Evaluation of the Aerodynamics of Drag Reduction Technologies for Light-duty Vehicles: a Comprehensive Wind Tunnel Study

In a campaign to quantify the aerodynamic drag changes associated with drag reduction technologies recently introduced for light-duty vehicles, a 3-year, 24-vehicle study was commissioned by Transport Canada. The intent was to evaluate the level of drag reduction associated with each technology as a function of vehicle size class. Drag reduction technologies were evaluated through direct measurements of their aerodynamic performance on full-scale vehicles in the National Research Council Canada (NRC) 9 m Wind Tunnel, which is equipped with a the Ground Effect Simulation System (GESS) composed of a moving belt, wheel rollers and a boundary layer suction system. A total of 24 vehicles equipped with drag reduction technologies were evaluated over three wind tunnel entries, beginning in early 2014 to summer 2015. Testing included 12 sedans, 8 sport utility vehicles, 2 minivans and 2 pick-up trucks. Two categories of drag reduction technologies were evaluated: i) those currently offered by the original equipment manufacturers (i.e. active grille shutters, partial underbody covers, bumper and wheel air dams); and, ii) emerging technologies that have market introduction potential, i.e., active ride height control, actively deployable bumper air dams and full under-body covers. The main findings of the experiments are presented in this paper by categories of vehicles and drag reduction technologies. A discussion on the use of wind averaged drag to evaluate the full impact of the technologies on fuel consumption is also presented.Cross Reference: