Research On Powertrain Matching And Simulation Of ECVT Hybrid Bus

Electric vehicles are the development trend of the automobile industry in the 21 st century.With "Made in China 2025" put forward,energy-saving and new energy vehicles have been listed as one of the national key development areas,in which electric vehicles are regarded as the core technology to solve the gap between the independent brand vehicles and the international advanced level.The battery as the key part of electric vehicles also suffers from some drawbacks such as short service life,low energy density,low safety,difficult charging and high cost,which make electric vehicles impossible to contend with traditional fuel automobiles in the cost performance and comfort level.In this context,it is of great significance to improve the traditional ISG hybrid system and design a hybrid system with simpler and more reliable structure,lower system cost and failure rate,and better fuel economy.Aiming to solve the problem of poor fuel efficiency in the existing hybrid power system,the hybrid power system comprised of "ISG motor + clutch" from Fujian Fugong Engineering Technology Co.,Ltd is selected as the research object to be investigated how to improve the oil-saving effect of the whole vehicle.In the study,we present a scheme in which the hybrid power system is constituted by "ISG motor + single planetary row".And then the research begins from two aspects: one is parameters matching of powertrain and the other is to optimize powertrain control strategy.The detailed theoretical calculation and matching analysis of each core component in the hybrid power system including the engine,generator,drive motor,planetary row and power battery are carried out.And finally the selection is completed.Based on the work mentioned above,this paper establishes the vehicle simulation model of ECVT hybrid electric system on account of MATLAB/Simulink,including engine model,generator model,drive motor model,planetary row model,power battery model,cycle simulation model,vehicle dynamic model and other simulation models and so on.And the logic threshold control strategy based on rules is formulated.In view of the specific working characteristics of engine,drive motor and power battery,the corresponding workspace is optimized to improve fuel economy.Meanwhile,the simulation model of vehicle control strategy is built.The dynamic performance(maximum speed,acceleration capability and the maximum climbing degree)and economic performance(maximum driving distance of pure electricity and power consumption of 100 km)of the vehicle were simulated to verify the effectiveness and rationality of the optimization scheme by the vehicle simulation model.At the same time,according to the relevant national standards and test regulations the performance test of the whole vehicle is carried out to further verify the scientificity and feasibility of the design for the optimization scheme.The simulation results and test results demonstrate that the designing scheme consisting of the power system and the control strategy makes it.Compared with the predecessor "ISG 2.0 hybrid power system" in the company,the fuel saving rate of the new scheme is increased from 43.95% to 57.47%,and the dynamic property is also significantly improved.