Underbody Drag Reduction Study for Electric Car Using CFD Simulations 2015-26-0211

Electric cars are the future of urban mobility which have very less carbon foot print. Unlike the conventional cars which uses BIW (Body in White), some of the electric cars are made with a space frame architecture, which is light weight and suitable for low volume production. In this architecture, underbody consists of frames, battery pack, electronics housing and electric motor. Underbody drag increases due to air entrapment around these components. Aerodynamic study for baseline model using CFD simulations showed that there was a considerable air resistance due to underbody components. To reduce the underbody drag, different add-ons are used and their effect on drag is studied. A front spoiler (air dam) is used to deflect the incoming air towards sides of the car. A under hood cover for front components, trailing arm cover for trailing arm and rear bumper cover for rear components were used to reduce underbody drag. Finally it is observed that aerodynamic behavior of the car improved drastically due to these add-ons.

In the current paper, results of different simulations are discussed in detail with respect to the underbody drag reduction of an electric car. Results of the CFD simulations are validated with wind tunnel measurements. Good correlation is achieved with the test results.