Hybrid powertrain with dual energy regeneration for boom cylinder movement in a hydraulic excavator

Abstract

This paper presents a powertrain integrated with an energy regeneration system designed to decrease energy consumption and emissions in hybrid hydraulic excavators. The feature of this powertrain is its integration of a hydrostatic transmission (HST), which optimizes torque and speed between the pump and power sources. Additionally, the energy regeneration system includes two distinct methods: employing an independent hydraulic motor or utilizing the hydraulic motor mode of the main hydraulic pump/motor to recapture potential energy from the boom cylinder. Furthermore, an energy management approach, leveraging an equivalent consumption minimization strategy, is proposed to distribute power requirements, aiming to maximize engine efficiency. Compared to existing hybrid and conventional systems, both experimental and simulation results show that the proposed system can achieve energy savings of up to 61.64%. Additionally, the energy regeneration efficiency of the proposed system can reach up to 73% during the cylinder lowering process.