Improving the Fuel Efficiency of Compact Wheel Loader With a Series Hydraulic Hybrid Powertrain

Abstract

A wheel loader is representative construction machinery that is designed to load material in off-road applications. The vehicle moves back and forth in the loading process, showing great hydraulic hybridization potential. The research target in this study is a compact wheel loader. By adding hydraulic energy storage device - hydraulic accumulator, it is turned into a series hydraulic hybrid. In this paper the system modeling and controllers design of series hydraulic hybrid wheel loader were illustrated. A tunable energy management strategy has been proposed and studied. By changing the hybrid weight factor in the strategy, the powertrain hybridization degree was adjusted without any additional hardware. This study shows that higher use of the hydraulic accumulator power indicates a higher degree of hydraulic hybridization. Results show that the series hydraulic hybrid wheel loader has a fuel saving of 18.9% compared to a hydrostatic wheel loader in the short loading cycle. Studies had also been conducted to show the trade-off between the fuel consumption and the vehicle performance with different hybridization degrees.