1. Professor, School of Energy and Power Engineering, Beihang Univ., Beijing 100191, China.
2. Ph.D. Candidate, School of Energy and Power Engineering, Beihang Univ., Beijing 100191, China.
3. Ph.D. Candidate, School of Transportation Science and Engineering, Beihang Univ., Beijing 100191, China.
4. Lecturer, School of Transportation Science and Engineering, Beihang Univ., Beijing 100191, China (corresponding author).