Innovative powertrain and advanced energy management strategy for hybrid hydraulic excavators

This paper presents an innovative powertrain managed by an advanced energy management strategy for hybrid hydraulic excavators to improve the overall energy efficiency. Here, a main pump is driven via a planetary gear by an engine and an electric motor/generator. A double clutch is integrated to adjust torque and speed of engine according to efficiency map enabling higher working efficiency. Potential energy of the boom cylinder can be converted and stored in a battery through an energy regeneration system. The advanced energy management strategy is designed by utilising extremum seeking and fuzzy techniques to optimally distribute power requirement. A fuzzy logic system is designed based on consideration of battery performance and aging to adjust a penalty function subsequently improving the overall system performance while prolonging the component lifetime. Simulations and real-time experiments have been carried out to evaluate the effectiveness of the proposed powertrain managed by the advanced energy management strategy.