ROLLING RESISTANCE IN PASSENGER VEHICLE TYRES

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 9, Issue 13, December 2018, pp , Article ID: IJMET_09_13_053 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed ROLLING RESISTANCE IN PASSENGER VEHICLE TYRES Dr.D.Rajasekar Professor, AMET Business School, AMET Deemed to be University, Chennai Dr. R Suresh Associate Professor, Department of Management Studies, Sri Sai Ram Engineering College, Chennai. Dr.B. Venkateswara Prasad Associate Professor, Department of Management Studies, Sri Sai Ram Engineering College, Chennai. ABSTRACT Reducing energy consumption is a national goal for many reasons, from economic and national security to improving air quality and reducing greenhouse gas emissions. Also, rising energy prices are having their effect on consumers and businesses, and have contributed to increases in the Consumer Price Index in recent years. A vehicle s fuel economy is affected by tire rolling resistance, therefore, fuel saving could be achieved by reducing tire rolling resistance. When a tire rolls on the road, mechanical energy is converted to heat as a result of the phenomenon referred to as rolling resistance. Effectively, the tire consumes a portion of the power transmitted to the wheels, thus leaving less energy available for moving the vehicle forward. Rolling resistance therefore plays an important part in increasing vehicle fuel consumption. Rolling resistance includes mechanical energy losses due to aerodynamic drag associated with rolling, friction between the tire and road and between the tire and rim, and energy losses taking place within the structure of the tire. This present study examines the possibility of reducing the Rolling Resistance in tyres of passenger vehicle with existing technology. Keywords: Greenhouse, Fuel economy, Rolling Resistance, Mechanical energy, Friction Cite this Article: Dr.D.Rajasekar, Dr. R Suresh and Dr.B. Venkateswara Prasad, Rolling Resistance in Passenger Vehicle Tyres, Journal of Mechanical Engineering and Technology, 9(13), 2018, pp INTRODUCTION A vehicle s fuel economy is affected by tire rolling resistance, therefore, fuel saving could be achieved by reducing tire rolling resistance editor@iaeme.com

2 Dr.D.Rajasekar, Dr. R Suresh and Dr.B. Venkateswara Prasad However, consumers often purchase less fuel-efficient tires when replacing their vehicles OE tires, as well as when purchasing subsequent sets of replacement tires. For example, during 2007 there were an estimated 51 million OE passenger and light truck tires sold in the United States, as opposed to an estimated 237 million replacement passenger and light truck tires Problem Statement Rolling resistance affects fuel consumption in the same way as natural phenomena like wind, slope and vehicle inertia, which must be overcome in order to move. Reducing rolling resistance reduces costs and helps preserve the environment. Reducing a vehicle s fuel consumption means cutting down on fossil fuels and releasing fewer exhaust gases into the atmosphere while lowering the vehicle s operating cost per kilometre. Rolling resistance has been reduced by a factor of three since the very first pneumatic tyres. In 1895, tyres had a rolling resistance coefficient of 25 kilograms per tonne, whereas green" tyre first produced in 1992 today offers a rolling resistance coefficient of kilograms per tonne without compromising either grip or resistance to wear. At the same time, considerable progress has been made on both vehicles (engine, aerodynamics) and roads (surfaces and profiles), enabling greater mobility for less energy. A new vehicle today uses fifteen percent less fuel and pollutes twenty times less than fifteen years ago. Therefore, the rolling resistance of replacement tires could have a significant impact on the fuel economy of the U.S. light-vehicle fleet.given the ecological constraints linked to the development of human activities in general and road transport in particular, further progress is crucial. Reducing rolling resistance will help to improve the situation. 2. LITERATURE REVIEW Bendtsen.H (2004) Rolling resistance, fuel consumption - This note on rolling resistance, fuel consumption and emissions is produced as a part of the Danish contribution to the SILVIA project. When the rolling resistance coefficient is increased, the fuel consumption is also increased consumption on different pavements. LaClair (2007) describes the concept of rolling resistance in simple terms: When a tire rolls on the road, mechanical energy is converted to heat as a result of the phenomenon referred to as rolling resistance. Effectively, the tire consumes a portion of the power transmitted to the wheels, thus leaving less energy available for moving the vehicle forward. Rolling resistance therefore plays an important part in increasing vehicle fuel consumption. Madhura Rajapakshe (2012) In Tire Rolling Resistance Ratings and Real World Fuel Savings reviewed domestic and international tire rolling resistance rating systems. The reliability of these rating systems in assisting consumers select fuel efficient tires and protect the environment, depends on how well the RR ratings differentiate real world fuel savings and GHG emissions. Davis, S. C. and S. W. Diegel. (2004) describes of how lowering the rolling resistance of replacement tires used on passenger cars and light trucks could affect Motor fuel consumption nationally; Tire wear life and the generation of scrap tires; Tire performance characteristics, including those affecting vehicle safety; and Total consumer spending on tires and fuel. And study examines the contribution of tires to vehicle fuel economy, the variability in energy performance among tires, and technical and economic issues associated with means of improving tire energy performance. The focus is on replacement tires designed for passenger cars as well as vehicles defined as light trucks and used mainly for personal transportation.duleep K.G and NAS (2005) The U.S. Department of Energy estimates that approximately 4.2 percent of the total energy available in the fuel you put in your tank is lost to rolling resistance during the operation of the vehicle. However, they point out that the peak first law (thermodynamic) efficiency of a modern spark-ignited gasoline engine is in the percent range (40-42% for diesels), and therefore tire rolling resistance consumes about a third of the usable energy actually transmitted to the wheels.therefore, considering rolling resistance in terms of the energy in the fuel tank is not a useful measure. For instance, only 12.6 percent of the energy in the fuel is finally editor@iaeme.com

3 Rolling Resistance in Passenger Vehicle Tyres transmitted to the wheels. The 4.2 percent of original fuel energy used by rolling resistance is actually 33 percent (4.2%/12.6%) of the total usable energy available to the wheels Objectives of the Study The study aims at finding the ways to reduce the level of Rolling Resistance of passenger vehicle tires without compromising performance by existing technology in the Industry. The study also analyses the impact of tyre resistance on fuel Efficiency. 3. METHODOLOGY A fishbone diagram is useful in brainstorming sessions to focus conversation. After the group has brainstormed all the possible causes for a problem, the facilitator helps the group to rate the potential causes according to their level of importance and diagram a hierarchy. The design of the diagram looks much like a skeleton of a fish. Fishbone diagrams are typically worked right to left, with each large "bone" of the fish branching out to include smaller bones containing more detail. Professor Kaoru Ishikawa created Cause and Effect Analysis in the 1960s. The technique uses a diagram-based approach for thinking through all of the possible causes of a problem. This helps you to carry out a thorough analysis of the situation. 4. RESULTS & DISCUSSIONS Figure 1 Cause & Effect Analysis on RR Improvement 4.1. Material Gauge Reduction To reduce the RR of existing 205/65 R16 Apterra HL by ~300gms (Min), a new design is proposed wherein the UT (Material Gauge) at shoulder region is reduced. Analysis conditions to be followed: Inflation Pressure 210 kpa Maximum Load 552 Kg Speed 80 kmph editor@iaeme.com

4 Dr.D.Rajasekar, Dr. R Suresh and Dr.B. Venkateswara Prasad RESULT Table 1: Analysis Report of existing & proposed Layout Parameters Existing Proposed Tyre Diameter (mts) Drum Diameter (mts) 2 2 Simulated Flat (Kg) Simulated Drum (Kg) Difference (gms) RR value for proposed layout is reduced by 365 gms compared to existing layout Belt Width Modification RESULTS Cap ply 1 and 2 are increasing while increasing the belt width. This is a logical effect since the cap ply is scaled automatically by the Xpert system. However the capply area in the F specification is growing more than double than the E specification. This is happening because of the fact that the cap ply is replacing the undertread in the F specification, since the undertread is being cut off by the wingtip. The belt strip area should not be changed since gauges are kept the same. However parasitical changes are happening due to the skewing effect the belt strip is encountering with increasing Increasing the belt width in combination width, a high drop results in an increase in deflection (flapping) of the belt. This increases the contribution of the belts, belt strip and cap ply to RR tremendously. To lower RR: Reduce the belt width to avoid the belt edge get into the high deflective zone Adjust the cavity shape in order to get a flatter belt such that deflection is reduced while running through contact RR value for proposed layout is reduced by 260 gms compared to existing layout by reducing the Belt Width Belt Angle Modification Differences are found in the two variants compared to the reference layout: Belt1/Belt 2: Pantographing during the curing stage is changing the belt angle as well as the belt width. The closer the belt angle gets to 45 o, the more it will get narrow. By reducing the green belt angle, pantograph narrowing of the belt gets reduced, resulting in a wider belt in cured state and therefore a higher cross sectional area. However this is not the case here. Since the cured belt width is set, the pantographing will only affect the belt gauge. The higher the belt angle, the more the gauge gets reduced, so a lower green belt angle will reduce in a thicker belt layer in cured state. RESULT A decrease of the belt angle results in: editor@iaeme.com

5 Rolling Resistance in Passenger Vehicle Tyres A decreased belt/tread stiffness. The reduced stiffness will increase the flexibility, leaving the rubber surrounding the belt to have more hysterical losses. Affected components are: base, belt rubber, cap ply, tread, belt strip Footprint gets elongated with decreasing the belt angle. A decrease of the RR contribution of: Rim cushion, due to a decreased stiffness and therefore an increased flexibility in the tread area. Less deformation leads to a lower RR contribution. RR value for proposed layout is reduced by 290 gms compared to existing layout Ply Turn up Height Modification Changing the ply turn up height, will affect (obviously) the ply area, the rim cushion area and the sidewall area: Ply area shows logical behavior Rim cushion gets increased in both cases. Expectation was that the sidewall area should not get changed. RESULT The ply s contribution to the total RR is not changing significantly. The small reduction of RR found in the L specification is due to the fact that the LRR sidewall compound is replacing the rim cushion compound. This happened with the changing transition line. No significant change in the specific RR contribution is found in any of the materials Fuel Consumption Estimation The results of the analysis of variance for the various fuel economy tests studied. The trends and 95 percent confidence limits of each test for miles per gallon, calculated for four tires of the specified rolling resistance mounted on the vehicle, versus the rolling resistance force values for the tires studied. Values of Probability less than 0.05 indicate that the variable (lbf) has a significant effect on rolling resistance. It shows the fuel economy as a percentage of the mean for each test versus the rolling resistance as a percentage of the mean rolling resistance. The scatter in the data is evident, but the overall trends are clear and the percentage decreases in fuel economy as tire rolling resistance increases show very similar trends. It have shown the effects of rolling resistance as percentage change in mileage for the vehicle (%mpg) that results from some percentage change in rolling resistance of the tires (%Rolling Resistance). These results agree with the calculated values of a 0.7 percent to 2.0 percent change in fuel economy for a 10 percent change in rolling resistance. Table 4: Mileage versus Rolling Resistance Rolling Resistance (lbs) Highway Mileage (MPG) City Mileage (MPG) 5. CONCLUSION editor@iaeme.com

6 Dr.D.Rajasekar, Dr. R Suresh and Dr.B. Venkateswara Prasad The study clearly indicates the importance of the RR of tyres with respect to fuel economy of vehicles in addition to reduction in the CO2 emission by way of reducing the RR values of tyres. To get the best performance of fuel economy using RR measurements, the user must maintain the correct/recommended tyre inflation pressure and avoid over-speeding and over-loading. Such awareness will also help consumers to take such precaution for the benefit of fuel economy, and such precaution will also help avoid road accident and tyre-burst during service condition. The RR study gives an opportunity to tyre manufacturers to upgrade their existing technology on a par with technology of the leading tyre manufacturers which the global market demands. REFERENCES [1] Duleep, K.G. (2005). Tires Technology and Energy Consumption,Improving the On-Road Performance of Motor Vehicles, International Energy Agency, Paris, France [2] Hall, D.E., & Moreland, J.C. (2001). Fundamentals of Rolling Resistance, Rubb. Chem. Technol., Vol.74. [3] LaClair, T. J., Gent, A.N., & Walter, J.D. (Ed.). (2006). Rolling Resistance in The Pneumatic Tire, Published under contract DTNH22-02-P Washington, DC: National Highway Traffic Safety Administration. [4] National Research Council of the National Academies (2006). Tires and Passenger Vehicle Fuel Economy, Special Report 286, Washington, DC: Transportation Research Board. [5] NHTSA. (2006), Tire Fuel Efficiency Consumer Information Program Development, Phase 2 Effects of Tire Rolling Resistance Levels on Traction, Treadwear, and Vehicle Fuel Economy, Published under DOT HS Washington, DC: National Highway Traffic Safety Administration. [6] Pillai, P.S. (1995). Total Tire Energy Loss Comparison by the Whole Tire Hysteresis and the Rolling Resistance Methods, Tire Science and Technology, TSTCA, Vol editor@iaeme.com