Energy efficiency analysis of integrated drive and energy recuperation system for hydraulic excavator boom

When the hydraulic excavator boom drops, the gravitational potential energy accumulated during the lifting process is converted into heat energy and dissipated through the throttling effect of hydraulic valve, which results in poor energy efficiency and higher temperature of hydraulic oil. A cooling system must be installed to lower the temperature, increasing the cost and complexity of the system. In order to solve the above problems, an integrated drive and energy recuperation system based on a three-chamber hydraulic cylinder is proposed. In the proposed system, one chamber of the three-chamber cylinder is directly connected to a hydraulic accumulator, storing and reusing the potential energy of the boom. The other two chambers are connected to the main driving circuit. The proposed system is first studied with an integrated co-simulation of the mechanical and hydraulic systems. Through the simulation, the energy saving performance of the new system is verified, and the initial pressure of the hydraulic accumulator is determined. In addition, the new system is tested on a 6-ton hydraulic excavator, and the results are compared with the ones of double-chamber hydraulic cylinder driving system. The test results show that with the proposed system, the energy consumption of the boom is reduced by 50.1% and the peak power of the power source is reduced by 64.9%. It is worth noting that the new method can be widely applied to all types of heavy lift device driven by hydraulic cylinders.