Browse Topic: Tire friction

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Recurrent Neural Network Model for On-Board Estimation of the Side-Slip Angle in a Four-Wheel Drive and Steering Vehicle15-17-01-00039/23/2023
Abstract A valuable quantity for analyzing the lateral dynamics of road vehicles is the side-slip angle, that is, the angle between the vehicle’s longitudinal axis and its speed direction. A reliable real-time side-slip angle value enables several features, such as stability controls, identification of understeer and oversteer conditions, estimation of lateral forces during cornering, or tire grip and wear estimation. Since the direct measurement of this variable can only be done with complex and expensive devices, it is worth trying to estimate it through virtual sensors based on mathematical models. This article illustrates a methodology for real-time on-board estimation of the side-slip angle through a machine learning model (SSE—side-slip estimator). It exploits a recurrent neural network trained and tested via on-road experimental data acquisition. In particular, the machine learning model only uses input signals from a standard road car sensor configuration. The model adaptability to different road conditions and tire wear levels has been verified through a sensitivity analysis and model testing on real-world data proves the robustness and accuracy of the proposed solution achieving a root mean square error (RMSE) of 0.18 deg and a maximum absolute error of 1.52 deg on the test dataset. The proposed model can be considered as a reliable and cheap potential solution for the real-time on-board side-slip angle estimation in serial cars.
Giuliacci, Tiziano Alberto, Ballesio, Stefano, Fainello, Marco, Mair, Ulrich, King, Julian
Topological Optimization of Non-Pneumatic Unique Puncture-Proof Tire System Spoke Design for Tire Performance15-17-01-00017/18/2023
Abstract Non-pneumatic tires (NPTs) have been widely used due to their advantages of no occurrence of puncture-related problems, no need of air maintenance, low rolling resistance, and improvement of passenger comfort due to its better shock absorption. It has a variety of applications as in earthmovers, planetary rover, stair-climbing vehicles, and the like. Recently, the unique puncture-proof tire system (UPTIS) NPT has been introduced for passenger vehicles segment. The spoke design of NPT-UPTIS has a significant effect on the overall working performance of tire. Optimized tire performance is a crucial factor for consumers and original equipment manufacturers (OEMs). Hence to optimize the spoke design of NPT-UPTIS spoke, the top and bottom curve of spoke profile have been described in the form of analytical equations. A generative design concept has been introduced to create around 50,000 spoke profiles. Finite element model (FEM) model is developed to evaluate the stiffness and damage-resisting performance of NPT-UPTIS spoke. The FEM methodology has also been validated with average accuracy of more than 95% for experimental vertical stiffness for commercial NPT-Tweel. The stiffness and damage-resisting performance of generated designs have been predicted with the help of machine learning regression models, which were trained on the FEM results of 200 such designs. These 50,000 generated designs have been categorized in four different categories based on different level of stiffness and damage resistance performance. In this study, one optimized design from each category has been selected and their performance have been validated with 3D FEM simulation. It has been found that the suggested topology optimization approach is efficient to generate UPTIS spoke designs with having ±30% stiffness with 17%, 40%, and 56% more damage resistance performances with respect to the starting reference design.
Dhrangdhariya, Priyankkumar, Maiti, Soumyadipta, Rai, Beena
Speed Planning System for Commercial Vehicles in Mountainous Areas2021-01-01264/6/2021
There are a large number of curves and slopes in the mountainous areas. Unreasonable acceleration and deceleration in these areas will increase the burden of the brake system and the fuel consumption of the vehicle. The main purpose of this paper is to introduce a speed planning and promotion system for commercial vehicles in mountainous areas. The wind, slope, curve, engine brake, and rolling resistances are analyzed to establish the thermal model of the brake system. Based on the thermal model, the safe speed of the brake system is acquired. The maximum safe speed on the turning section is generated by the vehicle dynamic model. And the economic speed is calculated according to the fuel consumption model. The planning speed is provided based on these models. This system can guide the driver to handle the vehicle speed more reasonably. According to the simulation, compared to cruise control, speed planning can save fuel consumption at a mean value of 9.13% in typical mountainous areas. The field test of a typical commercial vehicle shows that this system can increase fuel efficiency by 4.26% compared to an experienced driver during a journey in a mountainous area.
Peng, Dengzhi, Fang, Kekui, Tian, Zhongpeng, Zhang, Yuxiao, Tan, Gangfeng
Dynamic Cleat Test with Perpendicular and Inclined CleatsJ2730_202101 (Current)1/13/2021
This SAE Recommended Practice describes a test method for measuring the forces and moments generated at a high frequency response spindle when a rolling tire impacts a cleat. The cleat is configured either with its crest perpendicular, 90 degrees, to the path of the tire or optionally with its crest inclined at an angle to the path of the tire. The carriage to which the spindle is attached is rigidly constrained in position during each test condition to provide a good approximation to fixed loaded radius operation. The method discussed in this document provides impact force and moment time histories essentially free from variations due to tire non-uniformities. The method applies to any size tire so long as the equipment is properly scaled to conduct the measurements for the intended test tire. The data are suitable for use in determining parameters for road load models and for comparative evaluations of the measured properties in research and development.
Vehicle Dynamics Standards Committee
Rolling Resistance Measurement Procedure for Passenger Car, Light Truck, and Highway Truck and Bus TiresJ1269_202012 (Current)12/22/2020
This SAE Recommended Practice applies to the laboratory measurement of rolling resistance of pneumatic passenger car, light truck, and highway truck and bus tires. The procedure applies only to the steady-state operation of free-rolling tires at zero slip and inclination angles; it includes the following three basic methods:
Highway Tire Committee
STANDARD FOR TIRE TRACEABILITY CONTENT AND FORMAT FOR THE RADIO-FREQUENCY IDENTIFICATION (RFID) TAG AND ASSOCIATED TIRE DATA SETUSCAR39-1 (Current)11/19/2020
This standard describes a requirement for automotive tire traceability. It includes a definition of the RFID tag and the associated tire data set that can be accessed using the RFID tag as an identifier. The standard describes a unique identification and the associated data set for each tire produced by the tire fabricator. This data will either be provided or transmitted at the time of shipment to retailers, wholesalers or original equipment vehicle manufacturers. Tire identification code and data may be used for error proofing, determining the tire specifications or supporting any inquiries that occur for the duration of its automotive life.
USCAR
Rolling Resistance Measurement Procedure for Highway Truck and Bus TiresJ1379_202011 (Current)11/12/2020
This recommended practice applies to the laboratory measurement of the rolling resistance of pneumatic tires designed primarily for use on trucks and buses in normal highway service, as defined by the Tire and Rim Association, Inc. (TRA); it does not include light truck tires (designated LT). The procedure applies only to straight, free-rolling tires under steady-state operation and includes the following three basic methods:
Truck and Bus Tire Committee
The Measurement of Highway Truck and Bus Tire Rolling ResistanceJ1380_202011 (Current)11/9/2020
The force, torque, and energy methods of measurement are all in common use and should yield the same test results. Effects of steering, traction, and non steady-state tire operations are excluded from the recommended practice because they are still in the research stage. Methods of correcting laboratory data to road conditions are being developed.
Truck and Bus Tire Committee
Road Load Measurement Using Onboard Anemometry and Coastdown TechniquesJ2263_202005 (Current)5/26/2020
This SAE Recommended Practice establishes a procedure for determination of vehicle road load force for speeds between 115 km/h and 15 km/h (or between 70 mph and 10 mph). It employs the coastdown method and applies to vehicles designed for on-road operation. The final result is a model of road load force (as a function of speed) during operation on a dry, level road under reference conditions of 20 °C (68 °F), 98.21 kPa (29.00 in-Hg), no wind, no precipitation, and the transmission in neutral.
Light Duty Vehicle Performance and Economy Measure Committee
Research on Factors to Influence Coasting Resistance for Electric Vehicles2020-01-10684/14/2020
The research on coasting resistance is vital to electric vehicles, since the smaller the coasting resistance, the longer the coast-down distance. Vehicle coast resistance consists of rolling resistance, vehicle inner resistance and the aerodynamic drag. The vehicle inner resistance is mainly caused by driveline’s friction loss and oil splash loss. The rolling resistance is decided by tire resistance coefficient, which is influenced by tires and road conditions. And the aerodynamic drag is affected by vehicle’s shape and air. In this paper, four factors including tire pressure, road surface condition, atmosphere temperature, and recirculation on or off are examined. Experimental tests have been conducted on three different vehicles: one subcompact sedan, one compact sedan and one subcompact SUV. Then experimental results have been imported to simulation model to investigate the corresponding influence on NEDC range. The outcome shows that, when the tire pressure is 20% less, the average coasting resistance is increased by 1% to 3% depending on vehicle types, which indicates a decrease in NEDC range by around 2%. And with atmosphere temperature in 6 to 32°C range, the resistance is decreased by 0.48% for every 1°C increased. On wet road surface, the average coasting resistance is increased by 10% - 20%, which could decrease the NEDC range by 6% to 12%. As for the recirculation on or off, one vehicle with inside air recirculation on experiences an average 6% coasting resistance reduction. Other two vehicles have similar coasting resistances whether the recirculation is on or off. The overall results give a better understanding on how the coasting resistance is influenced by various factors and can instruct future vehicle’s low coasting resistance development. More factors such as brake calipers, tire size, and other corresponding influences will be studied in future tests.
Gong, Guan, Zhao, Chen, Zhou, Xiaohang, Deng, Chenghao, Jiang, Hanli, Yu, Cheng, Yu, Fuyong, Ren, Yong, Zhou, Anjian
A Study on the Effect of Tire Temperature and Rolling Speed on the Vehicle Handling Response2020-01-12354/14/2020
Rubber is a non-linear viscoelastic material which properties depend upon several factors. In a tire two of these factors, namely the temperature and excitation frequency, are significantly influenced by the vehicle operating conditions. In the past years, applied research studied how rubber viscoelastic characteristics affect structural and frictional tire properties. The present study focuses on how these effects interact with the vehicle handling response. Based on state of the art theory of friction, structural properties of rubber and on experimental evidence, the dependency of key tire parameters on temperature and rolling speed is established. These results are then used in combination with a single-track vehicle model to assess their impact on key vehicle parameters; as an example, the understeer coefficient, yaw resonance peak / damping and maximum acceleration are studied. Furthermore, to ensure accurate results in realistic situations, a novel tire thermodynamic model is used in combination with a detailed 14 degrees of freedom vehicle model in a numerical simulation environment. The simulations permit to study the mutual effects between tire temperature, rolling speed and vehicle dynamics. Quantitative figures are given that determine the impact on the specific vehicle handling parameters in different operating conditions. It is finally concluded that, in most cases, a higher tire temperature and / or higher rolling speed results in a degradation of the vehicle handling response.
Lugaro, Carlo, Alirezaei, Mohsen, Konstantinou, Ioannis, Behera, Abhijeet
An Experimental Methodology for Measuring Resistance Forces of Light-Duty Vehicles under Real-World Conditions and the Impact on Fuel Consumption2020-01-03834/14/2020
A vital element of any vehicle-certification test is the use of representative values for the vehicle resistance forces. In most certification procedures, including the WLTP recently adopted by the EU, the latter is achieved mainly through coast down tests. Subsequently, the resistance values measured are used for setting up the chassis-dyno resistances applied during the laboratory measurements. These reference values are obtained under controlled conditions, while a series of corrections are applied to make the test procedure more repeatable and reproducible. In real driving, the actual vehicle road loads are influenced by a series of factors leading to a divergence between the certified fuel consumption values, and the real-world ones. An approach of calculating representative road loads during on-road tests can help to obtain a more unobstructed view of vehicle efficiency and, when needed, confirm the officially declared road loads. This approach is also essential for validating simulations and achieving better estimates of the actual fuel consumption, a requirement introduced by the new policy adopted in the EU. In this study, a series of on-road experiments were conducted, under real-world conditions, on three vehicles, belonging to different vehicle body-categories, a supermini, a B segment cross-over city car, and a light-duty commercial vehicle. A wheel rim torque-measurement system (strain gauge torque sensors) was used to record the torque at the wheels accompanied by a wheel rotational-speed sensor. The present paper presents the results and investigates the capacity of such kind of tests to measure road loads with precision and accuracy. The calculated resistance forces are compared against the ones officially declared at type approval or measured via dedicated coast down tests. Results show satisfactory accuracy and repeatability, ranging within a ±3-7% range for the aerodynamic resistance, and point out margins for improvement. Simulation models are subsequently used to quantify the impact on real-world fuel consumption and CO2 emissions. The road loads measured using the method lead to similar fuel consumption simulation results as the official road loads with deviations in total simulated CO2 emissions remaining within ±6% of the measured values in the majority of the cases.
Komnos, Dimitrios, Fontaras, Georgios, Ntziachristos, Leonidas, Pavlovic, Jelica, Ciuffo, Biagio
The Effect of Structural Damping Foam on Tire Vibration10-04-02-00062/28/2020
During the vehicle design state, vehicle noise and vibration are taken into consideration. The tire is a large contributor to the noise and vibration experienced inside the vehicle cabin. Any unevenness or asperities in the road cause the tire structure to vibrate, which in turn causes components in the vehicle to vibrate and generate noise. It is common in the industry to use foam inserts inside the tire air cavity that reduces the noise generated. This foam is typically intended to reduce a specific resonance in the tire-the resonance due to the air cavity. Recently, there is interest in using foam as a structural damper to reduce structural resonances in the tire. A new analytical tire model for determining the effect that structural damping foam has on the noise and vibration characteristics of the tire has been developed. The theoretical formulation of this model is presented, as well as comparison with experiments and a parametric analysis of the model. The model shows good agreement with experimental results and also gives some additional insights into how the tires’ response can be altered by different design parameters.
Sams, Thomas
Rolling Resistance Measurement Procedure for Passenger Car, Light Truck, and Highway Truck and Bus TiresJ1269_201912 (Historical)12/10/2019
This SAE Recommended Practice applies to the laboratory measurement of rolling resistance of pneumatic passenger car, light truck, and highway truck and bus tires. The procedure applies only to the steady-state operation of free-rolling tires at zero slip and inclination angles; it includes the following three basic methods:
Highway Tire Committee
Effect of Tyre Inflation Pressure on Rolling Resistance: Comparing the Values of Coefficient of Rolling Resistance and Rolling Resistance at Variable Tyre Inflation Pressure2019-28-241511/21/2019
1. Rolling resistance, is nothing but the rolling drag, is the force resisting the motion when a body rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation of the wheel, roadbed, etc. It is recovered when the pressure is removed, in the form of hysteresis losses and permanent deformation of the tyre surface. So, the rolling resistance contributes to the deformation of roadbed as well as tyre surface of the vehicle. Factors contributing in rolling resistance are tyre inflation pressure, wheel diameter, speed, load on wheel, surface adhesion, sliding and relative micro-sliding between the surfaces of contact. In this concerned paper we are significantly working on effect of tyre inflation pressure on rolling resistance and taking all other factors constraint.
Tripathi, Siddharth, Karwal, Amit Kumar, Mishra, Mukund, Wazir, Dushyant
Performance Gains of Load Sensing Brake Force Distribution in Motorcycles2019-28-242611/21/2019
Commercial motorcycles and scooters incorporate independent circuits for front and rear brake actuation, thus precluding load-dependent brake force distribution. In all cases of manual brake force modulation between the front and rear wheels, there is poor compensation for the changes in wheel loads on the account of longitudinal weight transfer, thus making it challenging to provide an adequate braking force to each wheel. The ratio in which the braking force should be distributed between the front and the rear wheels is dependent on the motorcycle’s geometry, weight distribution, mechanical sizing of braking system components, and is a variable based on the instantaneous deceleration. This connotes that a fixed bias of front and rear braking forces can be optimized only for a narrow range of motorcycle’s deceleration. Maximum braking performance occurs just prior to wheel lock-up, as a sliding tire provides less grip than a rolling tire. This is also the scenario when both the tires are doing the maximum work in decelerating the motorcycle. Therefore an optimal brake force distribution is one that locks both the wheels at the same instant. In practice, however, a rider would avoid a front wheel lock-up as it would make the motorcycle challenging to steer. In theory, an apt distribution of the braking forces between the front and rear wheels maximizes the overall braking efficiency of the motorcycle whilst reducing its stopping distance. This paper examines the plausible performance gains of load sensing brake force distribution in a motorcycle.
Chakraborty, Apurva
Continental Tire rolls towards a smart-and-connected future19AUTP10_0910/1/2019
It is difficult to become emotional about tires except when they-literally-let us down. But tires are set to get smarter, communicate more effectively and react to changing road conditions. Each of these will play a role in meeting the demands of autonomous- and electric-vehicle (AV/EV) development. “They will be tires that take care of themselves and provide highly supported driving,” said Dr. Philipp Struck, Continental Tire's head of tire line development. “Mobile data will be essential as we become more autonomous and drive more EVs.”
Birch, Stuart
Stability of Wheel Tractors during Braking2019-01-21429/15/2019
The dynamic distribution of normal reactions between the axles of the wheeled tractor has a significant impact on the stability against skidding and the wheeled tractor braking effectiveness. At the same time, the clarification of the normal reactions distribution between the axles allows to choose more rational braking forces distribution between the axles. It is shown that the best way to ensure the highest braking efficiency is the braking mode when the rear wheels of the tractor are at the blocking limit. An assessment of the expediency of installing brake mechanisms on only one axle of the tractor was made. The increase of braking efficiency of wheeled tractors with all brake wheels provided that they ensure directional stability is considered. The laws of braking forces distribution between the axles of wheel tractors for different sequence of wheels locking are determined. Using the method of partial accelerations an improved method for estimating the effect of a brake system on the stability of wheeled tractor is proposed. The criterion in the form of angular acceleration in the road plane ώz, by the value and sign of which one we can estimate the operational stability of the brake mechanisms has obtained.
Podrigalo, Mikhail, Kholodov, Mykhailo, Klets, Dmytro, Dubinin, Yevhen, Savchenkov, Borys, Koryak, Alexander, Rudzinskyi, Volodymyr, Viktoriia, Zadorozhnia, Polianskyi, Oleksandr
Electrifying Long-Haul Freight—Part I: Review of Drag, Rolling Resistance, and Weight Reduction Potential02-12-03-00179/5/2019
Abstract Electric heavy-duty tractor-trailers (EHDTT) offer an important option to reduce greenhouse gases (GHG) for the transportation sector. However, to increase the range of the EHDTT, this effort investigates critical vehicle design features that demonstrate a gain in overall freight efficiency of the vehicle. Specifically, factors affecting aerodynamics, rolling resistance, and gross vehicle weight are essential to arrive at practical input parameters for a comprehensive numerical model of the EHDTT, developed by the authors in a subsequent paper. For example, drag reduction devices like skirts, deturbulators, vortex generators, covers, and other commercially available apparatuses result in an aggregated coefficient of drag of 0.367. Furthermore, a mixed utilization of single-wide tires and dual tires allows for an optimized trade-off between low rolling resistance tires, traction, and durability. Lastly, a combination of different lightweight vehicle components manufactured from aluminum and magnesium alloys, carbon fiber composites, titanium, and high-strength steel presents a substantial reduction in overall vehicle weight. Overall, a comparison of a potential EHDTT with a standard Class-8 heavy-duty tractor-trailer (HDTT) reveals a possible reduction in the aerodynamic coefficient of drag by 40%, rolling resistance by 21%, and vehicle weight by approximately 37% prior to electrification. These improvements provide a stronger baseline for electrification to increase the overall range and longevity of an EHDTT making them a more viable option in the market. However, to achieve these advances still requires significant research into commercial feasibility and real-world data under varying conditions with enhanced simulation tools playing a meaningful role.
Depcik, Christopher, Gaire, Anmesh, Gray, Jamee, Hall, Zachary, Maharjan, Anjana, Pinto, Darren, Prinsloo, Arno
Empirical Investigation on the Effects of Rolling Resistance and Weight on Fuel Economy of Medium-Duty Trucks02-12-03-00168/28/2019
Abstract Vehicle rolling resistance and weight are two of the factors that affect fuel economy. The vehicle tire rolling resistance has a more significant influence than aerodynamics drags on fuel economy at lower vehicle speeds, particularly true for medium- and heavy-duty trucks. Less vehicle weight reduces inertia loads, uphill grade resistance, and rolling resistance. The influence of weight on the fuel economy can be considerable particularly in light- to medium-duty truck classes because the weight makes up a larger portion of gross vehicle weight. This article presents an empirical investigation and a numerical analysis of the influences of rolling resistance and weight on the fuel economy of medium-duty trucks. The experimental tests include various tires and payloads applied on a total of 21vehicle configurations over three road profiles. These tests assessed the sensitivity of the vehicle’s fuel economy toward rolling resistance and weight. Several experimental results showed inconsistent and counterintuitive trends of the effects of rolling resistance coefficients and weights on fuel economy. The consequences of rolling resistance and vehicle payload are compound and influenced by vehicle speed, road profile, and tire pressure. The irregularities of weight variances’ impact on rolling resistance requires further investigation in the strain level of the tire deformation.
Liao, Gene Y., Card, Brandon, O’Malley, Molly
Determination of a Tyre’s Rolling Resistance Using Parallel Rheological Framework2019-01-50696/20/2019
Nowadays, rolling resistance sits at the core of tyre development goals because of its considerable effect on the car’s fuel economy. In contrast to the experimental method, the finite element (FE) method offers an inexpensive and efficient estimation technique. However, the FE technique is yet to be a fully developed product particularly for rolling-resistance estimation. An assessment is conducted to study the role of material viscoelasticity representation in FE, in linear and non-linear forms, through the use of Prony series and parallel rheological framework (PRF) models, respectively, on the tyre’s rolling-resistance calculation and its accuracy. A unique approach was introduced to estimate the rolling resistance according to the tyre’s hysteresis energy coefficient. The non-linear PRF choice resulted in rolling-resistance calculations that reasonably match that of the experimental work and the literature for various vertical load and inflation cases, whereas the Prony series option was found irresponsive to the tyre’s deformation in which it gave unreliable and infinitesimal outputs.
Aldhufairi, Hamad Sarhan, Olatunbosun, Oluremi, Essa, Khamis
Multi-Chamber Tire Concept for Low Rolling-Resistance06-12-02-00094/8/2019
Rolling-resistance is leading the direction of numerous tire developments due to its significant effect on fuel consumption and CO2 emissions considering the vehicles in use globally. Many attempts were made to reduce rolling-resistance in vehicles, but with no or limited success due to tire complexity and trade-offs. This article investigates the concept of multiple chambers inside the tire as a potential alternative solution for reducing rolling-resistance. To accomplish that, novel multi-chamber designs were introduced and numerically simulated through finite-element (FE) modeling. The FE models were compared against a standard design as the baseline. The influences on rolling-resistance, grip, cornering, and mechanical comfort were studied. The multi-chambers tire model reduced rolling-resistance considerably with acceptable trade-offs. Independent air volumes isolating the tread from sidewalls would maintain tire’s profile effectively. Different air concentration across the tire’s chambers gave the tire extended versatility. Rolling non-uniformity depends upon inner-chambers’ stability, sidewalls’ flexibility and tire/chamber(s) integration.
Aldhufairi, Hamad Sarhan, Essa, Khamis, Olatunbosun, Oluremi
Uncertainty in Radius Determined by Multi-Point Curve Fits for Use in the Critical Curve Speed Formula2019-01-04284/2/2019
The critical curve speed formula used for estimating vehicle speed from yaw marks depends on the tire-to-road friction and the mark’s radius of curvature. This paper quantifies uncertainty in the radius when it is determined by fitting a circular arc to three or more points. A Monte Carlo analysis was used to generate points on a circular arc given three parameters: number of points n, arc angle θ, and point measurement error σ. For each iteration, circular fits were performed using three techniques. The results show that uncertainty in radius is reduced for increasing arc length, decreasing point measurement error, and increasing number of points used in the curve fit. Radius uncertainty is linear if the ratio of the standard deviation in point measurement error (σ) to the curve’s middle ordinate (m) is less than 0.1. The ratio σ/m should be less than 0.018 for a radius found using a 3-point circular fit to be within 5% of the actual value 95% of the time. Increasing the number of points used for the fit reduces uncertainty in radius: a 15-point fit reduces the 95% prediction interval width by up to 42%, or allows a shorter yaw mark arc angle with the same uncertainty in radius.
Heinrichs, Bradley, Mithrush, Troy
Research on Technique for Correction of Running Resistance with Focus on Tire Temperature and Tire Thermal Balance Model2019-01-06234/2/2019
At present, measurements of running resistance are conducted outdoors as a matter of course. Because of this, the ambient temperature at the time of the measurements has a considerable impact on the measurement data. The research discussed in this paper focused on the temperature characteristic of the tires and developed a new correction technique using a special rolling test apparatus. Specifically, using a tire rolling test apparatus that made it possible to vary the ambient temperature, measurements were conducted while varying the levels of factors other than temperature that affect rolling resistance (load, inflation pressure, and speed). Next, a regression analysis was applied to the data for each factor, and coefficients for a relational expression were derived, making it possible to derive a quadratic equation for the tire rolling resistance correction formula. It was verified that the application of the new correction formula reduced variation in running resistance from 2.7% (in the case of regulation correction) to 1.0%. In addition, in order to offer a simpler method of realizing the same correction, a technique for correction using a conventional tire rolling test apparatus and based on the material characteristics of the tire tread rubber was also developed. It was verified that this method allowed the same degree of correction. Giving consideration to the application of the method to future tire modeling, the development of heat generation and dissipation models for tire rolling tests was also examined. The addition of terms for the temperature characteristic of the tread rubber and heat generation and dissipation between the tire and the drum reduced error between measured and predicted values to ±0.6%.
Hotaka, Takeshi, Sakai, Tomonori, Miura, Hideki
Tire Ply-Steer, Conicity and Rolling Resistance - Analytical Formulae for Accurate Assessment of Vehicle Performance during Straight Running2019-01-12374/2/2019
The aim of the paper is to provide simple and accurate analytical formulae describing the straight motion of a road vehicle. Such formulae can be used to compute either the steering torque or the additional rolling resistance induced by vehicle side-slip angle. The paper introduces a revised formulation of the Handling Diagram Theory to take into account tire ply-steer, conicity and road banking. Pacejka’s Handling Diagram Theory is based on a relatively simple fully non-linear single track model. We will refer to the linear part of the Handling Diagram, since straight motion will be considered only. Both the elastokinematics of suspension system and tire characteristics are taken into account. The validation of the analytical expressions has been performed both theoretically and after a subjective-objective test campaign. By means of the new and unreferenced analytical formulae, practical hints are given to set to zero the steering torque during straight running. Additionally, the vehicle rolling resistance during straight motion is studied. It is found that front toe seems primarily set for reasons that are related to the steering system, other than tires. Reducing front toe could reduce energy consumption up to 1% on a WLTP mission.
Lattuada, Alessandro, Mastinu, Gianpiero, Matrascia, Giuseppe
DATC spells progress for defense prototyping19AUTP02_032/1/2019
A public-private partnership between the U.S. Army's TARDEC and SAE International is making it easier for suppliers to engage the government on military ground-vehicle technology projects. A slogging bureaucracy, miles of “red tape” and a sea of acronyms are just some of the hurdles that keep many suppliers from working with the U.S. defense industry on ground-vehicle projects. For years the government, led by the U.S. Army Tank-Automotive Research, Development and Engineering Center (TARDEC), sought to develop a streamlined procurement process. Their aim was to speed the adoption of private-sector innovations, particularly for prototype development, while expanding access for smaller, non-traditional military suppliers. A breakthrough came in 2016, when TARDEC partnered with SAE International's Industry Technologies Consortia affiliate to form the nonprofit Defense Automotive Technologies Consortium; DATC currently has 190 members-70% of which are non-traditionals. The consortium serves as a gateway between the government and the auto industry for OTA Prototype projects (OTAs, or Other Transaction Agreements, run for seven years, during which up to $700 million in projects can be awarded).
Brooke, Lindsay
Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model2019-26-01791/9/2019
Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque. A detailed simulation based study using ADAMS/CAR has been performed to assess the contribution of various full vehicle sub-systems, primarily suspension & powertrain sub-system towards the said problem statement. The dynamic interaction between road, suspension, powertrain and BIW has been is the focus of study both in time and frequency domain. This simulation helped understand the factor effects and contribution levels and correlates well with the subjective feel observed on the physical vehicle on low-mu track. This model has been further used to provide design recommendation on the compliance parameters to overcome the issue at hand. Test has been conducted with recommended tire grip properties and suspension bushing parameters which lead to reduction in cabin noise
Singh, Vivek, Prasad, Tej, Srivastava, Harshit
Analysis of Effect of Tire Inflation Pressure, Inflation Fluids, Load and Speed on Tire Performance2019-26-03681/9/2019
There are various losses associated with passenger vehicle that affect its fuel economy as it is being operated. These losses include losses at engine, driveline, aerodynamic and rolling losses. While engine, driveline and aerodynamic losses are inherent with the vehicle due to large number of parts that are assembled together, rolling loss is associated with the vehicle tires and it is the only part of the vehicle that comes in contact with the road surface. The rolling resistance of inflated tires is an important component of rolling resistance to vehicle motion and contributes to vehicle fuel consumption. Hence the effect of tire parameters such as inflation pressure, speed and load are the subject of much current interest. Also effect of type of inflation fluid on tire performance is a need of investigation. This work is focused on the design and development of tire testing setup to test the tire performance parameters like rolling resistance and tire temperature by varying the load, speed, inflation pressure and inflation fluids. Tire 135/70 R12 65 S was selected for testing. The test was conducted under various loads, speed, inflation pressure and inflation fluids were air and nitrogen. The result of experimental analysis shows that there is increase in rolling resistance and tire temperature with increase in speed and load. Also, the rolling resistance and tire temperature increases with decreasing the inflation pressure. For determining the better performance of tire among air and nitrogen, the test was conducted by varying the inflation pressure, load and speed. The results of experimental analysis shows that the tire with nitrogen gas resulted in to lower rolling resistance and lower tire temperature as compared with air.
Thombare, Dhananjay Ganpati
ABS Optimization for a Two-Wheeler Based on Tire-Road Friction Characteristics2019-26-00171/9/2019
Anti-lock Braking System (ABS) is a well-known active safety technology widely used in cars. Recently, it has become a mandatory safety feature for two-wheelers. In principle, ABS ensures an optimum braking performance by not allowing the tire to slip beyond a certain level. This guarantees steering stability and peak braking performance of the tire during panic braking situations. As the ABS controller depends on the tire characteristics information for its algorithm, a change in tire or pavement can vary the optimum operating range of ABS. In addition to this, motorcycle tires differ from a car tire in terms of its construction, dimension and compound. Therefore, the motorcycle tire’s performance envelope cannot be directly compared to a car tire. This work presents a methodology which aims to acquire the tire-road friction characteristics of three different tires for a study motorcycle on different friction surfaces through experimentation and estimation techniques. The optimum pressure release slip thresholds for the three tires on different surfaces are then determined from the obtained tire characteristics. Further, the ABS controller is calibrated based on the determined parameter set for the three study tires and the performance of the study motorcycle is evaluated. The chosen slip thresholds were able to utilize all the three tires sufficiently to meet the performance targets as set by IS14664.
Ranjan, Ashish, Srivastava, Shreyansh, Anantha, Prashanth
Tire Side Force Characteristics with the Coupling Effect of Vertical Load and Inflation Pressure10-03-01-000211/9/2018
The tire vertical load and inflation pressure have great influence on tire steady- and non-steady-state characteristics and, consequently, on the vehicle handling and stability. The objective of this article is to reveal the coupling effect of tire vertical load and inflation pressure on tire characteristics and then introduce an improved UniTire side force model including such coupling effect through experimental and theoretical analysis. First, the influence of the tire vertical load and inflation pressure on the tire characteristics is presented through experimental analysis. Second, the theoretical tire cornering stiffness and lateral relaxation length model are introduced to study the underlying mechanism of the coupling effect. Then, an improved UniTire side force model including the coupling effect of tire vertical load and inflation pressure is derived. Finally, the proposed improved UniTire side force model is validated through tire steady-state and transient data. The coupling effect of tire vertical load and inflation pressure on tire cornering stiffness and lateral relaxation length is decided by the variation of the half length of tire contact patch and the carcass stiffness caused by the tire vertical load and inflation pressure changes.
Guo, Konghui, Chen, Ping, Xu, Nan, Yang, Chao, Li, Fei
Comparison of Different Variable Braking Force Systems2018-01-186510/5/2018
An automobile braking system has a crucial role in the safety of the passengers and riding quality of the vehicle. The braking force mainly depends on the normal reaction on the wheel and the coefficient of adhesion between the tire and the road surface. The required braking force for a vehicle varies with the load on the vehicle. If the applied braking force is greater than the required brake force, wheel gets locked which results in increased stopping distance. In order to prevent the wheel lock at low load conditions or deficient braking force at extremely high load conditions, a variable braking force system is developed. Whenever a motorcycle is loaded, the normal reaction on the rear wheel is increased. Thus, the amount of braking force required to halt the motorcycle with minimum stopping distance and stability of the motorcycle is based on the pillion load on the motorcycle. Hence, the amount of braking force developed between the road surface and the tire is varied in the variable braking force system. In this research work, three different variable brake force systems are compared. The different braking force systems are obtained by varying the effective disc radius or varying the pedal leverage or varying the area of piston. Simulation on the vehicle stopping distance is performed to compare the stopping distance of conventional braking system to Variable braking force system.
Subramanian, Chidambaram, Vinayaga Sundaram, Ganesh
Commercial Truck and Bus SAE Recommended Procedure for Vehicle Performance Prediction and ChartingJ2188_201807 (Current)7/25/2018
This SAE Recommended Practice takes into account modern standardized methods for collecting and summarizing data that has an effect on vehicle steady-state performance, such as engine output (gross and net), transmission losses, drivetrain efficiency, vehicle aerodynamic devices for various vehicle and body configurations, as well as road surface variations and air density variations resulting from altitude and barometric effects. The procedure does not address vehicle transient performance (acceleration, braking, and cornering), because of the considerable amount of additional data required such as moment of inertia of all the rotating parts. Nor does it address vehicles with torque converters and automatic transmissions. This document is, therefore, intended for vehicles having fixed-ratio type transmissions and positive engagement clutches. Metric and ISO unit conversions are provided in the metric conversion tables at the end of this procedure (see Appendix B). Some modern vehicles with electronic engine controls have the ability to vary the maximum engine revolutions for each gear, as well as permitting the power or rpm to increase if more time is spent in the lower gears, as when climbing a grade. These special cases can be handled by this procedure, just by customizing the data for each transmission ratio and superimposing the long-term data on top of the instantaneous data. All of the equations are written in a form suitable for programming into a mainframe or desk-top computer, using a spreadsheet/database or a higher level language, such as Basic, Fortran, Pascal, C or Unix, etc. However, they are simple enough, to be performed on a hand-held calculator.
Truck and Bus Powertrain Committee
Control Optimization of a Charge Sustaining Hybrid Powertrain for Motorsports2018-01-04164/3/2018
The automotive industry is aggressively pursuing fuel efficiency improvements through hybridization of production vehicles, and there are an increasing number of racing series adopting similar architectures to maintain relevance with current passenger car trends. Hybrid powertrains offer both performance and fuel economy benefits in a motorsport setting, but they greatly increase control complexity and add additional degrees of freedom to the design optimization process. The increased complexity creates opportunity for performance gains, but simulation based tools are necessary since hybrid powertrain design and control strategies are closely coupled and their optimal interactions are not straightforward to predict. One optimization-related advantage that motorsports applications have over production vehicles is that the power demand of circuit racing has strong repeatability due to the nature of the track and the professional skill-level of the driver. The repeatable behavior from lap to lap allows for the efficient utilization of dynamic programming (DP) techniques to optimize vehicle speed and power management for a given race track, which is the focus of this research. The DP strategy is derived and described in detail using a hybrid rallycross vehicle as an example. The DP strategy minimizes lap time while sustaining battery charge at the end of each lap. Constraints on engine torque, electric motor power, battery capacity and tire friction are incorporated into the proposed strategy. The DP also generates an execution map that can be used for real-time on-vehicle implementation. This map includes optimal vehicle speed and power management strategies for all possible situations that the vehicle can experience during the real racing event.
Zhu, Qilun, Song, Shixin, Tan, Xiaoping, Song, Chuanxue, Prucka, Robert
Sensitivity Analysis of Simulated Postimpact Vehicle Motion Using Design of Experiments (DOE)2018-01-05264/3/2018
An important component of the process of the reconstruction of a vehicle crash involves the modeling of the motion of the vehicle(s) before and after a collision. Depending on the conditions, this motion might be modeled using a vehicle dynamics simulation program. In the simulated dynamics of vehicle motion, the tire forces are the predominant means by which the path of the vehicle is determined, with aerodynamic loads being the other force acting on the vehicle. Recent literature on this topic investigated the effect of the steer angle of the front wheels on the postimpact trajectory of a light vehicle for a large initial angular velocity. This paper looks more broadly at the modeling of light vehicle postimpact motion using vehicle dynamics simulation but for a wider range of factors. Design of experiments (DOE) is used to rank the effect of various physical factors of vehicle postimpact motion. The response variable used in the DOE analysis uses the rest position of the vehicle (characterized by the x and y coordinates of the CG and the vehicle heading, θ) for a given combination of factor changes. The results of the study show that in the four different designs that were conducted, a trend in the response was consistent. The single factor that consistently appeared in the various DOE analyses (with various factor combinations) was the tire-to-roadway frictional drag coefficient. Various other factors and 2-factor combinations were also found to be significant. Some of the significant factors are not intuitively obvious, such as aerodynamic drag.
Brach, R. Matthew, Capser, Shawn
Modeling of Tire-Wet Surface Interaction Using Finite Element Analysis and Smoothed-Particle Hydrodynamics Techniques2018-01-11184/3/2018
This paper focuses on predicting the rolling resistance and hydroplaning of a wide base truck tire (Size: 445/50R22.5) on dry and wet surfaces. The rolling resistance and hydroplaning are predicted at various inflation pressures, loads, velocities, and water depths. The wide base truck tire was previously modeled and validated using Finite Element Analysis (FEA) technique in virtual performance software (Pam-Crash). The water is modeled using Smoothed-Particle Hydrodynamics (SPH) method and Murnaghan equation of state. A water layer is first built on top of an FEA rigid surface to represent a wet surface. The truck tire is then inflated to the desired pressure. A vertical load is then applied to the center of the tire. For rolling resistance tests variable constant longitudinal speeds are applied to the center of the tire. The forces in the vertical and longitudinal directions are computed, and the rolling resistance is calculated. The effect of the longitudinal speed on rolling resistance on the wet surface also includes the prediction of the hydroplaning speed. The results are analyzed, and the effect of each parameter is investigated.
El-Sayegh, Zeinab, El-Gindy, Moustafa, Johansson, Inge, Oijer, Fredrik
Evaluation of Alternative Steering Devices with Adjustable Haptic Feedback for Semi-Autonomous and Autonomous Vehicles2018-01-05724/3/2018
Emerging autonomous driving technologies, with emergency navigating capabilities, necessitates innovative vehicle steering methods for operators during unanticipated scenarios. A reconfigurable “plug and play” steering system paradigm enables lateral control from any seating position in the vehicle’s interior. When required, drivers may access a stowed steering input device, establish communications with the vehicle steering subsystem, and provide direct wheel commands. Accordingly, the provision of haptic steering cues and lane keeping assistance to navigate roadways will be helpful. In this study, various steering devices have been investigated which offer reconfigurability and haptic feedback to create a flexible driving environment. A joystick and a robotic arm that offer multiple degrees of freedom were compared to a conventional steering wheel. To evaluate the concept, human test subjects interacted with the experimental system featuring a driving simulator with target hardware, and completed post-test questionnaires. Based on the data collected, drivers’ lane keeping performance was superior using a haptic robotic arm with haptic feedback to the joystick and steering wheel with an improvement of up to 70.18% during extreme maneuvers. Haptic feedback, with a lane keeping algorithm, can assist the operator in steering the vehicle given the likely deterioration of driving skills when autonomous vehicles become prevalent.
Wang, Chengshi, Wang, Yue, Wagner, John R.
Integrated Chassis Control for Vehicle Stability under Various Road Friction Conditions2018-01-05524/3/2018
This paper presents an integrated chassis control method for vehicle stability under various road friction conditions without information on tire-road friction. For vehicle stability, vehicle with an integrated chassis control needs to cope with the various road friction conditions. One of the chassis control method under various road conditions is to determine and/or limit control inputs based on tire-road friction coefficient. The tire-road friction coefficient, however, is difficult to estimate and still a challenging task. The key idea for the proposed method without the estimation of the tire-road friction coefficient is to analyze and control vehicle states based on a tire slip angle - tire force phase plane, i.e. based on these vehicle responses: tire forces and tire slip angles of front/rear wheels. Based on the phase plane, vehicle instability is detected and the vehicle is controlled to regain the vehicle stability and maneuverability under various road conditions without tire-road friction information. The proposed algorithm consists of two sequential parts: Supervisor part and Chassis control part. The supervisor detects the vehicle instability based on the tire slip angle and tire force phase plane. Based on this information, the supervisor determines a desired slip angle to make the vehicle stable. The chassis control part decides control inputs. From tire slip angle dynamics, a desired yaw moment is calculated to minimize error between the desired slip angle and current vehicle states. For tracking the desired yaw moment, the optimal coordination of the chassis control part optimally allocate the desired yaw moment to each chassis module. The proposed algorithm has been investigated through computer simulations under various road setting. The simulation results show that the proposed control method well copes with maneuver on the various road conditions.
Joa, Eunhyek, Yi, Kyongsu, Bae, Hyungjune, Sohn, Kimo
The Method of Constructing the Diagrams of Shear Stresses in the Contact Zone of an Slipping Wheel With Soil2018-01-13354/3/2018
The process of interaction of the driving wheels of mobile energy resources with soil is considered. A computational and experimental method is proposed for plotting the shear stresses in the contact zone of the skid wheel with a supporting surface, based on the use of normal stresses obtained for specific ground conditions. The character of the interaction of the driving wheel of the tractor with various types of supporting base has been studied in detail: a dirt road, stubble, a field prepared for sowing. It is revealed that, contrary to the generally accepted ideas, the slipping wheel has practically no adhesion zone in the contact spot. After touching the tiller of the supporting surface, it immediately begins to shift backward. Therefore, when calculating the shear stresses in the contact patch of the skid wheel with the support, it is more correct to assume that the shift of the elementary points increases as they move away from the entrance to the contact zone and depends on the amount of slippage. When rolling the drive wheel, even with a slight slippage on the deformable surface, there is practically no bonding zone at the point of contact between the two contacting bodies (the tire and the ground). On the surface of the soil, normal stresses reach their maximum, gradually decreasing with increasing depths of its layers. With a slight slipping (up to 10 %), the maximum tangential stresses occur at the back of the contact spot - in the zone of the largest shear deformations of the soil. As the traction load increases, the tangential contact stresses are shifted to the center of the contact patch - to the zone where the deformations of the soil did not exceed the optimum level characteristic for each specific soil type. Thus, the elongation of the tire contact patch is effectively up to a certain level limited by the limiting values of shear deformation of the soil above which the tangential stresses cease to grow and even begin to decline for most types of cohesive soils. It was found that an excessive increase in shear deformation of the soil at slippage leads to a decrease in the efficiency of the wheeled propulsor.
Izmailov, Andrei, Revenko, Valerij, Godzhaev, Zakhid
Wet or Dry Pavement Passenger Car Tire Peak and Locked Wheel Braking TractionJ345_201802 (Current)2/15/2018
This SAE Recommended Practice defines the best known techniques for evaluating peak and locked wheel braking traction. It covers an important phase of tire braking traction, namely, the wet or dry pavement straight ahead conditions. However, this is but a small portion of the whole field of tire traction. As test procedures are established for other phases of this complex study, additional supplementary procedures will be written. A discussion of this entire subject is contained in Appendix B to this recommended practice.
Highway Tire Committee
Experimental Evaluation of Rotational Inertia and Tire Rolling Resistance for a Twin Roller Chassis Dynamometer2017-36-021211/7/2017
Chassis dynamometers are important equipment to perform vehicular experiments in the automotive industry. Usually, these equipments are used according to standard procedures for emissions, fuel consumption, and performance analyses. In this paper, an alternative procedure was developed to experimentally determine the dynamometer inertia and losses related to bearings and transmission systems. Furthermore, a study on the tires rolling resistance, considering a double tire-roller contact, was carried out. The experiments were performed in a 4x2 chassis dynamometer with four rollers, equipped with an eddy current brake (coupled to a transmission reducer of 2.5 instrumented with a 3000 Nm torque flange) and with a 30 CV AC electric motor (coupled to a planetary transmission with reduction of 4.43 and instrumented with a 500 Nm torque flange). The dynamometer was also instrumented with an encoder system for speed measurement. All data were acquired by NI/LabVIEW™ software and post-processed in Matlab™ and Excel™ interfaces. The initial experiments resulted in the overall dynamometer bench inertia and equivalent inertias of the braking and electric motorization systems. The secondary experiments provided equations to determine the losses of the braking and electrical motorization systems, the overall bench losses and the vehicle/bench total rolling resistance according to the vehicle speed. Finally, a simplified coast-down experiment was performed on the dynamometer, and the results were compared to a Matlab/Simulink™ model of a hypothetical vehicle with similar mass.
Eckert, Jony Javorski, Bertoti, Elvis, Costa, Eduardo dos Santos, Santiciolli, Fabio Mazzariol, Yamashita, Rodrigo Yassuda, de Alkmin e Silva, Ludmila Corrêa, Dedini, Franco Giuseppe
Parameters Estimation of a Tire Model Based on Julien’s Theory2017-36-017711/7/2017
This paper uses an inverse problem approach to estimate parameters of a tire model based on Julien’s Theory (JT). The modeling process of an all-wheel drive (AWD) vehicle is presented in this work, as well as JT and Pacejka’s Magic Formula (MF) tire models. Numerical simulations of the longitudinal vehicle dynamics, considering MF, provide pseudo-experimental data to the inverse problem. Particle Swarm Optimization (PSO), Random Restricted Window (R2W) and Differential Evolution (DE) are used to estimate the parameters of the JT tire model. Accuracy, computational time, efficiency and efficacy of the models are compared regarding the behavior of the performance responses of the vehicle. Throughout this process, Julien’s Theory is validated for use in future studies of vehicle dynamics.
de Oliveira, André Noronha, Campos, Caroline Goulart, Peralta, Alejandro Oscar, Neto, Ricardo Teixeira da Costa, Caldeira, Aldélio Bueno
Influence of Inflation Pressure of a Tire on Rolling Resistance and Fuel Consumption2017-36-009511/7/2017
Resistive forces are a great source of fuel consumption in vehicles. In particular, rolling resistance represent the major resistance force at low speeds. It is highly influenced by the inflation pressure of the tire and vertical load over it. In the present work, a computer model is created with the objective of investigating the influence of tire inflation pressure on fuel consumption and rolling resistance force. Pressure is varied and parameters analyzed at different vehicle speeds for two different calculation methods. Results show significant decrease in fuel consumption and rolling resistance force as inflation pressure is augmented.
Thiriet, Arthur Braga, Pujatti, Fabrício José P., Araújo, Paulo César S.
Development of Low Fuel Consumption Tire for Small Motorcycles2017-32-008611/5/2017
A low fuel consumption tire with an affordable price that is applicable for small motorcycles marketed mainly for India and Southeast Asian countries was developed. Two contradicting requirements, which are reduction of the rolling resistance and retention of the wet grip performance, were satisfied by applying a method based on viscoelastic properties of the tread rubber. Regarding the composition of compound of the tread rubber, the amounts of carbon black and oil were reduced instead of using silica. In addition, a polymer having a high glass transition temperature was employed. Moreover, response to the roll motion, which is unique in motorcycles, was made satisfactory to the requirement by modifying the dynamic modulus E* of the tread rubber. With those measures, the rolling resistance was reduced by more than 15% to conventional tires while maintaining the basic performances such as tire grip and stability in maneuvering.
Takayanagi, Shinji, Sakai, Kiyotaka, Iwasa, Takashi, Matsumura, Tomoyuki, Yamaguchi, Shigehiro, Tanaka, Kenji
Measurement of Passenger Car, Light Truck, and Highway Truck and Bus Tire Rolling ResistanceJ1270_201710 (Current)10/12/2017
The force, torque, and power methods of measurement are all in common use and should yield the same test results. Effects of steering, traction, surface texture, and non-steady-state tire operations are excluded from the recommended practice because they are still in the research stage.
Highway Tire Committee
Stepwise Coastdown Methodology for Measuring Tire Rolling ResistanceJ2452_201707 (Current)7/26/2017
This SAE Recommended Practice is applicable to pneumatic Passenger Car “P” Type, Light Truck Metric, and Light Truck High Flotation tires, or similar tires approved by bodies other than Tire & Rim Association. The methodology is applicable within normal operating ranges of vertical load and inflation pressure, and for velocities between 115 km/h and 15 km/h (71 mph and 9 mph) during a relatively short duration event such as a coastdown. This procedure is applicable only to operation in the free-rolling mode at zero slip and camber angle for ambient temperatures between 20 °C and 28 °C (68 °F and 82 °F) and for surfaces with diameters of 1.2 m (48 in) diameter or greater. Details regarding the equipment, tires, and test methods used specifically for validation of this document are included in Appendix A. Two basic measurement methods covered by this document are as follows:
Highway Tire Committee
SUPPLIER EYE17AUTP06_076/1/2017
Are you innovating for NVH? I'll never forget the experience, as a kid, of lifting the massive steel hood of my father's 1971 Dodge Monaco and seeing nothing but V8 engine and a few rubber hoses. The vast compartment was so uncluttered, I could look straight down and see the pavement. By comparison, the view under today's vehicle hoods reveals a dense landscape of technologies aimed at acoustic control: covers, shields and insulators designed to keep injector clatter, induction honk and even pulley whirl muffled. Supplier innovations are central to winning the ongoing war with NVH-noise, vibration and harshness. The battle started decades ago and will certainly increase in the future. This is an engineering realm with numerous tradeoffs involving total piece cost, capital cost, stranded fixed capital, tooling complexity/count, system optimization, flexibility, intellectual property and even downstream warranty. But because NVH (more accurately, the lack of it) has direct impact on the end customer, it has become a commitment rather than an option across vehicle segments.
Performance Comparison between ABS 4S/4M and ABS 4S/3M2017-36-00015/24/2017
After the anti-skid brake system (ABS) introduction, mandatory for all vehicles in the Brazilian market, manufacturers have given increasing attention to optimized systems which meet legal and safety requirements. For commercial vehicles, an alternative for the ABS, which presents feasibility, is the configuration 4S/3M (4 wheel-speed sensors and 3 modulator valves) in substitution to the configuration 4S/4M. In other words, application of just one modulator valve to control the brakes of the same axle, front or rear, instead of independent control per each brake of the vehicle. The aim of this paper is to present a performance comparison between a brake system fitted with ABS configuration 4S/3M and an ABS configuration 4S/4M. To this end, both configurations were tested on the same vehicle application in accordance with the Brazilian legislation, CONTRAN 519/15. In addition, a test on which the vehicle was prepared with an unusual load distribution was performed in order to verify if the proposed system would be capable to keep its performance. A discussion regarding feasibility of ABS 4S/3M on 6x2 or 6x4 trucks is also presented.
de Souza, Luís Fernando Nuss, de Oliveira, Antônio Carlos, Vetter, Narã Vieira
Automation and Robotics - The Trend Towards Cyber Physical Systems in Agriculture Business2017-01-19325/10/2017
The digital transformation offers Europe tremendous opportunities of more efficient production using Cyber Physical Systems (CPS), which will enable new concepts for future farming systems. The very fast development of information and communication technologies is driving the evolution of mobile machines into cyber-physical systems with virtually no limitations for communication. Automation is the most important trend in the development of agricultural mobile machines due to the open potential of efficiency increases at all levels (machine, process and farm operation). CPS technologies are going to deliver solutions at the system and enterprise level by supporting real time and strategic decisions while enabling much higher system transparency and controllability within the sustainability tri-angle.
Herlitzius, Thomas
Deceleration Rates of Vehicles with Disabled Tires2017-01-14273/28/2017
Tire disablement events can cause a drag force that slows a vehicle. In this study, the magnitude of the deceleration was measured for different phases of 29 high speed tire tread separation and air loss tests. These deceleration rates can assist in reconstructing the speed of a vehicle involved in an accident following a tire disablement.
Koch, Daniel, Beauchamp, Gray, Pentecost, David
Design of Roof Rack Rails with Cost and Weight Optimization2017-01-13083/28/2017
The fuel efficiency of a vehicle depends on multiple factors such as engine efficiency, type of fuel, aerodynamic drag, and tire friction and vehicle weight. Analysis of weight and functionality was done, to develop a lightweight and low-cost Roof rack rail. The Roof rack rail is made up of a lightweight material with thin cross section and has the design that allows the fitment of luggage carrier or luggage rack on the car roof. In starting this paper describes the design and weight contribution by standard Roof rack rail and its related parts. Secondly, the selection of material within different proposed options studied and a comparison of manufacturing and design-related factors. Thirdly, it has a description of the design of Roof rack rail to accommodate the luggage carrier fitment on the car roof. Moreover, optimizations of Roof rack rail design by continuous change in position, shape, and parts used. Finally, the detail of the lightweight and cost effective Roof rack rail design. Cause and countermeasure detail of the surface defects occurred in parts during mass production. Moreover, a realization of value engineering of 70% in the above-mentioned new Roof rack rail.
Softa, Abhishek, Shami, Anuj, Khurana, Rajdeep Singh
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