Title: Discrete ratio control strategy of the automotive powertrain with electro-mechanical continuously variable transmission

Authors: Junlong Liu; Dongye Sun; Xiaojun Liu; Yong You; Sheng Liu

Addresses: College of Transportation, Shandong University of Science and Technology, Qingdao 266590, China; State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China ' State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China ' State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China ' State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China ' State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China

Abstract: In the automotive powertrain with electro-mechanical continuously variable transmission (EMCVT), a small fluctuation of the throttle opening or the velocity will lead to the fluctuation of the EMCVT speed ratio. However, the speed ratio variation is useless and will increase the energy consumed by the EMCVT actuator. In this study, a discrete ratio control strategy is proposed to solve this problem. The continuous speed ratio of the EMCVT is discretised based on discretised engine speed. In order to verify its effectiveness, this ratio control strategy is simulated with the EMCVT powertrain model using MATLAB/Simulink. The results show that the speed ratio fluctuation is eliminated with the discrete ratio control strategy and the energy consumed by the EMCVT actuator is reduced, and the results also show that the discrete ratio control strategy has a positive effect on the vehicle comfort performance.

Keywords: vehicle design; automotive powertrain; EMCVT; electromechanical continuously variable transmission; discrete speed ratio control strategy; transmission performance; dynamic performance; economic performance.

DOI: 10.1504/IJVD.2019.110735

International Journal of Vehicle Design, 2019 Vol.81 No.1/2, pp.76 - 92

Accepted: 12 May 2020
Published online: 28 Oct 2020 *

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