Efficiency analysis and evaluation of energy-saving pressure-compensated circuit for hybrid hydraulic excavator

A hydraulic cylinder driven scheme combining a pressure compensator and an energy recovery device together has been proposed to achieve good control operation and energy-saving capability simultaneously. In this paper, its efficiency characteristics are further investigated in order to provide analytical and experimental references to practical applications. Since an excavator owns multiple actuators, a general schematic configuration including hydraulic cylinders with and without energy recovery is developed and analyzed. Based on the analysis of energy losses in every conversion, component selections and possible improvements are discussed, and then the design flowchart and criteria of key parameters are also presented. Finally, experiments under different load and velocity conditions are implemented on a test bench. Energy distributions, recovery efficiencies and component efficiencies are all evaluated.