Study On Parameter Matching Optimization Of City Bus Power System Based On Operating Conditions

The actual driving conditions of the vehicle play a crucial role in the development and testing of the vehicle.It is an important prerequisite for the optimization of the parameters of the vehicle power system and the formulation of control strategies in accordance with the driving conditions of the actual road state of the vehicle.Because of the regional differences in the driving conditions of the automobile,it is necessary to construct urban working conditions,regional working conditions,and line conditions.This provides effective theoretical support for dynamic system parameter matching,economic analysis,and vehicle control strategy optimization for different cities,different regions,and different line vehicles.With the rapid development of new energy vehicles,pure electric buses are widely used in the automotive field.The operating status of urban public transport is affected by factors such as line,climate and road traffic flow.Therefore,the development of urban public transport driving condition and the realization of a “one city,one landmark” have important practical significance for improving the power and fuel economy of urban buses.The matching and optimization of pure electric buses power system parameters based on actual urban road driving conditions has become a research hotspot in the industry.The paper will start research from the following three aspects:Firstly,Xi'an city bus line screening and data collection are completed.The short-stroke is divided for the pre-processed data.Cluster analysis are used to construct transient driving condition of Xi'an city bus.Based on the transient conditions and sample data,the modal driving conditions are developed using the transient transfer mode method and multi-objective optimization method.The work also includes working condition verification and comparison of modal working condition construction methods.Secondly,based on the developed transient and modal operating conditions,parameter matching is performed for the different structural pure electric bus power systems.By analyzing the actual road demand power and prototype parameters,the motor and battery selection are completed.Then parameters of motor,battery,and drivetrain can be reasonably matched.Drivetrain parameters are used as optimization variables.The economical efficiency of the entire vehicle establishes a mathematical model for optimization.Simulated annealing particle swarm optimization algorithm was used to optimize the speed ratios of the two types of drivetrains.Finally,CRUISE software was used to establish two structural vehicle simulation models,according to the matching optimization parameters and driving conditions.Then simulation calculations are implemented through the design of dynamic and economical calculation tasks.The rationality verification of the optimized matching scheme was completed by comparing the performance indicators before and after optimization.The performance indicators of the optimized two structures were compared and analyzed.Then,the influence of vehicle structural form on vehicle performance under specific conditions is studied.