Aerodynamic Development of the GAC ENO.146 Concept

This paper describes the aerodynamic development process and features of the flow field of the GAC ENO.146, a concept vehicle shown in Guangzhou Auto Show 2019, which achieved a CD of 0.146. Key factors in the design process, including how design decisions are made and how the interactions occur between aerodynamicists and designers are explained in detail. The design language forms the next generation of BEVs. The aerodynamic development philosophy is guided by three principles: minimizing flow separation, maximizing rear pressure recovery, and controlling tire wake. This vehicle took full advantage of the unique 2-1-2-1 seating configuration that allowed a tapered tail design with a narrower rear track to further minimize the size of the rear recirculation zone, improving rear pressure recovery. In order to reduce induced drag, detailed studies on roofline and diffuser angles were conducted to develop the optimal combination, eliminating any loss of flow momentum. The diffuser design also served to eliminate flow separation caused by the rear wheels. In addition to that, active aerodynamic devices were employed to reduce interaction between freestream and wheelhouse air. A comparison was also made between ENO.146 and Aion S, a GAC production EV to illustrate future development potentials. Through the development of ENO.146, the aerodynamic development process of ENO.146 serves as a template for future projects, providing expertise and best practices of aerodynamic development for both engineers and designers.