1. Professor, Research Center for Advanced Powertrain Technology, Dept. of Energy and Power Engineering, Hunan Univ., Changsha 410082, China.
2. Postgraduate, Research Center for Advanced Powertrain Technology, Dept. of Energy and Power Engineering, Hunan Univ., Changsha 410082, China.
3. Professor, Key Laboratory of Shaanxi Province for Development and Application of New Transportation Energy, School of Automobile, Chang’an Univ., Xi’an 710064, China (corresponding author).