Abstract
KEYWORDS – Hybrid electric vehicle (HEV), Powertrain configuration, Dynamic programming (DP), Performance map, Fair comparison
ABSTRACT –
In this paper, the full potentials of five selected powertrain configurations are investigated and compared. First, the four representative commercialized powertrain configurations in HEV market were selected: parallel, series-parallel, multi-mode THS II with speed reduction gear, and 2nd generation volt. In addition to four typical configurations, the new configuration which was developed at KAIST (Korea Advanced Institute of Science and Technology) Vehicle Dynamics and Control Lab (VDC Lab), was included as well. Evaluation and comparison of five powertrain configurations’ full potentials are non-trivial, because there are many design variables; planetary gear ratio, transmission gear ratios, final drive gear ratio, and component size. Since parallel system has a transmission, an equitable comparison of HEVs is challenging because of different cost. In this study, it is assumed that a transmission cost is comparable to the small electric machine, it enables to compare those systems fairly. The same vehicle specification has applied to over all five powertrain configurations to fix the cost of five configurations. Furthermore, possible combinations of design variables are considered for each configuration in order to ensure that the full potentials of each HEV powertrain configurations. Both the fuel economy and acceleration performance are evaluated by using a global optimal control algorithm, Dynamic Programming (DP). Simulation results shows that the new developed powertrain configuration of KAIST has superior performance compare to the others.