Tire thermal analysis and modeling

Abstract

Tires are of paramount importance in vehicle dynamics. They are the only vehicle’s components in contact with the road and hence transmitting necessary forces and moments for the vehicle to accelerate, brake and turn. So far, temperature influence on tire behavior has not hold car manufacturers’ interest so much. Tire models were usually limited to be mathematical models taking into account tire and axle geometry mechanical properties, normal load and inflation pressure. However, some differences appeared when comparing forces and moments estimated by tire models and measured test data. Part of these differences is now believed to be due to variation in tire thermal properties when the tire is subject to different stress types (slip and camber angles, normal load, inflation pressure, vehicle speed…). The aim of this study is to perform a thermal analysis of the tire. How its surface temperature varies depending on various conditions and how these variations influence the tire behavior will be of prior concern. Hence, some indoor tests will be performed by positioning the tire on the MTS Flat-Trac® III tire test system and using infrared sensors to measure the tire surface temperature. Experiments will be based on an experimental design where all the parameters believed to have an influence on the tire temperature will vary. Results will allow understanding which parameters are of primary importance for the temperature and will also be used to build up an empirical tire thermal effects model. This latter will be used in parallel with the currently used Pacejka model and take into account the variation of tire performance in terms of lateral forces. Eventually, the validation of the model will be done performing full vehicle tests.