| In order to cope with the problem of global warming, the growing shortage of oilenergy and the pollution of the living environment, development of HEVs (hybridelectric vehicles) become the hot spot and the most promising direction. Transmissionsystem is the basic and key component which determines the performance, operatingmode and fuel consumption of HEVs. The planetary coupling mechanism is usedwidely in HEVs’ power split mechanism. In addition to the different power sources andclutches, transmission schemes also have complex planetary coupling mechanism,different connection relations among them constitute various HEV powertrains, whichnaturally has a wide range of effects on HEVs’ performance.In this paper, taking ISG electric variable transmission HEV as the object of study,the main contents of the paper are as follows:①Based on the traditional graph theory, a graph theory model of HEV was built.Then, a planetary gear adjacency matrix and a component adjacency matrix were usedto judge the isomorphic scheme by the output coding. Took the existing industrial HEVsresearched by different companies and research institutions as examples, establishedgraph theory model of their transmission systems.②Took the design goals of ISG electric variable transmission HEV into account,studied all the possible transmission schemes.Graph theory and graph model was usedto filter. Then in order to further screen the possible schemes, the lever analogy wasapplied to analyze the vehicle performance.③Based on the basic loop method of graph theory, described the planetarycoupling with kinematics equations.Respectively took the Prius-THS and GM-AHShybrid system as examples, according to the graph theory model and dynamic model,establish the kinematics matrix and the dynamic matrix. Built the dynamic models andthe dynamic matrix of different ISG HEVs’configurations, then used the dynamicprogramming-based global optimal control strategy simulation operation, and confirmedthe optimized configuration according to the best fuel economy.④In order to analyze further performance of ISG electric variable transmissionHEV of the selected configuration, established all the key components model. Dynamicprogramming equation according to the ISG hybrid system was built and completeglobal optimum search was operated. Analyzed the results of the simulation and optimization. Finally, analyzed the effect of the characteristic parameters of theplanetary coupling mechanism and the final drive ratio on vehicle performance. |
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