Research on Two-speed AMT Shift Control Strategy for Pure Electric Commercial Vehicles

Abstract

At present, in the rapid development of the automobile industry, the field of pure electric vehicles is full of vitality. Among them, motorization of commercial vehicles is undoubtedly one of the important means to solve environmental degradation and energy shortage. Based on a pure electric commercial vehicle, this paper matches and calculates the motor parameters and AMT transmission ratio according to the basic parameters and performance indexes of the vehicle. The research design and simulation of the shift control strategy are also completed. The simulation results show that the automatic shift control strategy is designed to meet the dynamic and economic requirements of the vehicle and it has certain practical reference value. Introduction In recent years, with the rapid development of China s economy and the improvement of people s living standards, vehicles have gradually entered the homes of ordinary people, and their holdings have increased year by year. However, environmental degradation and energy shortages have begun to constrain the development of the traditional automobile industry. Therefore, people are eager to find a way to replace traditional fuel vehicles, and the development of electric vehicles is undoubtedly one of the main solutions [1]. At present, most of the pure electric vehicles use a fixed speed ratio one-speed reducer. This transmission system has a simple structure and low cost, but puts high requirements on the performance of the drive motor. At the same time of high instantaneous torque, the drive motor is necessary to provide a higher operating speed in the constant power zone to meet the dynamic design requirements of the vehicle [2]. In addition, in order to ensure the vehicle speed range, more motor working points will fall in the low speed-high load area and high speed-low load area, which greatly reduces the motor efficiency. Therefore, the development of the transmission system structure of electric vehicles tends to be two-speed or multiple-speed, and relevant research has been done at home and abroad [3,4,5,6]. Based on the above problems, this paper designs a two-speed AMT according to the design parameters of a pure electric commercial vehicle and designs a comprehensive shift schedule that considers both dynamic and economic performance. Finally, the automatic shift control strategy is studied. Vehicle Parameters The basic parameters of a pure electric commercial vehicle are shown in Table 1. Electric vehicle power systems need to meet the dynamic requirements of the vehicle. The power of a vehicle can be evaluated by three indicators: maximum speed, maximum grade, and acceleration performance. The power performance requirements of this pure electric commercial vehicle are shown in Table 2.