Development of Powertrain Integrated Energy Regeneration System in Hybrid Hydraulic Excavator

A new hybrid powertrain configuration of a hydraulic excavator which is integrated into an energy regeneration system to recover energy in a boom cylinder is presented in this paper. In which, a main pump is supplied power from both engine and an electric motor/generator. The working point of the engine can be adjusted by changing the speed of the electric motor/generator to maintain the engine in its high-efficiency region. During the moving down process, the potential hydraulic energy of the boom cylinder is converted to electric energy through a hydraulic motor and the electric motor/generator and stored in a battery. Then, during the acceleration process, the stored electrical energy can be discharged to the electric motor/generator (motor mode) to support the engine. A real test bench is fabricated to validate the advantage of the proposed powertrain. The experiment results indicated that the energy regeneration efficiency could reach up to 37%.