An energy saving rule-based strategy for electric-hydraulic hybrid wheel loaders

Abstract

Recently, hybrid electric vehicles are getting popular as they are both clean and efficient. As one of the hybrid electric powertrains, the battery powered parallel electric-hydraulic hybrid powertrain (PEHHP) is zero emission and has better drive performance. But the energy use of the PEHHP highly depends on the control strategy. A proper energy management strategy is critical for torque distribution and hybrid powertrain efficiency improvement. In this paper, a real-time rule-based strategy is proposed to determine the torque distributions of the PEHHP. The proposed rule-based strategy is based on the component efficiency analysis. And it optimizes the electric motor operating points. Experiments are conducted to show the operation results of the parallel electric-hydraulic hybrid wheel loaders. The powertrain energy use of the proposed rule-based strategy is close to that of the global optimal dynamic programing strategy, with energy use gaps of 2.99%, and 6.10% in simulation and experiment respectively.