Potential energy recovery method based on alternate recovery and utilization of multiple hydraulic cylinders

摘要

The working device weight of hydraulic excavators far exceeds that of its lifted material, requiring a large amount of energy to maintain the frequent motion of lifting and lowering. Recovering and utilizing this energy is an effective means of energy-saving for excavators. The existing electric recovery method faces disadvantages which include excessive energy conversion, a complicated system, and high cost. In this paper, an energy alternate recovery and utilization system (EARUS) based on multiple hydraulic cylinders is proposed. The concept of weight-balanced is applied to match the weight of the working device with the pressure of the hydraulic accumulator. Energy alternate recovery and utilization are realized in different hydraulic cylinders, so that the weight-balanced circuit and the original system perform the necessary oil exchange, overcoming the reliability problem of the existing isolated weight-balanced system with long-term operation. The efficiency of EARUS is comprehensively analyzed through simulation and an experiment using the methodology of energy flow decomposition. The working device motion characteristics of EARUS are then quantitatively analyzed. Results show that, compared with the original system, the energy recovery efficiency of EARUS is 65.9%, and the comprehensive energy-saving rate is 41.6%. The boom single-action time is shortened by 2.6 s, and the velocity fluctuation of the boom cylinder at the start of lowering decreases by 75%. The research findings provide an important framework for the engineering applications of this new system.