A Research On Vehicle Control Strategy Of Series-parallel Hybrid Electric Bus

To cope with the increasingly serious energy crisis and environmental problems, the hybrid electric bus with good fuel economy and low emission has become an important type of new energy vehicle, and has the great market value. To develop the ideal vehicle control strategy is an important way to achieve energy conservation and emission reduction for the hybrid electric bus, which has become the important technology of the hybrid electric bus research and development. A domestic series-parallel hybrid electric bus is selected as the study object. Based on the analysis of the working modes of the hybrid electric powertrain, the forward simulation model of the powertrain is built in CRUISE software. With the control goal for a better vehicle fuel economy, two kinds of the vehicle control strategy on the basis of the logic threshold control and the fuzzy logic control are designed and studied respectively. The validity and correctness of the two different vehicle control strategies are verified by simulation and comparative analysis.Firstly, the structure of the series-parallel hybrid electric powertrain is analyzed. Combined with the actual operation features, the working modes of the hybrid powertrain and the energy flow of every mode are analyzed.Secondly, the structure framework of the hybrid electric powertrain is built by forward modeling ideas in CRUISE software. Then the forward simulation model of the hybrid electric powertrain is established after the mechanical, the electrical and the control signals among the modules connected, and the detailed parameters of each module are configured.Thirdly, with the control goal for a better vehicle fuel economy, two kinds of vehicle control strategies, the logic threshold control strategy based on the torque distribution rules and the fuzzy logic control strategy based on fuzzy control, are designed and studied respectively. And the rules of the mode switching, the driving/braking torque distribution rules and the fuzzy logic control rules are designed. Then the Simulink models of the two different vehicle control strategies are established in Matlab software.Lastly, the simulation analysis of the dynamic and economic performance using the two vehicle control strategies is carried out after the configuration of the simulation tasks. The simulation results are analyzed by comparing with the actual vehicle running results. The simulation results show that the two different vehicle control strategies are able to achieve the lower fuel consumption on the premise of keeping a good dynamics performance. The fuel consumption is reduced and the fuel economy is improved. The validity and correctness of the two different vehicle control strategies are verified.This research will be of a certain reference for the research and development of the hybrid electric bus’ s vehicle control strategy.