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Viewing 1 to 30 of 15219
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
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
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
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
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
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
2014-10-13
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
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
Jianyi Tian, Hongming Xu, Ramadhas Arumugam Sakunthalai, Dai Liu, Cheng Tan, Akbar Ghafourian
Abstract Engine transient operation has attracted a lot of attention from researchers due to its high frequency of occurrence during daily vehicle operation. More emissions are expected compared to steady state operating conditions as a result of the turbo-lag problem. Ambient temperature has significant influences on engine transients especially at engine start. The effects of ambient temperature on engine-out emissions under the New European Driving Cycle (NEDC) are investigated in this study. The transient engine scenarios were carried out on a modern 3.0 L, V6 turbocharged common rail diesel engine fuelled with winter diesel in a cold cell within the different ambient temperature ranging between +20 °C and −7 °C. The engine with fuel, coolant, combustion air and lubricating oil were soaked and maintained at the desired test temperatures during the transient scenarios. Instantaneous engine performances including torque and speed, gaseous emissions such as CO, THC and NOx, and particulate emissions for its number and mass are analyzed during each transient scenario under different ambient conditions.
Technical Paper
2014-10-01
Sermet Yucel, Melinda Moran Lucking, Jon Magnuson, Germana Paterlini, Benjamin Worel
Fuel economy and performance vary significantly with the vehicle design and configuration, road profile, and payload. The variation is more pronounced for heavy-duty trucks and understanding its origin is critical to maximizing fleet profitability. In this paper we demonstrate a method to continuously estimate fuel consumption breakdown over resistive forces while the vehicle is driven on a public highway. The method is fast, cost-effective, and capable of analyzing trip segments as short as one second. The method utilizes a non-linear Kalman filter and a vehicle dynamical model that has a coupled longitudinal and vertical motion. The paper presents the breakdown of fuel consumption and an estimate of road grade profile obtained by driving a heavy-duty vehicle at the MnROAD research facility in Albertville MN. The road grade profile of the high-volume segment on Westbound Interstate 94 and the fuel consumption breakdown of the MnROAD heavy-duty test truck were estimated from recorded Control Area Network (CAN) signals and known vehicle parameters.
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 (R2) for data correlation are investigated. The mathematical structure of R2 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
Britney J. McCoy, Arman Tanman
Abstract In-use testing of diesel emission control technologies is an integral component of EPA's verification program. Device manufacturers are required to complete in-use testing once 500 units have been sold. Additionally, EPA conducts test programs on randomly selected retrofit devices from installations completed with grants by the National Clean Diesel Campaign. In this test program, EPA identified and recovered a variety of retrofit devices, including diesel particulate filters (DPFs) and diesel oxidation catalysts (DOCs), installed on heavy-duty diesel vehicles (on-highway and nonroad). All of the devices were tested at Southwest Research Institute in San Antonio, Texas. This study's goal was to evaluate the durability, defined here as emissions performance as a function of time, of retrofit technologies aged in real-world applications. A variety of operating and emissions criteria were measured to characterize the overall performance of the retrofit devices on an engine dynamometer.
Technical Paper
2014-09-30
Shaoyun Sun, Yin-ping Chang, Qiang Fu, Jing Zhao, Long Ma, Shijie Fan, Bo Li, Andrea Shestopalov, Paul Stewart, Heinz Friz
Abstract In the development of an FAW SUV, one of the goals is to achieve a state of the art drag level. In order to achieve such an aggressive target, feedback from aerodynamics has to be included in the early stage of the design decision process. The aerodynamic performance evaluation and improvement is mostly based on CFD simulation in combination with some wind tunnel testing for verification of the simulation results. As a first step in this process, a fully detailed simulation model is built. The styling surface is combined with engine room and underbody detailed geometry from a similar size existing vehicle. From a detailed analysis of the flow field potential areas for improvement are identified and five design parameters for modifying overall shape features of the upper body are derived. In a second step, a response surface method involving design of experiments and adaptive sampling techniques are applied for characterizing the effects of the design changes. The characterization is followed by an optimization step to find the best possible drag improvement from these design changes.
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
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
Bongkeun Choi
Abstract In this paper an effective technology of virtual thermal test of disc brake with several advanced analytic techniques was presented. With the virtual thermal test process, thermal performance of brake system could be easily evaluated without any possibility of great errors that used to happen in the past. In addition to the classical result of CFD, this virtual thermal test produced several valuable applications such as thermal deformation of rotor, optimization of thermal performance and estimation of braking distance.
Technical Paper
2014-09-28
Abdulwahab A. Alnaqi, Suman Shrestha, David C. Barton, Peter C. Brooks
Abstract Aluminium alloys have been used extensively in the automotive industry to reduce the weight of a vehicle and improve fuel consumption which in turn leads to a reduction in engine emissions. The main aim of the current study is to replace the conventional cast iron rotor material with a lightweight alternative such as coated aluminium alloy. The main challenge has been to meet both the cost and functional demands of modern mass-produced automotive braking systems. A sensitivity analysis based on the Taguchi approach was carried out to investigate the effect of various parameters on the thermal performance of a typical candidate disc brake. Wrought aluminium disc brake rotors coated with alumina on the rubbing surfaces were determined to have the best potential for replacing the conventional cast iron rotor at reasonable cost. Optimisation of the structure was subsequently carried out using a genetic algorithm on the selected coated aluminium disc brake rotor. This determines the optimum thickness of the coating and the composition of the substrate based on selected criteria.
Technical Paper
2014-09-28
Kenneth D. Norman, Amandeep Singh
Abstract 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 (TOP) 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, independent automotive testing companies, U.S.
Technical Paper
2014-09-16
Steven David Angus Fletcher, Patrick Norman, Stuart Galloway, Graeme Burt
Abstract The development of the More-Electric Engine (MEE) concept will see an expansion in the power levels, functionality and criticality of electrical systems within engines. However, to date, these more critical electrical systems have not been accounted for in existing engine certification standards. To begin to address this gap, this paper conducts a review of current engine certification standards in order to determine how these standards will impact on the design requirements of More-Electric Engine (MEE) electrical system architectures. The paper focuses on determining two key architectural requirements: the number of individual failures an architecture can accommodate and still remain functional and the rate at which these failures are allowed to occur. The paper concludes by discussing how the derived failure rates begin to define a set of design requirements for MEE electrical architectures, considering various operating strategies, and demonstrates their application to example MEE electrical system architecture designs.
Technical Paper
2014-09-16
Jon Hagar
Abstract 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, some industry verification test efforts only show that a system meets requirements which while necessary, are not sufficient to fully address a product's system-software testing. Managers, engineers, and testers may not be familiar with the wide variety of test concepts, approaches, and standards available for system-software testing-many of which can save projects money and effort in the long run. Newer software test standards and advanced techniques can offer a wealth of knowledge and improvement opportunities for software products. This paper offers a review of emerging software test concepts and standards in which teams will find potential value toward their improvement efforts 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 tools and standards New standards-driven testing to address verification and validation (V&V), testing, and documentation.
Technical Paper
2014-09-16
Khadeeja Nusrath, Ankur Sarmah, Jatinder Singh
This paper presents the implementation of flight path reconstruction (FPR) and wind estimation techniques applied to a high performance fighter aircraft. The analysis is carried out for the flight test data gathered and stored in a Crash Data Recorder (CDR). The data signals obtained from CDR are generally highly noisy, with frequent data drop outs and also with low sampling rate. The estimation technique applied for data reconstruction is the extended Kalman filtering (EKF). The reconstructed trajectories can be compared with the actual flight trajectories such that, in case of unavailability of data from other sources (e.g., digital flight control computer), the algorithm should be able to reconstruct the trajectories with the minimum set of data available from the CDR. Wind estimation along with the trajectory reconstruction can give better accuracy in airspeed as well as flow angles. The algorithm also aims at determining the bias/systematic instrument errors and generating accurate aircraft state trajectories.
Technical Paper
2014-09-16
Andreas Himmler
Abstract To make the development of complex aircraft systems manageable and economical, tests must be performed as early as possible in the development process. The test goals are already set in advance before the first hardware for the ECUs exists, to be able to make statements about the system functions or possible malfunctions. This paper describes the requirements on and solutions for test systems for ECUs that arise from these goals. It especially focuses on how a seamless workflow and consistent use of test systems and necessary software tools can be achieved, from the virtual test of ECUs, which exist only as models, up to the test of real hardware. This will be shown in connection with a scalable, fully software-configurable hardware-in-the-loop (HIL) technology. The paper also covers the seamless use of software tools that are required for HIL testing throughout the different test phases, enabling the reuse of work products throughout the test phases.
Technical Paper
2014-09-16
Evan Racine, Zachary Lammers, Street Barnett, John Murphy, Quinn Leland
Abstract The purpose of this study is to set up a laboratory test apparatus to analyze aircraft flight control EMAS' electrical and thermal energy flow under transient and dynamic flight profiles. A hydraulic load frame was used to exert load to the EMA. The actuator was placed within an environmental chamber which simulates ambient temperature as function of altitude. The simulated movement or stroke was carried out by the EMA. The under test EMA's dynamic load, stroke, and ambient temperature were synchronized through a real time Labview DAQ system. Motor drive voltage, current, regenerative current, and motor drive and motor winding temperature were recorded for energy analysis. The EMA under test was subjected to both transient and holding load laid out in a test matrix. It was found that the transient missions of EMAS presented the most electric demand on the aircraft electric power supply system while holding presented the most severe thermal stress on the EMAS, where the EMAS operated at 0% efficiency and all the electric power converted to heat.
Technical Paper
2014-06-02
Jennifer Suggs, Benjamin Burns, Richard Martinez, Don Smith, Amelie Isin
The United States Environmental Protection Agency (U.S. EPA) National Enforcement Investigations Center (NEIC) has developed a test method for the analysis of washcoat material in small engine catalytic converters. Each small engine catalytic converter contains a metallic monolith. Each metallic monolith is removed from its outer casing, manually disassembled, and then separated into washcoat and substrate. The washcoat material is analyzed for platinum group metals (PGMs) using X-ray fluorescence (XRF) spectrometry. Results from the XRF analysis are used to calculate PGM ratios in the washcoat. During monolith disassembly, care is taken to minimize loss of washcoat or substrate, but some material is inevitably lost. The recovered washcoat mass does not necessarily equal the quantity of washcoat that was present in the intact catalytic converter. A maximum washcoat mass can be estimated by combining the masses of the recovered washcoat and the material loss during monolith disassembly.
Technical Paper
2014-05-07
Eraldo de Jesus Soares, Alan M. Oliva, Camilo A. Adas, Fernando C. Dusi, Paulo Sergio P. Santos, Marco A. Fogaça Accurso, Marcus Kliewer
Abstract The purpose of this paper is to show a multiaxial bench test for static and dynamic testing of leaf springs for suspension of commercial vehicles. The bench test simulates the critical operating conditions (track, ramp, speed bump on track, curves and braking), with stroke control for strength and deformation analysis. One of the main advantages in bench test is to reduce the time of the test, its repeatability, its cost saving and monitoring its performance through inspections and graphic records. The aim of the test is to evaluate the behavior in durability of the components, to analyze the possible failure mode and to be able to approve or reject the component based on the test's results. Criteria were set to accelerate the test by comparing signals measured on the field and bench test with deflection by stress curves. These criteria were maintained under extreme conditions for longer than the observed in previous and real applications. With this, the low incidence of strength and stroke is measured by optimizing the time of the test.
Technical Paper
2014-05-07
Fabio Augusto Schuh, Leandro Luís Corso, Leonardo Hoss
Abstract Applying knowledge available at technical literature for cycle counting, damage caused by each load cycle through S-N curve, and fatigue damage accumulation by Palmgren-Miner rule, durability prediction is performed for a leafspring of a commercial vehicle with 6×4 suspension system. Max principal tension is measured by means of strain gages in the most representative points for fatigue life of the leafspring, determined with FEA, while vehicle runs over off-road track in a proving ground. Load and tension are also measured in a laboratory bench test for this component. Correlation between off-road track and bench test is then performed. Finally, representative samples of the component are tested with dynamic loading until fatigue fracture in bench test, and using data from these tests, statistical analysis is performed with application of Weibull distribution, allowing life prediction in statistical terms.
Technical Paper
2014-04-28
Christian Fischer, Rainer Wagener, Tobias Melz, Heinz Kaufmann
Abstract The fatigue life approach is the main topic of structural durability. Improved methods for the numerical fatigue analysis should be based on experimental results. In some fields of material testing progress in research are very hard to achieve. Especially the regime of amplitudes below the knee point of the SN-curve with a huge number of load cycles to failure is one of these challenges with respect to fatigue tests. With standard testing devices, 108 to 1010 cycles cannot be achieved in a reasonable time span because of their low and limited testing frequencies or their inflexible control systems concerning variable amplitude loading. For this reason, a new piezo based testing facility has been developed by Fraunhofer LBF which is capable to master this challenge. Built up with a high performance piezo actuator and a specially designed high frequency load frame this testing facility enables test frequencies up to 1.000Hz and locking forces of 10kN. The control technique realises variable load amplitudes as well as variable frequencies to test materials under realistic load sequences.
Viewing 1 to 30 of 15219