Chery QQ3-EV Range-Extender Layout Design Based On Aerodynamics

The biggest factor that restricts the development of EV is the capacity of the battery and its mileage. Extended-range device is one of the devices which used for improving electric vehicle mileage. Currently there only exist built-in extended-range device while detachable extended-range device is still in the research stage. This paper designs three detachable extended-range device layout scheme, and ingenuity to the multidisciplinary design optimization method to achieve the best balance in some aspects like: modeling, air-dynamic performance, economic performance, comfortable performance and other aspects. First we choose a pure electric cars of Chery QQ3-EV and then match it with extended-range units to identify good layout. In order to reduce wind coefficient, increase the mileage for each of the different layout scheme design of the extended-range device configuration scheme, and to optimize the modeling and air-dynamic characteristics , achieve the best balance between the scheme, here build the QQ3-EV and its extended range with 1 : 1 scale digital model with the software PROE, as Precise as the real EV, and then export into the aerodynamics calculation software FLUENT to carry out drag coefficient, air dynamic characteristics calculation. Estimate each model dynamic performance based on the calculation results. At the same time for each program carry out in-depth design, get rendering effect chart, and through the questionnaire survey from different user groups on each shape comfort to achieve fuzzy scores. At last this paper launched the multidisciplinary optimization selection. In order to verify the calculation results of FLUENT accuracy, this paper first launched the research of rearview mirror of automobile styling and drag coefficient calculation using the same boundary condition as QQ3-EV. The result of drag coefficient and surface pressure coefficient is the same as the actual wind tunnel results which verified the validity of the calculation. This paper also carried out 25 different kinds of mirror calculation for aerodynamic characteristics and then used the result to guide the extended-range device modeling design.