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Viewing 31 to 60 of 10319
2015-09-27
Technical Paper
2015-01-2683
Sarah Chen, Steve Hoxie
Developing a quiet brake system has been a constant task for OEM as well as their brake suppliers. Squeal problems may taint the image of a car manufacturer and cause substantial revenue loss from warranty claims despite the fact that the brake remains fully functional and safe. As a major component in the brake system, the rotor plays significant role in brake noise performance. Because of the cost and damping property advantages, gray iron is still the most widely used material for brake rotor application. When pads/rotor coupling is looked at to minimize noise issues, however, most efforts have been on pads and insulators. Rotor specifications are rather general and the component is typically accepted based on grades defined by mechanical property minimum (mostly in G3000 SAE J431).
2015-09-27
Technical Paper
2015-01-2684
Seongjoo Lee, ShinWook Kim, ShinWan Kim, Seong Rhee
A correlation between brake squeal and disc wear was reported previously. This investigation was undertaken to confirm the correlation and to characterize the disc wear particles transferred to the sliding surface of the NAO pad. It is found that the iron distribution on the pad is very non-uniform; at some locations, the iron concentration reaches the level of Low Steel Lomets (15-20wt%); and squealing brakes exhibit increased amounts of transferred disc wear particles on the pad surface. These transferred particles are found as small and flattened thin metallic sheets, which are different from relatively large “metal pick-up” pieces.
2015-09-27
Technical Paper
2015-01-2689
Katsuhiro Uchiyama, Yuji Shishido
Last year we presented the FEA simulation of  “spring - mass (Pad’s shape) model” from stick-slip phenomenon for improvement of creep groan. Creep groan is one of representative groan noise on automobile brake system.    As a result of parameter study with various pad shape (chamfer, slot, etc.…), we showed that brake pad with radial slot angle has a range which increases creep groan performance.   This year we would like to present our study for advantageous direction for reduction of creep groan which will focus on friction material Mu vs. Velocity (M-V) property, friction material physical properties and relative velocity between brake pads and rotor by advanced brake assembly FEM model which considers torsional stiffness of suspension.
2015-09-27
Technical Paper
2015-01-2690
Joo Sang Park
This paper introduce several practical cases to cure the squeal noise by investigating pad unstable behaviour and self-excited vibration, and propose frequency guide lines for better noise performance. These guide lines are very useful for designers especially at the initial design stage. By using historical DOE, practical frequency guide lines will be proposed to achieve better noise performance at the initial design stage by using historical database analysis. This study has some limitations that the guide lines are available for disc. It will be further study for other brake components. In conclusion, the practical guide lines for robust disc design will be proposed after analyzing a pad unstable behaviour and disc self-excited vibration during squeal by theoretical , numerical and experimental approach. Finally the guide lines is validated by statistical approach by reviewing historical DOE for various brake systems.
2015-09-27
Technical Paper
2015-01-2691
Ju Young Kim, Jeongkyu Kim, Young Min Kim, Wontae Jeong, Hojoon Cho
In the brake system, unevenly distributed disc-pad contact pressure distribution during braking is not only a loss of braking power but also a main cause of system instability which lead to squeal noise. In this reason there has been various attempts to measure contact pressure distribution. In the brake industry, static pressure distribution is measured and utilized to guess actual pressure distribution. In this study new test method is designed to quantitatively measure dynamic contact pressure distribution between disc and pad in vehicle testing. Upon various driving conditions and shape of pad, characteristics of dynamic contact pressure distribution were analyzed. Based on those results, analytical model updated and found to better detect propensity of brake squeal.
2015-09-27
Technical Paper
2015-01-2707
Wei Li
This reseach presents the energy recuperation eddy current retarder (ERECR) which could offer a solution for the energy consumption and overheating issues of the conventional eddy current retarders. The ERECR consists of 3 main systems, namely Eddy Current Braking (ECB) system, Energy Recuperation (ER) system and Electrical Control System. The ER system which could recycle the kinetic energy from constrant speed downhill and the braking condition is mainly concerned in this research. By proposing a novel designed generator integrated with the dual-plate eddy current retarder, the ER system could generate electric energy to fulfill the energy demand of ECB system while offering respective braking torque. First, the energy flow for the vehicle braking and degrading was analyzed and the energy recovery potential under these conditions was calculated.
2015-09-27
Technical Paper
2015-01-2674
Dragan Aleksendric, Velimir Cirovic, Dusan Smiljanic
Customer perception of brake pedal feel quality, depends on both the customer's subjective judgment of quality and the actual build quality of the brake system. The brake performance stability represents an important aspect of a vehicle performance and its quality of use. This stability is needed especially in brake by wire system and braking system with regenerative braking. In order to provide stable braked pedal feel i.e. consistent the brake performance against the brake pedal travel, the model of the brake performance versus the brake pedal travel needs to be established. In this paper new hybrid neuro-genetic optimization model was developed for dynamic control and optimization of the disc brake performance during a braking cycle versus the brake pedal travel. Based on such model, the brake performance optimization of the passenger car has been provided against the brake pedal travel.
2015-09-27
Technical Paper
2015-01-2675
Erik Tobin, David Bortz, Tod Policandriotes
This paper describes test results from a new, copper-free para-aramid needlefelt composite friction material enhanced with nanoparticles. Kevlar felt-reinforced polyimide, enhanced with nanoparticles, exhibit a higher coefficient of friction than similar friction materials without nanoparticles but retain the low wear rate exhibited by those materials during full scale dynamometer testing, using the J2430 test. The threshold nanoparticle content to produce appreciable friction coefficient gains was determined. At the content levels investigated, the rotor wear was virtually undetectable while wear rate was comparable with those materials without nanoparticles. Agglomeration and distribution of nanoparticles was investigated as it pertains to friction performance and wear. New environmental regulations limiting copper content in friction materials will restrict the use of popular components found in conventional friction.
2015-09-27
Technical Paper
2015-01-2662
Daniela Plachá, Pavlina Peikertova, Jana Kukutschova, Poh Wah Lee PhD, Kristina Čabanová, Jiří Karas, Jana Kuchařová PhD, Peter Filip
The brake wear contribution to the environmental pollution has been extensively discussed, with major focus on asbestos and heavy metals released to the environment. Only limited attention was paid to released organic compounds generated during friction processes, although the organic and carbonaceous components are not the minor part in brake lining formulations. Friction processes in brakes are associated with relatively high temperatures and high pressures on the friction surfaces which relates to the thermal decomposition of the organic components in friction materials and to brake lining thermal fade. Thus, this study focuses on the identification of organic compounds released from a model low metallic brake material.
2015-09-27
Technical Paper
2015-01-2703
Guirong Zhuo, Fei Yu, Yilin Ren
The braking torque allocation of the ABS of the electro-hydraulic brake system in the electric vehicles is studied and the braking torque is distributed based on the frequency in order to achieve good braking effect. There are two common braking torque allocation strategies based on frequency : one is based on the principle of filter filter and the other is based on the weighted least squares algorithm. For the former the paper selects butterworth filter to perform the braking torque allocation, then the ABS braking torque allocation strategy based on Butterworth filter and the braking torque allocation strategy based on the weighted least squares are analyzed respectively and then contrast their braking effect with Simulink.The results show that the effect of the allocation strategy based on weighted least squares is more ideal and its control is more precise by contrast.
2015-09-27
Technical Paper
2015-01-2679
David B. Antanaitis
The proposed paper will describe how brake pad sizing (area and volume) affects fade behavior and useable life on the race track, and propose a methodology for determining the optimal brake pad size for high performance vehicles.
2015-09-27
Technical Paper
2015-01-2692
Giulia Garello, Niccolò Patron, Pietro Buonfico, Luca Martinotto
Nature of braking friction is extremely complex and a deeper understanding of the physical mechanisms that govern the energy dissipation at the interface of friction pair is an important tool to create an even deeper knowledge of tribological behavior of friction material. Friction brakes need to transform kinetic energy into heat: a complete knowledge of thermal effects during this process in every brake component is an essential part of brake design. As referred to brake pads, the analysis of dyno testing data highlighted experimental evidences related to thermo-mechanical effects, such as the different wear resistance capabilities of material classes (NAO and Low Steel). Tribological characteristics are not constant under all testing conditions and they strongly depend on temperature being the direct consequence of kinetic energy dissipation. The aim of this work is to explain the relation between wear and energy for different type of friction materials.
2015-09-27
Technical Paper
2015-01-2698
Guirong Zhuo, Subin Zhang
In this paper, a novel Electromechanical Brake actuator (EMB) is redesigned aimed at an electric vehicle driven by wheel hub motor. The two way ball screw is adopted in this mechanism. Clearance automatic adjustment and parking braking function is added in this mechanism. As a consequence, fast braking response is achieved and the wear difference of the inner and outer pads can be minimized and the initial braking force can also be improved. The electric vehicle is based on a traditional chassis. In this electric vehicle which driven by wheel hub motor, the brake disc and brake actuator will be correspondingly moved inside because wheel hub motor will take up inner space of wheel hub. As a result, the actuator might interfere with the suspension and steering systems and influence hard spot of chassis design. To solve this problem, conversely installed caliper program is used in this paper.
2015-09-27
Technical Paper
2015-01-2699
Songyun Xu, Zhuoping Yu, Lu Xiong
With the electrification and intelligentialization of vehicle, requirements on more intelligent and integrated brake system are put forward. A novel integrated-electro-hydraulic brake system(I-EHB) for automotive is presented to fulfill these requirements. Based on the analysis of requirements the operating mode of I-EHB are formed. Then the system function modes and system topological structure are proposed. After the selection of components the parameter design is accomplished by modeling the system. According to the above-mentioned design method an I-EHB prototype made. I-EHB consists of active power source (APS), pedal feel emulator (PFE), electro control unit (ECU) and hydraulic control unit (HCU). APS includes motor, master cylinder and retarding mechanism consisting of warm, gear and gear rack. Using test rig the system characteristics of I-EHB are tested. According to test friction and non-linear phenomena in hydraulic pressure control are found.
2015-09-27
Technical Paper
2015-01-2702
Chihoon Jo, Jaeseung Cheon, Jongsung Kim, Yongsik kwon
The EMB converts the electric set values into clamping forces at the brakes through an independent motor control at each wheel. EMB systems are now being developed by automobile part suppliers. In particular, as the market share of electrically powered vehicles, such as hybrid electric vehicles, elctric vehicle and fuelcell elctric vehicle, has expanded, the EMB makes it possible to recuperate the braking energy in the overall control loop of the braking unit, even in electrically powered vehicles. However, in order to commercialize, the EMB has many problems such as production competitiveness, reliability and regulations. A new concept, the Hybrid Electro-Mechanical Brake(hEMB) is characterized by a dual piston structure linked by hydraulics inside of the caliper. It is possible to reduce motor, actuator size and backup system in emergency through amplification of dual piston.[1] The hEMB is composed of caliper system, dual piston, screw, BLAC type motor and actuator.
2015-09-27
Technical Paper
2015-01-2708
Yi Yang, Liang Chu, Liang Yao, Chong Guo
During the vehicle braking, the Regenerative braking system (RBS) transforms the kinetic energy into electric power, storing it in the power sources. To increase the energy recycling rate, secure the baking process, it is required using hydraulic braking pressure to coordinately compensate the regenerative braking pressure. The traditional hydraulic pressure control algorithm, used in regenerative braking system coordinated control, has obvious laddering in the effect of braking. Unit control cycle pressure deviation seriously affect the comfort and the braking feel on the vehicle.
2015-09-27
Technical Paper
2015-01-2661
Amir Reza Daei, Nima Davoudzadeh, Peter Filip
Brake linings have complex microstructure and consist of different components. Fast growing automotive industry requires new brake lining materials to be developed at considerably shorter time periods. The purpose of this research was to generate the knowledge for optimizing of brake friction materials formula with mathematical methods which can result in minimizing the number of experiments/test, saving development time and costs with optimal friction performance of brakes. A combination of processing methods, raw materials and testing supported with the Artificial Neural Network allowed achieving excellent results in a very short time period. Friction performance and wear data from a series of FAST and full scale dynamometer tests, information about the process applied, and relevant data characterizing the friction layers developed for particular performance characteristics were used to train an artificial neural network, which was used to optimize the formulations.
2015-09-27
Technical Paper
2015-01-2677
Amir Reza Daei, Diptarka Majumdar, Peter Filip
Automotive brake lining materials are complex composites consisting of numerous ingredients allowing for their optimal performance. Since regulations are increasingly limiting Cu content in brake pads and Cu exhibits extremely high thermal conductivity, graphites, being excellent heat conducting materials themselves, are often considered for use as potential Cu replacement.This paper surveys the role of two types of graphites (from Superior Graphite) with high thermal conductivity but different mechanical properties and morphology: the so-called i) purified flake graphite (PFG) and the ii) resilient graphitic carbon (RGC).
2015-09-27
Technical Paper
2015-01-2681
Ramakanta Routaray
In a two wheeler efficient braking becomes indispensable. CBS, ABS plays a significant achievement in meeting the required braking efficiency. Conversely for non CBS, non ABS bikes, braking efficiency becomes a challenging task for Two wheeler OEM suppliers. This is because of the customers’ affordability for the required degree of efficiency. This paper depicts the innovative design of brake drum pertaining to its functional aspect; catering to meeting customer needs economically. Cast iron Brake drum is redesigned with an engineered solution which allows draining the water in rainy season. This has been verified though mathematical approach about contact area between liner and brake drum. Thereafter proto part has been made as per 3D concept. Test Results of proposed design have been compared the existing drum brake system.
2015-09-27
Technical Paper
2015-01-2704
Michael Herbert Putz, Harald Seifert, Maximilian Zach, Markus Schiffer, Jure Peternel
Accuracy of sensor-less control of an electro-mechanical brake At first glance a friction brake should be controlled by pressure or normal force to produce predictable brake force. Controlling an actuator (and hence brake pad) position basically seems to introduce uncertainties to normal force and brake force, because the position at first view tells little about actual normal force. The electro-mechanical brake (EMB) of Vienna Engineering (VE) can be operated by position-control, either without normal force sensor (saving costs) or with it. For position control a relation between actuator position and brake torque is used. The basic assumption behind is that a certain actuator position produces a given deformation in the brake and at known elastic behavior the deformation produces a certain normal force.
2015-09-27
Technical Paper
2015-01-2694
Cheng Ruan, Lijun Zhang, Dejian Meng
Research Objective During light to moderate braking at high speed, the local high temperature phenomenon can be observed on the brake disc surfaces, known as hot spots. The occurrence of hot spots will lead to negative effects such as brake performance fade, thermal judder and local wear, which seriously affect the performance of vehicle NVH. In this paper, based on the bench test of a ventilated disc brake, the basic characteristics of hot spots is obtained and the evolution process of temperature field and disc deformation is analyzed in detail. Methodology A stop brake bench test under different initial speeds and brake pressures is completed on a Link Model 3900 brake dynamometer. The temperature field and deformation of the disc surface is obtained via inferred thermal camera and non-contact displacement sensors. The space distribution characteristic and time evolution characteristic of disc temperature field and deformation is analyzed.
2015-09-27
Technical Paper
2015-01-2676
Lenin Singaravelu D, Vijay R, Rahul M
Brake is a mechanical member used for converting kinetic energy into heat energy by friction. The friction is produced by the friction material which is in contact with matting surface. In 1989, the asbestos was banned globally due to its health hazards, led to booming of non-asbestos products. Now it is the era of making eco friendly products by using natural and its waste products, crab shell powder and palm kernel shell are one among them. Crab shell and palm kernel shell powders are produced by grinding the crab shell and palm kernel shell respectively to fine mesh and thereafter treatment with solution of chloroform and methanol (2:1) at room temperature for 1 hour to remove fat was done. In this present work, the friction composites are developed in the form of standard brake pads from crab shell powder following the weight percentage of 4,8,12 and is compensated by palm kernel shell powder with weight percentage of 12,8,4.
2015-09-27
Technical Paper
2015-01-2701
Meixia Ji, Xuexun Guo, Zhenfu Chen, Bin Wang
The control forms of the vehicle have transited from hydraulic or mechanical control to electrical control owing to the soaring development of electronic technology. Compared with the traditional mechanical parking brake system, the electrical control of brake named Electrical Parking Brake System (EPB) has developed and overcomes the disadvantages of operation complexity, insufficient brake force, driver fatigue, etc. What’s more, it shares common actuators and realizes the communication between other electrical control systems to advance the vehicle industry to intellectualization. With such superiority, the Electrical Parking Brake System has aroused much interest .The most complex point in building the simulation model lies in the description of friction.
2015-09-27
Technical Paper
2015-01-2685
Diego Masotti, Patric Neis, Ney Ferreira, Kássio Gomes, Jean Poletto, Luciano Matozo
The present work presents evaluation of the sliding surface morphology of brake pads during stick-slip process. For doing that, a brake friction material was subjected to slide against a brake disc under conditions favorable to produce stick-slip phenomenon. The experiments were conducted in a laboratory-scale tribometer, which was especially designed to test brake pads used in vehicle. Optical microscope images of the material’s surface were obtained at different stages of the braking test. These images were post-processed in appropriate computational software and by means of the segmentation technique the real contact area, size and amount of contact plateaus related to the brake pad surface were estimated. Coefficient of friction resulting from the tests was measured and it is also discussed throughout this paper.
2015-09-27
Technical Paper
2015-01-2670
Achim Reich
Residual brake torque (RBT) is generated in disc brakes as a result of contact (dynamic friction) between brake disc and brake pads when the braking system is not actuated. Among the negative implications of RBT are, notably, dispensable additional fuel consumption as well as increased pad wear, which can also unfold as uneven along the pads` surfaces. The paper is based on extensive knowledge acquired through manifold measurement-based studies and contains a comprehensive assessment of the main topics related to the subject. Aiming to provide an overview about the motivation and importance of efforts to reduce RBT, effects on the environment as well as on consumption of resources are contemplated both within a general frame and for a number of selected specific cases.
2015-09-27
Technical Paper
2015-01-2666
Scott Lambert
The Global Brake Safety Council sees an increase in disc brake pads that are prematurely replaced before the end of the friction lining life cycle, due to: Rust related issues such as separation of friction lining from the disc brake shoe Fluctuation in critical dimensions A leading cause for both issues is the use of mill scale steel, or ‘black steel’ (non-pickled and oiled). In the North American aftermarket, as there are little or no steel specifications for disc brake shoes, black steel is increasingly used. GBSC conducted research of discarded disc brake pads from job-shops and engaged in discussions with metallurgists, major pad manufacturers and OE brake foundation engineers to identify root causes of premature pad replacement and the effects of black steel used for disc brake shoe manufacturing. Mill scale is embedded in and around the bond line of the friction lining and the disc brake shoe, causing a weaker bond, susceptible to rust jacking.
2015-09-27
Technical Paper
2015-01-2687
Aditya Kant Choudhary, Yogesh Mense, Saurabh Singh, Mahesh Shridhare
Brake noise is one of the common complaints and an irritant not just for the vehicle occupants but equally for the passers-by. Brake noise is actually vibration that is occurring at a frequency that is audible to the human ear. This occurrence of brake noise like brake squeal (>1 kHz) and groan (<1 kHz) is often very intense and can lead to number of customer complaints. During a brake noise event, vehicle basic structure and suspension system components are excited due to brake system vibration and result in a resonance that is perceived in the form of a noise. Proposed work discusses an experimental study that is carried out on a commercial vehicle for addressing customer complaints regarding disc brake squeal and groan noise. Based on the preliminary inputs, vehicle level study was carried out in order to simulate the problem and objectively capture its severity.
2015-09-27
Technical Paper
2015-01-2667
David B. Antanaitis, Chris Ciechoski, Mark Riefe
The proposed paper will cover new research into the role of piston material, geometry, and piston to bore clearance in determining the brake torque variation sensitivity and propensity for thermal roughness of a brake corner.
2015-09-27
Technical Paper
2015-01-2696
Shuichi Okada
We had developed Electric Servo Brake System, which can control brake pressure accurately with a DC motor according to brake pedal force. Therefore, the system attains quality brake feeling while reflecting intentions of a driver. By the way, "Build-up" is characteristics that brake effectiveness increases in accordance with the deceleration of the vehicle, which is recognized as brake feeling with a sense of security as not to elongate an expected braking distance at a downhill road due to large-capacity brake pad such as sports car and large vehicles. Then, we have applied the optical characteristic control to Hybrid vehicles with Electric Servo Brake System by means of brake pressure control and regeneration brake. Hereby, we confirmed that the control gives a driver the sense of security and the reduction of pedal load on the further stepping-on of the pedal.
2015-09-27
Technical Paper
2015-01-2680
Kazuhiko Tani, Hironori Nakamura
There are two brake systems regularly installed in a motorcycle. They are a front brake system operated by right hand, and a rear brake system operated by right foot or left hand. They generally function separately. Moreover, these two systems have different braking characteristics. To make them easy to operate, we have applied a couple of advanced brake systems to large motorcycles and scooters. They are Combined Brake System (CBS), Antilock Brake System (ABS) and the combined system of them. In small motorcycles, some models have a hydraulic disc brake both in the front and rear wheels but many of them have a hydraulic disc brake in front and a mechanical drum brake in rear. Accordingly, it was necessary to develop a new system that links the hydraulic system and the mechanical system to allow an application of CBS to these models.
Viewing 31 to 60 of 10319

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