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CURRENT
2017-09-19
Standard
J2710_201709
This SAE Recommended Practice describes test methods for measuring and identifying the natural frequencies for the lower order modes of an inflated radial tire with a fixed spindle while expending modest effort and employing a minimum of test equipment. The methods apply to any size of radial tire so long as the test equipment is properly scaled to conduct the measurements for the intended test tire. Two types of boundary conditions are considered for the tire: unloaded and loaded against a flat surface. The test involves the performance and measurement of an input vibratory force (excitation) to the tire and the corresponding vibratory output (response). 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. NOTE 1—The focus of this standard is identification and reporting of the lower order natural frequencies of the tire using a simple test procedure.
2017-09-18
WIP Standard
J1574/1
The parameters measured according to this SAE Recommended Practice will generally be used in simulating directional control performance in the linear range. (The “linear range” is the steady-state lateral acceleration below which steering wheel angle can generally be considered to be linearly related to lateral acceleration.) But they may be used for certain other simulations (such as primary ride motions), vehicle and suspension characterization and comparison, suspension development and optimization, and processing of road test data. This document is intended to apply to passenger cars, light trucks, and on-highway recreational and commercial vehicles, both non-articulated and articulated. Measurement techniques are intended to apply to these vehicles, with alterations primarily in the scale of facilities required.
2017-09-18
WIP Standard
J1574/2
This SAE Information Report presents the background and rationale for SAE J1574-1. The motor vehicle industry is working toward a more complete understanding of the factors affecting the motions of vehicles on the roadway, by using a variety of techniques that predict responses to road and operator inputs. The capability to predict responses is desirable so that vehicles can be designed for optimum safety and utility. In addition to the force and moment properties of the pneumatic tires, a number of vehicle and suspension parameters affect the response of the vehicle; these include weight, center-of-gravity location, moments of inertia, suspension ride and roll rates, suspension kinematic and compliance properties, and shock absorber characteristics. These parameters must be quantified in order to predict vehicle responses. Measurement of most of these parameters will be limited to determining their values in the linear range for use in directional control simulations.
2017-09-17
Technical Paper
2017-01-2528
Seongjoo Lee, JeSung Jeon, JooSeong Jeong, Byeongkyu Park, ShinWook Kim, ShinWan Kim, Seong Kwan Rhee, Wan Gyu Lee, Young sun Cho
It is widely believed or speculated that higher pad compressibility leads to reduced brake squeal and that caliper design can affect brake squeal. After encountering anecdotal contradictory cases, this investigation was undertaken to systematically generate basic data and clarify the beliefs or speculations. In order to adjust pad compressibility, it is common to modify pad molding temperatures, pressures and times, which in addition to changing the compressibility, changes friction coefficient and physical properties of the pad at the same time. In order to separate these two effects, NAO disc pads were prepared under the same molding conditions while using different thicknesses of the underlayer to achieve different compressibilities, thus changing the compressibility only without changing the friction coefficient and physical properties of the pad.
2017-09-17
Technical Paper
2017-01-2533
Thomas J. Hall
Abstract As Pure Electric Vehicles have become a recent entrant to the higher end Passenger Vehicle Market, general interest in the overall technology has expanded beyond the environmental interest into the pure performance opportunities associated with electrically driven vehicles. Recently a new Racing Series has formed that is dedicated to Electric Vehicle Racing. Specifically the Formula-E® series has emerged as a venue for competition for Pure Electric open wheel race cars competing on Road Courses throughout the world. Success in the race series is influenced by the available energy that can be stored in the battery along with the applicable electrical efficiencies associated with the drive and control of the Propulsion Motors. The Race series also allows Regenerative Braking.
2017-09-17
Technical Paper
2017-01-2530
Georg Peter Ostermeyer, Johannes Otto, Seong Kwan Rhee
Abstract The dynamics and, in particular, the NVH phenomena in brakes are still in the focus of research. Recent investigations of for example Rhee et al. show two principal vibrational forms of the linings on the rotor [1]. The first form is characterized by vibrations where both linings are in-phase (minimal differential torque between the inner pad and the outer pad). This produces in-plane vibrations of the rotor and results in high-frequency squealing events in the brake. The second form is an antiphase vibration of the brake linings with respect to each other (increased differential torque between the inner pad and the outer pad). This produce directly out-of-plane vibrational modes of the disc, which results in lower-frequency caliper and rotor oscillations. One hypothesis is that different wear densities of the linings essentially characterize the two vibrational modes.
2017-09-17
Technical Paper
2017-01-2531
Georg Peter Ostermeyer, Bastian Recke
Abstract In recent years, characteristic structures in the boundary layer of high-load contacts such as brakes have been reported, which have an important impact on the dynamics of the tribological contact. Usually, local assumptions concerning the friction of these patches are used to reach global conclusions about the brake system. Several numerical methods (e.g. Cellular Automata) have been developed which make use of such assumptions. The validation of these methods through measured data tends to be laborious and costly. Sprag-Slip elements are friction elements which are typically considered to exclusively undergo static friction. Such elements have been sporadically utilized towards describing friction in brake applications. In this paper, many locally distributed Sprag-Slip elements are used to model the global dynamics of braking friction. The results show good agreement with the measured characteristics of brakes.
2017-09-17
Technical Paper
2017-01-2504
Scott Lambert
Abstract As the brake industry moves completely into globalization, a standardized method to define and validate the dimensions of backing plates, in a way that is both clear and feasible, is of critical importance for manufacturers at all tiers. The plate drawing not only defines the component as it fits into a brake assembly; it is also what the plate supplier relies on to define the plate for manufacture. If a drawing does not define every dimensional aspect of the product with perfect clarity, in ways that are easily measured, loss of time and resources will result from questions and/or mistakes. This paper proposes an SAE standard for defining the dimensional requirements of backing plates on the drawings themselves, and defining the measuring procedures used to validate those dimensions.
2017-09-17
Technical Paper
2017-01-2505
Mahesh Shridhare, Santosh Sonar, Manish Ranawat, Ajit Kumar Jindal
Abstract This paper explains a method to estimate and reduce brake pulling of vehicles due to force difference between RH and LH brake during straight ahead braking. One of the cause of brake pulling during straight ahead braking is brake force difference between right and left brakes of front and rear axles. It is challenging to eliminate this unwanted pulling especially during panic braking in shorter wheelbase vehicles having high center of gravity (CG) and drum brake on all wheels. A mathematical model is developed to estimate amount of brake pulling from known parameters like brake force, tire properties, steering geometry, suspension hard points, vehicle CG, scrub radius, castor angle etc. Vehicle tests were conducted to measure amount of brake pulling and close correlation was observed between vehicle test results and derived model.
2017-09-17
Technical Paper
2017-01-2503
Binyu Mei, Xuexun Guo, Bo Yang, Shengguang Xiong, Gangfeng Tan
Abstract In order to ensure driving safety, heavy vehicles are often equipped with hydraulic retarder, which provides sustained, stable braking torque and converts the vehicle kinetic energy into heat taken away by the cooling system when traveling on a long downhill. The conventional hydraulic retarder braking torque is modulated by adjusting the liquid filling rate, which leads to slow response and difficult control. In this paper, a new kind of magnetorheological (MR) fluid hydraulic retarder is designed by replacing the traditional transmission oil with MR fluid and arranging the excitation coils outside the working chamber. The braking torque can be controlled by the fluid viscosity of MR fluid with the variation of magnetic field. Compared with the traditional hydraulic retarder, the system has the advantages of fast response, easy control and high adjustment sensitivity.
2017-09-17
Technical Paper
2017-01-2508
Xianyao Ping, Shengguang Xiong, Gangfeng Tan, Jialiang Liu
Abstract Using friction brakes for long time can increase easily its temperature and lower vehicle brake performance in the downhill process. The drivers' hysteretic perception to future driving condition could mislead them to stop untimely the engine brake, and some other auxiliary braking devices are designed to increase the brake power for reduction of the friction brake torque. The decompression engine brake has complex structure and high cost, and the application of eddy current retarder or hydraulic retarder on the commercial vehicles is mainly limited to their cost and mass. In this paper, an innovative brake guidance system for commercial vehicles with coordinated friction brakes and engine brake is introduced to guide the drivers to minimize the use of the friction brakes on the downhill with consideration of future driving conditions, which is aimed at releasing the engine brake potential fully and controlling the friction brake temperature in safe range.
2017-09-17
Technical Paper
2017-01-2509
Guirong Zhuo, Ruonan Xue, Subin Zhang, Cheng Wu, Kun Xiong
Abstract Electromechanical Braking System (EMB) stops the wheel by motor and related enforce mechanism to drive braking pads to clamp the friction plate. It is compact in sized as well as faster in response, which solves the issue of potential leakage and slows response of traditional hydraulic brake system. The institutions at home and abroad have put forward all kinds of new structural schemes of EMB. At present, there are various EMB structural schemes, but the analysis and evaluation of these schemes are relatively few. In this paper, on the basis of a large number of research, the EMB actuator is modular decomposed according to function ,then the parametric 3D model library of each function module is established. According to brake requirements of the target vehicle, a development platform is set up to match EMB actuator structure scheme quickly.
2017-09-17
Technical Paper
2017-01-2506
Saikiran Divakaruni, HT Chang
Abstract Friction material back plate design, manufacturing and consistent quality are some of the key attributes for better brake performance. Historically, the auto industry’s focus on back plate quality has been limited to drawing dimensions. Recently, vehicle manufacturers across the globe are tightening caliper performance criteria to achieve near zero drag for fuel consumption regulations and improved NVH to attract end customers. To meet these new stringent requirements, friction and back plate suppliers need to focus, in more detail, on how to improve the backing plate quality and better understand the interface characteristics of back plate/pad assembly to caliper performance. While many key characteristics of the back plate were identified in past assembly design process, there has been vague understanding to connect with caliper performance, thus, the definition of back plate quality has been limited to basic dimensional measurement.
2017-09-17
Technical Paper
2017-01-2512
Matteo Corno, Federico Roselli, Luca Onesto, Sergio Savaresi, Frank Molinaro, Eric Graves, Andrew Doubek
Abstract Anti-lock braking systems are one of the most important safety systems for wheeled vehicles. They reduce the braking distance and, most importantly, help the user maintain controllability and steerability of the vehicle. This paper extends and adapts the concept of Anti-lock braking systems to tracked vehicles, specifically to snowmobiles. Snowmobiles are an interesting development platform for two main reasons: 1) track dynamics, despite being analogous to tire dynamics, present important differences that help understanding the features of the control algorithm and 2) snowmobiles are simple and rugged vehicles with a limited set of sensors, making the design of an effective control system challenging. The paper designs a track-deceleration based ABS algorithm and tests it both in straight riding and cornering.
2017-09-17
Technical Paper
2017-01-2507
Matthias Hoch, Michal Kaczmarek, Markus Ahr
Abstract The demand for zinc-nickel coatings continuously increases in the automotive industry due to their high corrosion protection as well as superior wear and heat resistance compared to pure zinc platings. The state-of-the-art plating systems in the brake caliper industry are acid zinc-nickel electrolytes, as only they allow for direct plating on cast iron. Cast iron is the most common base material for the production of automotive brake components due to excellent mechanical and thermal properties. Well suited coatings will preserve the functional properties and provide additional advantages like improved corrosion protection and homogeneous and long lasting appearance. Consistently increasing quality demands, extended warranty periods and cost pressure lead to further developments and force the industry to look for new solutions.
2017-09-17
Technical Paper
2017-01-2513
Haocheng Li, Zhuoping Yu, Lu Xiong, Wei Han
Abstract In this paper, an integrated electronic hydraulic brake(I-EHB) system is introduced, which is mainly composed of a motor, a worm gear, a worm, a gear, a rack etc. The friction leads the system to the creeping phenomenon and the dead zone. These phenomenon seriously affect the response speed and the hydraulic pressure control .In order to realize the accurate hydraulic pressure control of I-EHB system, a new friction compensation control method is proposed based on LuGre dynamic friction model. And the theoretical design of adaptive control method is designed based on the feedback of the master cylinder pressure and the operating state of the system. Then the stability of the control method is proved by Lyapunov theorem. A co-simulation model is built with Matlab/Simulink and AMESim, so as to prove the validity of the control method.
2017-09-17
Technical Paper
2017-01-2510
Shengguang Xiong, Gangfeng Tan, Bo Yang, Longjie Xiao, Yongbing Xu, Yishi Wang
Abstract Fluid auxiliary braking devices can provide braking torque through hydraulic damping, fluid auxiliary braking devices can also convert vehicular inertia energy into transmission fluid heat energy during the braking, which can effectively alleviate the work pressure of the main brake. Traditional hydraulic auxiliary braking devices use transmission fluids to transmit torque, however, there is a certain lag effect during the braking. The magnetorheological fluid (MR fluid) can also be used to transmit torque because it has the advantages of controlling braking torque linearly and responding fast to the magnetic field changed. The temperature of MR fluid will increase when the vehicle is engaged in continuous braking. MR fluid temperature changes will cause a bad influence on the efficiency stability of auxiliary braking.
2017-09-17
Technical Paper
2017-01-2516
Xiong Yang, Jing Li, Hui Miao, Zheng Tang Shi
Abstract A general principle scheme of IEHB (Integrated Electro-Hydraulic Brake system) is proposed, and the working principle of the system is simply introduced in this paper. Considering the structure characteristics of the hydraulic control unit of the system, a kind of time-sharing control strategy is adopted to realize the purpose of independent and precise hydraulic pressure regulation of each wheel brake cylinder in various brake conditions of a vehicle. Because of the strong nonlinear and time varying characteristics of the dynamic brake pressure regulation processes of IEHB, its comprehensive brake performance is mainly affected by temperature, humidity, load change, the structure and control parameters of IEHB, and so on.
2017-09-17
Technical Paper
2017-01-2517
Michael Herbert Putz, Thomas Zipper
Abstract On Electro-Mechanical Brakes (EMB) spring-support can be necessary for releasing the brake without electrical energy. Advantageous brake-configurations can make use of the spring over the whole actuation range during engage and release. Such optimized spring support is known as “energy-swing. Under loss-less conditions the spring force could be in permanent equilibrium with the force required to press the pad, i.e. the brake could be controlled without actuation energy. In reality this will not be fully achievable as actuation losses and different operational conditions need to be covered. Still, significant advantages can be gained. The EMB of Vienna Engineering (VE) fulfills a key condition for energy-swing as it facilitates using the spring for engage- and release-support. Car brakes must release automatically when power is off.
2017-09-17
Technical Paper
2017-01-2514
Wei Han, Lu Xiong, Zhuoping Yu, Haocheng Li
Abstract BBW (Brake-by-wire) can increase the electric and hybrid vehicles performance and safety. This paper proposes a novel mechatronic booster system, which includes APS (active power source), PFE (pedal feel emulator), ECU (electronic control unit). The system is easily disturbed when the system parameters and the outside conditions change. The system performance is weakened. The cascade control technique can be used to solve the problem. This paper develops an adaptive cascade optimum control (ACOC) algorithm based on the novel mechatronic booster system. The system is divided into main loop and servo loop, both of them are closed-loop system. The servo-loop system can eliminate the disturbance which exists in the servo loop. So the robustness of the cascade control system is improved than which of the general closed-loop control system. Different control object is respectively chosen. The control-oriented mathematical model is designed.
2017-09-17
Technical Paper
2017-01-2515
Christian Riese, Armin Verhagen, Simon Schroeter, Frank Gauterin
Abstract The ongoing changes in the development of new power trains and the requirements due to driver assistance systems and autonomous driving could be the enabler for completely new brake system configurations. The shift in the brake load collective has to be included in the systems requirements for electric vehicles. Many alternative concepts for hydraulic brake systems, even for decentralized configurations, can be found in the literature. For a decentralized system with all state of the art safety functionalities included, four actuators are necessary. Therefore, the single brake module should be as cost-effective as possible. Previous papers introduced systems which are for example based on plunger-like concepts, which are very expensive and heavy due to the needed gearing and design. In this paper a comparison between a state of the art hydraulic brake system using an electromechanical brake booster, and a completely new decentralized hydraulic brake concept is presented.
2017-09-17
Technical Paper
2017-01-2534
Silvia Faria Iombriller, Wesley Bolognesi Prado
Summary Considering that the most part of commercial vehicles are equipped with air brakes it is very important assure specific technical requirements for air brake system and its components. In addition, the effects of brake system failure are more critical for commercial vehicles which require more attention on their requirements details. Historically, the development of air brakes technology started on North America and Europe and consequently two strong and distinct resolutions were structured: FMVSS 121 and ECE R.13, respectively. For passenger cars were developed the ECER.13H to harmonize North American and European resolutions. However, for commercial vehicles regional applications, culture and implementation time must be considered. These commercial vehicles peculiarities must be understood and their specific requirements harmonized to attend the global marketing growth.
2017-09-17
Technical Paper
2017-01-2535
Yongbing Xu, Binyu Mei, Longjie Xiao, Wanyang XIA, Gangfeng Tan
Abstract The continuous braking for the brake drum will cause the brake thermal decay when the heavy truck is driving down the long slope in the mountain areas. It reduces the heavy truck’s braking performance and the braking safety. The engine braking and the hydraulic retarder braking both consume the kinetic energy of the heavy truck and can assist the truck driving in the mountain areas. This research proposes a combined hill descent braking strategy for heavy truck based on the recorded information of the slopes to ensure the braking safety of the heavy truck. The vehicle dynamic model and the brake drum temperature rising model are established to analyze the drum’s temperature variation during the downhill progress of the heavy truck. Then based on the slope information, the combined braking temperature variation is analyzed considering the characteristics of the engine braking, the drum braking and the hydraulic retarder braking.
2017-09-17
Technical Paper
2017-01-2485
Tarun Teja Mallareddy, Peter Blaschke, Sarah Schneider, Daniel J. Alarcón
Abstract Brake squeal is an NVH issue experienced by brake systems and vehicle manufacturers for decades. This leads to customer dissatisfaction and the questioning of the quality of the brake system. Advanced testing tools, design modification, dynamometer testing, vehicle validation etc., are performed to study, analyze and eliminate this problem. But still it continues to exist nowadays. One of the most important reasons is the complexity of the brake pad having non-linear material properties. Therefore, it is imperative to understand the behavior of the brake pad in terms of its dynamic properties (eigenfrequencies, damping and mode shapes) under varying boundary conditions. Experimental Modal Analysis (EMA) is used to study the dynamic properties of any structure and is generally performed under free-free boundary conditions. An approach to study brake pads under pressure condition is a step towards reality, as brake pads squeal only during braking events.
2017-09-17
Technical Paper
2017-01-2484
Yoshiyuki Yamaguchi, Tsuyoshi Kondo
Abstract Previous studies have shown that the disc vibration mode during braking noise is not always the same and there are some types of mode. Until now, disc brake noise studies are reported regarding out of plane noise primarily, and there are many noise countermeasure methods. On the other hand, there is short research history of “Inplane mode noise” which disc vibrates to circumstance direction with extension and contraction movement. Therefore, there are few studies which are explained the noise mechanism in detail in the view point of pad. In this report, we discuss energy which flows into pad surface at inplane noise braking and focused friction force variation by the surface pressure change especially. The inflow energy was calculated by the pad’s displacement of disc rotating direction(ΔX) and pad thickness variation(Δh) which is acquired by 3D scanning laser Doppler measurement system. This technique was made in reference to the past research.
2017-09-17
Journal Article
2017-01-2482
Meechai Sriwiboon, Nipon Tiempan, Kritsana Kaewlob, Seong K Rhee, Donald Yuhas
Abstract Disc pad physical properties are believed to be important in controlling brake friction, wear and squeal. Thus these properties are carefully measured during and after manufacturing for quality assurance. For a given formulation, disc pad porosity is reported to affect friction, wear and squeal. This investigation was undertaken to find out how porosity changes affect pad natural frequencies, dynamic modulus, hardness and compressibility for a low-copper formulation and a copper-free formulation, both without underlayer, without scorching and without noise shims. Pad natural frequencies, modulus and hardness all continuously decrease with increasing porosity. When pad compressibility is measured by compressing several times as recommended and practiced, the pad surface hardness is found to increase while pad natural frequencies and modulus remain essentially unchanged.
2017-09-17
Journal Article
2017-01-2481
Vishal Mahale, Jayashree Bijwe, Sujeet Sinha
Abstract Potassium titanate (KT) fibers/whiskers are used as a functional filler for partial replacement of asbestos in NAO friction materials (FMs). Based on little information reported in open literature; its exact role is not well defined since some papers claim it as the booster for resistance to fade (FR), or wear (WR) and sometimes as damper for friction fluctuations. Interestingly, KT fibers and whiskers (but not powder) are proved as carcinogens by the International Agency for Research on Cancer (IARC). However, hardly any efforts are reported on exploration of influence of KT powder and its optimum amount in NAO FMs (realistic composites) in the literature. Hence a series of five realistic multi-ingredient compositions in the form of brake-pads with similar parent composition but varying in the content of KT powder from 0 to 15 wt% (in the steps of 3) were developed. These composites were characterized for physical, mechanical, chemical and tribological performance.
2017-09-17
Technical Paper
2017-01-2519
Sangbum Kim, Jae Seung Cheon, Inuk Park, Yongsik kwon
Abstract An Electrical Parking Brake (EPB) system is a device that operates to park the vehicle automatically with the push of a button instead of using conventional hand or foot levers which in some ways makes it the first by wire type of brake system. As such, it is being considered in some vehicle architectures as an automatic redundant backup for vacuum-less brake systems or autonomous cars. The EPB system is generally divided into cable puller and motor on caliper (MOC) types. Recently, the MOC type EPB is being more widely applied in the global market due to product competitiveness and cost effectiveness. The MOC type EPB is composed of the caliper body, torque member, pad assembly, nut assembly and actuator. Among them, the caliper body and torque member play a main role in the robustness of the EPB system and occupy more than 80% of the total weight.
2017-09-17
Technical Paper
2017-01-2518
Thomas J. Hall
Abstract The Los Angeles City Traffic Brake Test Schedule has been an established procedure used almost universally for generations by vehicle manufacturers to evaluate and validate braking systems for the attributes of NVH and brake wear behavior. The Los Angeles driving route, commonly known as the Los Angeles City Traffic Test (LACT), has long been considered an effective and “quasi” extreme set of real world driving conditions representative of the US passenger vehicle market and have been covered in other analysis including SAE Technical Paper 2002-01-2600 [1] The performance of a vehicle, relative to braking, in LACT conditions is typically influenced by basic vehicle and brake system attributes including the ratios of vehicle mass to brake sizing attributes, friction material selection, and the acceleration, drag, and cooling behavior of the vehicle.
2017-09-17
Journal Article
2017-01-2523
Seonho Lee, Yoongil Choi, Kyuntaek Cho, Hyounsoo Park
Abstract Raceway Brinell damage is one major cause of wheel bearing (hub unit) noise during driving. Original Equipment Manufacturer (OEM) customers have asked continuously for its improvement to the wheel bearing supply base. Generally, raceway Brinelling in a wheel hub unit is a consequence of metallic yielding from high external loading in a severe environment usually involving a side impact to the wheel and tire. Thus, increasing the yielding strength of steel can lead to higher resistance to Brinell damage. Both the outer ring and hub based on Generation 3 (Gen. 3) wheel unit are typically manufactured using by AISI 1055 bearing quality steel (BQS); these components undergo controlled cooling to establish the core properties then case hardening via induction hardening (IH). This paper presents a modified grade of steel and its IH design that targets longer life and improves Brinell resistance developed by ILJIN AMRC (Advanced Materials Research Center).
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