Research On Optimization And Calibration Of Hybrid Electric Vehicle Performance Based On Simulation Technology

With continuous improvement of people living standards,automobiles have become an essential tool for daily travel.At the same time,the automobile has become universal and popular due to the low cost.Therefore,the output and ownerships of automobiles increase year by year,which has led to a series of problems: the increasing dependence on imported oil resources and the environmental pollution,which compel many countries to compete in the horizon of research and development of new energy vehicles.Due to the limitations of technology and infrastructures of pure electric vehicles,there is still a way to go to achieve large-scale production.Therefore,hybrid electric vehicles that have characteristics of fuel automobiles and pure electric vehicles have become an ideal choice for developing new energy vehicles.In this paper,the vehicle structure is determined based on the vehicle powertrain matching and components selection,an energy management control strategy is designed by setting rules and co-simulation is finished by connecting vehicle models with control strategy by simulation Interface,the optimization and calibration of software in the loop are carried out on the value of the logic threshold of the control strategy.Firstly,the structure of the whole vehicle is determined and the selection of the components and the parameters matching are carried out.The structure of the whole vehicle is the evaluation basis of the vehicle's power performance and economy.Based on the components selection and parameters matching,the structure of the whole vehicle is determined as the single axle parallel that is front-engine and rear-drive,placing a clutch between the engine and the motor,conducting switching among the pure electric vehicle driving,engine driving alone and mixed driving mode finished by controlling the opening and closing of the clutch.At the same time,the vehicle components selection and parameters matching are carried out based on the knowledge of automobile theory and the original intention of researching and development.Secondly,the vehicle energy management control strategy is designed based on Matlab/Simulink/Stateflow and the vehicle model is built by AVL-Cruise,the co-simulation is conducted by Interface included by AVL-Cruise.The energy management control strategy has a great influence on the power and economy of the whole vehicle.In this paper,based on the information including battery SOC,speed and demand torque,the energy management strategy makes engine operate in the best interval by controlling vehicle running in different operation mode for achieving the goal of saving energy and reducing emission.Next,the joint simulation is finished by connecting the control strategy with the vehicle model through the Interface.The simulation result shows that the fuel consumption of the whole vehicle has been greatly decreased than the original vehicle.Finally,the hybrid electric vehicle optimization calibration platform in the software loop is built based on the optimization software Isight and the optimization results are analyzed.For hybrid electric vehicle,when the vehicle structural layout and system components selection have been determined,the fuel economy performance is mainly determined by the optimization degree of vehicle energy management control strategy.By selecting optimal variables,constraints and setting up optimization targets,the values of the logic threshold of the control strategy are optimized and calibrated in the platform by using the combination optimization algorithm.Through the comparison of the results before and after the optimization,the effectiveness of the software in the optimization of the loop optimization platform is proved.