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2015-09-29
Technical Paper
2015-01-2833
Ashley L. Dunn, Brian Boggess, Nicholas Eiselstein, Michael Dorohoff, Harold Ralston
Brake chamber construction allows for a finite stroke for pushrods during brake application. As such, the Federal Motor Carrier Safety Regulations (FMCSRs) mandate maximum allowable strokes for the various chamber types and sizing. Brake strokes are often measured during compliance inspections and post-accident investigations in order to assess vehicle braking performance and/or capability. A number of forensic studies have been performed, and their results published, regarding the effect of brake stroke on braking force and heavy truck stopping performance. All of the studies have relied on a brake supply pressure in the neighborhood of 100 pounds per square inch (psi). When brake strokes are measured in the field, following the Commercial Vehicle Safety Alliance (CVSA) procedure, the application pressure is prescribed to be maintained between 90 and 100 psi.
2015-09-29
Technical Paper
2015-01-2756
Basaran Ozmen, Mehmet Bakir, Murat Siktas, Dr. Serter Atamer, Dr. Roman Teutsch
Securing the desired durability of suspension components is one of the most important topics for the vehicle designers because these components undergo multiaxial variable amplitude loading in the vehicle. Leaf springs are essential for the suspension system of trucks and should be considered as a security relevant part in the product development phase. In order to guide the engineers in the design and testing department, a simulation method was developed as explained in the paper “Bakir, M., Siktas, M., and Atamer, S., "Comprehensive Durability Assessment of Leaf Springs with CAE Methods," SAE Technical Paper 2014-01-2297, 2014”. In this new study, the main aim is to present the validation of this newly developed CAE method for the durability of leaf springs depending on the results from testing and measurement in the rough road and test bench.
2015-09-29
Technical Paper
2015-01-2835
Sughosh J. Rao, M. Salaani, Devin Elsasser, Frank Barickman, Joshua L. Every, Dennis A. Guenther
This study was performed to showcase the possible applications of the Hardware in the Loop (HIL) simulation environment developed at The National Highway Traffic Safety Administration (NHTSA) Vehicle Research and Test Center (VRTC) research lab, to test heavy truck Electronic Stability Control (ESC) systems. In this study, the HIL simulation environment was used to recreate (an interpretation of) an actual accident scenario involving a single tractor-trailer. The scenario was then simulated with and without an ESC system to investigate the advantages afforded by the ESC system, if any. An acutal crash scenario reported in the Large Truck Crash Causation Survey (LTCCS), involving a single tractor-trailer was chosen. The crash scenario was interpretted as a path following problem and three possible driver intended paths were developed from the accident scene data. A path following algorithm was implemented in Simulink to simulate these paths.
2015-09-29
Technical Paper
2015-01-2901
Shaoyun Sun, Genghua Liao, Qiang Fu, Kelong Lu, Jing Zhao, Zhengzheng Li, Jiaquan Chen, Guang Shi, Sacha Jelic, Bo Li
Trucks are designed to carry heavy load, which implies high demanding design criteria for save operation. Heavy load means a lot of energy is needed to displace the load. During a stop, the kinetic energy is transferred into heat, which can be problematic in case of excessive proportions and/or when the heat cannot be removed from the system properly. The brake system therefore needs to be designed such to be able to absorb large of amount of heat and transfer the heat out of its system by either convection, conduction and/or radiation. All three heat transfer modes play an important role since the drum brakes of trucks are not much exposed to external airflow, a significant difference from disk brakes of passenger cars analyzed in previous studies. This makes it a complex heat transfer problem which is not easy to understand. Numerical methods provide insight by visualization of the different heat transfer modes.
2015-09-29
Technical Paper
2015-01-2872
Massimiliano Ruggeri, Andrea Cervesato, Carlo Ferraresi
Performance requests and machine automation, in conjunction with new regulations for agriculture, earthmoving and construction machines, represent today the most difficult challenge for machine designers and researchers. Machine control systems complexity and functional safety regulation compliance, are the most complex requirements to deal with in new machines design. The paper describes a steering system design, of a 6 wheels agricultural front articulated self-propelled machine, that must comply with new regulations in terms of functional safety. The vehicle steering is driven by an electro-hydraulic system, totally controlled using by wire electronics; the rear wheels are independently steering and controlled. This architecture requires a too high functional safety performance level.
2015-09-29
Technical Paper
2015-01-2745
Florian Bauer, Jan Fleischhacker
A Hardware-in-the-Loop (HiL) system for Electronic Control Units (ECU) of electro-pneumatic brake systems is presented. The HiL system runs a real-time capable vehicle model comprising of both the vehicle dynamics and the electro-pneumatic brake system. The dynamic behaviour of the vehicle can be simulated either by a real-time multi-body vehicle model or by a simpler system dynamic (double-track) model. To assess the quality of the system dynamic vehicle model, it was compared to the multi-body vehicle model which was validated with comprehensive experimental results. Discrepancies can be seen for highly unsteady manoeuvres. Reasons for these discrepancies caused by the modelling topology of the system dynamic vehicle model will be given. In order to simulate the electro-pneumatic brake system, a real-time model has been developed and validated. The different topologies of brake systems can be assembled from components and integrated into the vehicle model.
2015-09-29
Technical Paper
2015-01-2753
Xiujian Yang, Ruocheng Zhu, Jin Gao
Tractor semi-trailer as a type of widely-used heavy duty freight vehicle is with relatively poor handling and lateral stability and is easy to fall into a lateral instability such as jackknife, trailer swing even causing an fatal accident. In this paper, attention is concentrated on a novel design concept for a tractor semi-trailer vehicle to improve the handling and lateral stability performances comprehensively by optimizing the whole vehicle arrangement and relevant design parameters. According to the previous public reports, the indexes such as Load Transfer Ratio(LTR), Static Rollover Threshold (SRT), Rearward Amplification Ratio (RWA) and Ratio of Yaw Rate (RYR) as very effective measures are often used to evaluate the handling and stability performances for a tractor-trailer vehicle. However, each of those indexes works individually and only focuses on a certain aspect with less relations to others.
2015-09-29
Technical Paper
2015-01-2751
Igor Baseski, Kenneth Norman, David Ryan, Stefanie Stahara
At the request of the U.S. Army’s Tank Automotive Command (TACOM) laboratory facilities have been built to measure the suspension and mass parameters of the U.S. Army and civilian wheeled vehicles. This is part of an ongoing effort to model and predict vehicle dynamic behavior, so as to build vehicles that are less prone to roll over, have better handling stability, and perform better in rough terrain. These new machines, called the Suspension Parameter Identification and Evaluation Rig (SPIdER) and Vehicle Inertial Properties Evaluation Rig (VIPER), are part of a set of large test devices at TACOM’s facility in Warren, MI. The SPIdER machine operates by holding the vehicle body fixed using a variety of clamps and chains that are arranged specifically for each vehicle. Hydraulic cylinders are used to move an “axle frame” in bounce or roll under each axle being tested. Combinations of bounce and roll can be used, which could be used to simulate roll under different loading conditions.
2015-09-29
Technical Paper
2015-01-2760
Andrei Izmailov, Vladimir Shevtsov, Alexandr Lavrov, Zahid Godzhaev, Vladimir Pryadkin
Maximum pressure is an essential parameter determining the degree of environmental impact of pneumatic tractor wheels on soils. The authors of the paper offer a method for determining and adjusting maximum pressure of a pneumatic tractor wheels on the supporting surface. The paper contains an analysis of the variation of maximum pressure on soils for various values of internal tire pressure and vertical load on a wheel. The above method allows parameters for systems of monitoring and adjustment of maximum pressure on soils to be set up by measuring tire flexure and adjusting it through changing the internal air pressure.
2015-09-29
Technical Paper
2015-01-2731
Xingjian Gu, Guoying Chen, Changfu Zong
As a new form of electric vehicle, four-wheel-independent electric vehicle inherits a large number of advantages of in-wheel motor drive electric vehicle for the huge difference from the traditional vehicle in mechanical structure. The vehicle is driven by four in-wheel motors and the steering system is controlled by X-By-Wire (XBW). Steering system is liberated from traditional mechanical steering mechanism and forms an advanced vehicle with all-wheel independent driving, braking and steering. Compared with conventional vehicles, it has more controllable degrees of freedom. The integrated vehicle dynamics control systems help to achieve the steering, driving and braking coordinated control and improve the vehicle’s handling stability and safety. In order to solve the problem of lacking of vehicle state information in the integrated control, some methods are used to estimate the vehicle state of four-wheel-independent electric vehicles with XBW.
2015-09-29
Technical Paper
2015-01-2733
Benedicts Samraj, Vivek Seshan
This paper is a study of reaction forces and its effects on the chassis due to rear idler position. Rubber Track layouts and traction have been focus of most research work, here we study the effect of Rear Idler position on layout and chassis structure through simulated analysis. An agriculture paddy combine harvester with rubber track is considered for the purpose of this work. Firstly the complete undercarriage is modeled in 3D using Creo and exported to Pro Mechanica for simulation. The real time forces, constraints were applied and the results were correlated to actual field results. The simulations were optimized through several iterations to match the field test results. The simulation and field test results show good agreement to the forces and constrains applied for simulation. Secondly the model was simplified for relative analysis and simulated for different rear idler positions with alternate tensioning methods.
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
2015-01-2680
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.
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
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
2015-01-2696
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
2015-01-2708
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
2015-01-2667
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
2015-01-2679
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
2015-01-2703
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
2015-01-2702
Chihoon Jo, Yongsik kwon, Jaeseung Cheon, Jongsung Kim
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
2015-01-2701
Meixia Ji
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
2015-01-2673
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
Technical Paper
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
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
2015-01-2662
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
2015-01-2661
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
2015-01-2693
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
Technical Paper
2015-01-2692
Giulia Garello, Niccolò Patron, Pietro Buonfico
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
2015-01-2694
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.
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