Performance analysis and parametric design of the dual-mode planetary gear hybrid powertrain

Abstract

The multimode electrically variable transmissions (EVTs) are an advancement of the conventional planetary gear hybrid powertrains (PGHPs). Using the analytical methodologies once applied to the single-mode PGHP, the dual-mode PGHP was investigated. The transmission efficiency and the system optimal operation point maximizing the system overall efficiency were analysed. With the system optimal operation points, the fuel economies of the dual-mode PGHP vehicle were calculated assuming constant-velocity cruising and NEDC mode driving. The top velocity and the acceleration performance were also estimated. To assign appropriate parameters for the new system, the design space and the optimization problem were defined using the vehicle performances from the analyses. An approach with various optimization techniques is proposed, and the optimal parametric design is obtained. The dual-mode PGHP showed improvements in efficiency and dynamic performances compared with the single-mode PGHP. In particular, the powertrain is expected to have advantages because it uses a smaller-sized motor/generator (MG) or two identical machines as two MGs.