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Viewing 1 to 30 of 7970
2016-09-27
Technical Paper
2016-01-8010
M. Kamel Salaani, David Mikesell, Chris Boday, Devin Elsasser
Rear-end collisions account for roughly 20% of all police-reported heavy truck crashes in 2004, and the heavy truck was the striking vehicle in 60% of these cases. In light of this, Automatic Emergency Braking (AEB), an electronically-assisted means of avoiding or mitigating frontal collision, could have significant safety benefits. Field testing of such systems using real vehicles is necessarily limited by the danger and expense inherent in crash-imminent scenarios, especially when the system is not designed to eliminate all collisions but rather reduce their severity. Hardware-in-the-Loop (HiL) systems have the potential to enable safe and accurate laboratory testing and evaluation of AEB systems. This paper describes the setup and experimental validation of such a HiL system.
2016-09-27
Technical Paper
2016-01-8006
John Reid, Stewart Moorehead, Alex Foessel, Julian Sanchez
A transformation of agriculture began reached commercial maturity at the beginning of this century that has provided increased customer value from the basis of automating steering system control in crop production systems. The maturity of this technology has led to increased machine system productivity over the last decade leading to increasingly integrated solutions with increased customer value in terms of comfort and productivity. This sets agricultural production ecosystem on a course of new forms of innovation opportunity at the worksite level that is being greatly accelerated by the maturity of the technologies supporting cyber-physical systems. This paper will review the progress from the perspective of the customer value and the industry execution of autonomous driving technologies and will describe the pathways to autonomous worksites, in addition to the challenges to the industry with the emergence of new business models for autonomy.
2016-09-27
Technical Paper
2016-01-8012
Daniel E. Williams, Amine Nhila, Kenneth Sherwin
A large percentage of commercial vehicles transport freight on our interstate highway system. These vehicles spend the vast majority of their duty cycle at high speed maintaining a lane. As steering is integrated into ADAS, objective performance measures of this most common mode of commercial vehicle operation will be required. Unfortunately in the past this predominant portion of the commercial vehicle duty cycle was overlooked in evaluating vehicle handling. This lanekeeping mode of operation is also an important, although less significant portion of the light vehicle duty cycle. Historically on-center handling was compromised to achieve acceptable low speed efforts. With the advent of advanced active steering systems, this compromise can be relaxed. Objective measures of lanekeeping are developed and performance of various advanced steering systems is quantified in this important operating mode.
2016-09-27
Technical Paper
2016-01-8044
Guoyu FENG, Wenku Shi, Henghai Zhang, Qinghua Zu
In order to predict the fatigue life of heavy commercial vehicles thrust rod made of rubber material dumbbell specimens and uniaxial tensile fatigue tests. Based on the measured data samples to the maximum principal strain injury parameters established rubber uniaxial fatigue life prediction models. In the longitudinal tension and compression loading, fatigue life V rods were predicted, and by the uniaxial fatigue test verification, the results show that the maximum principal strain prediction model, the maximum error is less than 10% predicted better results. Show by dumbbell specimen data, the establishment of a spherical hinge rubber life prediction model method, it is possible to predict the fatigue life of the thrust rod.
2016-09-27
Technical Paper
2016-01-8027
Stefan Steidel, Thomas Halfmann, Manfred Baecker, Axel Gallrein
Rolling resistance and tread wear of tires do particularly influence the maintenance costs of commercial vehicles. Although the tire labeling is established in Europe, it is meanwhile well-known that, due to the respective test procedures, these labels do not hold in realistic application scenarios in the field. This circumstance arises from the development phase of tires, where the respective performance properties are mainly evaluated in tire/wheel standalone scenarios in which the wide range of usage variability of commercial vehicles cannot be considered adequately. Within this article we address a method to predict indicators for rolling resistance and tread wear of tires in realistic application scenarios considering application-based factors of influence like specific customers, operation circumstances, regional dependencies, fleet specific characteristics etc. Moreover, the prescribed methodology may also be transferred to the prediction of fuel consumption and emission.
2016-09-27
Technical Paper
2016-01-8121
Riccardo Bianchi, Addison Alexander, Andrea Vacca
Vibrations at the cabin or at the implements of construction machinery represents important drawbacks from the points of view of machine productivity, safety and operator comfort. Oscillations of these machines are particularly relevant due to the absence of shock absorbers, typical of many machines such as wheel loaders, and their use in uneven ground conditions. Several hydraulic solutions have been proposed in the past to reduce oscillations at both the cabin or at the machine boom. Particularly, cabin oscillations can be attenuated by properly counteracting the exciting oscillatory forces from the tires with motion of the boom. Many state of the art machine utilize a passive methods to implement this strategy. The present work introduces a novel active solution, based on the control of the boom actuator without involving modifications of the standard hydraulic system.
2016-09-27
Technical Paper
2016-01-8033
Guoying Chen
According to the vehicle’s driving conditions, electronically controlled air suspension (ECAS) systems can adjust not only the stiffness and damping of the suspension but also the height of vehicle body, so that better ride comfort and handling stability will be achieved, which can’t be realized by traditional passive suspension. This paper presents a design and implementation of ECAS controller for vehicle. The controller is aimed at adjusting the static and dynamic height of the vehicle. To exactly track the height of the vehicle and satisfy the control demand of air suspension, a height sensor decoding circuit based on the inductance sensor is designed. Based on it, a new height control algorithm is adopted to achieve rapid and precise control of vehicle height. In order to verify the functions of the controller, we construct a test bench whose excitation source is provided by hydraulic system.
2016-09-27
Technical Paper
2016-01-8029
Chrysostomos-Alexandros Bekakos, George Papazafeiropoulos, Dan J. O'Boy, Jan Prins
Significant research has been made regarding the interaction of off-road vehicles with deformable terrains, such as snow and sand. The driving response of the tire during travelling on off-road surfaces is crucial for the driving behavior of off-road vehicles. The majority of existing models developed so far are mainly based on empirical or semi-empirical relationships, the pressure-sinkage equation developed by Bekker being the most known. The latter relationship is developed based on certain assumptions, such as invariant soil parameters and a uniform pressure distribution along the width of the tire. These assumptions entail weaknesses in the formulation of the model, which in most cases lead to inadequate validation. In this study, an analytical model of a tire interacting with various types of soils has been developed.
2016-09-27
Technical Paper
2016-01-8034
hao sun, Guoying Chen
Distributed steering system is new type in vehicle chassis system which uses motors to control the steering angle of each wheel respectively. Relying on the design of steering angle allocation, the handling and stability of the vehicle can be enhanced greatly. In the paper, the steering angle allocation is researched based on a two freedom model considering tire cornering characteristics. Through the obtained relationship between tire side-slip angle and vehicle speed, yaw angular velocity and front wheel angle, combining the Ackerman geometrical relationship, the distributed steering angle allocated suit to front-wheel independent steering (2WIS)and four-wheel independent steering(4WIS)are put forward. After that, simulated analysis are carried out setting tire wear pattern and vehicle stability as target. Improvements in tire wear pattern are determined by evaluating the optimization in tire lateral force, while the vehicle stability is determined by side slip angle.
2016-09-27
Technical Paper
2016-01-8028
Chao Yang, Nan Xu, Konghui Guo
This paper focuses on the modeling process of incorporating inflation pressure into the UniTire tire model for pure cornering. Via observing and manipulating the tire experimental data, the effects of inflation pressure on the tire cornering property are analyzed in detail, including the impacts on cornering stiffness, the peak friction coefficient, the curvature of transition region and the pneumatic trail. And the brief mechanism explanations are also given for some of those impacts. The results show that some effects of inflation pressure are similar to that of vertical load on the non-dimensional tire cornering property, and also have strong interactive effects between the two operating conditions. Therefore, in order to obtain concise expressions, the inflation pressure is incorporated into the UniTire tire model by analogy with the expressions for vertical load, and the interactive effects are also taken into account.
2016-09-27
Technical Paper
2016-01-8112
Jorge Leon, Jose M. Garcia, Mario J. Acero, Andres Gonzalez
Electric motors have energy efficiency and performance advantages over traditional internal combustion engines. Nevertheless, when used for transportation, they have limited ranges due to the state of current energy storage technologies. In order to improve efficiency and increase the range of operation of electric vehicles, complementary energy regeneration systems can be used. A hydraulic energy recovery system is proposed to be used as a regenerative system for supplementing energy storage. This system consists of a hydraulic accumulator, a low pressure reservoir and a hydraulic pump/motor. The pump/motor device transforms kinetic energy into hydraulic energy during breaking, to move the hydraulic fluid from the low pressure reservoir to the hydraulic accumulator. This energy can later can be used to propel the vehicle. The proposed system is particularly useful for vehicles in heavy start-stop traffic and public transportation.
2016-09-18
Technical Paper
2016-01-1942
Sarah Chen, Steve Hoxie
Developing a brake system with high overall customer satisfaction rating is a constant challenge for OEMs as well as their brake suppliers. Brake system performance is directly linked to the engagement between the rotor and pads. The materials for the rotors and pads play a key role in the nature of the engagement. Therefore, it is critical to have a good understanding of brake rotor materials to meet performance targets. Due to its superior thermal handling capacity, damping characteristics, wear and cost advantages, gray iron is the most widely used brake rotor material in the industry. G30 per ASTM A48 is generally specified for most brake rotors with minimum tensile strength of 200 Mpa and Brinell hardness of 187~241. G20 is also widely used for brake rotors, especially when people are looking for brake smoothness and optimal pad life. This study has found that variation in gray iron material can considerably affect brake output, wear, DTV, BTV, and noise propensity.
2016-09-18
Technical Paper
2016-01-1929
Nimrod Kapas, Ajith Jayasundera
There is an increasing interest in transient thermal simulations of automotive brake systems using CFD software. This paper presents a detailed high-fidelity simulation tool for modeling complete braking cycles including both the deceleration and the acceleration phases. During braking, this model applies the total heat input directly at the friction interface on the contacting rotor and pad surfaces. Based on the conductive heat fluxes within the surrounding parts, the solver automatically determines the division of the thermal energy flowing from the friction interface into the solid volumes of the rotor and the pad. The convective heat transfer between the surfaces of solid parts and the cooling airflow is simulated through conjugate heat transfer, and radiative heat exchange between solid surfaces is captured by using the discrete ordinates model.
2016-09-18
Technical Paper
2016-01-1930
Heewook Lee
Contamination protection of brake rotor has been a challenge for auto industry for a long time. As contamination of rotor causes corrosion and it in turn causes many issues like pulsation and short rotor and lining lives, splash shield became a common part for most vehicles. While rotor splash protection shield provides contamination protection for brake rotor, it makes brake cooling performance worse as it blocks air reaching brake rotor. Therefore, balancing between contamination protection and enabling brake cooling has become key critical factor when splash shield is designed. Although analytical capability of brake cooling performance has become quite reliable, due to lack of technology to predict contamination pattern the design of splash protection shield has relied on engineering judgment and vehicle test. Optimization opportunities were restricted by cost and time associated with vehicle test.
2016-09-18
Technical Paper
2016-01-1932
Niclas Strömberg
During several years a toolbox for performing virtual rig tests of a brake disc has been developed by the author. A thermo-flexible multi-body model of a test rig is derived and implemented. A thermo-mechanical model of the pad-disc system is formulated including thermo-elasticity, frictional contact and wear. The energy balance at the contact interface is governed by contact conductance that depends linearly on the contact pressure and the frictional heat depends on a temperature dependent coefficient of friction. Instead of adopting a standard Lagrangian approach, the disc is formulated in an Eulerian frame like a fluid. This is then coupled to the pad most accurately by using Signorini’s contact conditions, Coulomb’s law of friction and Archard’s law of wear. The numerical treatment of these laws are performed by applying an augmented Lagrangian formulation, which in turn is solved with a non-smooth Newton method.
2016-09-18
Technical Paper
2016-01-1944
Seongjoo Lee, JeSung Jeon, ShinWook Kim, ShinWan Kim, Seong Rhee, Wan Gyu Lee, Young Sun Cho, Jeongkyu Kim
It is widely known that brake squeal repeatability and reproducibility are difficult to achieve whether a run on a vehicle on the road, a vehicle on a chassis dynamometer or a single brake on a noise dynamometer. At one time, the same brake may generate only low-frequency squeals (1.5 - 5 kHz) and at another time, only high-frequency squeals (5 - 20 kHz). More specifically, on a chassis dynamometer, the left side may produce only low-frequency squeals (or high-frequency squeals) while the right side produces only high-frequency squeals (or low-frequency squeals), or mixed squeals at different rates. The same phenomenon is observed when brakes are run on a noise dynamometer; more low-frequency squeals at one time or more high-frequency squeals at another time on an apparently same brake system. This study was undertaken to find out what causes these discrepancies.
2016-09-18
Technical Paper
2016-01-1935
Binyu Mei
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
2016-01-1940
Scott Lambert
Industry requirements to improve fuel economy now drive the automotive industry to continually find ways to reduce vehicle mass, particularly to components contributing to ‘un-sprung’ weight. One such component is the steel disc brake backing plate, with commercial vehicle applications weighing as much as 2 kg each; however until now there have been no lightweight alternatives offered. To address this growing requirement, NUCAP Global developed a composite disc plate design which consists of 2 thin-gauge steel facing plates integrally bonded to a phenolic core via mechanical attachment. While the composite design results in the immediate advantage of significant weight reduction, up to 40% on larger vehicle applications, it must also meet or exceed the same function and performance criteria required for solid steel plates by industry standard test methods. Additionally, manufacturability and cost must be factors.
2016-09-18
Technical Paper
2016-01-1941
Tie Wang, Xin Gao, Zhiwei Zhang
Vehicle hydraulic retarder is applied in heavy-duty trucks and buses as an auxiliary braking device. In traditional cooling system of hydraulic retarder, working fluid is introduced into heat exchanger to transfer heat to cooling liquid in circulation, whose heat is then dissipated by engine cooling system, not enabling waste heat of working fluid used effectively. In hydraulic retarder cooling system based on Rankine cycle, organic working fluid transfers heat with hydraulic retarder working fluid in Rankine cycle, and then outputs power through expansion machine. It can both reduce heat load of engine cooling system, and enhance thermal stability of hydraulic retarder while recovering and utilizing braking energy. First of all, according to the target vehicle model, hydraulic retarder cooling system model based on Rankine cycle is established.
2016-09-18
Technical Paper
2016-01-1913
Alessandro Sanguineti, Andrea Bonfanti, Federico Tosi, 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
2016-01-1943
Tadayoshi Matsumori, Yoshitsugu Goto, Noboru Sugiura, Kenji Abe, Yoshihiro Osawa, Yosuke Akita, Satoshi Wakamatsu, Katsuya Okayama, Kyoko Kosaka
This paper deals with the friction coefficient COF variation in a disk brake system when the wear debris between the brake pad and the disc rotor contains water. In our previous study, it was experimentally found that little moisture content leads to high COF compared with COF under dry condition. Based on the results, we propose a hypothesis that agglomerates composed of the wet wear debris induce COF variation when the agglomerates stand at gaps between friction surfaces. In this paper, for supporting the hypothesis, firstly, testing the friction property of the wet wear debris, we confirm that capillary force affects COF variation. After that, using a particle-based simulation assuming firstly and secondary particles of wear debris, we simulate the wear debris behavior with or without the capillary force.
2016-09-18
Technical Paper
2016-01-1933
Mingzhuo Li, Dejian Meng, Lijun Zhang
Brake judder severely affects the riding comfort and safety of vehicle. For the brake corner system, a rigid-flexible coupling model are established based on ADAMS. In the model, brake pads, caliper, anchor and knuckle are flexible body, and the contacts between pads and disc and the contact between pads and caliper are defined in detail. Meanwhile, the vibration acceleration of the brake corner components and the contact forces between disc and pads are used as evaluation index and the evaluation system of brake judder are improved. The analysis results show that the novel model and evaluation system can be used to predict brake judder effectively.
2016-09-18
Technical Paper
2016-01-1911
Philippe Dufrenoy
A multiscale model of a disc brake including material and surface heterogeneities Y. Waddad; V. Magnier; P. Dufrénoy* ; G de Saxcé University of Lille Cité scientifique Avenue Paul Langevin F-59655 Villeneuve d’Ascq Cedex * Corresponding author : philippe.dufrenoy@univ-lille1.fr During friction it is well known that the real contact area is much lower to the theoretical one and that it evolves constantly during braking. It influences drastically the system’s performance. Conversely the system behavior modifies the loading conditions and consequently the contact surface area. This interaction between scales is well-known for the problematic of vibrations induced by friction but also for the thermomechanical behavior. Indeed, it is necessary to develop models combining a fine description of the contact interface and a model of the whole brake system. This is the aim of the present work. The macroscopic model is obtained with Finite Element analysis.
2016-09-18
Technical Paper
2016-01-1912
Bo Hu, Sydney Luk, Peter Filip
Copper and copper alloys are widely used in friction materials such as brake pad formulations as one of key ingredients by providing good thermal conductivity and high temperature friction stability to achieve desired friction performance, fade and wear resistance. However, the use of copper or copper containing material is being restricted in brake pads due to environment and health concerns. Extensive works have been made to explore the copper substitutes but most of these efforts became ineffective and failed with issues either thermal fade or excessive pad/rotor wear. In this paper, friction and wear responses were examined when a metallic composite material was used as the copper substitute in NAO and Low-met brake formulations where the copper and copper alloys were added 8% and 22% respectively.
2016-09-18
Technical Paper
2016-01-1934
Arun Kumar Prasad, Baskar Anthonysamy, Gopalakrishn V. A., Gurdeep Singh Pahwa
Fierce completion in India’s automotive industry has led to constant production innovation among manufactures. 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 design and fine tune the braking performance with low cost and short life cycle. Braking performance of automotive vehicle is facilitated by the adhesion between the tyre and the ground. Braking force generated at the wheels of a vehicle have to appropriately match to the adhesion. Antilock braking system (ABS) is used for this purpose. ABS is a modern braking system which could significantly improve directional stability and reduce stopping distance of a vehicle. However this system still too complicated and expensive to use in low end compact car and pickup truck.
2016-09-18
Technical Paper
2016-01-1931
Aaron Völpel, Georg Peter Ostermeyer
In today’s research and development of brake systems the model-based prediction of complex vibrations and NVH phenomena play an important role. Despite the efforts, the high dimensional computational simulation models only provide a limited part of the results gained through experimental measurements. Several reasons are discussed by the industry and academic research. One potential source of these inadequacies is the very simple formulation of the friction forces in the simulation models. Due to a significant shorter computation time (by orders of magnitude), the complex eigenvalue analysis has been established, in comparison to the transient analysis, as the standard method in the case of industrial research, where systems with more than one million degrees of freedom are simulated.
2016-09-18
Technical Paper
2016-01-1915
Meechai Sriwiboon, Seong Rhee, Kritsana kaewlob, Nipon Tiempan, Rungrod Samankitesakul
Two formulations have been selected and tested for this investigation; Low-Copper NAO and Copper – Free NAO. Each formulation was processed to achieve 3 levels of porosity; 12, 17 and 22%. Each sample was tested for hardness (HRR, HRS, and HRL), natural frequencies and compressibility plus performance testing for friction, wear and brake squeal. This paper describes correlations or lack of them between all the measurements.
2016-09-18
Technical Paper
2016-01-1937
Taylor Erva, Adam Loukus, Luke Luskin
Aluminum metal matrix composite brake rotors with a selective ceramic function reinforcement gradient (FRG) have been developed for automotive applications. This paper will highlight the design, manufacturing, and testing of the rotors. Weight saving of an aluminum composite rotor in comparison to an industry standard cast iron rotor is 50-60%. With this material change comes design considerations to manage rotor temperature, rotor surface integrity, and friction. Manufacturing methods to meet these design constraints were needed to develop a viable high performance aluminum composite rotor. High pressure squeeze casting with soluble coring techniques were developed to incorporate the selective FRG MMC rotors. Dynamometer testing was performed, concentrating on brake friction and temperature to evaluate the macro and micro interfaces in the rotors.
2016-09-18
Technical Paper
2016-01-1957
Seonho Lee, Heejae Kang, Ohchul Kwon, Chirl Soo Shin
A trend in automotive parts development is the pursuit of long life, high quality and reliability. The increase in service life of automotive wheel bearings, by improving the rolling contact fatigue (RCF) life of bearing steels, was investigated. Conventional studies of bearing steels and heat treatments have dealt with quenching and tempering (Q/T) in 52100 steel. This study is a new trial to increase the strength of bearing steels by special austempering in phases after general Q/T heat treatments.
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.
Viewing 1 to 30 of 7970