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The powertrain system plays a crucial role in electric vehicles, exerting significant impact on both the dynamic and economic performances. A breakthrough has been observed by using the dual-motor powertrain system, which outperformed its single-motor counterparts. This study reports a dual-motor powertrain with magnetorheological technology. The powertrain consists of two motors, two magnetorheological brakes and a planetary gear set. Via regulating the brakes, the power transmission flow can be controlled to realise different torque ratios and velocities. The synergetic control of motors and brakes is capable of achieving smooth gear shifting without interruption. This paper details the design of the powertrain system: the structural configuration of the magnetorheological brakes is highlighted, the magnetic field distribution of the brakes under different currents is simulated by COMSOL Multiphysics, and the torque capacities of the brake are also calculated.

Using highly efficient powertrain is one of the most important and effective approaches to increase the driving distance of electric vehicles (EVs). In this paper, a novel two-speed dual-clutch transmission (DCT) is proposed. The transmission is comprised of two traditional friction clutches and two-stage planetary gear sets. One clutch connects the input sun gear and the other connects the input carrier. The Simulink models including an electric motor and two-speed DCT are established. Gearshift schedule based on fuzzy logic which reflects the driver’s intensions is adopted to improve the dynamic and economic performance of the novel transmission. The simulation model is built using MATLAB/Simulink® to validate the effectiveness of the proposed gearshift schedule compared with the conventional two-parameter gearshift schedule. Simulation results show that both the dynamic and economic performance of the novel DCT for EVs are improved with the proposed fuzzy logic gearshift schedule.

A novel magnetorheological fluid dual clutch (MRFDC) for electric vehicle transmission is proposed in this article. The structure was based on the MR fluid clutch and traditional dual clutch equipped on internal combustion engine vehicle. Therefore the MRFDC combines the advantages of MR fluid clutch and dual clutch transmission (DCT) to achieve high control accuracy and fast response. The structure of MRFDC was designed by Unigraphics (UG) three-dimensional (3D) modeling software. Then, finite element analysis (FEA) for magnetic field was conducted by ANSYS under different applied currents from 0.1A to 1A with 0.1A space to obtain the relation between the applied current and magnetic field. In this article, Herschel-Bulkley model is used to predict the MR fluid behavior because of the high shear rate of MR fluid.