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2015-10-19 ...
  • October 19-20, 2015 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
Training / Education Classroom Seminars
Stringent requirements of reduced NOx emission limits in the US have presented engineers and technical staff with numerous challenges. Several in-cylinder technical solutions have been developed for diesel engines to meet 2010 emission standards. These technologies have been optimized and have yielded impressive engine-out results in their ability to reduce emissions to extremely low levels. However, current and state-of-the-art in-cylinder solutions have fallen short of achieving the limits imposed on diesel emissions for 2010.
2015-10-14
Event
2015-09-30 ...
  • September 30-October 1, 2015 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
Training / Education Classroom Seminars
As diesel emissions regulations have become more and more stringent, diesel particulate filters (DPF) have become possibly the most important and complex diesel aftertreatment device. This seminar covers many DPF-related topics using fundamentals from various branches of applied sciences such as porous media, filtration and materials sciences and will provide the student with both a theoretical as well as an applications-oriented approach to enhance the design and reliability of aftertreatment platforms.
2015-09-14 ...
  • September 14-15, 2015 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
Training / Education Classroom Seminars
Heat transfer affects the performance, emissions and durability of the engine as well as the design, packaging, material choice and fatigue life of vehicle components. This course covers the broad range of heat transfer considerations that arise during the design and development of the engine and the vehicle with a primary focus on computational models and experimental validation covering the flow of heat from its origin in the engine cylinders and its transfer via multiple paths through engine components.
2015-09-06
Technical Paper
2015-24-2514
Marco Piumetti, Samir Bensaid, Nunzio Russo
A set of nanostructured CeO2-based catalysts with different topological and textural properties (CeO2-nanocubes, CeO2-nanocubes over ZSM-5-type zeolite, CeO2-nanorods, mesoporous CeO2 and CeO2-SCS) has been prepared to investigate the shape-dependency activity of ceria towards soot combustion under different reaction. The physico-chemical properties of the prepared materials have been studied using complementary techniques. The best performances, in terms of the total oxidation of soot, have been achieved for the CeO2-nanocubes, due to the abundance of coordinative unsaturated atomic sites on the exposed surfaces. However, better results, in terms of the onset of soot oxidation, have been obtained for high-surface-area materials, thus reflecting the key role of surface area at low temperatures. Activity tests have suggested the surface-sensitivity of soot oxidation over the prepared ceria-based materials, when the reaction temperature was above 410 °C or 370 °C.
2015-09-06
Technical Paper
2015-24-2516
Panayotis Dimopoulos Eggenschwiler, Daniel Schreiber
Particulate matter (PM)in diesel exhaust is captured in diesel particulate filters (DPFs). Since increased PM load in the filter and thus increased pressure drop across the filter deteriorates the engine performance, the filter load of the DPF has to be removed during a process referred to as regeneration. Measures for successful regeneration aim at accelerating soot oxidation and increase fuel consumption. Regeneration lay-out and thus fuel consumption increase is strongly depending on the oxidation behavior of soot. The aim of the present study is the investigation of soot oxidation characteristics. Therefore particle filters have been loaded with soot using the exhaust gas of small heavy duty vehicle operated under defined conditions on an engine dynamometer. The particle filters have been then dismantled and fragmented on their constituting segments. Each filter segment has been regenerated individually in a specifically designed test bench.
2015-09-06
Technical Paper
2015-24-2399
Christina Nikita, Yannis Hardalupas, Alexander Taylor
The aim of this paper is to evaluate how adequately pressure loss coefficients models, broadly used in 1D engine simulation tools, perform over typical, engine-like exhaust pulses propagating in manifolds formed of three-branch junctions. These coefficient models have been developed over the years to match experimental data of steady flow measurements or shock tube tests usually targeting the mean pressure levels of the pipes comprising the manifold. However, engine exhaust flow is highly unsteady and manifolds are nowadays of a complex shape which aggregates the 3D structure of the flow. Usually these features lead to significant pressure losses than what 1D models are capable to artificially recreate with the use of existing coefficients. For this purpose, a comparison is made between loss coefficients analytical calculations and CFD simulations using the OpenFOAM software.
2015-09-06
Technical Paper
2015-24-2502
Yujun Liao, Panayotis Dimopoulos Eggenschwiler, Alexander Spiteri, Lorenzo Nocivelli, Gianluca Montenegro, Konstantinos Boulouchos
The injection process of urea-water solution (AdBlue) determines initial conditions for reactions and catalysis and is fundamentally responsible for optimal operation of selective catalytic reduction (SCR) systems. The spray characteristics of four, commercially available, injectors (one air-assisted and three pressure-driven with different nozzle-hole configurations) are investigated with non-intrusive measuring techniques. Injection occurred in the crossflow of a channel blowing preheated air in an exhaust duct similar configuration. The effect of several gas temperatures and flows on the spray propagation and entrainment has been extensively studied by shadow imaging. Shadow images, in addition, show that the spray of the pressure-driven injectors is only marginally affected by the gas crossflow. In contrast, the air assisted spray is strongly deflected by the gas, the effect increasing with increasing gas flow.
2015-06-25
Event
In this workshop, a design process for mufflers is offered. Steps that may be taken during the 1) clarification of task, 2) conceptual design, 3) detailed design, and 4) prototyping phases are outlined, and the process is demonstrated at each step for a cross-flow type muffler. Basics and tips for both plane wave analysis and numerical simulation are discussed. Measurement of transmission loss using the two-load method will be described and demonstrated using a transmission loss test bench.
2015-06-24
Event
This session covers experimental, computational, and analytical efforts related to the basic mechanisms and control techniques of noise and vibration in the breathing system (induction, combustion chamber, and exhaust) of naturally aspirated and supercharged/turbocharged engines. Noise sources include airborne, flow, flow‐acoustic and flow‐structure coupling.
2015-06-24
Event
This session covers experimental, computational, and analytical efforts related to the basic mechanisms and control techniques of noise and vibration in the breathing system (induction, combustion chamber, and exhaust) of naturally aspirated and supercharged/turbocharged engines. Noise sources include airborne, flow, flow‐acoustic and flow‐structure coupling.
2015-06-24
Event
This session covers experimental, computational, and analytical efforts related to the basic mechanisms and control techniques of noise and vibration in the breathing system (induction, combustion chamber, and exhaust) of naturally aspirated and supercharged/turbocharged engines. Noise sources include airborne, flow, flow‐acoustic and flow‐structure coupling.
2015-06-15
Technical Paper
2015-01-2318
Wang Wenzhu, Liu Gang, Cheng Mianhong, Wei Jun
Abstract The hanger location layout is crucial, because it is related to the rubber hanger life, the natural frequency of the exhaust system and the force transferred to the body from the exhaust system. In order to solve the hanger layout problem of a new developed automotive exhaust system, the finite element method (FEM) of the automotive exhaust system including the powertrain was established. The correctness of the FEM model was verified by means of experimental modal analysis. Using average driving DOF displacement (ADDOFD) method, the hanger Location was arranged. The static and vibration analysis of the exhaust system was carried out to verify the hanger location layout. The weight analysis results indicate that the maximum displacement of the rubber hanger satisfies the design requirements. The static analysis results under 4g acceleration indicate the maximum stress meets the strength requirements of the material.
2015-06-15
Technical Paper
2015-01-2308
Yitian Zhang, David W. Herrin
Abstract The two-load method is commonly applied to determine the transmission loss for a muffler especially if an impedance tube rig is used. Although one procedure and algorithm is detailed in ASTM E2611, the quality of the transmission loss curve is dependent on several factors that are not discussed in detail in the standard. In this paper, several practical concerns are investigated including (1) the number of channels used in the measurement, (2) the selection of the reference channel, and (3) the choice of data processing algorithm (transfer or scattering matrix). Results are compared for a simple expansion chamber first, then for mufflers of other types. Recommendations are made for obtaining smoother transmission loss curves for various measurement methods.
2015-06-15
Technical Paper
2015-01-2309
David Neihguk, M.L. Munjal, Abhinav Prasad
Abstract The bias flow in Concentric Tube Resonator (CTR) is a flow-induced phenomenon in which the pressure gradient along the radial direction is produced by the kinetic energy of the flow. As a result, the flow dynamics in CTR is characterized by bias flow into the annular cavity in the upstream and outflow from the annular cavity in the downstream of the flow. This is due to the change in direction of the radial component of the bias flow at a point called the point of recovery, as a consequence of mass conservation. The pressure drop of CTR is a complex function of the momentum flux and other geometric parameters such as porosity, open area ratio, discharge coefficient of the perforated holes, bias inflow, bias outflow, grazing flow and length. In this study, numerical experiments are conducted to obtain an empirical formula for the friction factor of perforated pipes which are extensively used in automotive mufflers.
2015-06-15
Journal Article
2015-01-2305
Xin Hua, David W. Herrin, Yitian Zhang
Abstract A recently developed superposition approach for determining the insertion loss of a two-inlet muffler is reviewed. To validate the approach, calculated and measured insertion losses are compared for a small engine muffler with two inlets and one outlet. After which, the phasing between the two inputs is varied and the insertion loss is evaluated. Results show that the insertion loss is strongly affected by the phasing between sources at low frequencies while phasing between sources has a lesser impact at high frequencies. At the conclusion of the paper, the theory for applying the superposition approach to transmission loss is reviewed.
2015-06-15
Journal Article
2015-01-2316
Weam Elsahar, Tamer Elnady
Abstract In several applications, two-inlet single-outlet mufflers are possible to encounter in exhaust systems. They are usually used to merge two exhaust streams from two similar engines or from two sides of an engine. They have an advantage of reducing the back pressure on the engine(s). There is a lot of published research on the analysis of single-inlet single-outlet mufflers acting as a two-port. On the other hand, there are a few publications on the analysis of two-inlet single-outlet mufflers due to their complexity representing a three-port. A three-port is characterized by a 3×3 Scattering Matrix. The nine elements of this matrix represent the 3 reflection coefficients at each port, and the 6 transmission coefficients between the 3 ports in both directions. In this work, a two-inlet single-outlet muffler is studied. The elements of the scattering matrix were measured using the two-source two-microphone technique with and without flow.
2015-06-15
Technical Paper
2015-01-2317
Zhenlin Ji, Yiliang Fan
Abstract A simulative program named as MAP (Muffler Analysis Program) is developed for the rapid calculation and analysis of acoustic characteristics of duct muffling systems. The program is based on the plane wave theory and uses the Visual Basic 6.0 to create a friendly GUI (Graphic User Interface) for input of the geometrical and physical parameters to build and modify the duct muffling systems quickly. The relations among the acoustic elements are established by using the transfer matrix method, the transmission loss (TL) and insertion loss (IL) may be calculated, and then the results are plotted in terms of curves. Map allows designer to change parameters of the duct muffling systems expediently, in order to examine the effects of design changes on the acoustic attenuation characteristics and finally to get an acceptable solution.
2015-06-15
Journal Article
2015-01-2314
Adrien Mann, Min-Suk Kim, Barbara Neuhierl, Franck Perot, Robert Powell, Thomas Rose, Jan Krueger
Abstract Exhaust and muffler noise is a challenging problem in the transport industry. While the main purpose of the system is to reduce the intensity of the acoustic pulses originating from the engine exhaust valves, the back pressure induced by these systems must be kept to a minimum to guarantee maximum performance of the engine. Emitted noise levels have to ensure comfort of the passengers and must respect community noise regulations. In addition, the exhaust noise plays an important role in the brand image of vehicles, especially with sports car where it must be tuned to be “musical”. However, to achieve such performances, muffler and exhaust designs have become quite complex, often leading to the rise of undesired self-induced noise. Traditional purely acoustic solvers, like Boundary Element Methods (BEM), have been applied quite successfully to achieve the required acoustic tuning.
2015-06-15
Journal Article
2015-01-2315
Giulio Lenzi, Giovanni Ferrara, Andrea Fioravanti
Abstract The acoustic performance of mufflers with single-inlet and single-outlet are well described using Insertion Loss (IL) and Transmission Loss (TL). These parameters represent the acoustic damping on the engine emission and on the incident pressure wave respectively. However, for mufflers with multi-inlet these parameters depend also on the sources characteristics, as consequence their use is quite difficult. In the present work the acoustic performance of a double-inlet and single-outlet muffler are experimentally evaluated in terms of reflection and transmission coefficients of each port of the muffler itself. These coefficients are used to evaluate the Insertion Loss of the manifold muffler taking into account specific sources on the inlets. The characteristic coefficients are also used to predict the acoustic emission of the manifold muffler using a known engine source on the two inlets.
2015-06-15
Journal Article
2015-01-2312
P. Wang, J. Li, T. W. Wu
Abstract A simplified method to model perforated tubes in mufflers is the equivalent transfer impedance approach. Various empirical formulas that consider the porosity, hole diameter, wall thickness, and flow type have been proposed to date. They normally work very well under the conditions that the formulas are intended for. However, there are situations that the empirical formulas may not be able to cover. In this paper, we propose a simple BEM-based numerical procedure to determine the transfer impedance from a small perforate sample, and then send the transfer impedance to the muffler BEM model for analysis purposes. Numerical results are verified in three test cases.
2015-06-15
Technical Paper
2015-01-2313
Bryce Gardner, Abderrazak Mejdi, Chadwyck Musser, Sébastien Chaigne, Tiago De Campos Macarios
Abstract Flow strongly affects the propagation of acoustics wave transmission within a duct and this must be addressed by the vibro-acoustic modelling of duct systems subject to non-uniform flow. Flow impacts both the effective sound propagation speed in a duct and refracts the sound towards or away from the duct walls depending on whether the acoustic waves are propagating in the direction of the flow or against the flow. Accurate modeling of the acoustic propagation within a duct is crucial for design and “tuning” of muffler systems that need to strongly attenuate narrowband acoustic sources from the engine. Muffler systems that may avoid matching acoustic resonances to engine narrowband sources when no flow is present may experience shifting of resonances to frequencies that match engine sources and cause problems when the flow during a real operating condition is present.
2015-06-15
Technical Paper
2015-01-2310
Edward Ray Green
Abstract The Sound Transmission Loss of automotive intake and exhaust components is commonly measured using the four microphone tube method per ASTM E2611 [1]. Often area adapters are used to match the component diameter to that of the tube apparatus. These area adapters affect the Sound Transmission Loss measurement, especially at very low frequencies. The use of the Transfer Matrix Technique to remove the effect of the area adapters is described. The improvements for step and cone area adapters are compared.
2015-06-15
Technical Paper
2015-01-2311
Aditya Palsule, Arun Budama, Nandakumar Somasundaraeswer
Abstract Development of split Catalytic Converter (Cat-Con)-Muffler system was done to be used in front engine low floor (FELF) Bus from perspective of cost saving, modularity and reduction in complexity. This system is developed as an alternate to an existing solution of integrated Cat-Con and muffler. The paper describes the development of a split Cat-Con and muffler exhaust system for a FELF Bus, so as to meet cost and time considerations. The development also had to achieve a feasible solution, which could be installed within the packaging volume of the existing configuration of FELF while meeting the regulatory requirements [1] for Pass by noise (PBN), and at the same time conforming to backpressure limits set for optimum engine performance. Multiple design - prototypes - test iterations were carried out to meet the PBN and back pressure target for FELF Bus. The final solution was developed which achieved both the requirements within the specified space constraints.
2015-06-15
Technical Paper
2015-01-2211
Michael J. Santora, Dillon Savage
In the present study by the University of Idaho Clean Snowmobile Challenge (UICSC) team, the necessity, history, and research of noise reduction strategies in two-stroke snowmobile exhaust is presented. Testing and design is discussed to show the decision making process of College Design Series (CDS) teams. The UICSC CDS team is comprised of mechanical, electrical, and computer engineers. The development from static to dynamic noise cancellation is explained as a proof of concept and to further demonstrate CDS design. The study presents math models that validate the noise reduction technique. The noise reduction includes a mechanically active quarter-wave resonator (MAQR). Viability is given for the design and is presented with supporting implementation data. Control for the resonator platform is discussed. It is proven that mechanically active noise cancellation is an effective, lightweight, and simple solution to noise cancellation.
2015-06-15
Technical Paper
2015-01-2233
Hudson P Vijayakumar, V Shivaraj, T Sukumar, Suresh Gaikwad
Abstract Generally the brake system products are mounted on chassis with brackets which are subjected to dynamic loads due to road undulations. Exhaust brake is used to restrict the engine exhaust flow passage and thereby creates a back pressure in the engine for reducing the engine speed. This in turn reduces the vehicle speed. This is widely used in the vehicles operating in the hilly areas. This product is mounted on the exhaust passage and the air cylinder sub-assembly which actuates the exhaust brake is mounted on a bracket. Automotive industries perform durability tests on vehicles to reduce the failure on end-user environment. An assembly which has cleared the durability test got failed on addition of a spring into the assembly. The inclusion of spring is for enhancing the performance of the overall assembly.
2015-06-15
Technical Paper
2015-01-2266
Andrzej Pietrzyk
Abstract Several of the exterior noise sources existing around a vehicle can cause airborne noise issues at relatively low frequencies. SEA, traditionally used for airborne sound issues is not suitable for the frequency range of interest. Finite Element analysis has been used. Handling of the non-reflecting condition on the outer boundary of the exterior cavity is an issue. Recently, advances have been made in several commercially available codes, which made the analysis practical. Including the poro-elastic material model for foam-based carpets is also becoming practically possible. The purpose of the current study is to investigate the practical applications of those new developments against test data, and to estimate the feasibility of using these procedures in the vehicle development projects. Measurements were carried out in a new semi-anechoic chamber at Volvo Cars.
2015-06-15
Technical Paper
2015-01-2306
John G. Cherng, Weiwei Wu, Peiran Ding, Mike Hebbes, Henry Zhang
Abstract This study presents an efficient process to optimize the transmission loss of a vehicle muffler by using both experimental and analytical methods. Two production mufflers were selected for this study. Both mufflers have complex partitions and one of them was filled with absorbent fiberglass. CAD files of the mufflers were established for developing FEA models in ANSYS and another commercial software program (CFEA). FEA models were validated by experimental measurements using a two-source method. After the models were verified, sensitivity studies of design parameters were performed to optimize the transmission loss (TL) of both mufflers. The sensitivity study includes the perforated hole variations, partition variations and absorbent material insertion. The experimental and sensitivity analysis results are included in the paper.
2015-06-02
Magazine
Balancing GDI fuel economy and emissions Will OEMs have to adopt gasoline particulate filters to comply with stringent new emissions regulations? Top engineers discuss current developments. Cameras look to go the distance Automakers seek vision systems with greater distances, improved reliability, and more functionality, thanks to ruggedized complementary metal-oxide semiconductor technologies. Mixing metals Cadillac pursues aluminum/steel mix for new CT6 luxury sedan, leading to advances in body assembly.
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