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Viewing 31 to 60 of 10324
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
2015-01-2689
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
2015-01-2684
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
2015-01-2669
Bernhard Schmittner
Electric parking Brake was introduced in 2000 with an actuator integrated into the caliper, controlled by a standalone ECU. Then a variety of actuator technologies were realized. Cable pullers, motor on caliper, actuator in drum in hat with different control concepts. In 2012 the boom started - with a concentration on caliper integrated systems and with an integration of the ECU into the ESC system. New developments are requiring EPB out of different aspects - comfort and controllable standstill are requested. So EPB systems have to be adapted to the upcoming situation. Under the influence of the commercial situation the EPB systems and actuators have to be updated with a focus on standardization, modular boxes and simplification. A look on system and actutor principles and solutions shows a way to fullfill these requirements.
2015-09-27
Technical Paper
2015-01-2676
D. Lenin Singaravelu, R. Vijay, M. Rahul
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
2015-01-2677
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
2015-01-2698
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
2015-01-2703
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
2015-01-2708
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
2015-01-2704
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
2015-01-2683
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
2015-01-2681
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
2015-01-2702
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
2015-01-2675
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
2015-01-2701
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
Journal Article
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
Journal Article
2015-01-2668
Ulrich Ungethuem, Dirk Simon
The hydraulic brake products like brake calipers, master cylinders and boosters are the foundation of today complex vehicle brake systems. The state of the art application leads very often to an individual design, due to the fulfillment of customer requirements within the available installation space. Also the enormous pressure on cost and time require optimized design processes. Therefore Continental developed the product configuration software CoBra. Within this software tool, the engineering is able to react very fast on demands. Starting with the brake sizing parameters and the customer interface definition, CoBra supports the design engineer to select the necessary components and positioning them accordingly, considering the actual design standards. The data based configuration software collects all necessary design parameters and provides an export to parametric CAD start up models.
2015-09-27
Journal Article
2015-01-2670
Achim Reich, Angelo Sarda, Martin Semsch
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
2015-01-2673
Toshikazu Okamura
Brake judder is one of the most serious problems in automotive-brake systems and brake discs play a significant role in judder. There are two types of brake judder: cold and hot. Hot judder is caused by the thermo-mechanical deformation of a disc rotor due to high-speed brakings. There are several causes and shapes of disc’s thermo-mechanical deformation, e.g. coning and wave-like shapes. The circumferential wave-like shapes of brake discs are typically found as a butterfly shape in the second order of the rotational speed and corrugation (or heat spots) around tenth order of that. They are caused by thermo-mechanical buckling and are the significant cause of hot judder. The author focuses on the effects of material and dimensional homogeneity on the transient and permanent deformation of ventilated discs in the low orders of the rotational speed during repetitive high-speed brakings.
2015-09-27
Journal Article
2015-01-2672
Aihong Meng, Jian Song
High speed on-off valve controlled by pulse width modulation (PWM) of high frequency can get the valve floated at a certain opening which is adjusted by changing the duty ratio. In consequence, the valve can control the flow and pressure linearly so that it is used widely in vehicle control systems. In this paper, it is analyzed that the effect of the valve’s parameter on the linear control performance improvement, which includes the extending of duty ratio range and the improving of control precision during low pressure. The inlet valve of automotive electronic stability program(ESP)is taken for example. The motion of the valve is mainly determined by the electromagnetic force, the flow force and the spring force. The flow force has not been deeply analyzed in previous related articles. Based on the fluid dynamic theory, the flow force mathematical model is derived in this paper.
2015-09-27
Journal Article
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
Journal Article
2015-01-2693
Neno Novakovic
Aircraft antiskid brake control system is considered one of the most complex aircraft systems whose performances depend not only on subsystem parameters but rather on many other external conditions and physical parameters which are difficult to control and predict. Over the years with significant help from programmable electronic devices, data acquisition components and real time computing power, aircraft brake control system performances and fault diagnostic have been simulated and analyzed from various aspects. In that process, dynamic simulation and mathematical modeling of hydro-mechanical brake control elements, like antiskid/brake control valves and hydraulic brake assemblies, becomes a major subject. Based on the task to enhance aircraft brake control system diagnostic methods, this article presents one approach in mathematical modeling and numeric identification method of the hydro-mechanical brake control components.
2015-09-27
Journal Article
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
Journal Article
2015-01-2662
Daniela Plachá, Pavlina Peikertova, Jana Kukutschova, Poh Wah Lee, Kristina Čabanová, Jiří Karas, Jana Kuchařová, 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
Journal Article
2015-01-2678
Diego Adolfo Santamaria Razo, Johan Decrock, Ann Opsommer, Maarten Fabré, Fernao Persoon
Friction performance is the consequence of the interaction between rotor and friction material surfaces. In order to stop the car, kinetic energy has to be transformed into heat, plastic deformations, chemical reactions and wear debris (1). The latest generates the formation of the so called third body layer and its initiation, growth and degradation will generate the actual friction coefficient and wear (2). Third body layer is composed by a semi continuous layer formed by primary and secondary plateaus (3) and its chemical composition depends upon the combination of compounds present in the friction material formulation, rotor chemical composition and quality, environmental conditions and testing procedures (2). Nevertheless some raw materials seem to promote third body layer formation more than others. The main chemical composition of the plateaus are iron oxide –probably coming from the rotor- copper, carbon, silicon and calcium (3).
2015-09-27
Journal Article
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
Journal Article
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
Journal Article
2015-01-2682
Masaaki Nishiwaki, Ryutaro Misumi
High brake performance is required for vehicle safety. At the same time, mass reduction of brake system is also required for vehicle economic long run. Under these backgrounds, high friction coefficient pad materials come to be adopted for brake system. But it is well known that brake squeal is often caused by high friction coefficient pad materials. Therefore, brake squeal research is one of very important technical issues for vehicles design. Disc brake squeal is caused by small disturbance in dynamic unstable systems. Today, disc brake squeal can be simulated by FE Analysis in actual disc brake, but it is remained a technical issue of small disturbance, brake squeal trigger of friction force variation. Low-frequency disc brake squeal around 2 kHz can be caused by forced vibration during brake application, which is shown by N.Ishihara and me in references (1). This research suggests the trigger of disc brake squeal generation.
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.
2015-09-01
Journal Article
2015-01-9113
Rui Ma, Philip Chin, John B. Ferris, Cannon Cheng, Eric neisen, Alexander Reid
Abstract The vertical force generated from terrain-tire interaction has long been of interest for vehicle dynamic simulations and chassis development. To improve simulation efficiency while still providing reliable load prediction, a terrain pre-filtering technique using a constraint mode tire model is developed. The wheel is assumed to convey one quarter of the vehicle load constantly. At each location along the tire's path, the wheel center height is adjusted until the spindle load reaches the pre-designated load. The resultant vertical trajectory of the wheel center can be used as an equivalent terrain profile input to a simplified tire model. During iterative simulations, the filtered terrain profile, coupled with a simple point follower tire model is used to predict the spindle force. The same vehicle dynamic simulation system coupled with constraint mode tire model is built to generate reference forces.
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