Tire Rolling Resistance Research Articles

Design of Low Rolling Resistance Tire Structure Based on Region Energy Loss

Design of Low Rolling Resistance Tire Structure Based on Region Energy Loss

DYNAMIC PROPERTIES AND TIRE PERFORMANCES OF COMPOSITES FILLED WITH CARBON NANOTUBES

ABSTRACT Carbon nanotubes (CNTs) have been widely studied in rubber goods and tire compounds to improve, for example, antistatic and thermal conductivity performances. CNTs were applied in passenger tire tread compounds to improve comprehensive tire performances, especially wet traction. High frequency dynamic properties of CNT-filled compounds were revealed for the first time. There was good correlation between compound dynamic properties and vehicle tire test results. The influence of CNTs on tire performances and their mechanisms was investigated and explained by the dynamic properties and master curve analysis in the frequency domain. Substituting 50 phr carbon black N234 by 20 phr CNTs could maintain hardness but increased static and dynamic moduli, which was beneficial for the tire handling, with 0.25 point improvement in the subjective testing. For the CNT-filled compounds, 1.5% traction improvement on a dry road and 6.5% traction improvement on a wet road can be explained successfully by the increased hysteresis loss (tan δ) and decreased storage modulus (G′) at high frequency domain (104–108 Hz). It is implied by Williams–Landel–Ferry law calculation that a strong interaction between CNTs and rubber resulted in higher temperature dependence; however, the trade-off was a 7% higher tire rolling resistance coefficient and 33% worse wear resistance for the CNT tires. CNT-filled compounds were demonstrated to have superior handling and traction performances suitable for racing and sports car tires.

Enhancing the Silanization Reaction of the Silica-Silane System by Different Amines in Model and Practical Silica-Filled Natural Rubber Compounds.

Diphenyl guanidine (DPG) is an essential ingredient in silica-reinforced rubber compounds for low rolling resistance tires, as it not only acts as a secondary accelerator, but also as a catalyst for the silanization reaction. However, because of concern over the toxicity of DPG that liberates aniline during high-temperature processing, safe alternatives are required. The present work studies several amines as potential alternatives for DPG. Different amines (i.e., hexylamine, decylamine, octadecylamine, cyclohexylamine, dicyclohexylamine, and quinuclidine) are investigated in a model system, as well as in a practical rubber compound by taking the ones with DPG and without amine as references. The kinetics of the silanization reaction of the silica/silane mixtures are evaluated using model compounds. The mixtures with amines show up to 3.7 times higher rate constants of the primary silanization reaction compared to the compound without amine. Linear aliphatic amines promote the rate constant of the primary silanization reaction to a greater extent compared to amines with a cyclic structure. The amines with short-alkyl chains that provide better accessibility towards the silica surface, enhance the primary silanization reaction more than the ones with long-alkyl chains. The different amines have no significant influence on the rate constant of the secondary silanization reaction. The amine types that give a higher primary silanization reaction rate constant show a lower flocculation rate in the practical compounds. For the systems with a bit lower primary silanization reaction rate, but higher extent of shielding or physical adsorption that still promotes higher interfacial compatibility between the elastomer and the filler surface, the rubber compounds show a lower Payne effect which would indicate lower filler-filler interaction. However, the flocculation rate constant remained high.

Improved tire-soil interaction model using FEA-SPH simulation

The purpose of this paper is to predict the rolling resistance of a free rolling off-road truck tire (size 315/80R22.5) over several soils. The soils are modelled using Smoothed-Particle Hydrodynamics (SPH) in the software package “Pam-Crash”. The soil models are calibrated using data obtained from published pressure-sinkage and shear-strength tests. The truck tire used in this study was modelled using Finite Element Analysis (FEA) and validated in previous studies. The tire-soil interaction algorithm is implemented in Pam-Crash software package to capture node-symmetric node-to-segment contact with edge treatment. The rolling resistance coefficient is computed from simulations and then validated against physical measurements. The rolling resistance coefficient is calculated for different terrains, such as dry sand, dense sand, clayey soil and hard surface. In addition, the rolling resistance is also computed for various tire inflation pressures and applied vertical loads. The research results presented in this paper will be further used for soil mixing-layering investigation.

타이어 회전저항 계수가 차량의 연비 및 CO2 배출량에 미치는 영향에 관한 연구

타이어 회전저항 계수가 차량의 연비 및 CO2 배출량에 미치는 영향에 관한 연구

Do Changes in Temperature and Inflation Pressure Affect Rolling Resistance During Road and Track Testing for Fuel Economy of Class 8 Tractor-Trailers?

Data from air cavity thermistors, tire pressure monitoring systems (TPMS), and SAE J1269 rolling resistance tests were analyzed to evaluate the significance of changes in tire pressure on rolling resistance during fuel economy tests of class 8 tractor trailers. Thermistor data show that air cavity temperatures vary, with the main increase happening during the warm-up run, and measurable cooling during the fuel measurement breaks between runs. Inflation pressure also increases by 50 - 70 kPa during the warm-up run, but once the tire has warmed up, the pressure is more stable, rarely varying by more than 20 kPa during a test run. Results of SAE J1269 rolling resistance tests allow estimation of rolling resistance force for any specified load and inflation pressure. Using the test weight of the truck, rolling resistance force was estimated for inflation pressures ranging from 550 to 860 kPa. The relationship between the inflation pressure and rolling resistance was roughly linear. The relationship was then used to estimate changes in fuel consumption due to changes in inflation pressure normalized to the cold inflation pressure. For each change of relative inflation pressure of 5%, rolling resistance would change by about 1%. Using a common return factor of a 1% change in fuel consumption for every 5% change in rolling resistance, a change in relative inflation pressure of 5% would result in a change of fuel consumption of about 0.2%. The precision of the J1321 fuel economy tests was measured to be plus or minus about 1%. This suggests that the warm-up run provided for in the test method stabilizes the tire pressure and rolling resistance, and that interference due to changes in rolling resistance during a test run or between runs is a concern only for tests that measure small changes in fuel consumption. While the results obtained here are used to assess the effect of inflation pressure on the SAE J1321 test and only apply to the particular tires tested, the method of analysis may be useful in the assessment of the effect of over- or underinflated tires on fuel consumption in the wider long-haul trucking fleet.

Rolling Resistance of Wheelchair tire

Rolling Resistance of Wheelchair tire

Developments in tyre design for lower rolling resistance: A state of the art review

Future sustainability of road transportation will require substantial improvement in the efficient use of energy by road vehicles. As new technologies being deployed reduce total vehicle energy consumption, the contribution of tyre rolling resistance to total energy consumption continues to increase. For this reason tyre rolling-resistance is starting to drive the focus of many tyre developments nowadays. This is because the rolling-resistance can be responsible for 20–30% of the total vehicle fuel consumption. Thus, lowering the rolling-resistance would help to reduce the fuel consumption (i.e. CO2, NOx and hydrocarbon emissions) and hence improve the environment greatly given the large number of vehicles used globally. It is found that the primary source of the rolling-resistance is the tyre deformational behaviour (i.e. hysteresis damping) which can account for 80–95% of the total rolling-resistance. This paper reviews the state of the art in tyre design, research and development for lower rolling-resistance, with focus on the primary source for the rolling-resistance (i.e. mechanical hysteresis damping), from three perspectives: the structural lay-up; the dimensional features; and the materials compound(s) of the tyre.

Physics-Based Deformable Tire–Soil Interaction Model for Off-Road Mobility Simulation and Experimental Validation

A physics-based deformable tire–soil interaction simulation capability that can be fully integrated into the monolithic multibody dynamics computer algorithm is developed by extending a deformable tire model based on the flexible multibody dynamics approach to off-road mobility simulations with a moving soil patch technique and it is validated against test data. A locking-free nine-node brick element is developed for modeling large plastic soil deformation using the multiplicative finite strain plasticity theory along with the capped Drucker–Prager failure criterion. To identify soil parameters including cohesion and friction angle, the triaxial compression test is carried out, and the soil model developed is validated against the test data. In addition to the component level validation for the tire and soil models, the tire–soil interaction simulation capability developed in this study is validated against the soil bin mobility test results. The tire forces and rolling resistance coefficients predicted by the simulation model agree well with the test results. It is shown that effect of the wheel loads and tire inflation pressures is well captured in the simulation model. Furthermore, it is demonstrated that the moving soil patch technique, with which soil behavior only in the vicinity of the rolling tire is solved to reduce the soil model dimensionality, leads to a significant reduction in computational time, thereby enabling use of the high-fidelity physics-based tire–soil interaction model in the large-scale off-road mobility simulation.

Influence of temperature on the tyre rolling resistance

Temperature is a very important factor controlling rolling resistance of road vehicle tyres. There are at least three different temperatures that may be considered as important factors controlling thermal conditions of the rolling tyre. The most common measure of the thermal conditions during tyre rolling is ambient air temperature. The other two are: pavement temperature and “tyre” temperature. Tyre temperature is the most difficult to establish, as temperatures of different parts of rolling tyres differ considerably, thus there is a problem to obtain representative values. In the authors’ opinion, air temperature is the most universal and reliable parameter to measure. The article presents results obtained in the Technical University of Gdansk during laboratory and road measurements of different car tyres rolling on different pavements. The knowledge of rolling resistance characteristics is important for modelling car dynamics as well as fuel consumption. It is also necessary to establish proper test conditions in the future standardized on-road method of measuring rolling resistance. The results indicate that generally each tyre and pavement combination is influenced by the air temperature in a unique way, but at the same it is possible to propose some general influence factors that may be used to normalize measurements to the standard temperature of 25 °C.

Effect of High Aspect Ratio Fillers on the Performance of Styrene-Butadiene Rubber

ABSTRACTAmong the many material performance properties of vulcanized elastomers for tire tread application, rolling resistance and wet traction are particularly important since both greatly impact fuel efficiency and traction of a vehicle. Rolling resistance and wet traction are generally negatively correlated, i.e., with the increase in rolling resistance of a tire, its wet traction decreases. Silica nanofillers are often used for achieving the desired balance of wet traction and rolling resistance. However, the high cost of silica limits its wide spread application. In this research we studied the effects of using fillers with different aspect ratios (calculated by dividing the long dimension of a filler by its short dimension) on the performance of vulcanized styrene butadiene rubber (SBR), a common rubber for tire tread application. Three high aspect ratio fillers were used: aragonite calcium carbonate, wollastonite and carbon nanofiber. For comparison purpose, spherical silica filler was also included. We found that the high aspect ratio fillers were efficient in improving the wet traction and rolling resistance as well as enhancing the mechanical energy dissipation of SBR. Among the three high aspect ratio fillers studied, wollastonite provided the best wet traction and rolling resistance balance due to its high aspect ratio and compatibility with the base rubber. The effects of fillers induced crosslinking on the dynamic performance were also discussed.

A nano-mechanical instability as primary contribution to rolling resistance

Rolling resistance ranks among the top ten automobile megatrends, because it is directly linked to fuel efficiency and emissions reduction. The mechanisms controlling this phenomenon are hidden deeply inside the complexity of tire tread materials and do elude direct experimental observation. Here we use atomistic molecular modelling to identify a novel nano-mechanical mechanism for dissipative loss in silica filled elastomers when the latter are subjected to dynamic strain. The force-vs-particle separation curve of a single silica particle-to-silica particle contact, embedded inside a polyisoprene rubber matrix, is obtained, while the contact is opened and closed by a cyclic force. We confirm the occurrence of spontaneous relative displacements (‘jolts’) of the filler particles. These jolts give rise to energy dissipation in addition to the usual viscous loss in the polymer matrix. As the temperature is increased the new loss mechanism becomes dominant. This has important technical implications for the control and reduction of tire rolling resistance as well as for many other elastomer composite applications involving dynamic loading.

Contact stiffness considerations when simulating tyre/road noise

Tyre/road simulation tools that can capture tyre vibrations, rolling resistance and noise generation are useful for understanding the complex processes that are involved and thereby promoting further development and optimisation. The most detailed tyre/road contact models use a spatial discretisation of the contact and assume an interfacial stiffness to account for the small-scale roughness within the elements. This interfacial stiffness has been found to have a significant impact on the simulated noise emissions but no thorough investigations of this sensitivity have been conducted. Three mechanisms are thought to be involved: The horn effect, the modal composition of the vibrational field of the tyre and the contact forces exciting the tyre vibrations. This study used a numerical tyre/road noise simulation tool based on physical relations to investigate these aspects. The model includes a detailed time-domain contact model with linear or non-linear contact springs that accounts for the effect of local tread deformation on smaller length scales. Results confirm that an increase in contact spring stiffness causes a significant increase of the simulated tyre/road noise. This is primarily caused by a corresponding increase in the contact forces, resulting in larger vibrational amplitudes. The horn effect and the modal composition are relatively unaffected and have minor effects on the radiated noise. A more detailed non-linear contact spring formulation with lower stiffness at small indentations results in a reduced high-frequency content in the contact forces and the simulated noise.

FURTHER EVIDENCE OF FILLER–FILLER MECHANICAL ENGAGEMENT IN RUBBER COMPOUNDS FILLED WITH SILICA TREATED BY LONG-CHAIN SILANE

ABSTRACT The present study discusses that filler–filler mechanical engagement resulting from the grafted long-chain silanes on the silica surface is indeed a reinforcing mechanism in rubber composites, as already speculated by nonlinear viscoelastic properties in our previous study. The existence and severity of such a phenomenon are assessed purely by isolating the energetic contribution of reinforcement from interfering with filler mechanical engagement in the silica network formation and breakdown processes. In a novel approach, the driving force of fillers to flocculate energetically at elevated temperatures was defined using surface energy theories, and it was adjusted to be similar in two composites having silica treated by short- and long-chain silanes. Filler–filler mechanical engagement was monitored by tracking network formation (filler flocculation) in a matrix of styrene–butadiene rubber and also by conducting various dynamic viscoelastic experiments on liquid paraffin suspensions having short- and long-chain silica of similar surface energy. Results consistently confirmed the existence of mechanical engagement between silica particles having the long-chain silane in both rubber compounds and paraffin suspensions. The results may find applications in the rolling resistance of tires, for example, where stabilization of the filler network by displacing the peak energy dissipation of the network breakdown from applied service strains to larger values would be of technical importance.

A model for prediction of the transient rolling resistance of tyres based on inner-liner temperatures

ABSTRACTMeasurements of rolling resistance in thermal equilibrium of a tyre, like measurements according to ISO 28580, do not allow statements about rolling resistances under other driving conditions. Such statements, however, are necessary to determine the energy consumption in driving cycles. Especially for the proper calculation of electric-vehicle remaining ranges and the selection of the respective driving strategies, the real amount of energy consumption is required. This paper presents a model approach, which by means of only one standardised rolling resistance measurement can be parameterised and, considering the present driving speed and tyre temperature, can predict the respective current rolling resistance.

The Influence of the Concentration of an ‘n-butyllithium–amine-containing Modifier’ Initiating System on the Copolymerisation of 1,3-butadiene and Styrene

The influence of the concentration of an initiating system consisting of n-butyllithium and an amine-containing modifier on the copolymerisation of 1,3-butadiene and styrene in a hexane solvent was studied. The molecular characteristics and the microstructure of specimens of the obtained solution-polymerised styrene butadiene rubber (s-SBR) were determined by gel permeation chromatography on a Breeze liquid chromatograph (Waters) and by IR spectroscopy on a Spectrum GX 100 spectrometer (PerkinElmer) in accordance with ISO 21561/2. It was shown that a reduction in the amount of the initiating system is accompanied with a reduction in the copolymerisation rate and in the monomer conversion, and also with an increase in the average molecular weights of the copolymer. It was established that a reduction in the initiating system concentration in the reaction medium leads to a reduction in the content of 1,2-units in the rubber. A comparative analysis of data for rubber compounds based on the synthesised s-SBR and data for rubber compounds based on standard rubber indicates that their mechanical properties are at the same level. However, the tg δ at 60°C (determined on an RPA 2000 instrument) for rubber compounds based on a trial specimen has a lower value, which will make it possible to produce tyre rubbers providing a lower tyre rolling resistance.

Reliability of the virtual elevation method to evaluate rolling resistance of different mountain bike cross-country tyres

ABSTRACTAlthough a low rolling resistance is advantageous in mountain bike cross-country racing, no studies have used the virtual elevation method to compare tyres from different manufacturers as used in international competitions so far. The aims of this study were to assess the reliability of this method, to compare the off-road rolling resistance between tyres and to calculate the influence on off-road speed.Nine 29-in. mountain bike cross-country tyres were tested on a course representing typical ground surface conditions 5 or 6 times. The coefficient of rolling resistance was estimated with the virtual elevation method by 3 investigators and corresponding off-road speeds were calculated.The virtual elevation method was highly reliable (typical error = 0.0006, 2.8%; limits of agreement <0.0005, r ≥ 0.98). The mean coefficient of rolling resistance was 0.0219 and differed from 0.0205 to 0.0237 (P < 0.001) between tyres. The calculated differences in off-road speed amounted to 2.9–3.2% (0% slope) and 2.3–2.4% (10% slope) between the slowest and the fastest tyre.The reliability of the method and the differences in rolling resistance between the tyres illustrate the value of testing tyres for important competitions on a representative ground surface using the virtual elevation method.

Tyre rolling resistance and its influence on fuel consumption

Rolling resistance of tyres is one of the major resistive forces acting on any wheeled vehicle. Unfortunately, it is also one of the forces very difficult to measure. It is estimated that in certain traffic conditions (like for example constant speed driving with slow or moderate speed) so called Rolling Resistance Impact Factor may be as high as 0.3. This means that reduction of rolling resistance by 50% would lead to 15% of energy savings. The paper presents road measuring method of tyre rolling resistance and unique equipment used by the Technical University of Gdańsk designed to perform measurements of passenger car tyres. It also discusses road pavement, tyre and environmental conditions influence on rolling resistance. Also selected data describing current situation related to rolling resistance on different road pavements and rolling resistance of modern passenger car tyres including tyres specially designed for electric and hybrid vehicles are presented.

Technology for Reducing Tire Rolling Resistance

Reducing automobile tire rolling resistance is an effective measure for achieving fuel cost savings and reducing CO2 emissions, which contributes to global warming. In this report, mechanisms to represent tire rolling resistance and the methods to control it will be explained.

Finite Element Modeling with Embed Rebar Elements and Steady State Rolling Analysis for Rolling Resistance Test of Pneumatic Tire

Finite element model of tire rolling resistance test on the drum was developed using 3D steady state rolling analysis coupling with pre-inflation of 2D axisymmetric tire analysis. The complex components of the radial tires composing tread, sidewall, ply layers, steel belts, and lead wires were modeled using rebar elements which were embed into the rubber element using the tying equation. The Mooney-Rivlin hyperelastic constitutive model was employed to describe the large deformation behavior of tread and sidewall, while other components such as plies, steel belts and bead wires were assigned the linear isotropic material. The tire rolling resistance system was modeled by inflation of slick tire and compression on the drum for the footprint analysis regarding the rolling resistance test. The tire’s steady state characteristics such as footprint contact pressure, rolling resistance force, and time response characteristic of tires were predicted instead the experiment of the prototype.