Vehicle Ride Height Change Due To Radial Expansion Of Tires

Open access

Abstract

In general, tire deformations caused by wheel rotation are not taken into account when developing vehicle aerodynamics. On the road the tires radially expand as speed increases, which affects the actual ride height of a vehicle. In turn this often increases the real aerodynamic drag compared to values obtained using CFD or a wind tunnel as the mass flow across the relatively rough underbody increases with ground clearance. In this study, on-road ride heights were measured while running a vehicle in a straight line with fixed velocity whilst the aerodynamic lift of the vehicle was determined in a wind tunnel. Subsequently, the relationships between ride height and axle load were obtained by loading the vehicle at standstill with ballast. By comparing the ride heights at high and very low velocities with expected vertical displacement caused purely by aerodynamic lift force as computed according to the ride height - axle load equations, the ride height change due to tire radial expansion was determined.

[1] COGOTTI, A. Evolution of performance of an automotive wind tunnel. Journal of Wind Engineering and Industrial Aerodynamics. 2008, vol. 96, 6-7, s. 667-700. DOI: 10.1016/j.jweia.2007.06.007.

[2] DUELL, E. et al. The BMW AVZ Wind Tunnel Center. SAE Technical Paper 2010-01-0118. 2010.

[3] STERNÉUS, J., T. WALKER and T. BENDER. Upgrade of the Volvo Cars Aerodynamic Wind Tunnel. SAE Technical Paper 2007-01-1043. 2007.

[4] SAPNARAS, D. and I. DIMITRIOU. Experimental Analysis of the Underbody Pressure Distribution of a Series Vehicle on the Road and in the Wind Tunnel. SAE Technical Paper 2008-01-0802. 2008.

[5] HUCHO, W-H. Aerodynamics of Road Vehicles. 4 ed. Warrendale: Society of Automotive Engineers, 1998, 918 s. ISBN 07-680-0029-7.

[6] LANDSTRÖM, C., L. JOSEFSSON, T. WALKER and L. LÖFDAHL. Aerodynamic Effects of Different Tire Models on a Sedan Type Passenger Car. SAE Technical Paper 2012-01-0169. 2012.

[7] VDOVIN, A., L. LÖFDAHL, S. SEBBEN and T. WALKER. Investigation of vehicle ride height and wheel position influence on the aerodynamic forces of ground vehicles. In: International Vehicle Aerodynamics Conference 2014. 2014.

[8] REGERT, T. and T. LAJOS. Description of flow field in the wheelhouses of cars. International Journal of Heat and Fluid Flow. 2007, vol. 28, issue 4, s. 616-629. DOI: 10.1016/j.ijheatfluidflow.2007.04.017.

Journal of Middle European Construction and Design of Cars

The Journal of Czech Technical University

Journal Information

Metrics

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 97 97 13
PDF Downloads 46 46 13