient way to enhance energy efficiency. The velocity of actuator is controlled by electric motor or pump directly, eliminating throttling losses from control valve. Therefore, a separate electro-hydrostatic actuator system is proposed for working function of electric wheel loader, to prevent additional load and utilize commercially available hydraulic components. Modeling and parameter design are conducted. A mode-based control strategy is developed. The simulation study is carried out to verify the feasibility of system and control strategy. The system performance and energy comparison between proposed system and centralized load-sensing baseline system are conducted. Results demonstrate the efficiency of proposed system improves from 37.6% to 71.9% compared to baseline system.