Title: Power-on gear downshift of electric vehicles using I-AMT with an overrunning clutch

Authors: Jinlong Hong; Bingzhao Gao; Hong Chen

Addresses: State Key Laboratory of Automotive Simulation and Control, Jilin University (Campus NanLing), Renmin Str. 5988, Changchun 130025, China ' State Key Laboratory of Automotive Simulation and Control, Jilin University (Campus NanLing), Renmin Str. 5988, Changchun 130025, China ' State Key Laboratory of Automotive Simulation and Control, Jilin University (Campus NanLing), Renmin Str. 5988, Changchun 130025, China; Department of Control Science and Engineering, Jilin University (Campus NanLing), Renmin Str. 5988, Changchun 130025, China

Abstract: Torque interruption of automated manual transmission (AMT) electric vehicles (EVs) can be avoided by introducing a two-speed inverse AMT (I-AMT). An overrunning clutch is designed in this study to replace the traditional gear shift mechanism. The gear shift process of the introduced two-speed I-AMT with overrunning clutch can be divided into inertia and torque phases, and the control performance of the two phases greatly affects the overall shift quality. Unlike gear upshift, power-on gear downshift produces greater vehicle jerk due to its larger torque requirement. Thus, this study introduces the structure of the overrunning clutch and validates its dynamic characteristics. Then, the dynamics and control problems during power-on gear downshift are described in detail. A control scheme is also proposed, wherein optimal trajectory tracking control is used during the inertia phase and linear feedforward control is applied during the torque phase. Lastly, simulation results demonstrate that the seamless gear downshift of the proposed transmission can be realised whilst the shift shock is kept sufficiently small.

Keywords: power-on gear downshift; inverse-AMT; overrunning clutch; electric vehicle.

DOI: 10.1504/IJPT.2019.099631

International Journal of Powertrains, 2019 Vol.8 No.2, pp.115 - 131

Available online: 03 May 2019 *

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