Comparison of four-wheel-drive hybrid powertrain configurations

The stringent fuel economy and emission standards enforce sport sedan and sport utility vehicle employ four-wheel-drive (4WD) hybrid powertrain to achieve better fuel economy and acceleration performance simultaneously. This paper reviews and conducts a comparative study of four 4WD hybrid configuration types: series, series-parallel, power-split and compound-split configurations. To make a fair comparison of fuel economy and acceleration performance, an integrated hierarchical optimization framework is presented, which solves the parameters sizing and energy management problem simultaneously. The pareto-front optimal design of each configuration is derived. According to detailed energy analysis, a novel multi-mode configuration is proposed by adding clutches between planetary gear nodes of compound-split configuration. By combining multiple modes, the proposed configuration achieves better fuel-saving and acceleration performance than initial configuration. Moreover, this comparative study takes into consideration the cost, control complexity and off-road performance. The results show that the power-split one adopting three motor/generators (MGs) shows superior fuel economy and acceleration performance than others, while the proposed multi-mode configuration maintains a competing performance with less MGs. In addition, the series-parallel configuration has great comprehensive potential. (C) 2020 Elsevier Ltd. All rights reserved.