Research On Shift-Decision Of Hybrid Electric Bus

As the global energy issues and environmental problems becoming more and more serious, the demands of energy-saving and environment-protection on vehicles becomes higher and higher. As a reliable substitute for traditional vehicle, HEV (Hybrid Electric vehicle) has a great development and application. The essence of HEV is to improve the working situation of engine and to recover braking energy using electrical motor. As a result, the economical performance is improved and the emission is reduced. This paper described the principle and factors of the shift-decision of HEV buses equipped with ISG (Integrative Starter Generator) and TM (Traction Motor).In the aspect of dynamic shift schedule, the influence of ISG and TM on HEV is studied in detail. SOC ( State of Charge) is regarded as the third factor which represents the state of ISG based on the traditional two-factor dynamic shift schdule.In the aspect of economic shift schedule, the equivalent fuel consumption of electric motor is used to calculate. And SOC ( State of Charge) is regarded as same as in the dynamic shift schedule. Considering the demand of practical running of the vehicle, intellectual shift schedule is researched and developed with respect to engine start-up, braking, ramping and steering states. Software and hardware of AMT control module are developed, which mainly focus on the software of shift decision and the process flow of the shift schedule when AMT working in passive and active states.AMT has been installed on the HEV bus and works well. Compared with the manual transmission on the same type of vehicle, AMT is much better in vehicle integrated control. Compared with the traditional shift decision, the strategy in this paper can improve the dynamic and economic performance obviously. This paper provides valuable references in AT shift schedule and software/ hardware development.