The Simulation With Modeling And Optimization Research For Powertrain Of Pure Electric City Bus

In all kinds of new energy vehicles,pure electric vehicles’ power comes directly from electric energy closed to zero release.Meanwhile,because of the higher efficiency of electric motor compared to internal combustion engine,pure electric vehicle has the characteristic of high energy utilization rate.For the restriction of the endurance mileage and energy consumption level on pure electric vehicle currently,it has a great effect on its promotion.Therefore,research on powertrain of pure electric vehicle in order to promote the performance especially the economy has important significance on energy conservation and technology development of pure electric vehicle.This thesis relies on the technical support of national 863 project also with the special project of national internal technology cooperation.Modeling simulation and optimization research are carried out around the powertrain of one pure electric city bus.Firstly,evaluation analysis is operated on the performance of pure electric vehicle which combines with effects of different gears and driving cycles on the performance.Then,the improvement and parameters matching solution in this thesis is confirmed by those analyses.At the premise of performance satisfied,powertrain makes up with an added four-speed transmission which can diminish the size of electric motor is applied and rational parameters of electric motor,battery and transmission is matched.Secondly,the research of modeling and simulation is carried out.Simulation results of dynamic and economy performance are obtained by using AVL-Cruise.Meanwhile,the modeling approach and rationality are approved through real test of the bus.Based on the method of modeling approved,simulation analysis is performed on the bus after parameters matching and the effect of performance improvement with this matching method can be proved.Finally,in order to achieve the optimal energy consumption level,multi-island genetic algorithm is adopted to optimize the powertrain ratio further with the constraints of dynamic performance indexes.After matching and optimization,compared to the original bus,dynamic performance improves by 16.7% with economy performance by 14.7% totally,which verifies that the method of matching and powertrain ratio optimization are effective and reasonable.This thesis has simulated and optimized the powertrain of one pure electric city bus,and results shows a double lifting on dynamic and economy performance.The method of matching and optimizationmentionedin this thesis has reference value towards the design of powertrain on pure electric city bus and the reduction of energy consumption.