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Viewing 31 to 60 of 10680
2016-09-18
Technical Paper
2016-01-1910
Philippe Dufrenoy
A methodology to identify the bulk properties of friction material from their formulation V. Magnier; I. Serrano; AL. Cristol ; P. Dufrénoy* University of Lille Cité scientifique Avenue Paul Langevin F-59655 Villeneuve d’Ascq Cedex * Corresponding author : philippe.dufrenoy@univ-lille1.fr Friction materials for braking applications are made of a high number of components leading to bulk properties which guarantee the performances. Development are mainly made by a trial-error methodology due to the misunderstanding of the relationship between formulation and process and properties. In this work we propose to identify this relationship by an experimental methodology combined with microstructural analysis. The first step is the description of the microstructure obtained by tomographic analysis leading to quantitative information about the morphology of the components, their distribution in the volume, orientations, etc.
2016-09-18
Technical Paper
2016-01-1918
Yusuke Aoki, Yasuyuki kanehira, Yukio Nishizawa
Brake squeal is an uncomfortable noise that occurs while braking. So, it is an important issue for automobile quality to prevent brake products from squealing. Brake shims are widely used to reduce squeal occurrence rate. To quantify the anti-squeal effect of shims, loss factor has been measured with a bending mode tester, instead of repeating many dynamometer tests. However, there are cases where measurement results have less correlation to actual squeal suppression rate. Therefore, we have to evaluate the anti-squeal effect by dynamometer or on an actual car until the best shim can be selected. In this work, we focused on the differences between measurement conditions and actual braking conditions of shims to obtain a good correlation. The bending mode tester measures loss factor under pressure-free condition even though shims are compressed by pistons or cylinders towards the backplate of the pad.
2016-09-18
Technical Paper
2016-01-1923
Lorne R. Dyar, Yuichiro Akita, Scott Paul, Joseph Lepito, Yoshio Ishikawa, Tomohiro Watanabe
An advanced braking system must be developed for a next generation hybrid sports car that achieves an intuitive brake feeling in all conditions, ultimate circuit performance and reduction of CO2 per vehicle. This paper outlines the integration of brake-by-wire with traditional high-performance braking hardware and describes the technology needed to achieve this performance. Key focus areas to generate these results are brake feeling control, corner hardware specification considerations and brake cooling balance.
2016-09-18
Technical Paper
2016-01-1914
Pavlina Peikertova, Miroslava Kuricova, Alena Kazimirova, Jana Tulinska, Magdalena Barancokova, Aurelia Liskova, Marta Staruchova, Mira Horvathova, Silvia Ilavska, Eva Jahnova, Michaela Szabova, Miroslav Vaculik, Jana Kukutschova, Karla Kucova, Maria Dusinska, Peter Filip
Particulate air pollution from road traffic currently represents significant environmental and health issue. Attention is also paid to the “non-exhaust pollution sources,” which includes brake wear debris. During each brake application, the airborne and nonairborne particles are emitted into the environment due to wear. High temperatures and pressures on the friction surfaces initiate chemical and morphological changes of the initial components of brake pads and rotating counterparts. Understanding of impact of matter released from brakes on health is vital. Numerous studies clearly demonstrated that particulate matter caused potential adverse effects related to cytotoxicity, oxidative stress, stimulation of proinflammatory factors, and mutagenicity on the cellular level. This paper compiles our main results in the field of genotoxicity, immunotoxicity, and aquatic toxicity of airborne brake wear particles.
2016-09-18
Technical Paper
2016-01-1938
Xin Gao, Tie Wang, Mengzuo Han
Hydraulic retarder is an auxiliary brake used by commercial vehicle in long slope brake. Working liquid generates a lot of heat during hydraulic retarder working. If the heat is not properly managed, it will seriously affect hydraulic retarder braking performance. Refrigerant outlet temperature of condenser in Rankine cycle is lower, condensing more fully. But the two-phase area of evaporator reduces or even disappears. Anyhow, Rankine cycle evaporate-condensate system parameter setting not reasonable will affect efficiency of whole system and the temperature stability of hydraulic retarder. The article uses Rankine cycle which refrigerant is R141b to replace hydraulic retarder original cooling system. It can make hydraulic retarder heat exchange in time and working fluid temperature stability in a smaller range.
2016-09-18
Technical Paper
2016-01-1928
ByeongUk Jeong, Sang Do Kwak, Cheol Ki Kim
Owing to the enhanced requirement of brake free noise these days, more damping kits should be installed in the braking system. Success of doing this properly causes softness in the brake system which results in the loosened stroke feeling of brake pedal, the increased compressibility by durability. A study for detailed factors to aggravate brake feeling was done as a solution to prevent these from happening. In this paper, we present our work based on experiments to measure compressibility of shims by the influence of variations in different parameters, for example, of adhesive shims (bonding spec., steel and rubber thickness), piston’s shapes (different contact areas to the shims), and the numbers of durability. We installed the brake feeling measurement system extended from brake pedal to caliper. Experimental parameters were compared with brake feelings in vehicle using it. The optimization for brake feeling was determined by design for six sigma (DFSS).
2016-09-18
Technical Paper
2016-01-1921
Yusuke Sunagawa, Tsuyoshi Kondo
Brake squeal noise is generally classified into two vibration modes of disc. One is called “out-of plane mode” which vibrates in disc’s out-of-plane direction. The other is “In-plane mode” which vibrates in disc’s in-plane direction, it means the disc is contracted partially or is extended. There are few “In-plane noise” analysis reports from Disc pad standpoint, so it has been unclear how disc pad contributes to “In-plane mode” until now. This paper confirms that we successfully analyzed direct pad vibration mode by laser scanning under in-plane mode condition. Based on these results, we assume that pad stiffness affected in-plane mode and carried out validation tests.
2016-09-18
Technical Paper
2016-01-1916
Raffaele Gilardi, Davide Sarocchi, Loredana Bounous
A wide range of different carbon powders is available and currently used in friction materials like coke, graphite and carbon black. The effect of the type of carbon on braking performance has been extensively investigated in the past and it has been demonstrated that graphite can play an important role in copper-free brake pads. However, there are no studies about the influence of carbon powders on the processability of brake pads. Brake pads need to be painted in order to avoid corrosion. Usually electrostatic painting is used on industrial scale, which requires the brake pads to be conductive. NAO brake pads (and especially Cu-free NAO brake pads) are rather insulating, and therefore difficult to paint. In this presentation we’ll show how special carbon powders can increase the electrical conductivity and therefore allow easy painting of brake pads. Based on these investigations, a new copper-free NAO formulation has been developed.
2016-09-18
Technical Paper
2016-01-1909
Diego Adolfo Santamaria Razo, Fernao Persoon
Environmental and financial factors are leading developments in the automotive industry, friction materials are not an exception. Different associations around the globe are increasing their attention in regards to fine dust emissions. End users are increasing their focus on comfort and cost due to global economic conditions. Two of these factors are directly related to each other: comfort and fine dust. They are the result of tribologic mechanisms deriving in pad and disc wear. Such mechanisms linked to friction performance are the consequence of the interaction between friction material surface and disc surface. The definition of what is being formed between the two surfaces is a continuously evolving layer called third body layer (transfer layer, tribologic film, among others) and it has been deeply studied in different papers. In order to be formed and to work properly, the third body layer needs to possess a strong chemical and mechanical stability.
2016-09-18
Technical Paper
2016-01-1936
Ashesh Anil Shah, Kshitiz Raj
Brake system for any vehicle plays an important role, as safety comes at highest level , also domestic and international safety norms for commercial vehicles are stringent. In current scenario of highly competitive commercial market, Payload advantage comes at peak level in customer demand list, also maintainability plays an important role to make sure least vehicle downtime linked to customer profitability. Finally, if product has less complexity (reducing no. of parts), then it will provide add on benefit to any organization. Considering these customer oriented perspectives mainly payload & maintenance along with regulation compliance , we have proposed new Disc brake system for heavy duty commercial vehicle providing maximum payload benefit along with enhancement in maintainability. It has also enhanced performance and meeting all legislative criteria at aggregate and vehicle level.
2016-09-18
Technical Paper
2016-01-1948
Axel Freiwald, Gunn Hwang
Axel Freiwald, Infineon Technologies AG Germany Gunn Francis Hwang, Infineon Technologies Korea Co. Ltd Connecting mobile communication channels to vehicles’ networks is currently attracting engineers in a wide range. Herein the desire of vehicle manufacturers to remotely execute software updates over the air (SOTA) within electronic control units (ECU) is probably the field of highest attention at the moment. Today software updates are typically done at vehicle service stations and connecting the vehicles’ electronic network via the onboard diagnosis (OBD) interface to a service computer under the control of trained technicians. SOTA means putting the update process into the hands of the driver.
2016-09-18
Technical Paper
2016-01-1949
John David Fieldhouse, Joe Gelb
Emissions from road vehicles has so far concentrated on exhaust gases and as such regulation has been limited/focused in that direction. Following increasing global concerns regarding environmental issues there is some move towards extending regulations to “whole vehicle emissions”, which will include tyre and brake debris. This concern is exemplified by the demand for low copper pads following the discovery of high concentrations of copper in San Francisco Bay – blamed on brake debris being washed into the bay with each rainfall. It is difficult to confirm or contradict such claims because effective dust collection has never been considered necessary, or viable. The design of a braking system involves a delicate balance between the friction pair, the disc and pad, where the pad is a complex blend of constituents to provide predictable characteristics, not least a known and consistent friction level.
2016-09-18
Technical Paper
2016-01-1950
Guirong Zhuo, Subin Zhang, Kun Xiong
As is known to all, structure of the chassis has been greatly simplified as the application of in-wheel motor in electric vehicle (EV) and distributed control is allowed. The micro EV can alleviate traffic jams, reduce the demand for motor and battery capacity due to its small size and light weight and accordingly solve the problem that in-wheel motor is limited by inner space of wheel hub. As a result, this type of micro EV is easy to be recognized by the market. In the micro EV above, two seats are side by side and the battery is placed in the middle of the chassis. Besides, in-wheel motors are mounted on rear axle and only front axle retains traditional hydraulic braking system. Based on this driving/braking system, distribution of braking torque, system reliability and braking intensity is analyzed in this paper.
2016-09-18
Technical Paper
2016-01-1951
Björn Dingwerth
Brake components happen to operate under some of the harshest conditions a surface on a car may experience. Choosing the right surface finishing is crucial for the component’s overall quality. Selection of the right finish from a choice of alternatives to a large extend is driven by performance, available finishing quality and finally cost of the coating. The zinc-nickel alloy has shown to be an excellent coating for corrosion protection of cast iron hydraulic brake components while being cost competitive with other alternatives. But that corrosion protection is far from being the sole advantage over the other alternatives. There is many other beneficial properties in this zinc-nickel alloy that account for an even faster pace the share of components finished with zinc-nickel grows at in these days.
2016-09-18
Technical Paper
2016-01-1953
Michael Herbert Putz, Harald Seifert, Maximilian Zach, Jure Peternel
Vienna Engineering (VE) is working since more than eight years on an electro-mechanical brake (EMB) with a special eccentric and highly non-linear actuation mechanism. The principle allows e.g. high brake torque in approx. 50 milliseconds with only approx. 3 A rms actuator current at 12 V. This EMB reached an elaborated state and versions for passenger cars, elevators, railway and commercial vehicles (CVs) were derived. Now, as the EMB is going to road tests, it is necessary to closely fulfill safety requirements. What these safety requirements are and how they can be fulfilled is discussed in this paper: That are properties of the overall system and of the mechanics and electronics of the single brake. The overall brake system for EMBs needs a truly redundant power supply, a safe control bus and a safe brake pedal. The mechanics of a single brake can be required to release when power is off and it must not get mechanically stuck.
2016-09-18
Technical Paper
2016-01-1955
Liangyao Yu, Xiaohui Liu, Xiaoxue Liu
The traditional vacuum booster is gradually replaced by Brake-by-Wire system (BBW) in modern passenger car, especially Electric Vehicle. Different from solenoid valve based BBW system, typical BBW system employed in latest vehicle design is using a DC motor to build the brake pressure through a reduction mechanism and a brake master cylinder. Although vehicle's braking performance is greatly improved by using BBW, the system will inevitably consume some energy of the vehicle power supply, thus introducing unexpected drawback in comparison with the traditional vacuum assist braking system, since it doesn't need any electric power. Therefore the analysis of energy consumption on typical DC motor based BBW system under typical driving cycles will contribute to advanced design of current advanced braking system.
2016-09-18
Technical Paper
2016-01-1958
Seungpyo Lee, Nahyon Lee, Jongkeun lim, Jungyang Park
Automotive Generation 3 wheel bearings play important roles including transmission of power and carrying vehicle weight and are designed to last the life of a vehicle without servicing. When mounted to the vehicle steering knuckle by bolts, distortion occurs to the outer ring, including the seal mounting location and raceways, which can affect this performance. In this paper, finite element methods using commercial software MSC.MARC is performed to analyze the outer ring distortion. Elasto-plastic and contact analyses are carried out to compute the clamping behavior of the outer ring, bolts, and the knuckle under various conditions. In particular, evaluating the effect of concavity of the outer ring flange to reduce outer ring deformation and ensure optimum bearing fatigue life performance is considered.
2016-09-18
Technical Paper
2016-01-1959
Laura Sguotti, Davide Olivieri, Domenico Bosco
For the first time in history, in December 2015, 195 countries reached a universal and legally binding global climate agreement at the Paris climate conference (COP21). The agreement is challenging, as the target is to keep the global warming below two degrees Celsius by 2100, compared to the temperature in pre-industrial levels. Without a global action, current previsions for global warming are above four degree Celsius. Two thirds of the greenhouse gases, responsible for the global warming, are carbon dioxide (CO2) mainly coming from the combustion of fossil fuels. Transportation contributes to around 30% (reference U.S.) of the CO2 emissions. It is clear how important it is for original equipment manufacturers (OEMs) to reduce the emission of their vehicles. SKF is firmly committed to take its responsibility to actively contribute to a better, cleaner future. SKF BeyondZero is the Group's strategy to increase the positive impact on the environment.
2016-09-18
Technical Paper
2016-01-1926
Matthew Robere
Brake pad to rotor adhesion during exposure to corrosive environments, commonly referred to as “stiction”, continues to present braking engineers with challenges with prediction issues in early phases of development and in resolution once the condition has been identified. The goal of this study took on two parts – first to explore trends in field stiction data and how different testing conditions can help to better duplicate the vehicle issue at the component level, and second to explore the impacts of various brake pad physical properties variation on stiction propensity via a controlled design of experiments. Part one will involve comparison of various productionized hardware configurations on component level stiction tests with different levels of prior braking experience to evaluate conditioning effects on stiction breakaway force.
2016-09-18
Technical Paper
2016-01-1935
Binyu Mei, Xuexun Guo, Gangfeng Tan
With the continuous increasing requirements of commercial vehicle weight and speed on highway transportation, conventional friction brake is difficult to meet the braking performance. To ensure the driving safety of the vehicle in the hilly region, eddy current retarder has been widely used due to its fast response, lower prices and convenient installation. Electric eddy current retarder breaks the vehicle through the electromagnetic force generated by the current, and converted vehicle mechanical energy into heat through magnetic field. Air cooling structure is often used in the traditional eddy current retarder and cooling performance is limited, which causes low breaking torque, thermal recession, low reliability and so on. A water jacket has been equipped outside the eddy current region in this study, and the electric eddy current retarder is cooled through the water circulating in the circuit, which prolongs its working time.
2016-09-18
Technical Paper
2016-01-1919
Joo Sang Park, Min Gyu Han, Seon Yeol Oh
Basically caliper piston leading offset is to make a squeal noise bad based on sprag-slip theory. This paper introduce the experimental test results to investigate the relationship between the leading offset and the squeal noise. Also using a transient analysis and a complex eigenvalue analysis(CEA) simultaneously, the comparison between the experimental approach and the numerical approach is carried out to understand the squeal mechanism caused by the sprag-slip of pad behavior. During the squeal, the ODS is recorded by 3D laser vibrometer to correlate CAE results. Even if CEA is very popular CAE tool to study the squeal noise induced by a self-excited vibration, there are some limitations to duplicate the real phenomenon containing unstable behaviors due to pad weak contact stiffness and friction characteristics depending on the relative velocity because of considering self-excited vibration mechanism only.
2016-09-18
Technical Paper
2016-01-1925
David B. Antanaitis
The strong focus on reducing brake drag, driven by a historic ramp-up in global fuel economy and carbon emissions standards, has lead to renewed research on brake caliper drag behaviors and how to measure it. However, with the increased knowledge of the range of drag behaviors that a caliper can exhibit comes a particularly vexing problem – how should this complex range of behaviors be represented in the overall road load of the vehicle? What conditions are encountered during coastdown and fuel economy testing, and how should brake drag be measured and represented in this conditions? With the Environmental Protection Agency (amongst other regulating agencies around the world) conducting audit testing, and the requirement that published road load values be repeatable within a specified range during these audits, the importance of answering these questions accurately is elevated. This paper studies these questions, and even offers some methodologies for addressing them.
2016-09-18
Technical Paper
2016-01-1927
Christian Riese, Prof. Dr. Frank Gauterin
New technologies like alternative power trains and driver assistance systems have a big impact on brake system development. Most of the development work aims at the improvement of actuation and modulation of the brake system. The basic hydraulic network remained nearly the same over decades and still has to meet these new requirements. Previous papers have focused mainly on studying the behaviour of single components, like for example the brake hose fluid consumption in detail. Other papers studied the complete system but simplified it extremely, so that some relevant effects are neglected. In this work, one focus is to study the influence of single relevant components, like the hydraulic unit and the hoses on the overall system performance. For this measurements with a complete hydraulic brake system, including a state of the art electromechanical brake booster and single component measurements for identification are conducted.
2016-09-18
Technical Paper
2016-01-1954
Zhe Xiong, Xiaofei Pei, Xuexun Guo, Chengcai Zhang
In this paper a new pressure control method of a modified accumulator-type Electro-hydraulic Braking System (EHB) is proposed. The system is composed of a hydraulic motor pump, an accumulator, an integrated master cylinder, a pedal feel simulator, valves and pipelines. Two pressurizing modes are switched between by-motor and by-accumulator to adapt different pressure boost demands. A differentiator filtering raw sensor signal and calculating pedal speed is designed. By using the pedal feel simulator, the relationship between wheel pressures and brake force is decoupled. The relationships among pedal displacement, pedal force and wheel pressure are calibrated by experiments. A model-based PI controller with predictor is designed to lower the influences caused by delay. Moreover, a self-tuning regulator is introduced to deal with the parameter’s time-varying caused by temperature, brake pads wearing and delay variation.
2016-09-18
Technical Paper
2016-01-1913
Alessandro Sanguineti, Federico Tosi, Andrea Bonfanti, Flavio Rampinelli
Organic brake pads for automotive can be defined as brake linings where the bonding matrix is constituted of high-temperature thermosetting resins. Bonded together inside the polymeric binder are a mix of components (e.g. abrasives, lubricants, reinforcements, fillers, modifiers…), each playing a distinctive role in determining the tribology and friction activity of the final friction material. The herein reported work presents novel inorganic “alkali-activated”-based materials suitable for the production of alternative brake linings (i.e. brake pads), by means of an unconventional low-temperature wet process. Exploiting the hydraulic activity of specific components when exposed to an alkaline environment, such peculiar inorganic materials are capable of coming to a complete hardening without the need of traditional high-temperature energivorous procedures.
2016-09-18
Technical Paper
2016-01-1920
Deaglan O'Meachair, Stamatis Angelinas, Matthew Crumpton, Antonio Rubio Flores, Juan Garcia, Pablo Barles
Bentley Motors Ltd. has developed a Carbon Silicon Carbide (CSiC) brake system for it’s Mulsanne product, introduced at 17MY. The CSiC brake system is conceived as a performance brake system, and as such offers notable improvements in brake performance In developing the brake system, particular focus was placed on meeting the refinement levels required for a premium product, and indeed as the flagship model for Bentley Motors, NVH refinement of the brake system was of particular concern. This paper intends to discuss the technical performance of the brake system and review the NVH performance of the brakes. This paper will also demonstrate the effect of vehicle isolation on the cabin NVH, and ultimately the passenger experience, by comparing the noise and vibration content in the wheel arch with that apparent to the driver.
2016-09-18
Technical Paper
2016-01-1960
Yukihisa Takayama, Bradley James Williams
Currently automotive demand has rapidly expanded in newly emerging markets and countries with developing infrastructure. Rolling bearings for automotive wheels, Hub Unit Bearings, used in the new markets, are required to prevent premature failures due to water ingress into the bearing. Extreme weather and developing infrastructure in emerging markets causes the bearings to be exposed to large amounts of contamination and water. This level of exposure can potentially generate damage to the Hub Unit Bearing rolling surfaces. Automotive bearings are also required to incorporate low friction technology to reduce overall fuel consumption of automobiles. Growth in emerging markets tends to increase the amount of global carbon dioxide emissions. The use of low friction technologies in automotive bearings can contribute to a reduction in carbon dioxide emissions for the automotive industry.
2016-09-18
Technical Paper
2016-01-1947
Albert Boretti
The operation of a conventional passenger car is characterised by increasing or maintaining kinetic energy when accelerating or cruising the vehicle by using an internal combustion engine, and reducing kinetic energy by using the friction brakes. The energy used by the friction brakes to slow the vehicle with traditional powertrains is gone, dissipated in heat, and never to be recovered. This is a source of endless energy management frustration, and one major obstacle to drastically reduce the fuel consumption in the internal combustion engine. There is however no good reason why it shouldn't be otherwise and it can be done with the introduction of Kinetic Energy Recovery Systems (KERS). Full hybrid and electric vehicles recover the kinetic energy during braking but have very well-known environmental, economic and societal pros and cons.
2016-09-14
Technical Paper
2016-01-1905
Gaoming Fang, Hui Chen
Electric Power Steering (EPS) is the actuator of some lateral-dynamic-related Advanced Driver Assistance Systems (ADAS). A driving simulator with an EPS will be much helpful for the ADAS development. However, if a real EPS is used in the driving simulator, it is quite difficult to realize the road reaction force accurately and responsively. To overcome the weakness above, a virtual EPS platform is established in this paper. The virtual EPS platform contains two parts: one is the vehicle and EPS model, the other is the steering force feedback actuator (SFFA) of the Steer-by-Wire (SBW) system. The SFFA is the interface between the driver and the EPS/vehicle model. The reactive torque of the SFFA is obtained based on the models, which should be equivalent to the torque that the driver feels when operating a real EPS. Meanwhile, the input of the EPS model is the steering angle of the SFFA.
2016-09-14
Technical Paper
2016-01-1871
Renxie Zhang
Path following controller of a six-wheel skid-steering vehicle is designed. The vehicle speed is controlled through engine speed control and the lateral vehicle steering is controlled through hydraulic braking on each side. Contrary to the common approaches considering non-holonomic constraints, vehicle dynamic characteristics and rotating wheels are considered. A hierarchical control structure is applied in this vehicle control system. The kinematic controller works out the reference yaw rate and reference vehicle speed. And a robust dynamic controller tracks the reference signal. In addition, the dynamic controller takes actuator ability into account.
Viewing 31 to 60 of 10680

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