Shift Quality Amelioration of EV with AMT by Speed Regulation

Abstract

Due to torque interruption and clutch friction of Automated Manual Transmissions (AMT) during gear shift, the shift quality is not as positive as other kinds of transmissions, several ways to improve shift quality such as reduce shift time have been researched. During the gear shift process in AMT, new gear speed needs to be regulated as gear ratio changes. In this paper, the research topic is concerning gear shift process of an AMT of electric vehicles, the influence of the speed difference between new gear and synchronizer on gear shift time is studied. Powertrain model of the electric vehicles with AMT is built in ADAMS and several simulations are conducted. Simulation results demonstrate that by controlling the speed difference between new gear and synchronizer in a positive small range from 0rpm to +10rpm with the shift force at 200N, shifting synchronizer can be engaged in a short time. In addition, results also demonstrate that within small speed difference range, the existence of synchronizer ring has little effect on gear shift performance, which illustrates that the structure of AMT on electric vehicles can be simplified.