Structure Improved Design And Optimization Of The Housing Of Power Split Device In HEV

HEV is a kind of hybrid vehicle and electric vehicle which combines a con-ventional internal combustion engine (ICE) propulsion system with an electricpropulsion system. It is a better solution for the transition from conventional carsto pure electric vehicles. Series-Parallel HEV, combining the advantages of seriesand parallel, gives full play to the strengths of engine and electric motor. Thepower-split device (PSD) is the core of series-parallel HEV, different workingmodes can be switched by its corresponding means, and its performance influ-ences the performance of vehicle directly.The Toyota Prius, using planetary gear train as PSD, has achieved great suc-cess in hybrid vehicle market. As the research of HEV goes further, the require-ment for PSD with independent intellectual property rights becomes more andmore significant. In this paper the housing structure of the new PSD which basedon the theory of applying the traditional differential as PSD in HEV has been im-proved.Firstly, based on the Prius’ Matlab/simulink model in Advisor, the PSD pow-er train dynamic model is built. The gears of PSD are redesigned according to theworking condition obtained from the simulation, and the result of the finite ele-ment analysis shows the design method is reasonable.Secondly, the housing structure of the traditional differential is improved toobtain a more reasonable space layout. Then, the improvement is assessed by FEAmethod, and the stiffness of the housing is pointed out to be one of the majorpoints that causes gear mesh failure.Thirdly, the standard of the housing stiffness is set by applying FEM on PSDgears under increasing gear shaft deflection angle and gear recession distancewhich caused by the insufficient rigidity of the PSD housing.Finally, along with CAD-CAE computer-aided tools, metamodeling tech-niques including response surface methodology and radial basis function are ap- plied in order to optimize the housing. With the high accuracy RSM surrogatemodel, the housing of the PSD is optimized.