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Viewing 31 to 60 of 11057
2017-09-17
Technical Paper
2017-01-2487
Yasuyuki Kanehira, Yusuke Aoki, Yukio Nishizawa
Brake squeal is uncomfortable noise that occurs while braking. It is an important issue for automobile quality to prevent brake products from squealing. Brake shims are widely used to reduce squeal occurrence rate. In particular, laminated shims can effectively suppress squeal via the viscoelastic damping of an adhesive layer. However, there are cases where the damping performance at low temperature and the durability performance at high temperature deteriorate. In that regard, we thought of applying frictional damping to shims instead of relying on a temperature-sensitive adhesive layer. To study the application of frictional damping as a new damping mechanism for shims, it is necessary to clarify the characteristics thereof. In order to quantify the damping performance of shims, loss factor has been generally measured with a bending mode tester. However, the influence of friction cannot be evaluated because it is measured under pressure-free condition.
2017-09-17
Technical Paper
2017-01-2499
Xianyao Ping, Meifang Wu, Gangfeng Tan, Yuxin Pang, Yu Tang, Di Wu
The engine brake is widely used as auxiliary brake device for its continuous brake torque. The engine brake performance is usually determined in the laboratory or proving ground according to relevant standards. The main purpose of this paper is to introduce an on-vehicle measurement system to measure the engine brake performance in the driving process. The on-vehicle measurement system makes use of the vehicle driving information to deduce the engine brake performance during transportation, which can reduce the test times in the laboratory or proving ground and the sensor cost. The measurement system based on the vehicle longitudinal dynamics can adapt to various vehicle automatically without measuring the vehicle or engine parameters before installation. And the measurement system can also estimate gross vehicle mass approximately.
2017-09-17
Technical Paper
2017-01-2505
Mahesh Shridhare, Santosh Sonar, Manish Ranawat, Ajit Kumar Jindal
It is well established that one of the causes of brake pulling during straight ahead braking of the vehicle is torque difference between Left and Right wheel brakes. This paper explains a method to estimate and reduce brake pulling of a Light commercial vehicle (LCV) caused by such a brake torque difference during panic braking. It is challenging to eliminate this unwanted brake pulling in shorter wheelbase LCV having all drum brakes and high center of gravity. A mathematical model is developed to estimate extent of brake pulling from known parameters like brake torque at each wheel, tire properties, steering geometry, vehicle center of gravity location etc. With the help of this model the sensitivity of each parameter change on vehicle pulling derived & it supported for optimizing the DOE. Vehicle tests have been done to measure extent of brake pulling along with measurement of brake torque and speed etc.
2017-09-17
Technical Paper
2017-01-2509
Guirong Zhuo, Ruonan Xue, Subin Zhang, Cheng Wu, Kun Xiong
Electromechanical Braking System(EMB)stops the wheel by using motor and related enforce mechanism to drive braking pads to clamp the friction plate. It is compact-sized as well as faster-responsive, which solves the spillage and slow response of traditional hydraulic brake system. The institutions at home and abroad have put forward all kinds of new structural scheme 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 decomposition according to function and the parametric 3D model library of each function module is established. According to the braking requirements of the target vehicle, a development platform is set up to match EMB actuator structure scheme quickly.
2017-09-17
Technical Paper
2017-01-2507
Matthias Hoch, Michal Kaczmarek, Markus Ahr
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 homogenous 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
With the development of electric vehicles, electronic hydraulic brake system becomes a hot spot of present research. In this paper,a new type of 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. Motor and mechanical structure can cause friction, which 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. Because of the external interference or the abrasion of the system, the main parameters will change over time. So the adaptive control is of great importance. 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.
2017-09-17
Technical Paper
2017-01-2514
Wei Han, Lu Xiong, Zhuoping Yu, Haocheng Li
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 concrete configuration and working principle of booster is proposed. A test bench which consists of booster, master cylinder, wheel cylinder and braking pipelines is set up. PI (Proportional-integral) control algorithm is used in the closed-loop system. Through the test bench, dynamic characteristic of the system are tested. But the system is easily disturbed when the outside conditions changes. The system performance is weakened. The cascade control technique can be used to solve the problems. This paper develops an novel adaptive cascade optimum braking control algorithm based on the mechatronic booster system. The system is divided into main loop and servo loop, both of them are closed-loop system.
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 anecdotalcontradictory 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 molding temperatures, pressures and times, which in addition to changing the compressibility, changes the coefficient of friction 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 for the underlayer to achieve different compressibilities, thus changing compressibility without changing thecoefficient of friction. Test results show brake squeal increasing with increasing compressibility, contrary to the common belief.
2017-09-17
Technical Paper
2017-01-2530
Georg Peter Ostermeyer, Johannes Otto, Seong Kwan Rhee
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. The first form is characterized by vibrations, where both linings are in phase. This produces in plane vibrations of the rotor and results in high-frequency squeeling events in the brake. The second form is an antiphase vibration of the brake linings with respect to each other. This produce directly out of plane vibrational modes of the disc. This results in lower-frequency caliper and rotor oscillations. One hypothesis is that different wear densities of the linings essentially characterize the two vibrational modes. This paper deals with a low dimensional dynamical system and examines the vibrations, the associated wear characteristics, and analyzes essential influencing parameters on the different vibrational events.
2017-09-17
Technical Paper
2017-01-2506
Saikiran Divakaruni, HT Chang
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 regulation 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 critical characteristics of 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
2017-01-2486
Kyung Jae Lee, Dong Won Kim, Daekyung Ko
Brake grinding noise is caused by the friction of the disc and pads. The friction generates vibration and it transmits to the body via the chassis system. We calle it structure-borne noise. To improve the noise in the vehicle development, the aspects of chassis or body's countermeasure occurs many problems, cost and time. In this reason many brake company try to make solution with brake system, like brake friction materials or disc surface. However the countermeasure of excitation system also have a lot of risk. It could occur side-effects of braking performance, and need to reverify brake noise like Creep-groan, Groan, Squeal, Judder and so on. In conclusion, It is very important making robust chassis system in initial vehicle development stage. This paper is about rear brake grind noise path analysis and countermeasure of chassis system. There are two steps to analysis. First step is impact hammer test like FRF, MODAL test.
2017-09-17
Technical Paper
2017-01-2492
Dejian Meng, Ziyi Wang, Lijun Zhang, Zhuoping Yu
Supposed disc surfaces have initial disc thickness variation (DTV) with 2 order sine function characteristics, a FE model of ventilated disc brake for transient thermomechanical coupling simulation was established. With the distribution of the temperature, the normal stress and the elastic deformation on disc surfaces for the evaluation, the influences of the initial DTV and its direction and maximum on thermomechanical coupling characteristics were analyzed. The simulation results show that the temperature, the normal stress and the thickness variation have a 2 order sine function characteristic in circumferential direction, which is the most important difference between the thermomechanical coupling characteristics with and without the initial DTV. The 2 order sine function distribution in circumferential direction is related with the initial DTV direction and tendency.
2017-09-17
Journal Article
2017-01-2481
Vishal Mahale, Jayashree Bijwe, Sujeet Sinha
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
2017-01-2491
Baskar Anthonysamy, Arun Kumar Prasad, Babasaheb Shinde
Fierce competition in India’s automotive industry has led to constant production innovation among manufacturers. This has resulted in the reduction of the life cycle of the design philosophies and design tools. One of the performance factors that have continues to challenge automotive designer is to design and fine tune the braking performance with low cost and short life cycle. Improvement in braking performance and vehicle stability can be achieved through the use of braking systems whose brake force distribution is variable. Braking force distribution has an important and serious role in the vehicle stopping distance and stability. In this paper a new approach will be presented to achieve the braking force distribution strategy for articulated vehicles. For this purpose, the virtual optimization process has been implemented. This strategy, defined as an innovative braking force distribution strategy, is based on the wheel slips.
2017-09-17
Journal Article
2017-01-2482
Meechai Sriwiboon, Nipon Tiempan, Kritsana Kaewlob, Seong K Rhee, Donald Yuhas
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 frequency, dynamic modulus, hardness and compressibility for a low-copper formulation and a copper-free formulation, both without underlayer. Pad natural frequency, modulus and hardness all 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 frequency and modulus remain essentially unchanged. However, there is no consistent pattern in compressibility change with increasing porosity, and thus a question arises on the validity of compressibility measurement.
2017-09-17
Technical Paper
2017-01-2493
Sivakumar Palanivelu, Jeevan Patil, Ajit Kumar Jindal
Brake system represents an important aspect of the vehicle dynamics apart from being an active safety system. The vehicle retardation and stopping distance completely depend upon the performance of brake system and the functionality of all components. However, the performance prediction of the entire system is a challenging task especially for a complex configuration such as multi-axial vehicle applications. Furthermore, due to its complexity most often the performance prediction by some methods is limited to static condition. Hence, it is very important to have equivalent mathematical models to predict all performance parameters for a given configuration in all different conditions. This paper presents the adopted system modelling approach to model all the elements of the pneumatic brake system such as dual brake valve, relay valve, quick release valve, front and rear brake actuators, foundation brake etc.
2017-09-17
Technical Paper
2017-01-2508
Xianyao Ping, Shengguang Xiong, Gangfeng Tan, Jialiang Liu
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
2017-01-2503
Binyu Mei, Xuexun Guo, Bo Yang, Shengguang Xiong, Gangfeng Tan
In order to ensure driving safety, heavy vehicles are often equipped with hydraulic retarder, which provides sustained and stable braking torque and converts the kinetic energy of the vehicle into heat taken away by the cooling system when the vehicle on a long downhill journey. The braking torque of conventional hydraulic retarder 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 impellers. 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
2017-01-2510
Shengguang Xiong, Gangfeng Tan, Bo Yang, Longjie Xiao, Yongbing Xu, Yishi Wang
Fluid auxiliary braking devices can provide braking torque through hydraulic damping and fluid auxiliary braking devices can also convert the vehicular inertia energy into transmission fluid heat energy during braking, which can effectively alleviate the work pressure of the main brake. Traditional hydraulic auxiliary braking devices use transmission fluid 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 of the magnetic field changed. The temperature of the MR fluid will increase when the vehicle with continuous braking. The changes in MR fluid temperature will cause a bad influence on the efficiency stability of the auxiliary braking.
2017-09-17
Journal Article
2017-01-2523
Seonho Lee, Yoongil Choi, Kyuntaek Cho, Hyounsoo Park
Raceway groove is one of the main factors of causable wheel noise on driving. Many OEM customers have asked continuously its improvement and even they are demanding to verify for proactive control at bearing companies. Generally, the raceway groove of wheel unit is consequence of metallic yielding from external load in exposed unspecific environment. It means stronger yielding strength of steel can leading to resist from brinell occurrence. Both outer ring and hub based on the Gen.3 wheel unit are manufactured using by 1055 bearing quality steel (BQS) and harden them as the case hardening like induction hardening (IH). This paper presents the originality development steel and its IH design that are targeted long life bearing and brinell resistance improving on raceway developed by ILJIN AMRC (Advanced Materials Research Center).
2017-09-17
Technical Paper
2017-01-2516
Xiong Yang, Jing Li, Hui Miao, Zheng Tang Shi
A general principle scheme of IEHB (Integrated Electro-Hydraulic Braking 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 braking conditions of a vehicle. Because of the strong nonlinear and time varying characteristics of the dynamic brake pressure regulation processes of IEHB, its comprehensive braking performance is mainly affected by temperature, humidity, load change, the structure and control parameters of IEHB, and so on.
2017-09-17
Technical Paper
2017-01-2535
Yongbing Xu, Binyu Mei, Longjie Xiao, Wanyang XIA, Gangfeng Tan
The continuous braking of the brake drum will cause the brake thermal decay when the heavy truck is driving down the long slope in the mountain areas. This reduces the braking performance and the braking safety. The engine braking and the retarder braking both consume the kinetic energy of the truck and can assist the truck driving in the mountain areas. This research proposes a combined braking strategy of the heavy truck in the mountain areas based on the mountain GIS information and the former recorded information of the slope gradient. The accelerator pedal is released in the middle of the uphill to assist the engine braking and access the shift between the kinetic energy and the potential energy. Different braking methods are allocated properly according to the slope length and gradient in the downhill. The vehicle dynamic model is established to analyze the speed variation and the truck’s braking characteristics on the long slope.
2017-09-17
Technical Paper
2017-01-2529
Jae Seol Cho, JongYun Jeong, Hyoung Woo Kim, Hwa Sun Lee, Yang Woo Park, Junghwan Lim, Yoonjae Kim, Jinwoo Kim, Byung Soo Joo, Ho Jang
An index to evaluate noise propensity of the brake friction material is introduced. The noise propensity index (NPI) is composed of the mechanical properties and surface topography of the friction material after burnish, which was closely related to the stick-slip profile found at relatively low velocity. The correlation between the noise occurrence and NPI was evaluated using commercial brake linings. Test results showed that the mechanical properties such as the ratio between surface stiffness and matrix stiffness and the surface properties such as the fraction and distribution of contact plateaus determined the noise propensity of brake friction materials with a good correlation of the noise occurrence and NPI.
2017-09-17
Technical Paper
2017-01-2500
Bo Huang, Wanyang Xia, Gangfeng Tan, Longjie Xiao, Zongsong Wang
Head-up Display (HUD) system can avoid divers’ distraction on dashboard and effectively reduce collisions caused by emergency events, which is gradually being realized by researchers around the world. However, the current HUD only displays information like speed, fuel consumption, other information like acceleration and braking can’t be displayed yet. This research will uses the color and position change of the indicator symbol to remind drivers of braking information like braking time, braking severity, which can alert drivers to make braking operations timely and accurately. The system has the advantages of safe, intuition and real-time. The vehicle safety speed is calculated according to the road parameters like adhesion coefficient, slope and curvature as well as vehicle parameters like vehicle mass and centroid. And then the appropriate braking operations like braking time are obtained by combining the vehicle status like speed and steering.
2017-09-17
Journal Article
2017-01-2501
ByeongUk Jeong, Hyong Tae Ryu, Kwang Ki Jung, Chang Jin Kim
Owing to the enhanced performance of engines these days, more heat should be dissipated in the braking system. Sucess of doing this properly causes more heat to the disc in the brake system which results in the deformation or scratches on the surface of it and a reduction in the appearance of the product. A study for detailed factors to aggravate this was done as a solution to prevent these form happening. In this paper, we present our work based on experiments to study MPU(Metal Pick Up) of the pad and the scoring(scratching)of the disc. MPU of which the main component is "Fe", is formed through the process of fusing the separated materials from the disc by friction wiht the pad, and by local heat generation to the pad. The occurrence of MPU and the possibility of the disc scoring resulting from this were studied by noting "Fe" which was transferred to the surface of the pad to different extent and degree of segregation according to the roughness of disc.
2017-09-17
Journal Article
2017-01-2502
David B. Antanaitis, Matthew Robere
The purchase of a new automobile is unquestionably a significant investment for most customers, and with this recognition, comes a correspondingly significant expectation for quality and reliability. Amongst automotive systems –when it comes to considerations of reliability - the brakes (perhaps along with the tires) occupy a rarified position of being located in a harsh environment, subjected to continuous wear throughout their use, and are critical to the safe performance of the vehicle. Maintenance of the brake system is therefore a fact of life for most drivers – something that almost everyone must do, yet given the potentially considerable expense, it is something that of great benefit to minimize.
2017-09-17
Journal Article
2017-01-2496
Enrico Galvagno, Antonio Tota, Alessandro Vigliani, Mauro Velardocchia
Brake systems represent important components for passenger cars since they are strictly related to vehicle safety: Anti-lock Braking Systems (ABS) and Electronic Stability Control (ESC) are the most well-known examples. The paper is focused on the characterization of the braking hydraulic plant and on the design of a pressure following control strategy. This strategy is aimed at pursuing performances and/or comfort objectives beyond the typical safety task. Caliper pressure dynamics is evaluated through a lumped parameter model which is used to design the controller. The low-level logic (focus of the paper) consists of a Feedforward and Proportional Integral controller. A Hardware In the Loop (HIL) braking test bench is adopted for pressure controller validation by providing some realistic reference pressure histories evaluated by a high-level controller.
2017-09-17
Journal Article
2017-01-2498
David B. Antanaitis, E Lloyd
This paper describes the development work that went into the creation of the J3052 “Brake Hydraulic Component Flow Rate Measurement at High Delta Pressure”, and also shows some example applications of it. The J3052 recommended practice is intended to measure flow characteristics through brake hydraulic components and subsystems driven by pressure differentials above 1 bar, and was anticipated by the task force to be invoked for components and subsystems for which pressure response characteristics are critical for the operation of the system (such as service brake pressure response and stopping distance, or pressure rise rate of a single hydraulic circuit in response to an Electronic Stability Control command).
2017-09-17
Journal Article
2017-01-2521
Stacey Scherer
Wheel bearing friction torque (“drag”) directly contributes to vehicle fuel economy and CO2 emissions. At the same time, one of the most important factors for long-term durability of wheel bearings is effective seal performance. Since these two factors are often in conflict, it is important to balance the desire for low friction with the need for optimal sealing. One factor that affects wheel bearing sealing performance is the distortion of the outer ring that occurs when the bearing is mounted to the steering knuckle with fasteners. Minimizing this distortion is not just important for sealing, however. This paper explores the relationship between the outer ring distortion and the resulting friction torque. A Design of Experiments approach was used in order to study the effects of the fastening bolt torque, constant velocity joint (CVJ) fastening torque, and outer ring distortion on component-level drag.
2017-09-17
Journal Article
2017-01-2522
Chao Wen, Lu Zhang, Tong Luo, Dejie Huang, Yu Liu
Bearing unit clearance is a key indicator that affects the fatigue life of products; an excessive or undersized clearance will lead to a short bearing life. Wheel bearing clearance can be divided into the state of assembly clearance and loading clearance, the final working clearance is at loaded state. Unloaded wheel bearing clearance is called the assembly state clearance, when the bearing in this state is loaded, it will be locked by a specific torque of the wheel axle bolt and produce an axial locking force, which causes the axial deformation of the raceway. So the assembly clearance will be changed and form the loading clearance, also known as working clearance. In order to obtain the working clearance of the wheel bearing, the axial locking force (referred to as the axial force) of the wheel bolt under certain torque is required to be tested and obtained on the basis of ensuring that the assembly clearance meets with the design requirements.
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