The Scheme Design And Parameter Optimization Of EVT Hybrid Powertrain With Single Planetary Row Based On Graph Theory And Intelligent Algorithm

With the universally advancing of the industrialization around the whole world and the substantial increase of the car ownership,finding an high efficient and energysaving vehicle driving mode has become the urgent subject in the automotive industry.The Hybrid Electric Vehicle(HEV)has become research hot spots in various countries due to the characters of longer extension mileage and lower pollution.Notably,because of the compact structure and the high efficiency,the Electric Variable Transmission(EVT)powertrain system is the main research direction in the HEV development.Aiming at the EVT powertrain system with single planetary row based on Graph Theory and Intelligent Algorithm,the following works is done:(1)This paper proposes a hierarchical graph model of planetary gear trains and enriches the application of Graph Theory in planetary gear trains.(2)The matrix models are proprosed based on the layered Graph Theory model of EVT hybrid transmission system,including the configuration model and the transmission model.(3)Three derived problems of the Graph Theory model were proposed to simplify the design and optimization process of EVT hybrid powertrain system.(4)The EVT powertrain system analysis methodology based on the Graph Theory was proposed.This method is simple and effective,and has the significance of promotion.(5)In this paper,a configuration fuel consumption model is proprosed,it combined Neural Network Algorithm and Dynamic Programming Algorithm to identify the fuel consumption of the EVT system based on the EVT configuration matrix.The research shows that the accuracy rate of this model is more than 99%.(6)In this paper,the Genetic Algorithm is introduced to find the optimal scheme of the EVT hybrid transmission system with single planetary row,the configuration matrix was transformed into genetic codes.Through the clutch degeneration method,the genetic range is limited to a specific configuration design space.Operators such as mating,mutation,and replication are used to search for optimal solutions under certain conditions in the way of population evolution.Studies show that this method can quickly and accurately find the target solution.(7)This paper optimizes the parameters of the optimal scheme for EVT hybrid transmission system with a single planetary row.Two key parameters are obtained from four parameters using Grey Correlation Analysis.Based on the transmission matrix of the EVT hybrid transmission system,a parametric fuel consumption model is established through Neural Network and Support Vector Machine of Regression,and the optimization parameters are obtained through the model.The research shows that the key parameters are selected accurately,the accuracy of the parameter fuel consumption model is over 99% and the optimization of parameters has a significant increase in the fuel economy of the transmission system.By combining the configuration fuel consumption model and the Genetic Algorithm,the optimal transmission scheme of the single planetary powertrain EVT hybrid power transmission system was found,and the parametric fuel consumption model was used to optimize its parameters,the optimal scheme of the EVT hybrid power transmission system with single planetary row after optimization parameters is obtained,its fuel economy is good.