Parameter design and performance analysis of shift actuator for a two-speed automatic mechanical transmission for pure electric vehicles

Abstract

Recent developments of pure electric vehicles have shown that pure electric vehicles equipped with two-speed or multispeed gearbox possess higher energy efficiency by ensuring the drive motor operates at its peak performance range. This article presents the design, analysis, and control of a two-speed automatic mechanical transmission for pure electric vehicles. The shift actuator is based on a motor-controlled camshaft where a special geometric groove is machined, and the camshaft realizes the axial positions of the synchronizer sleeve for gear engaging, disengaging, and speed control of the drive motor. Based on the force analysis of shift process, the parameters of shift actuator and shift motor are designed. The drive motor's torque control strategy before shifting, speed governing control strategy before engaging, shift actuator's control strategy during gear engaging, and drive motor's torque recovery strategy after shift process are proposed and implemented with a prototype. To validate the performance of the two-speed gearbox, a test bed was developed based on dSPACE that emulates various operation conditions. The experimental results indicate that the shift process with the proposed shift actuator and control strategy could be accomplished within 1 s under various operation conditions, with shift smoothness up to passenger car standard.

Moving magnet linear actuator with self‐holding functionality

“…The applications of electrical actuators in automotive traction drives vary from shift‐by‐wire to full electric gearboxes [9]. The gear shift actuator influences the shift quality, shift time and also driving comfort [10]. Reduction of the shift time leads to improvements in the vehicle performance such as acceleration time [11].…”

Control strategy of automated manual transmission based on active synchronisation of driving motor in electric bus

“…The motor output torque is directly transmitted to the wheels through the transmission, shaft, main reducer and the drive axle. Equation (13) shows that the jerk of the electric bus is proportional to the changing rate of the motor output torque. The jerk is also related to the gear, under the condition of a certain rate of restoring the motor torque.…”

Comparison on Energy Economy and Vibration Characteristics of Electric and Hydraulic in-Wheel Drive Vehicles

“…The multi-gear and multi-motor powertrains are widely researched in academia with the motivation of improving the electric vehicle energy economy and dynamic performance. The automated manual transmission (AMT) [4,5], dual clutch transmission (DCT) [6], automatic transmission (AT) [7,8] and continuous variable transmission (CVT) [9,10] have been implemented in electric vehicles.…”