The improvement in tire rolling efficiency is one of the key elements to optimize the fuel economy and thereby reduce the vehicle emissions. Earlier efforts to reduce the rolling resistance have mainly been focusing on new materials in the tire compounds. The overall research aim of this study is to present the potentials ofimplementing innovative chassis concepts with the focus on Wheel Corner Modules (WCM) by describing thepossibilities in affecting rolling resistance and relating them to previous research findings. The core idea of theconcept is to actively control and actuate all degrees of freedom in the wheel i.e. implementing steering,suspension and propulsion functions into a unique module which can be implemented in each corner of the vehicle. Using this concept the limitations of traditional wheel kinematics can be resolved extensively. This article presents the first step towards creating a vehicle simulation model that can show how the WCM functionality can influence the rolling resistance. A model of loss is chosen after analysing the behaviour of three different rubber models and then implemented into a brush tire model. An effective way, but less complicatedcompared to current methods, to introduce the loss into tire model is presented. In conventional suspensions, thedesign is compromising between for example safety, comfort and rolling resistance, etc. at all drivingconditions. However, using the WCM, the possibility of achieving a better compromise between those objectivesis possible. Finally, based on WCM functionalities a plausible control architecture is proposed.

This study aim to develop a three dimensional multi-line brush based tyre model for investigating the rolling resistance and energy loss in tyres. The losses in the model are characterised by the external losses originated from the sliding phenomenon in the tyre contact patch, and the internal losses due to the tyre viscoelastic nature which is employed by a rubber model. The Extended Brush tyre Model (EBM) proposed in this work can be used to estimate the dissipated energy and the rolling resistance under different driving manoeuvres and wheel conditions. This paper focuses on the estimation of energy loss and in-plane rolling resistance.

This paper describes a semi-physical tyre model that enables studies of rolling loss in combination with vehicle dynamic simulations. The proposed model, named extended brush tyre model (EBM), takes the effects of driving conditions, wheel alignment, and tyre materials into account. Compared to the basic brush tyre model, EBM includes multiple numbers of lines and bristles as well as integrated rubber elements into the bristles. The force and moment characteristics of the model are shown to have a good correlation with the Magic Formula tyre model and experimental data. The numerically estimated rolling resistance coefficients under different conditions are compared to findings in the literature, FE-simulations and experiments. The model can capture some aspects that are not covered by the available literature and experimental observations such as camber effect on rolling loss. EBM can be used as a platform for future studies of rolling loss optimisation using active chassis control.

While there are many tyre and vehicle dependent factors that affect the rollingresistance, the road properties play also an influential role in the overall resistance on the vehicle.The aim of this study is to develop amodel that can estimate the effect of road roughness on rollingresistance of tyres where both the texture-dependent and independent factors are contributing tooverall rolling resistance. In this paper, a method based on the self-affine fractal surfaces is usedto model realistic road characteristics in order to couple it with a brush based tyre model to beable to study the influence of road roughness on tyre rolling resistance. The simulation resultssuggest that the rolling resistance increases with increased RMS-value and both the macro- andthe micro-texture have an influence on the rolling resistance while the macro-texture effect is moreinfluential. The results of this paper can be related to the estimation of fuel economy on differentroad textures, from macro-texture to micro-texture and further optimisation of road surfaces.

The growing concerns about the environmental issues caused by vehicles and a strive forbetter fuel economy, urge the legislators to introduce conservative regulations on vehicletesting and homologation procedures. To have accurate evaluations, driving cycles thatcan sufficiently describe the vehicles’ conditions experienced during driving is a prerequisite.In current driving cycles there are still some issues which are disregarded. The aim ofthe presented work is to study the contribution of chassis and vehicle dynamics settings ontyre rolling loss in comparison with the original assumptions made in the NEDC, FTP andHWFET driving cycles. A half-car model including a semi-physical explicit tyre model tosimulate the rolling loss is proposed. For the chosen vehicle and tyre characteristics,depending on the specific chassis settings and considered driving cycle, considerable differenceup to 7% was observed between the energy consumption of the proposed- and conventionalapproach. The current work aims to provide the legislators with a betterinsight into the real effects of chassis and vehicle dynamics during the certification processto further improve the test related procedures required for homologation such as generationof road load curves. I.e., the aim is not to provide a new homologation process, sincethere are also other effects such as road roughness and tyre temperature that need to beconsidered. The results are also of interest for the vehicle manufacturers for further considerationsduring test preparation as well as in the development phase in order to reduce theenvironmental impacts.

The objective of this work is to present a new functionality of over-actuated systems, such as Wheel Corner Modules, to reduce the rolling loss in vehicles. The findings are based on numerical simulations using a bicycle model coupled with a newly proposed tyre model which is capable of simulating the tyre losses during vehicle motions. The results show that for the considered vehicle in the considered manoeuvre the rolling loss can be reduced about 25–40% by proper control of camber and slip angle combinations, while still maintaining the vehicle performance.