Boom Potential Energy Regeneration Method for Hybrid Hydraulic Excavators

Affected by complex operating conditions and working characteristics of the hydraulic system, hydraulic excavators suffer from large energy consumption, low energy utilization rate, and poor emissions for a long time. To improve the energy utilization efficiency and reduce the energy consumption of hydraulic excavators, a novel boom potential energy regeneration system (BPERS) for hybrid hydraulic excavators is proposed. Firstly, the structure and the working principle of the BPERS are explained, while a conventional boom-driving system (CBS) and an energy alternate recovery and utilization system (EARUS) are presented for comparison. Secondly, the mathematical model is established according to the system structure, following which the influence of the key component parameters on the energy-saving efficiency of the BPERS is analyzed. Then, an Amesim simulation model for both BPERS and CBS is established. The simulation results show that about 79.1% of boom potential energy can be recovered by the BPERS in the boom descends process, while the comprehensive energy-saving efficiency is 54.6% in a complete boom lowering and lifting process. Finally, a 50t hybrid hydraulic excavator test prototype is constructed, and the comparative experiments demonstrate that the BPERS significantly reduces the output energy of the main pump from 1039KJ to 576.1KJ in a certain working cycle, resulting in a comprehensive energy-saving efficiency of approximately 44.6%, which further confirmed the feasibility and outstanding energy-saving performance of the proposed method.