Study On The Shift Strategy Of Automated Manual Transmission In Parallel Hybrid Electric Bus

It has been more than100years since the first car was made. With the development ofautomobiles, the problems of environmental damage is being increasingly serious. More andmore people pay close attention to this situation and start to research new energy vehicleswhich can realize low emissions and low fuel consumption. New energyvehicles, including fuel cell, hydrogen energy, solar energy, electric and hybrid electricvehicle and so on. At present, hybrid electric vehicle is the best choice and the direction ofvehicle development. Based on a college-enterprise cooperative program, a single axleparallel hybrid electric bus with Automated Manual Transmission(AMT) is chosen to bethe research object. The shift strategy is investigated in this paper.(1)The structure and operation modes of the single shaft parallel hybrid electric bus areintroduced. The definition of AMT shift quality and its evaluating index are illustrated. Theshift process with active synchronization control strategy of the electric machine and engineis analyzed, then indicates the problems in the process. The dynamic model of hybrid electricbus with AMT powertrain is built up, the dynamic characteristics of each phase of shiftingprocess are analyzed, and a control strategy in which coordinatively controlled the electricmachine and engine to achieve shifting without clutch is proposed.(2) A vehicle model is built up with AVL Cruise. The desired module are selected, theenergetic and informational connections are established, the module parameters are setted.The advantages and disadvantages of two interfaces, Matlab DLL and Matlab API, arecompared.(3) A shift control strategy model is built up with Matlab/Simulink. The model consistsof three sections, Stateflow input section, Stateflow module and Stateflow output section.Each phase of shifting process is transformed to a state in Stateflow module. The triggercondition and the input and output of each state are described. (4)The simulation results of shifting without clutch are analyzed. The each phase ofshifting process is described. Then compared with the results of shift process with activesynchronization control strategy of the electric machine and engine. The result shows thestrategy of shifting without clutch can effectively improve the shift quality.