Measuring the rolling resistance of heavy vehicle tyres. Rolling resistance coefficient an overview sciencedirect topics. Rolling resistance wikipedia, the free encyclopedia. Free access to the official road load forces is a vital precondition for any independent verification measures. Page 1 of 8 with resistance due to rotational aerodynamic drag at the rolling resistance coefficients externalinternal tire surfaces. Dependency of coefficient of rolling resistance on pavement. Percentage of total resistance very low speeds 90 kmh 120 kmh inertial resistance 41 air resistance 63 75 rolling resistance 46 37 25 4 silka w energochlonnosc ruchu samochodu, warszawa, wkl 1997. C rr is a dimensionless quantity that describes resistance to forward motion per unit vehicle weight.
The most recent 21st century truck partnership 21ctp white paper 1 adopted the environmental protection agencys epas c d and c rr baselines from the proposed epanational highway traffic safety administration nhtsa greenhouse gas ghg rule that were to represent roughly the median of current in. Driving resistances of lightduty vehicles in europe. Equating the above two equations, and solving for b, gives b crrr. Rolling resistance is usually measured either indirectly, such as with coastdown tests and power meters, or under artificial conditions, such as rolling the tire on a steel drum. Rolling resistance forces d oppose to forward motion see fig.
The resistance force is zero when the normal force acting at the wheelroad surface is less than or equal to zero. Exploring the relationship of rolling resistance and. Thank you for the invitation to write about tire rolling resistance and especially. Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the. Furthermore, official inuse compliance measurements must be extended. Rolling resistance measurements at the mnroad facility. Note that the rolling resistance coefficient c is influenced by different variables like wheel design, rolling surface, wheel dimensions and more. Rolling resistance coefficient as affected from both transient and steadystate factors. The coefficient of rolling resistance of the truck tires varied from 0. Exploring the relationship of rolling resistance, tire. Rolling resistance is a measure of the force that must be overcome to roll or pull a wheeltrack over the ground.
The rolling resistance can alternatively be expressed as. The report states the coefficient of rolling resistance is a convenient concept since it allows one to compare. Based on the above simple equation it can be seen that by reducing the coefficient of friction of either the flooring or wheel material or both, the resistance to move can be reduced. The block can use a constant resistance coefficient or the pressure and velocity dependence of the sae j2452 standard. Rolling resistance can be expressed by the rolling resistance coefficient rrc or c rr, which is the value of the rolling resistance force divided by the wheel load.
This parametrical rolling resistance equation can be used as input in tire models like pac2002 or other. Using the results in the database, multivariable linear regression analyses are conducted to investigate the dependency of the crr on the other surface characteristics. Is the friction coefficient in that case, closer to kineticsliding coefficient or to a rolling resistance coefficient. The model is based on free rolling condition without taking the. Rolling resistance an overview sciencedirect topics. The rolling resistance linear contact model in pfc incorporates a torque acting on the contacting pieces to counteract rolling motion wensrich et al. Internal friction and tire flexing also add to rolling resistance. Rolling resistance is a measure of the retarding e.
It is affected most by ground conditions and loadthe deeper the wheeltrack sinks into the ground, the higher the rolling resistance. The general parametrical rolling resistance equation can relatively well estimate the rolling resistance force for all car tires. Later, researchers found out that the coefficient of rolling resistance for pneumatic tires is dependent on hysteretic loss from tire deformation which is affected by the vertical force applied to the tires and the tire inflation pressure in real driving situation. Meanwhile the rolling resistance coefficient of the pneumatic wheel does not show a clear relationship with weight. The tire rolling resistance coefficient of friction is as follows. F r rolling resistance or rolling friction n, lb f. This coefficient of rolling resistance is generally much smaller than the coefficient. Rolling resistance comes from friction between the wheel tread and the head of the rail partly, which also comes from s certain minute amount of flattening of the surfaces in contact. Rolling resistance measurement and model development. Rolling resistance can be reported as a drag force or as the coefficient of rolling resistance, rr mu. Rolling resistance and its relationship with tire pressure load and speed. The impact of official versus realworld road loads on co2.
The force that resists the motion of a body rolling on a surface is called the rolling. While the rolling resistance testing was conducted on all cells of the mnroad mainline, the primary objective relative to this project was to obtain the rolling resistance data for cells 7, 8, and 9 the portland cement. Therefore, the lower the crr value for the tire, the fewer watts that are consumed when riding your bike. Rolling resistance force an overview sciencedirect topics. Apr 29, 2018 rolling resistance and wheels rolling resistance physics gale academic onefile doent experimental and numerical stus on tire tread block friction characteristics based a new test device share this. For tyres with rolling resistance coefficient of 0. Rolling resistance coefficient values were obtained with a smooth, fabricreinforced rubber tread, type viii, 27. E38 with no fluid lift, drag or brake, this equation represents the tire rolling resistance slip friction coefficient on a clean surface. When it comes to rolling resistance, the combination of floor type, condition and wheel material play a large role in the values. One of the variables of the rolling resistance force equation is called the coefficient of rolling resistance crr. A direct method of measuring the rolling resistance of a.
Also, sand on the ground will give more rolling resistance than concrete. The rolling resistanceblock models the resistance force that acts on the wheel hub due to the rolling resistance at the roadwheel contact surface. Contents 1 primary cause 2 rolling resistance has different definitions 3 rolling resistance coefficient 4 measurement 5 physical formulas 6 rolling resistance coefficient examples 7 depends. Other factors such as road camber, temperature and rim width have a lesser effect on the rolling resistance force 1. Pavement texture evaluation and relationships to rolling. Rolling resistance coefficient due to effects of pavement surface road surface car tyre concrete, asphalt rolled gravel tarmacadam unpaved road field truck tyres concrete, asphalt rolling resistance coefficient 0. Average rolling resistance coefficients measured 0. A means of directly measuring rolling resistance in the field was developed. F rolling resistance coefficient nonpneumatic 33 lbs wheel 66 lbs 0. This research study the effect of tire inflation pressure on rolling resistance, contact. Effects of tire rolling resistance on class 8 tractortrailer. Swivel resistance swivel resistance is determined by the swivel bearing sizes, ball diameters and ball.
Rolling resistance rolling resistance is the reaction force acting on the bicycle due to the interaction between the mountain bike tyre and the terrain surface it. What kind and value is the friction coefficient of tank tracks on the move, when force is applied forward in the direction of the tracks movement. The equation for rolling resistance force is below. Tyre modelling for rolling resistance chalmers publication library. Pdf rolling resistance measurement and model development. Robust estimation of road friction coefficient for vehicle. Following a 2006 report to congress on passenger vehicle tire rolling resistance by the national academies, the agency initiated a research project to evaluate existing tire rolling resistance test methods and to examine correlations between tire rolling resistance levels and tire safety performance. Mar 30, 2021 bicycle rolling resistance special articles. Analysis of contact stresses and rolling resistance of truck.
Factors influencing rolling resistance vehicle velocity like the fuel consumption, rolling resistance also has a significant relationship with velocity. However, in practice, if you want to compare performance before and after making modifications to your car, you can get faster results just by measuring the time to decelerate from speed a to speed b. The formula to calculate rr mu is the drag force f rr divided by the weight w on the wheel. Fuel consumed by the rolling resistance force at 30 mph varied between 0. For comparison purposes a nondimensional measure of rolling resistance is used. Rolling resistance rolling resistance is the reaction force acting on the bicycle due to the interaction between the mountain bike tyre and the terrain surface it is travelling on. The value of rolling resistance is a function of the coefficient of rolling friction between metals, which increases as the load is increased. This provides some interesting information that should be considered when selecting a wheel for a person. Therefore, these are the drag coefficient and coefficient of rolling resistance calculated for my car. Factors influencing rolling resistance vehicle velocity. The rolling resistance contact model provided in pfc is a simple model, based on the linear model, that incorporates a torque acting on the contacting pieces and resisting rolling motion. A lower coefficient means the tires will use less energy to travel a certain distance. Exploring the relationship of rolling resistance, tire type.
Such simple relationships are used for crude calculations valid only for low speeds, the rolling resistance coefficient is more complex than just a simple value. Rolling resistance plays a critical role in fuel consumption. Tests were made at 4o yaw on various surfaces for both flooded and damp conditions, and the results are shown in figure 2 as a function of ground speed. Dem investigation on characteristics of rolling resistance. Rolling resistance and energy loss in tyres svea fordon.
The rolling resistance linear rrlinear model was used in the present simulations. The rolling resistance coefficient fr depends on the forward speed and may be expressed in terms of powers. Rolling resistance coefficient f0, f1, f2 road load coefficients european labeling g gravity constant gtr global technical regulation. The objective was to determine whether there is a relationship between tire rolling resistance and stopping distance for vehicles of this type. Rolling resistance can be measured using the following formula. Genta and morello 10 show this coefficient in terms of the normalized longitudinal force f x f z, but that is a matter of substituting the value of. Conventional buses may be equipped with manual or automatically shi. A free body diagram of the forces is shown in figure 1. The determination of the rolling resistance coefficient of a passenger. Nhtsa tire fuel efficiency consumer information program. Castor wheels roll resistance bulldog castors blog.
Calculate the rolling resistance keep in mind that at startup the force will be 2 to 2. Pdf rolling resistance hypothesis proof brian p wiegand. Low rolling resistance tires have been available from the tire industry since 1993, and every second tire sold today is a low rolling resistance tire. Tank tracks treads friction coefficient physics forums. The coefficient of rolling friction is estimated based on the energy dissipation. The rolling resistance coefficient of the nonpneumatic wheel increased when weight was added to the cart on most surfaces. Rolling resistance is defined as a measure of the force required to overcome the retarding effect between the tyres and road1 and is commonly represented by a rolling resistance coefficient, which can be determined by dividing the rolling resistance by the normal force applied to a truck tyre. North american council for freight efficiency driving. It is normally expressed in pounds and is a measure of the energy dissipated per unit of distance rolled. Given a tire design and a standard inflation pressure, a rolling resistance coefficient c rr can be found. Tests of two new polyurethane foam wheelchair tires. Effect of pavement conditions on rolling resistance. Technical university of gdansk, in poland, to conduct rolling resistance at the mnroad facility near albertville, minnesota.
Pdf nonlinear rolling friction of a tyrecaster system. Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body such as a ball, tire, or wheel rolls on a surface. Calculating rolling resistance with a parametrical equation. Pdf there is an increased focus worldwide on understanding and modeling rolling resistance because reducing the rolling resistance by. Rolling resistance is the force required to keep the wheel in constant motion. History of heavyduty truck aerodynamic and tire rolling resistance coefficients. Rolling resistance related to the road surface is responsible for about 20% of the co 2 emitted by a passenger car driving at 100 kmh haider et al. In addition, the friction coefficient between the tyre and road surface. Low rolling resistance tires have been available from the tire industry since 1993. Rolling resistance measurement and model development journal. The tire will deform to some extent, and that deformation will cause some. The force that resists the motion of a body rolling on a surface is called the rolling resistance or the rolling friction the rolling resistance can be expressed by the generic equation. The science of caster wheels and impact on workplace.
Rolling resistance coefficient an overview sciencedirect. Pdf estimation of the rolling resistance of tires brian. The other surface characteristics are coefficient of rolling resistance crr, roughness, friction, and tirepavement noise. Thk me en 7960 precision machine design linear rolling bearings 810 to recirculate or to not recirculate. If the aerodynamic influence of the different wheels within one interpolation family is not known, the selection shall be based on the highest expected aerodynamic drag. Rolling resistance coefficient grouped by surface pneumatic nonpneumatic figure 4. Bicycle rolling resistance rolling resistance tests. Therefore, for free rolling, straight ahead driving and neutral wheel alignment inplane rolling resistance coefficient will be used instead and in general the term rolling resistance coefficient. This resistance is dependent upon the load, wheel diameter, tread material, bearing type, caster offset and floor surface and temperature. If the aerodynamic influence of the different wheels within one interpolation family is not known, the selection shall be. The federal uniform tire quality grading utqg system ratings for traction and tread wear are the. Therefore, for free rolling, straight ahead driving and neutral wheel alignment inplane rolling resistance coefficient. The effects of rolling resistance and particle shape on the shear strength, deformation behavior and noncoaxiality are compared.
Normally the resistance and weight terms are expressed in the same unit, such as lb f, so that the quotient is. From wikipedia, the free encyclopedia rolling resistance. A crosssectional area of vehicle c drag coefficient based on the shape of the front of the train and other features affecting air turbulence etc. Tire inflation pressure of vehicle affects various factors such as fuel economy, tread wear, rolling resistance, contact patch area and braking distance etc. These methods either fail to provide actual or accurate rolling resistance coefficients.
1546 1218 1144 577 1223 1365 76 1371 1470 317 226 654 1599 1346 921 144 463 1224 1588 72 128 580 266 91 1415 1609 1002 311 1080 556 751 1682 1522