The relationship between rolling resistance and tyre operating conditions, with a focus on tyre temperature
Time: Wed 2022-06-01 10.00
Location: E3, Osquars backe 14, Stockholm
Subject area: Vehicle and Maritime Engineering
Doctoral student: Lisa Ydrefors , Farkostteknik och Solidmekanik, Vehicle Dynamics
Opponent: Prof. Jurek Ejsmon, Gdansk University of Technology
Supervisor: Prof. Annika Stensson Trigell, Farkostteknik och Solidmekanik; associate Prof. Jenny Jerrelind, Fordonsdynamik
Efforts to reduce greenhouse gas emissions from today’s increasing number of cars and trucks, are crucial in counteracting global warming. These efforts include the intent to reduce the effects of the resistive forces acting on the vehicle. Rolling resistance is one of these forces. A reduction in rolling resistance would aid in reducing greenhouse gas emissions, while also reducing the driving costs and increasing the driving range per charge for electric vehicles. This PhD research contributes to these efforts by the development of a rolling resistance measurement method on a flat track test equipment that avoids the curvature effects present in the standardised drum test. Another contribution is the development of a rolling resistance model that can describe the relationship between the tyre deformation and the forces acting on the tyre. The model is parametrised by results from the developed measurement method and is simple enough to be included in complete vehicle dynamicssimulations. In this thesis, the effects of different operational conditions, such as inflation pressure, tyre temperature, speed, load, road surface or tyre angles, are investigated and presented. The results from this investigation were used for the development of the measurement method for flat track test equipment. Tyre temperature is an important operating condition influencing rolling resistance and the proposed measurement method can be used to investigate rolling resistance at different tyre temperatures. The results obtained with the proposedmeasurement method, which are comparable to drum measurements performed under the same operating conditions, are used to parameterise the developed rolling resistance model. The model gives a good fit for the relationship between rolling resistance and tyre deformation. The measurement method and the model build a good platform for deeper investigations of rolling resistance and its connection to tyre temperature.