1. Ph.D. Student, School of Mechanical, Electronic and Control Engineering, Beijing Key Laboratory of Powertrain for Energy Vehicle, Beijing Jiaotong Univ., Beijing 100044, P.R. China.
2. Professor, School of Mechanical, Electronic and Control Engineering, Beijing Key Laboratory of Powertrain for Energy Vehicle, Beijing Jiaotong Univ., Beijing 100044, P.R. China (corresponding author).
3. M.A. Student, School of Mechanical, Electronic and Control Engineering, Beijing Key Laboratory of Powertrain for Energy Vehicle, Beijing Jiaotong Univ., Beijing 100044, P.R. China.