A novel downshifting strategy based on medium-time-distance information for hybrid electric bus

作     者：CHENG Shuo ZHANG Yan YANG YiYong FANG ShengNan LI Liang WANG XiangYu CHENG Shuo;ZHANG Yan;YANG YiYong;FANG ShengNan;LI Liang;WANG XiangYu

作者机构：State Key Laboratory of Automotive Safety and EnergyTsinghua UniversityBeijing 100084China School of Engineering and TechnologyChina University of Geosciences(Beijing)Beijing 100084China 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2021年第64卷第9期

页      面：1927-1939页

核心收录：

学科分类：0810[工学-信息与通信工程] 08[工学] 082304[工学-载运工具运用工程] 080204[工学-车辆工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0702[理学-物理学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 0823[工学-交通运输工程] 

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.51975048 and 51805290) 

主　　题：regenerative braking medium-time-distance information dynamic programming-rule based hybrid electric bus 

摘      要：Vehicle downshifting during braking for the hybrid electric vehicle(HEV) equipped with the automatic mechanical transmission(AMT) could adjust work points of the motor. Thus, downshifting has great potential to effectively improve the efficiency of braking energy recovery. However, the power interruption during shifting could cause some loss of regenerative energy ***, the choice of the downshifting point during vehicle braking which has crucial effect on energy recovery efficiency needs to be intensively studied. Moreover, the real-time application of the high-efficiency braking energy recovery strategy is a challenging problem to be tackled. Therefore, this paper proposes a dynamic-programming-rule-based(DPRB) downshifting strategy for a specific hybrid electric bus(HEB) driving condition. Firstly, the braking characteristic of the HEB during the process of pulling in is analyzed. Secondly, the medium-time-distance(MTD) demonstrating the dimension of time and space is proposed to define the boundary condition of the running bus. Then, look-up tables are established based on a dynamic programming algorithm offline using multiple sets of historical data. Thus, Based on the real-time driving data, whether to enter the optimal gear selection process can be decided online. Finally, simulations and hardware-in-the-loop(HIL) tests are carried out, and the results show that the proposed method can be indeed effective for braking energy recovery.