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Technical Paper
2014-10-13
S. Reifarth, V. Rajagopal, K. Gritzun, H.-E. Angstrom
The distribution of EGR between the cylinders of an internal combustion engine has been shown to have large impact on the engine emissions. Especially at high EGR, the combustion reacts sensibly to variations in the EGR-rate. A cylinder that receives excessive EGR produces soot particles while a cylinder with too little EGR has increased NOx-emission. It is therefore important to have knowledge about the mixing in an engine. This study compares two different EGR-mixing measurement methods. The first is based on CO2 measurement with standard probes, placed at 36 different locations in the intake manifold of the engine. The second method uses a laser beam and a detector to gain information about the mixing with a high time-resolution, placed at six positions of the intake manifold. Additionally, 1-D simulations are used to gain information about the mixing process. To vary the mixing process on the engine, two different air/EGR mixers are used and their mixing performance is evaluated.
Technical Paper
2014-10-13
S. Reifarth, E. Kristensson, J. Borggren, A. Sakowitz, H.-E. Angstrom
The use of EGR for NOX reduction is today a standard technology for diesel engines. The mixing of air and EGR is an important issue, especially for high-pressure EGR systems. An uneven distribution of EGR between the cylinders can lead to higher overall engine emissions when some cylinders produce more soot, others more NOX than they would with a perfectly even distribution. It is therefore important to understand the processes that control the mixing between air and EGR. The mixing is influenced by both the geometry of the mixing area and the pulsating nature of the flow. The aim of this work is to point out the high importance of the pulses present in the EGR-flow. By simulation in 1-D and 3-D as well as by a fast measurement method, it is shown that the EGR is transported in the air flow in packets. This implies that the timing between intake valve opening and the positioning of the EGR packets has a high influence of the distribution of EGR between the cylinders. The ability of 1-D and 3-D simulation to predict the behavior is evaluated.
Technical Paper
2014-10-13
Jianye Su, Min Xu, Peng Yin, Yi Gao, David Hung
Spark-ignition direct-injection (SIDI) gasoline engine, especially in downsized boosted engine platform, has proven to be one of the most promising concepts to improve vehicle fuel economy, and are increasing their market share relative to port fuel injection (PFI) engines in U.S., European and Chinese vehicles. However, higher particle number emission associated with operating the engine at higher loads provide additional challenges for meeting future stringent emission regulations. In this study, the potential of using multiple injection strategies (double injection and triple injection strategy during the intake stroke in homogeneous combustion mode) to reduce particle number emission was investigated using Horiba Mexa SPCS1000 in a 2.0 liter boosted SIDI gasoline engine at 1000 rpm, 11 bar BMEP condition. To clarify the mechanism for the particle emission benefit by multiple injection strategies, three-dimensional (3D) Computational Fluid Dynamics (CFD) model of the in-cylinder process was realized using CONVERGE software with the inputs from GT-Power® engine simulation.
Technical Paper
2014-10-13
Jinyoung Jang, Young-Jae Lee, Ohseok Kwon, Minseob Lee, Jeonghwan Kim
The emissions from vehicle are affected by engine type, fuel and engine oil making particulate matter (PM) 13% of total PM. In this study, engine oil is focused to show the effect of engine oils on PM and other emission. Group III base oil, Group III base oil with additives and poly alpha olefins (PAO’s) with additives are tested and have identical SAE grad for same vehicle. Gasoline vehicle, which has direct injection system, and diesel vehicle, which has no PM trap, were selected because those vehicles clearly emit PM more than port fuel type gasoline and diesel with PM trap vehicle. Combined mode test, consisting of FTP 75 and highway drive mode, are used to assess exhaust emission and fuel economy. The number of PM was counted using PPM-S, which is based on the measurement of electrical charge carried by particles. Regulated emissions and fuel economy for gasoline vehicle were analyzed by HORIBA gas analyzer with sampling bags. Diesel vehicle’s emissions and fuel economy were analyzed by PIERBURG gas analyzer.
Technical Paper
2014-10-13
Haichao Fu, Yinhui Wang, Xinyan Li, Shi-Jin Shuai
An experimental study on particulate emission was conducted on four cars from Chinese market, three of which powered by gasoline direct injection (GDI) engines and the other one powered by port fuel injection (PFI) engine. Experiments were performed on a chassis dynamometer over new European driving cycle (NEDC). Particulate mass and number were measured using PMP system, and transient particulate number and size distribution were measured through DMS500 Fast Particulate Spectrometer. Three kinds of gasoline with RON 91.9, 94.0 and 97.4 were tested on these four cars to find impacts of RON on particulate emission. In order to get what extent cold start influences the particulate emission, both cold and hot start NEDCs were tested. Large scale of particles were emitted from both GDI and PFI cars during cold start condition (first 200s of NEDC). Compared with cold start NEDC, hot start NEDC particulate mass of these three GDI cars decreased by 65.1%, 27.9% and 66.3% respectively, and particulate number of these three GDI cars decreased by 58.5%, 34.0% and 53.3% respectively.
Technical Paper
2014-10-13
Barouch Giechaskiel, Urbano Manfredi, Giorgio Martini
Current vehicle exhaust legislation for diesel vehicles prescribes particle number (PN) limits for solid particles >23 nm. The legislation was extended to include gasoline direct injection (G-DI) vehicles since 2014. Target of this paper was to investigate whether smaller than 23 nm solid particles are emitted from engines in considerable concentration focusing on G-DI engines. The literature survey and the experimental investigation of 5 vehicles showed that engines emit solid sub-23 nm particles. The average percentage over a cycle (WLTP) is higher for G-DIs (40%) compared to diesel engines (20%). These percentages are relatively low considering the emission limit levels (6x10^11 p/km) and the repeatability (10-20%) and reproducibility of the particle number method (50%). These percentages are close to the percentages expected theoretically not to be counted due to the 23 nm cut-off size (5-15%). High emissions can be found when additives are added in the fuel or lubricant. Based on this literature survey, the PN legislation should remain the same.
Technical Paper
2014-10-13
Kotaro Tanaka, Masatoshi Takano, Shuji Iimura, Kai Miyamura, Mitsuru Konno
 Ammonia (NH3) contributes to the production of secondary particulate matter (PM) as ammonium nitrate (NH4NO3) and ammonium sulfate ((NH4)2SO4). Recent studies have indicated that NH3 emission from automobiles may increase as a result of using a system for the urea selective catalytic reduction of NOx. In addition, the operating condition of the automobile plays an important role in the formation of NH3 in automobile exhaust. Therefore, it is very important to perform real-time measurements of the NH3 concentration in automobile exhaust.  Recently, highly sensitive near-IR laser absorption spectrometer has been employed to obtain measurement of NH3. This instrument allows in-situ measurements of highly time-resolved NH3 emission levels in automobile exhaust. However, the effect of the CO2 included in automobile exhaust on the measurement of NH3 has not been evaluated in detail. Because the CO2 concentration in automobile exhaust has been 2 or 3 orders of magnitude higher than the NH3 concentration, there is a possibility that spectral overlap by CO2 lines and/or the spectral broadening of NH3 by CO2 could have an influence on the measurement of the NH3 concentration.  
Technical Paper
2014-10-13
Barouch Giechaskiel, Giorgio Martini
Current heavy-duty engine and light duty vehicle exhaust legislation prescribes particle number (PN) limits for solid particles >23 nm. The legislation was extended to include gasoline direct injection (G-DI) vehicles since 2014 and will be applied to non-road mobile machinery. Target of this paper was to investigate whether existing PN measurement equipment are capable of measuring below 23 nm. More specifically, it was investigated 1) whether all volatile particles can be removed efficiently in the PN measurement systems 2) whether any artifacts happen in the PN systems (e.g. formation of non-volatile particles due to pyrolysis), and 3) whether by lowering the lower size the measurement uncertainty increases significantly. The main conclusions are: 1) The volatiles are not always removed efficiently in the PN measurement systems. The major issue is re-nucleation of sulfuric acid downstream of the evaporation tube. These particles typically do not grow at sizes above 23 nm. 2) There are indications of formation of 10 nm solid particles from hydrocarbons and sulfuric acid in the PN systems. 3) The measurement uncertainty due to differences between commercial systems will increase with lower cut-off size.
Technical Paper
2014-10-13
Amar Deep, Naveen Kumar, Ashish Karnwal, Dhruv Gupta, Vipul Vibhanshu, Abhishek Sharma, Jitesh Singh Patel
The interest of using alternative fuels in diesel engines has been accelerated exponentially due to a foreseen scarcity in world petroleum reserves, increase in the prices of the conventional fossil fuels and restrictions on exhaust emissions such as greenhouse gases from internal combustion (IC) engines initiated by environmental concerns. The constant trade-off between efficiency and emissions should be in proper balance with the conventional fuels in a fuel design process for future combustors. Unlike gasoline and diesel, alcohols act as oxygenated fuels. Adding alcohols to petroleum products allows the fuel to combust properly due to the presence of oxygen, which enhances premixed combustion phase, improves the diffusive combustion phase which increases the combustion efficiency and reduces air pollution. The higher activation energy of alcohols leads to better resistance to engine knocking that allows higher compression ratios and greater engine thermal efficiencies. Direct use of alcohol/diesel fuel blends is one of the most interesting possibilities because of their lower viscosity and similar physio-chemical properties to mineral diesel; most importantly, prior modifications on diesel engine are not required.
Technical Paper
2014-10-13
Jonathan Stewart, Andrew Woods, Roy Douglas, Richard O’Shaughnessy
With emission legislation becoming ever more stringent, automotive companies are forced to invest heavily in solutions to meet the targets set. To date, the most effective way of treating emissions is through the use of catalytic converters. Since the introduction of these converters as the main method of reducing automotive emissions, catalyst performance testing has become a major part of automotive research and development. One of the most critical aspects of the performance testing process is catalyst ageing. Legislation has been introduced stating that catalytic converters must meet the set emissions standards legislation up to a lifetime of 150,000 miles (LEV 2014-2022). The catalytic converter will deactivate over its lifetime due to a number of different factors, such as, thermal deactivation, poisoning, fouling and structural breakdown of the catalyst. It is therefore of the utmost importance for automotive companies to evaluate the performance of the catalytic converters under these conditions.
Technical Paper
2014-10-13
Jon Andersson, John May, Cecile Favre, Dirk Bosteels, Simon de Vries, Matthew Heaney, Matthew Keenan, Jonathon Mansell
The exhaust emissions of two Euro 6 diesel cars with different emissions control systems have been evaluated both on the road and over various chassis dynamometer test cycles. European emissions limits are currently set using the New European Driving Cycle (NEDC), but the European Commission is preparing additional test procedures to ensure that emissions are well controlled both in real use and over the legislative test cycle. The main focus of this work on ‘Real Driving Emissions’ (RDE) is on measurements using Portable Emissions Measurement Systems (PEMS) in real, on-road driving. A key focus of a test programme undertaken for AECC (the Association for Emissions Control by Catalyst) by Ricardo was therefore the use of PEMS systems to measure on-road emissions of both gaseous pollutants and particulate matter. This included measurement of particle number emissions with a new candidate system for this type of measurement. The results from this testing are compared with emissions measured over four different chassis dynamometer test cycles – the current legislative cycle (New European Driving Cycle, NEDC); the Common Artemis suite of test cycles (CADC) that is widely used in emissions modelling; the new Worldwide Light-duty Test Cycle (WLTC) defined by the UN Working Party on Pollution and Energy (GRPE) as part of the development of the Worldwide harmonised Light vehicles Test Procedure (WLTP); and a set of cycles produced by a Random Cycle Generator based on ‘short trip’ segments from the EU database used to construct WLTC.
Technical Paper
2014-09-30
Oscar Flores-Centeno, Manuel Fabela-Gallegos, David Vazquez-Vega, Carlos Blake-Cervantes, Ricardo Hernandez-Jimenez
The vehicle’s dynamic behavior is influenced mainly by the interaction of four factors: driver, vehicle, road an environment. Under given circumstances, perturbation of these factors can cause degradation of vehicles´ performance; as a result, an accident will take place affecting the vehicle itself, road infrastructure and injury or even death of passenger(s). In order to increase road safety is essential to fully understand the interaction of those factors on vehicle’s dynamic behavior, especially heavy vehicles due to its greater mass, dimensions and potential damage that can cause. This paper presents the effect of road condition on the dynamic behavior of a 3-axle straight-truck based on numerical simulations. Validated commercial software was used. Three different road conditions were studied, namely potholes, longitudinal level differences between adjacent lanes due to repairing process, and different surface friction coefficients also due to road repairing process. For numerical simulations, three standardized maneuvers were taken into account, namely, single and double lane change and panic braking.
Technical Paper
2014-09-30
Sijing Guo, Zhenfu Chen, Xuexun Guo, Quan Zhou, Jie Zhang
Hydraulic electromagnetic shock absorber (HESA) consists of hydraulic cylinder and check valves etc., by which the high-pressure oil produced by shock absorber reciprocation could be exported to drive the hydraulic motor, so as to drive the generator, and eventually recover the mechanical vibration energy otherwise dissipated by the traditional shock absorber as heat energy. Hydraulic Interconnected Suspension(HIS) can improve the vehicle roll and pitch stablity performance by interconnecting the chambers of the shock absorbers on the vehicle. To integrate both the advantages of HESA and HIS, a new type of suspension system is proposed in this paper, namely Hydraulic Interconnected Suspension system based on Hydraulic Electromagnetic Shock Absorber (HESA-HIS). HESA-HIS has three operating modes: energy-recovery priority mode, driving stability performance priority mode and energy-recovery and driving stability performance balance mode. The working principle of HESA-HIS in the three operating modes is introduced, and the mathematic theory model is deduced with relative automobile theory knowledge.
Technical Paper
2014-09-30
Mehmet Bakir, Murat Siktas, Serter Atamer
In today's world, there are a prominent number of weight & cost reduction projects within the vehicle engineering development activities. Regarding this phenomenon, a complete optimization study is applied to a 4-leaf pendulum leaf spring used in heavy duty trucks by reducing the number of leaves down to 3 together with weight and cost reductions. Leaf spring itself plays a crucial role in a heavy duty truck structure. Because of this purpose, the new designs should withstand all forces like the current design assuring same strength and fatigue characteristics. In other words, it should be lower in price and weight but at the same time strong enough to maintain its durability throughout its life time. This fact brings great responsibility to the development process of the new optimized leaf springs. Hence, a complete optimization process is applied from scratch till the very end which is illustrated in this paper. At the first step of the project, the stiffness of the leaf spring is calculated with an in-house software based on mathematical calculations using the thickness profile of the leaves.
Technical Paper
2014-09-30
Zhigang Wei, Limin Luo, Shengbin Lin
This paper reviews the correlation concepts and tools available, with the emphasis on their historical origins, mathematical properties and applications. Two of the most commonly used statistical correlation indicators, i.e., modal assurance criterion (MAC ) for structural deformation pattern identification/correlation and the coefficient of determination (R^2 ) for data correlation are investigated. The mathematical structure of R^2 is critically examined, and the physical meanings and their implications are discussed. Based on the insights gained from these analyses, a data scatter measure and a dependency measure are proposed. The applications of the measures for both linear and nonlinear data are also discussed. Finally, several worked examples in vehicle dynamics analysis and statistical data analyses are provided to demonstrate the effectiveness of these concepts.
Technical Paper
2014-09-30
William Bradford Bartow, Andres C. Moreyra, Trevor Hirst, Gregory H. Woyczynski, Alexis lefebvre, Gecheng Zha
This paper experimentally investigates the detailed flow field of base drag reduction method using passive jet boat-tail (JBT) with 3D PIV measurement in wind tunnel testing. JBT is a new method recently developed by Zha et al to reduce vehicle base drag using passive jet instead of a solid botatail. It has the advantage of no blockage in the base area, which is important for vehicle loading/unloading and is necessary for vehicle rear view mirrors that can not permit any visibility blockage. The wind tunnel experiment indicates that the JBT significantly reduces the wake width and depth(Fig. 1), and thus the base drag. The unsteady wake flaps up and down and left and right. The hypothesis is that the wake flapping transfers the energy to the coherent structures caused by the jet, and then further energizes the base flow region with base pressure increased. The wake profile area at 1.5 length downstream is reduced by about 40%.The 3D PIV measurement found that the jet creates a large circumferential gradient of the flow field, which enhances the entrainment and energy transfer.
Technical Paper
2014-09-30
Jouke Van der Krieke, Gandert Van Raemdonck
Improving aerodynamic quality, i.e. reducing drag, of semi-trailers will contribute largely to reduce the fuel consumption and the emissions of harmful gases of heavy duty vehicles. In the recent past WABCO developed an aerodynamically shaped skirt, called SideWing, for a European tractor semi-trailer configuration. This solution proved its efficiency during wind tunnel experiments, dedicated track testing and operational testing on public roads. In the Netherlands one is allowed to drive with a longer vehicle combination having a length of 25m, instead of 16.5m for the standard length. This longer combination has a tractor, a semi-trailer and a drawbar trailer. The semi-trailer is equipped with SideWings, while the drawbar trailer has regular skirts. Together with the fleet operator a test was conducted during operational activities to determine the fuel savings of the SideWings with the skirts on this particular vehicle combination. This fuel saving test was conducted with only one vehicle for a total period of fifteen months.
Technical Paper
2014-09-30
Youhanna William, Walid Oraby, Sameh Metwally
When driving a vehicle on the road, the driver has to compensate continuously for small directional deviations from the desired course due to disturbances such as crosswinds and road irregularities leading to unintended path deviation. With higher and larger side area such as buses and trucks, the influence of crosswind on the vehicle lateral dynamics behavior is much higher and the vehicle becomes more sensitive to side wind excitations. The study presents a practical theoretical method to judge the aerodynamic response of buses in the early design steps based on both aerodynamic and design parameters. A constant longitudinal velocity 2-DOF vehicle lateral dynamics model is used to investigate a bus lateral response under nine different wind gusts excitations. An accurate validated 3-D CFD simulation model of the bus shape results is integrated with carefully chosen design parameters data of a real bus chassis and body to obtain vehicle lateral dynamic response to the prescribed excitations.
Technical Paper
2014-09-30
Brian R. McAuliffe, Leanna Belluz, Marc Belzile
Terrestrial winds play an important role in affecting the aerodynamics of road vehicles. Of increasing importance is the effect of the unsteady turbulence structure of these winds and their influence on the process of optimizing aerodynamic performance to reduce fuel consumption. In an effort to predict better the aerodynamic performance of heavy-duty vehicles and various drag reduction technologies, a study was undertaken to measure the turbulent wind characteristics experienced by heavy-duty vehicles on the road. To measure the winds experienced on the road, a sport utility vehicle (SUV) was outfitted with an array of four fast-response pressure probes that could be arranged in vertical or horizontal rake configurations that provided measurements up to 4.0 m from the ground and spanning a width of 2.4 m. To characterize the influence of the proximity of the vehicle on the pressure signals of the probes, the SUV and its measurements system was calibrated in a large wind tunnel. On-road measurements of the turbulence intensities, turbulence length scales, wind spectra, and spatial correlations were performed.
Technical Paper
2014-09-30
Colin Britcher, Wael Mokhtar, Stephen Way
Commercial vehicle design, as well as associated aerodynamic test procedures, acknowledge the fact that many of these vehicles will operate in strong crosswind conditions for a significant fraction of their operational life. For example, the SAE "wind averaged" drag coefficient develops a weighted average CD based on operation at representative speeds in representative winds from arbitrary directions. Wind tunnel testing at a representative road speed over a range of yaw angles of +-15° is sufficient to populate the SAE equation. However, wind tunnel tests of commercial vehicles are often compromised due to the physical size of the model or other factors, leading to various concerns. An on-road crosswind develops a deep atmospheric boundary layer profile. The vehicle's road speed results in the relative velocity field at the vehicle being strongly curved. A curved flow field is practically impossible to generate in a wind tunnel with a substantial mean velocity, although some yacht sail testing is carried out at in curved flow facilities at much lower velocities.
Technical Paper
2014-09-28
Nils Perzborn, Carlos Agudelo, Georg Peter Ostermeyer
Inertia Dynamometers are commonly used to determine the friction coefficient of brake assemblies. Dynamometers are a well-established platform, allow testing under controlled conditions, exhibit a good correlation to many situations encountered in real driving, and are comparatively economical and less time consuming than a full vehicle test. On the other side of the spectrum during multiple discussions for laboratory testing is the use of scaled tribometer. These test devices make possible a test without the entirely brake system. This separation allows the investigation of the pure frictional-contact (frictional transfer layer) rapidly and independently of a given brake system or configuration. As the two test systems (inertia dynamometers and tribometer) may have different users with possibly different tasks are different, the question regarding how comparable the two systems are arises. This helps better defining the fields of investigations for the two methods. This paper focuses measurement of friction coefficient and the wear behavior using inertia dynamometer and scaled pin-on-disc tribometer.
Technical Paper
2014-09-28
Tomasz Grabiec
Wear and friction behaviour of disc brakes are the most important properties of disc brake system and are mainly addressed by appropriate selection and tuning of friction material. Disc material composition is often considered as “given”. The most common material used for brake disc is grey cast iron which can have carbon content between 3 to 4 percent. It is difficult to find in literature investigations related to influence of cast iron material in combination with modern low-met friction material on wear and friction performance of disc brakes. In this work, the author will try to analyse impact of brake disc material properties on wear and friction performance.
Technical Paper
2014-09-28
Chendi Sun, Xiaofei Pei
This paper presents how hardware-in-the-loop (HIL) simulations have been used for testing during the development of Anti-lock Braking System (ABS). The ETAS Labcar system is a popular tool for HIL tests. The vehicle model which is built in Matlab/Simulink is downloaded to run in Realtime-PC. The Labcar Integrated Platform (IP) can configure board cards which is a link between the model and ABS ECU. In this paper, a classical logic threshold control algorithm is adopted in ABS ECU. Through Labcar Experiment Environment (EE) various parameters can be monitored and modified conveniently. The HIL test of ABS ECU is implemented on high or low adhesion road respectively. The results show that, although response lag exists in the hydraulic braking system, the curves of velocity and pressure in wheel cylinders can be close to those on real road with proper adjustment of control parameters. So HIL simulations are invaluable, when considering the short development times required in the automotive industry.
Technical Paper
2014-09-28
ByeongUk Jeong, Hoon Kim, Woochul Kim, Sang Do Kwak
Owing to the enhanced performance of engines these days, more heat should be dissipated in the braking system. Failure of doing this properly causes temperature rise in the brake disc which result in the brake fade, disc distortion, brake judder, etc. A cooling-air-duct was proposed as a vial solution to prevent these from happening. In this paper, we present our work on experimentally optimized parameters such as direction, location, shapes and the size of the duct for the cooling-air-duct installation in real cars. We installed the duct extended from a front bumper to a rear wheel guard. Experimental parameters were compared with theoretical analysis using the impinging jet analysis, so the heat transfer coefficients were determined with the aid of FEM analysis. We found that our experimental study is consistent with theoretical analysis; therefore our results should serve an useful guideline for designing the cooling-air-duct.
Technical Paper
2014-09-28
Kenneth D. Norman, Amandeep Singh
Assessment of braking performance that includes brake fade is a critical part of the evaluation of military light tactical vehicles as it is for conventional light cars and trucks. These vehicles are sometimes called upon to operate in severe mountain regions that challenge the braking performance well beyond the environment in which these vehicles are normally operated. The U.S. Army Test Operating Procedure 2-2-608 includes a test schedule conducted in the mountainous region near Jennerstown, Pennsylvania. While this test procedure represents a typical mountain environment, it does not represent the most severe mountain descents that can be encountered across the United States. As a preliminary step to developing a representative severe mountain descent braking test, mountain roads throughout the United States were evaluated analytically to identify potential test venues. A literature search was first undertaken to identify test procedures and test sites that were utilized by automobile manufacturers, NATC, ATC, and the University of Michigan Transportation Research Institute (UMTRI).
Technical Paper
2014-09-28
Qiang Wang, Gang Qi, Guangrong Zhang, Xinyu Pu
A brake durability experiment method is proposed to simulate the brake durability vehicle road test. Brake shudder and noise will be happened in brake durability test. Brake shudder is difficult to address with lots of constituents, such as assembly run out, component stiffness, lining characteristic, thermal and corrosion, and so on. There are some test procedures to predict brake thermal roughness and pad cleaning corrosion performance to prevent brake shudder. The brake durability vehicle road test is performed to run brake NVH and wear, such as Mojacar in Spain and Huangshan test in China. The brake energy intensity and road excitation are the significant factors for brake rotor thickness variation generation causing the brake shudder in public road test. The study is focused on brake wear depending on brake energy intensity and brake temperature ,brake rotor TV generation induced by wear to simulate the brake durability road test. Brake durability road test was performed to obtain braking initial velocity, temperature, deceleration and brake pad wear during the test.
Technical Paper
2014-09-28
Jaroslaw Grochowicz, Carlos Agudelo, Shanglei Li, Harald Abendroth, Karl-Heinz Wollenweber, Achim Reich
The efforts of the ISO “Test Variability Task Force” have been aimed at improving the understanding and at reducing brake dynamometer performance test variability. In addition, dynamometer test results have been compared and correlated to vehicle testing. This paper focuses on assessing friction levels, friction coefficient sensitivity, and repeatability under ECE, GB, ISO, JASO, and SAE laboratory performance tests. With multiple companies (or programs) developing and assessing the friction coefficient and friction behavior under different methods, it is inevitable to avoid conflicts of performance requirements or lack of reproducibility or correlation of test results under different test methods. In order to provide an evaluation consistent with previous phases of the Task Force activities, the same brake corner assembly and same friction material is used for this study. The study is comprised of three main steps: (a) Conducting tests under several test procedures: • ISO 26867:2009 — Friction Behaviour Assessment for Automotive Brake Systems (two samples) • SAE J2522:2013 — Dynamometer Global Brake Effectiveness (two samples) • SAE J2784:2009 — FMVSS Inertia Dynamometer Test Procedure for Vehicles Below 4 540 Kg GVWR (two samples) • JASO C406:2000 — Passenger Car — Dynamometer Test Procedures (two samples) • ECE R90-02:2013-Annex 9 – Part A— Determination of friction behaviour by machine testing (three samples) • SAE J661:2012 — Brake Lining Quality Control Test Procedure (five samples) • GB 5763:2008 — Brake Linings for Automobiles (TBD samples) all dynamometer tests were conducted using the same inertia dynamometer to eliminate the reproducibility (dyno-to-dyno) component in the total variability evaluation.
Technical Paper
2014-09-28
Tobias Schramm, Georg Peter Ostermeyer
There are a few principal excitation mechanisms that brake system NVH simulations are based on, especially the high frequency squeal simulations. These mechanisms can be described by some simple mechanical models that exhibit excitation or self excitation effects induced by friction [1]. These models use very simple friction laws of Coulomb type, described by a friction coefficient that is either a constant or simple functions of some state variables, taking into account a Stribeck characteristic. Measurements from the AK-Master or SAE J2521, however, show that the friction coefficient is not a simple function of some state variables, describing a steady state behavior of friction. In the past several years, material dependent descriptions of the frictional brake interface have started attracting attention [2]. These aspects are greatly influenced by the tribological effects at the frictional interface, which can be characterized by typical wear patterns. To get a better understanding of the friction mechanisms between the brake pad and the disk, the topography of the disk have to be measured by in-situ nondestructive methods, which have to be on one side very fast because of the size of the data set and on the other hand these methods must be highly accurate to get the wear properties of ceramic disks f.i..
Technical Paper
2014-09-16
Hidefumi Saito, Shoji Uryu, Norio Takahashi, Noriko Morioka, Hitoshi Oyori
In this study, we seek solution to energy optimization issue of Environmental Control System (ECS) for electric aircraft. Aircraft ECS must have three functions as pressurization, ventilation, and temperature control. Non-bleed ECS based on more electric aircraft makes it possible to distribute the three functions to equipment. Motor Driven Fresh Air Compressor (MDFAC) mainly takes charge of pressurization function and ventilation function, therefore selection of equipment for temperature control function is important. We select not Air Cycle System (ACS) but Vapor Cycle System (VCS) as the equipment for temperature control function, for minimization of energy consumption by higher Coefficient of Performance (COP). We try to clarify specifications, configuration and weight of the VCS suitable for the temperature control function of single aisle aircraft, which is a non-bleed type aircraft equipped with MDFACs. To keep increase of flight fuel consumption by additional weight negligible, weight and rated performance of the VCS are set as the same as those of the ACS.
Technical Paper
2014-09-16
Jon Hagar
System testing can, in part, be defined as the application of concepts as an attempt to demonstrate that the implementation DOES NOT meet its intended use. Unfortunately many industry test efforts only show that a system meets requirements which, while necessary, is not sufficient to fully address a product's system testing. Many managers, engineers, and testers are not familiar with the wide variety of concepts and standards available for system and software testing-many of which can actually save projects money. Standards can offer a wealth of knowledge and can prove their value in any given product. This presentation offers a review of concepts and standards that many testers will find valuable including: - Math-based techniques which apply combinatorial, statistical, Design of Experiments (DOE), or domain-based concepts - Attack-based testing which focuses on common industry error taxonomies - Independent model-based testing using tooling and standards - New standards-driven testing to address verification and validation (V&V), testing, and documentation that few test teams are aware of.
Viewing 1 to 30 of 22513

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