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Viewing 211 to 240 of 15311
2016-09-27
Technical Paper
2016-01-8083
Hans Christian Doering, Norbert Meyer, Markus Wiedemeier
Abstract Increasing diagnosis capabilities in modern engine electronic control units (ECUs), especially in the exhaust path, in terms of emission and engine aftertreatment control utilize on-board NOx prediction models. Nowadays it is an established approach at hardware-in-theloop (HIL) test benches to replicate the engine's steady-state NOx emissions on the basis of stationary engine data. However, this method might be unsuitable for internal ECU plausibility checks and ECU test conditions based on dynamic engine operations. Examples of proven methods for modeling the engine behavior in HIL system applications are so-called mean value engine models (MVEMs) and crank-angle-synchronous (in-cylinder) models. Of these two, only the in-cylinder model replicates the engine’s inner combustion process at each time step and can therefore be used for chemical-based emission simulation, because the formation of the relevant gas species is caused by the inner combustion states.
2016-09-27
Journal Article
2016-01-8061
Thomas Howell, Bruce Swanbon, Justin Baltrucki, Alan Steines, Nancy Neff, Biao Lu
Abstract Heavy duty valvetrains have evolved over the last 20 years with the integration of engine braking into the valvetrain. Jacobs Vehicle Systems have developed the High Power Density (HPD) engine brake that increases retarding powe, especially at low engine speed. The system works by converting the engine from a 4 stroke during positive power into a 2 stroke for retarding power. This more than doubles the retarding power at cruise engine speeds reducing the need to downshift in order to control the vehicle, compensates for reduction in natural vehicle retarding due to aerodynamic and friction enhancements, and enables the same vehicle retarding power with a smaller displacement engine as engine downsizing becomes prevalent.
2016-09-27
Technical Paper
2016-01-8151
Prashanth Gururaja
Abstract To investigate the feasibility of various aerodynamic test procedures for the Phase 2 Greenhouse Gas (GHG) Regulations for heavy-duty vehicles in the United States, the US Environmental Protection Agency conducted, through Southwest Research Institute (SwRI), coastdown testing of several heavy-duty tractors matched to a conventional 53-foot dry-van trailer. Three vehicle configurations were tested, two of which included common trailer drag-reduction technologies. Air speed was measured onboard the vehicle, and wind conditions were measured using a weather station placed along the road side. Tests were performed on a rural road in Texas. One vehicle configuration was tested over several days to evaluate day-to-day repeatability and the influence of changing wind conditions. Data on external sources of road forces, such as grade and speed dependence of tire rolling resistance, were collected separately and incorporated into the analysis.
2016-09-27
Technical Paper
2016-01-8153
Prashanth Gururaja
Abstract To investigate the feasibility of various test procedures to determine aerodynamic performance for the Phase 2 Greenhouse Gas (GHG) Regulations for Heavy-Duty Vehicles in the United States, the US Environmental Protection Agency commissioned, through Southwest Research Institute, constant-speed torque tests of several heavy-duty tractors matched to a conventional 53-foot dry-van trailer. Torque was measured at the transmission output shaft and, for most tests, also on each of the drive wheels. Air speed was measured onboard the vehicle, and wind conditions were measured using a weather station placed along the road side. Tests were performed on a rural road in Texas. Measuring wind-averaged drag from on-road tests has historically been a challenge. By collecting data in various wind conditions at multiple speeds over multiple days, a regression-based method was developed to estimate wind-averaged drag with a low precision error for multiple tractor-trailer combinations.
2016-09-27
Journal Article
2016-01-8152
Brian R. McAuliffe, David Chuang
Abstract In an effort to support Phase 2 of Greenhouse Gas Regulations for Heavy-Duty Vehicles in the United States, a track-based test program was jointly supported by Transport Canada (TC), Environment and Climate Change Canada (ECCC), the U.S. Environmental Protection Agency (EPA), and the National Research Council Canada (NRC) to assess aerodynamic evaluation methodologies proposed by the EPA and to provide a site-verification exercise against a previous test campaign with the same vehicle. Coast-down tests were conducted with a modern aerodynamic tractor matched to a conventional 16.2 m (53 ft) dry-van trailer, and outfitted with two drag reduction technologies. Enhanced wind-measurement instrumentation was introduced, consisting of a vehicle-mounted fast-response pressure probe and track-side sonic anemometers that, when used in combination, provided improved reliability for the measurements of wind conditions experienced by the vehicle.
2016-09-27
Technical Paper
2016-01-8154
Abhijith Balakrishna, Gang Wang
Abstract The dynamic loading on the skin of a refrigeration unit mounted in the gap between tractor and trailer is studied while another trailer passes by on a freeway using transient computational fluid dynamics. Dynamic Meshing methodology available in Ansys Fluent was used to understand the transient pressure and flow regimes in and around the tractor trailer gap in general and refrigeration unit in particular, at various vehicle speeds. The influences of the lateral distance between the crossing trailers and vehicle speed on the pressure distribution on the refrigeration unit have been studied.
2016-09-27
Technical Paper
2016-01-8057
Michael Glensvig, Heimo Schreier, Mauro Tizianel, Helmut Theissl, Peter Krähenbühl, Fabio Cococcetta, Ivan Calaon
Abstract This paper presents the results of a long haul truck Waste Heat Recovery (WHR) system from simulation, test bench and public road testing. The WHR system uses exhaust gas recuperation only and utilizes up to 110kW of exhaust waste heat for the Organic Rankine Cycle (ORC) in a typical European driving cycle. The testing and simulation procedures are explained in detail together with the tested and simulated WHR fuel consumption benefit for different real life cycles in Europe and USA reaching fuel consumption benefits between 2.5% and 3.4%. Additionally a technology road map is shown which discusses the role of WHR in fulfilling the future CARB BSFC target value (minimum in map) of around 172 g/kWh.
2016-09-27
Technical Paper
2016-01-8140
Devaraj Dasarathan, Ashraf Farag, Matthew Ellis
Abstract Recent regulations on greenhouse gas (GHG) emission standards for heavy-duty vehicles have prompted government agencies to standardize procedures assessing the aerodynamic performance of Class 8 tractor-trailers. The coastdown test procedure is the primary reference method employed to assess vehicle drag currently, while other valid alternatives include constant speed testing, computational fluid dynamics (CFD) simulations, and wind tunnel testing. The main purpose of this paper is to compare CFD simulations with a corresponding 1/8th scale wind tunnel test. Additionally, this paper will highlight the impacts of wind tunnel testing on the total drag coefficient performance as compared to full scale open road analysis with and without real world, upstream turbulence wind conditions. All scale model testing and CFD simulations were performed on a class 8 tractor with a standard 53-foot dry-box trailer.
2016-09-27
Journal Article
2016-01-8023
Bernard Tanguay
Abstract A novel method was developed to predict the free-stream velocity experienced by a traveling vehicle based on track-side anemometric measurements. The end objective of this research was to enhance the reliability of the prediction of free-stream conditions in order to improve the accuracy of aerodynamic drag coefficient (CD) assessments from track tests of surface vehicles. Although the technique was applied to heavy-duty vehicles in the present work, it is equally applicable to any vehicle type. The proposed method is based on Taylor’s hypothesis, a principle applied in fluid mechanics to convert temporal signals into the spatial domain. It considers that the turbulent wind velocity fluctuations measured at one point are due to the "passage of an unchanging pattern of turbulent motion over the point". The method is applied to predict the wind velocity that the vehicle will experience as it encounters a wind pattern detected earlier by an anemometer located upwind.
2016-09-27
Technical Paper
2016-01-8144
John Lacey
Abstract The trucking industry is being encouraged by environmental and cost factors to improve fuel efficiency. One factor that affects fuel efficiency is the aerodynamic design of the vehicles; that is, the vehicles with lower aerodynamic drag will get better mileage, reducing carbon emissions and reducing costs through lower fuel usage. A significant tool towards developing vehicles with lower drag is the wind tunnel. The automobile industry has made great improvements in fuel efficiency by using wind tunnels to determine the best designs to achieve lower drag. Those wind tunnels are not optimum for testing the larger, longer heavy trucks since the wind tunnels are smaller than needed. The estimated costs for a heavy truck wind tunnel based on automotive wind tunnel technology are quite high. A potential nozzle concept to reduce wind tunnel cost and several other new possible approaches to lower wind tunnel costs are presented.
2016-09-20
Technical Paper
2016-01-2039
Prashant S. Vadgaonkar, Ullas Janardhan
Avionics industry is moving towards fly-by wire aircrafts with less reliance on mechanical systems leading to increase in the complexity of in-flight hardware elements. RTCA/DO-254 and EUROCAE ED-80 plays a vital role in the design assurance of airborne electronic hardware. RTCA/ DO-254 and EUROCAE ED-80 are the industry standards for Design Assurance Guidance for Airborne Electronic Hardware. The two different agencies FAA and EU regulate and apply this design assurance guidance to the regulatory law in CFR and EASA CS respectively. This paper discusses the need for DO-254 /ED-80 certification in Aerospace industry, the advantages and benefits to the avionics manufacturers. The paper presents the study made on similarities and differences between DO-254/ED-80.
2016-09-20
Journal Article
2016-01-2030
Jon Zumberge, Michael Boyd, Raul Ordonez
Cost and performance requirements are driving military and commercial systems to become highly integrated, optimized systems which require more sophisticated, highly complex controls. To realize benefits of those complex controls and make confident decisions, the validation of both plant and control models becomes critical. To quickly develop controls for these systems, it is beneficial to develop plant models and determine the uncertainty of those models to predict performance and stability of the control algorithms. A process of model and control algorithm validation for a dc-dc boost converter circuit based on acceptance sampling is presented here. The validation process described in this paper is based on MIL-STD 3022 with emphasis on requirements settings and the testing process. The key contribution of this paper is the process for model and control algorithm validation, specifically a method for decomposing the problem into model and control algorithm validation stages.
2016-09-20
Technical Paper
2016-01-2027
Brett Robbins, Kevin J. Yost, Jon Zumberge
Abstract Detailed machine models are, and will continue to be, a critical component of both the design and validation processes for engineering future aircraft, which will undoubtedly continue to push the boundaries for the demand of electric power. This paper presents a survey of experimental testing procedures for typical synchronous machines that are applied to brushless synchronous machines with rotating rectifiers to characterize their operational impedances. The relevance and limitations of these procedures are discussed, which include steady-state drive stand tests, sudden short-circuit transient (SSC) tests, and standstill frequency response (SSFR) tests. Then, results captured in laboratory of the aforementioned tests are presented.
2016-09-20
Technical Paper
2016-01-2058
Thibaut Billard, Cedric Abadie, Bouazza Taghia
Abstract The present paper reports non-electrically intrusive partial discharge investigations on an aeronautic motor. Relevancy, robustness and repeatability of partial discharge testing procedures, both on insulating materials characterization and on operating aeronautic equipment are essential to ensure reliability of the aircraft systems. The aim of this paper is to be the very first step of defining such procedures and the associated test equipment. To do so, the paper will start by providing an understanding of partial discharge phenomena and will review typical more electrical aircraft architecture. Key characteristics causing partial discharge risk to increase will be highlighted. The impact of harness length, high performance power electronics and voltage level increase on insulation system is demonstrated.
2016-09-20
Technical Paper
2016-01-2052
Virgilio Valdivia-Guerrero, Ray Foley, Stefano Riverso, Parithi Govindaraju, Atiyah Elsheikh, Leonardo Mangeruca, Gilberto Burgio, Alberto Ferrari, Marcel Gottschall, Torsten Blochwitz, Serge Bloch, Danielle Taylor, Declan Hayes-McCoy, Andreas Himmler
Abstract This paper presents an overview of a project called “Modelling and Simulation Tools for Systems Integration on Aircraft (MISSION)”. This is a collaborative project being developed under the European Union Clean Sky 2 Program, a public-private partnership bringing together aeronautics industrial leaders and public research organizations based in Europe. The provision of integrated modeling, simulation, and optimization tools to effectively support all stages of aircraft design remains a critical challenge in the Aerospace industry. In particular the high level of system integration that is characteristic of new aircraft designs is dramatically increasing the complexity of both design and verification. Simultaneously, the multi-physics interactions between structural, electrical, thermal, and hydraulic components have become more significant as the systems become increasingly interconnected.
2016-09-20
Journal Article
2016-01-2051
Andreas Himmler, Lars Stockmann, Dominik Holler
Abstract The application of a communication infrastructure for hybrid test systems is currently a topic in the aerospace industry, as also in other industries. One main reason is flexibility. Future laboratory tests means (LTMs) need to be easier to exchange and reuse than they are today. They may originate from different suppliers and parts of them may need to fulfill special requirements and thus be based on dedicated technologies. The desired exchangeability needs to be achieved although suppliers employ different technologies with regard to specific needs. To achieve interoperability, a standardized transport mechanism between test systems is required. Designing such a mechanism poses a challenge as there are several different types of data that have to be exchanged. Simulation data is a prominent example. It has to be handled differently than control data, for example. No one technique or technology fits perfectly for all types of data.
2016-09-20
Technical Paper
2016-01-2047
K. Suresh, Rajkumar Dhande, Udupi Ananthakrishna Acharya
Abstract Reducing the amount of physical testing is of importance in the aeronautical industry, where each physical test represents a significant cost. Apart from the cost aspect, it may also be difficult or hazardous to carry out physical testing. Specific to the aeronautic industry are also the relatively long development cycles, implying long periods of uncertainty during product development. In any industry a common viewpoint is that of verification, validation, and uncertainty quantification using simulation models are critical activities for a successful development of a product. In Aeronautical application, the design of store's structural equipments needs to be certified in accordance with MIL-T-7743F [1]. This paper focuses on a case study for shock analysis, whereby an attempt has been made to reduce the cost of certification by way of replacing the actual physical testing by a reliable high fidelity FE simulation.
2016-09-20
Technical Paper
2016-01-2044
Jeffrey J. Joyce, Scott Beecher, Laurent Fabre, Ramesh Rajagopalan
Abstract Over the past few decades, advanced methods have been developed for the analysis of digital systems using mathematical reasoning, i.e., formal logic. These methods are supported by sophisticated software tools that can be used to perform analysis far beyond what is practically achievable using “paper and pencil” analysis. In December 2011, RTCA published RTCA DO-178C [1] along with a set of technical supplements including RTCA DO-333 [2] which provides guidance on the use of formal methods towards the certification of airborne software. Such methods have the potential to reduce the cost of verification by using formal analysis instead of conventional test-based methods to produce a portion of the verification evidence required for certification.
2016-09-20
Technical Paper
2016-01-1994
Wei Wu, Yeong-Ren Lin, Louis Chow, Edmund Gyasi, John P. Kizito, Quinn Leland
Abstract For aircraft electromechanical actuator (EMA) cooling applications using forced air produced by axial fans, the main objective in fan design is to generate high static pressure head, high volumetric flow rate, and high efficiency over a wide operating range of rotational speed (1x∼3x) and ambient pressure (0.2∼1 atm). In this paper, a fan design based on a fan diameter of 86 mm, fan depth (thickness) of 25.4 mm, and hub diameter of 48 mm is presented. The blade setting angle and the chord lengths at the leading and trailing edges are varied in their suitable ranges to determine the optimal blade profiles. The fan static pressure head, volumetric flow rate, and flow velocity are calculated at various ambient pressures and rotational speeds. The optimal blade design in terms of maximum total-to-total pressure ratio and efficiency at the design point is obtained via CFD simulation.
2016-09-20
Technical Paper
2016-01-2004
M. Parvez Alam, Dinesh Manoharan
In this paper we discuss about the design and development of an “Autonomous Amphibious Unmanned Aerial Vehicle (AAUAV)” that can fly autonomously to the polluted water areas where human accessibility is formidable to test the water quality. The AAUAV system is an integrated multi-copter with tilt rotor capability to facilitate easy landing, navigation and maneuver on water. A 3D CAD model has been designed and analyzed. A specific propulsion system has been devised and lab tested. A proof of concept model has been made and tested in the field with its instruments to ascertain its technical/ operational feasibility. This system can also be tailored to collect and store the water samples from the polluted sites for further comprehensive research at the laboratory. AAUAV system is the novel solution to the polluted environment through a complete integrated system. This will be an effective alternative for the conventional water sampling techniques.
2016-09-20
Technical Paper
2016-01-2000
Mark Bodie, Thierry Pamphile, Jon Zumberge, Thomas Baudendistel, Michael Boyd
Abstract As technology for both military and civilian aviation systems mature into a new era, techniques to test and evaluate these systems have become of great interest. To achieve a general understanding as well as save time and cost, the use of computer modeling and simulation for component, subsystem or integrated system testing has become a central part of technology development programs. However, the evolving complexity of the systems being modeled leads to a tremendous increase in the complexity of the developed models. To gain confidence in these models there is a need to evaluate the risk in using those models for decision making. Statistical model validation techniques are used to assess the risk of using a given model in decision making exercises. In this paper, we formulate a transient model validation challenge problem for an air cycle machine (ACM) and present a hardware test bench used to generate experimental data relevant to the model.
2016-09-20
Technical Paper
2016-01-2064
Shashank Krishnamurthy, Stephen Savulak, Yang Wang
Abstract The emergence of wide band gap devices has pushed the boundaries of power converter operations and high power density applications. The wide band gap devices in conjunction with silicon on insulator electronic components enable the realization of power converters that can operate at high ambient temperatures that are typically found in aerospace engine environments. This paper describes the design and test of a power electronic inverter that converts a fixed input DC voltage to a variable voltage variable frequency three phase output. The design of the key functional components such as the gate drive, power module, controller and communication will be discussed in this paper. Test results for the inverter at high temperature are also presented.
2016-09-18
Technical Paper
2016-01-1932
Niclas Strömberg
Abstract During several years a toolbox for performing virtual rig tests of disc brake systems has been developed by the author. A thermo-flexible multi-body model of a test rig is derived and implemented by coupling two types of models: a finite element model and a multi-body model. The finite element model is a thermo-mechanical model of the pad-disc system that is formulated including thermo-elasticity, frictional contact and wear. The energy balance of the contact interface is governed by contact conductance that depends linearly on the contact pressure and the frictional heat depends on a temperature dependent coefficient of friction. Instead of adopting a standard Lagrangian approach, the disc is formulated in an Eulerian frame like a fluid. This is then coupled to the pad most accurately by using Signorini’s contact conditions, Coulomb’s law of friction and Archard’s law of wear.
2016-09-18
Technical Paper
2016-01-1953
Michael Herbert Putz, Harald Seifert, Maximilian Zach, Jure Peternel
Abstract Since more than eight years Vienna Engineering (VE) is working on an electro-mechanical brake (EMB) actuated by eccentrics and a highly non-linear actuation mechanism. The principle allows full braking in approx. 70 milliseconds (including air gap) and only approx. 3 A RMS actuator current at 12 V for classical ABS with oscillations. This EMB reached an elaborated state. Versions for passenger cars, elevators, railway and commercial vehicles (CVs) were derived. Now, as the EMB is going to road tests, it is necessary to fulfill safety requirements closely. What are these safety requirements and how can they be fulfilled? The properties of the overall system, of the mechanics and electronics of the single brake are discussed in this paper. The overall brake system for EMBs needs a truly redundant power supply, a safe control bus and a safe brake pedal. The mechanics of a single brake can be required to release when power is off and it must not get mechanically stuck.
2016-09-18
Journal Article
2016-01-1915
Meechai Sriwiboon, Seong Rhee, Kritsana Kaewlob, Nipon Tiempan, Rungrod Samankitesakul
Abstract As some brake engineers believe that brake squeal can be related to pad hardness, friction coefficient or compressibility while others disagree, a study has been undertaken to develop further insights. Two commercial formulas, one low-copper NAO and the other copper-free NAO, were made into disc pads of varying porosity without an underlayer and they were checked for specific gravity, porosity, hardness (HRS and HRR), natural frequencies, compressibility, friction, wear and squeal. With increasing porosity, the hardness and natural frequencies continue to decrease. The compressibility definitely does not increase, but rather slightly decrease or stays the same. The coefficient of friction decreases for the low-copper along with pad and disc wear reduction, and increases for the copper-free along with pad wear increase with no change in disc wear. No obvious correlation emerges between brake squeal and pad hardness, friction coefficient or compressibility.
2016-09-18
Technical Paper
2016-01-1913
Alessandro Sanguineti, Federico Tosi, Andrea Bonfanti, Flavio Rampinelli
Abstract Organic brake pads for automotive can be defined as brake linings with bonding matrix constituted of high-temperature thermosetting resins. Bonded together inside the polymeric binder are a mix of components (e.g. abrasives, lubricants, reinforcements, fillers, modifiers…), each playing a distinctive role in determining the tribology and friction activity of the final friction material. The herein reported work presents inorganic “alkali-activated”-based materials suitable for the production of alternative brake linings (i.e. brake pads), by means of an unconventional low-temperature wet process. Exploiting the hydraulic activity of specific components when exposed to an alkaline environment, such peculiar inorganic materials are capable of coming to a complete hardening without the need of traditional high-temperature energivorous procedures.
2016-09-18
Journal Article
2016-01-1925
David B. Antanaitis
Abstract The strong focus on reducing brake drag, driven by a historic ramp-up in global fuel economy and carbon emissions standards, has led to renewed research on brake caliper drag behaviors and how to measure them. However, with the increased knowledge of the range of drag behaviors that a caliper can exhibit comes a particularly vexing problem - how should this complex range of behaviors be represented in the overall road load of the vehicle? What conditions are encountered during coastdown and fuel economy testing, and how should brake drag be measured and represented in these conditions? With the Environmental Protection Agency (amongst other regulating agencies around the world) conducting audit testing, and the requirement that published road load values be repeatable within a specified range during these audits, the importance of answering these questions accurately is elevated. This paper studies these questions, and even offers methodology for addressing them.
2016-09-18
Technical Paper
2016-01-1920
Deaglan O'Meachair, Stamatis Angelinas, Matthew Crumpton, Antonio Rubio Flores, Juan Garcia, Pablo Barles
Abstract Bentley Motors Ltd. has developed a Carbon Silicon Carbide (CSiC) brake system for its Mulsanne product, introduced at 17MY. The CSiC brake system is conceived as a performance brake system, and as such offers notable improvements in brake performance. In developing the brake system, particular focus was placed on meeting the refinement levels required for a premium product, and indeed as the flagship model for Bentley Motors, NVH refinement of the brake system was of particular concern. This paper intends to discuss the technical performance of the brake system and review the NVH performance of the brakes. Particular attention is given to the methodology employed by Bentley Motors Ltd. and IDIADA Automotive Technology S.A. in identifying NVH concerns, and proposing and validating solutions in the field, through extensive NVH endurance runs. The performance of the system is benchmarked against similar systems offered by Bentley Motors.
2016-09-18
Technical Paper
2016-01-1918
Yusuke Aoki, Yasuyuki Kanehira, Yukio Nishizawa
Abstract Brake squeal is an uncomfortable noise that occurs while braking. It is an important issue in automobile quality to prevent brake products from squealing. Brake shims are widely used to reduce squeal occurrence rate. The anti-squeal effect of shims is quantified as damping properties measured with a bending mode tester, instead of repeating many dynamometer tests. However, there are cases where measurement results have less correlation to actual squeal suppression rate. Therefore, the evaluation of the anti-squeal effect with a dynamometer or on an actual car is needed until the best shim can be selected. To improve the predicted accuracy of the anti-squeal effect, the difference between measurement conditions and actual braking conditions of shims, was focused on. The bending mode tester measures loss factor under pressure-free conditions, even though shims are compressed by pistons or cylinders towards the backplate of the pad.
2016-09-16
Journal Article
2016-01-9019
Jan Grüner, Stefanie Marker
Abstract Standardized driving cycles, such as the New European Driving Cycle (NEDC) in Europe or the Federal Test Procedure 75 (FTP-75) in the U.S. are an important tool to certify new vehicle models. They are used to estimate real world fuel consumption as well as real world emissions. The latter has recently become more important with the stronger focus on green driving, resulting in much stricter emission regulations, while fuel consumption still remains one of the most important aspects in terms of economy and long term costs for the vehicle owner. However these cycles do not reflect the actual behaviour of the driver or regional influences (i.e. topography). Therefore, manufacturers have developed their own usage and test cycles and are able to extract data from the vehicle to analyse the individual driving behaviour and vehicle usage. Apart from that, Naturalistic Driving Observation (NDO) is interested in understanding the driver.
Viewing 211 to 240 of 15311