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Viewing 271 to 300 of 58642
2009-06-15
Technical Paper
2009-01-1946
Federica Franzoni, Massimo Milani, Luca Montorsi, Valeri Golovitchev
A novel concept of combined hydrogen production and power generation system based on the combustion of aluminum in water is explored. The energy conversion system proposed is potentially able to provide four different energy sources, such us pressurized hydrogen, high temperature steam, heat, and work at the crankshaft on demand, as well as to fully comply with the environment sustainability requirements. Once aluminum oxide layer is removed, the pure aluminum can react with water producing alumina and hydrogen while releasing a significant amount of energy. Thus, the hydrogen can be stored for further use and the steam can be employed for energy generation or work production in a supplementary power system. The process is proved to be self-sustained and to provide a remarkable amount of energy available as work or hydrogen.
2009-06-15
Technical Paper
2009-01-1947
J. Michael Langham
The purpose of this document is to introduce the design of a new type automobile engine & powertrain. The engine emulates, as closely as possible, the operation of the electric vehicle, and, as such, uses no starter and develops 100% torque at zero speed. It is lighter in weight and operates at a higher compression ratio than the standard automobile engine, while running on lower-octane gasoline. It only runs when power is needed at the wheels. Because it is more efficient than either the standard engine or the hybrid when running, and because it is off considerably more of the time than the hybrid, it can obsolete both.
2009-05-19
Technical Paper
2009-01-2064
Kurt Sheridan, Brian K. Wilson
Development of modern powertrains used in car and truck applications is more competitive than ever before. Powertrains and components previously considered to be advanced technology, such as hybrids and dual-clutch transmission technology, are now commonplace, being designed and manufactured in all worldwide markets. In order to stay competitive, powertrain OEMs must simultaneously optimize attributes such as performance, cost, weight, durability, fuel economy and NVH while producing new, desirable designs with reduced product development timelines. Oftentimes, the ideal solution for optimization of gear whine will result in an unexpected deterioration of durability, and vice versa. An advanced software tool was previously developed for the design of transmissions and transaxles, including analysis of the vibration, efficiency and durability performance under specified speeds and loads.
2009-05-19
Journal Article
2009-01-2063
Darrell Robinette, Randall S. Beikmann, Paul Piorkowski, Michael Powell
The objective of this investigation is to characterize the ability of loose gears to resist rattle in a manual transmission driven by an internal combustion engine. A hemi-anechoic transmission dynamometer test cell with the capability to produce torsional oscillations is utilized to initiate gear rattle in a front wheel drive (FWD) manual transmission, for a matrix of operating loads and selected gear states. A signal processing technique is derived herein to identify onset of gear rattle resulting from a standardized set of measurements. Gear rattle was identified by a distinct change in noise and vibration measures, and correlated to gear oscillations by a computed quantity referred to as percent deviation in normalized gear speed. An angular acceleration rattle threshold is defined based upon loose gear inertia and drag torque. The effects of mean speed, mean and dynamic torque, and gear state on the occurrence of loose gear rattle are reported.
2009-05-19
Technical Paper
2009-01-2066
Mohamad S. Qatu, Javed Iqbal
The advantages of having higher stiffness to weight ratio and strength to weigh ratio that composite materials have resulted in an increased interest in them. In automotive engineering, the weight savings has positive impacts on other attributes like fuel economy and possible noise, vibration and harshness (NVH). The driveline of an automotive system can be a target for possible use of composite materials. The design of the driveshaft of an automotive system is primarily driven by its natural frequency. This paper presents an exact solution for the vibration of a composite driveshaft with intermediate joints. The joint is modeled as a frictionless internal hinge. The Euler-Bernoulli beam theory is used. Lumped masses are placed on each side of the joint to represent the joint mass. Equations of motion are developed using the appropriate boundary conditions and then solved exactly.
2009-05-19
Technical Paper
2009-01-2065
Claire Chaufour, Erik Gustavsson, Arvid Norberg
This Paper is evaluating the development and effectiveness of using a Shearplate, a new and innovative approach to reduce powertrain noise and vibrations. The results show that the approach is offering monumental improvements in terms of reduced noise and vibrations. Sound quality evaluations also show very clearly that the approach is an effective countermeasure to the targeted problems. With the knowledge gathered during the development and with what is partly presented in this paper we now have an additional tool that car manufacturers can deploy in their efforts to design more fuel efficient and cleaner burning engines without sacrificing NVH performance.
2009-05-19
Technical Paper
2009-01-2060
Abdelkrim Zouani, Thomas Smith, Frank Valencia, Changshen Gan, Mamta Sabharwal, Chul Lee, Ankur Bhosale, Prasanna Kondapalli
The increased demand to reduce cost and weight is forcing engine manufacturers to replace some metal under hood components with high performance polymers. The use of these materials has often been avoided in this type of applications due to concerns around their long-term strength and temperature performance. In particular, the materials of choice for the oil pans in the gasoline engines, at the present time, are aluminum and stamped steel. This paper presents a case study to evaluate the NVH performance of a plastic oil pan designed to replace a stamped steel pan in a gasoline engine. Emphasis is given to the design features and material characteristics that were considered to achieve the required NVH performance.
2009-05-19
Technical Paper
2009-01-2057
Bernard Van Antwerpen, Diego d’Udekem, Jean-Luc Bourachot, Jean-Pascal Leandre, Alain Walbott, Benoît Bouvier
High pressure pipes of the diesel injection system seem to represent a weak point in terms of vibration and acoustic radiation of the whole injection system. Investigations have highlighted this phenomenon. The injectors induce acoustic waves which propagate in the viscous diesel contained in the injection pipes. A strong coupling can occur sometimes between these acoustic waves and the duct structural modes leading to intensive mechanical vibration and acoustic radiation; and sometimes to a possible failure of the pipe. Numerical simulations offer a good platform to predict such vibration and can be used in order to prevent any structural component failure and to decrease the resulting acoustic radiation. This paper presents a vibro-acoustic study performed with the finite element code ACTRAN to estimate which parameters play a role in this process and to provide some guidelines for avoiding problems.
2009-05-19
Technical Paper
2009-01-2062
Hu Jianjun, Qin Datong, Zhao Yusheng, Liu Yonggang
The working principle of dual mass flywheel - radial spring (DMF-RS) type torsional vibration damper was analyzed, and the design method of natural torsional vibration characteristics control of DMF-RS type torsional damper for automotive powertrains was studied herein. Based on the multi-freedom lumped mass - torsional vibration spring analysis model of powertrain, the natural torsional vibration characteristics of the system with DMF-RS type torsional damper were analyzed, and compared with the clutch type torsional vibration damper, the effectiveness of DMF-RS type torsional damper on the torsional vibration control was verified.
2009-05-19
Technical Paper
2009-01-2061
Scott Yu, Rob Higley
Imbalances of an automatic transmission have a direct impact on NVH. To measure those imbalances, one needs to overcome two hurdles: (1) Phase uncertainty of individual component imbalance due to clutch indexing; (2) Imbalance separation of transmission from other systems, such as driveshaft and engine crank, connected to the transmission. To attack those issues, an algorithm has been developed which can deal with the phase issue caused by clutch engagement, and separate transmission imbalance at the system level without individually measuring other system imbalances. The method has been verified with several vehicle programs in both vehicle and dynamometer tests.
2009-05-19
Journal Article
2009-01-2053
Charlie Teng, Steve Homco
With swelling gasoline prices, automotive OEMs have taken different approaches to improve vehicle fuel economy. One trend is to down-size the engine and to add turbo charging. One of the challenges in utilizing the turbocharger in passenger cars is to control the added NVH issues associated with this hardware, especially for the North American market where turbocharger use is scarce in gasoline engines. In this paper, the authors review an investigation on turbocharger related “whoosh” noise on a V6 engine. The whoosh noise, also called surge noise, is caused by the compressor working at or near surge conditions. Whoosh noise is a broad frequency band flow noise typically found during throttle tip-in conditions, but sometimes found even at steady state driving conditions. The root cause of whoosh noise and the detection methods are discussed in this paper. The countermeasures to reduce whoosh noises are also discussed.
2009-05-19
Technical Paper
2009-01-2056
M. Flekiewicz, P. Fabiś, B. Flekiewicz
The availability of gaseous fuels such as natural gas and propane butane mixtures has led to worldwide popularity of internal combustion engines running dual fuel or alternatively gas powered. These gaseous fuels are known as fuels more resistant to knocking than conventional liquid fuels and as less ones pollutant. Their better mixing with air is also well recognized. There are some works published on the use of gaseous fuels, but the problem of the combustion noise, as a very important source of information regarding the combusted fuel, is not receiving much attention. Combustion noise occurs in two forms, direct and indirect. It is transmitted throughout the engine block as a vibration at a different spectrum of frequencies. In this study an attempt is made to relate the combustion noise to the operating parameters for LPG, CNG and Hydrogen enriched CNG powered engine as compared to petrol fueled engine.
2009-05-19
Technical Paper
2009-01-2055
N. Orand, R. Rhote-Vaney
In the powertrain development of an automobile, the accurate prediction and understanding of the fuel supply and injection system behavior is necessary to achieve the targeted vehicle performance. With stronger demand from the customers for quieter vehicles, complementary functional objectives have to be met such as packaging, component or material change, or the modification of the fuel supply system layout. Understand the possible sources of noise and vibration from the fuel supply and delivery system requires having an analytical model of a complete fuel system, from the fuel pump assembly to the injectors. One has to note that adequate level of component details is required for the modeling and validation. In this study, the lumped-parameter model approach of the fluid dynamics on the fuel supply and delivery system has been developed and validated with the test results.
2009-05-19
Technical Paper
2009-01-2047
Ketan G. Kshirsagar, Scott R. Kiel, Mohan D. Rao
This paper describes the design, development and validation of a muffler for reducing exhaust noise from a commercial tele-handler. It also describes the procedure for modeling and optimizing the exhaust muffler along with experimental measurement for correlating the sound transmission loss (STL). The design and tuning of the tele-handler muffler was based on several factors including overall performance, cost, weight, available space, and ease of manufacturing. The analysis for predicting the STL was conducted using the commercial software LMS Virtual Lab (LMS-VL), while the experimental validation was carried out in the laboratory using the two load setup. First, in order to gain confidence in the applicability of LMS-VL, the STL of some simple expansion mufflers with and without extended inlet/outlet and perforations was considered. The STL of these mufflers were predicted using the traditional plane wave transfer matrix approach.
2009-05-19
Journal Article
2009-01-2048
I. J. Lee, A. Selamet, H. Kim, T. C. Kim, J. Kim
A multi-chamber silencer is designed by a computational approach to suppress the turbocharger whoosh noise downstream of a compressor in an engine intake system. Due to the significant levels and the broadband nature of the source spanning over 1.5 – 3.5 kHz, three Helmholtz resonators are implemented in series. Each resonator consists of a chamber and a number of slots, which can be modeled as a cavity and neck, respectively. Their target resonance frequencies are tuned using Boundary Element Method to achieve an effective noise reduction over the entire frequency range of interest. The predicted transmission loss of the silencer is then compared with the experimental results from a prototype in an impedance tube setup. In view of the presence of rapid grazing flow, these silencers may be susceptible to whistle-noise generation. Hence, the prototype is also examined on a flow bench at varying flow rates to assess such flow-acoustic coupling.
2009-05-19
Technical Paper
2009-01-2049
Ming Une Jen, Ming-Hung Lu
We assessed the feasibility of weight reduction concerning noise and vibration characteristics for engine components. Three alternatives were plastic intake manifold, stamped steel oil pan, and no balance shaft. The assessment indices were engine noise level, engine mount bracket vibration, and engine block vibration. Reducing the reciprocating mass and applying design alternatives made the removal of balance shaft feasible. The lightweight plastic intake manifold was beneficial to the engine vibration with a little improvement to the engine noise. The stamped steel oil pan, with optimal structural ribs design and EMS calibration, offered all the benefits of weight, vibration, and noise improvements.
2009-05-19
Technical Paper
2009-01-2052
Longxin Zhen, Zijun An, Qiang Li, Baocheng Wang
With ever-increasing oil and gasoline prices, automotive manufacturers are striving to improve fuel economy. There are many factors that affect vehicle fuel consumption, such as engine size, vehicle weight, driving habits, and more. For a particular vehicle, engine combustion quality is one of the most important factors that affect fuel economy. Engine combustion quality also directly affects engine emissions, vehicle drivability, and vehicle NVH. Automotive manufacturers have been using different technologies to control engine combustion quality, such as using low cost pressure transducers to measure and control engine combustion in real time. In this paper, the authors have proposed a method that could directly use the Crank Position Sensor (CPS) signal to measure engine combustion quality.
2009-05-19
Journal Article
2009-01-2042
Steven G. Mattson, David Labyak, Jeff Pruetz, Terence Connelly
A reactive aftermarket automotive style muffler was considered for development and validation of a procedure to numerically predict and experimentally validate acoustic performance. A CAD model of the silencer was created and meshed. The silencer interior included two sections of perforated pipe, which were included in the cavity mesh. A hybrid FE-SEA (Statistical Energy Analysis) numerical model consisting of a finite element acoustic cavity excited by a diffuse acoustic field at the inlet and coupled via hybrid junctions to SEA semi-infinite fluids on both the inlet and outlet. The hybrid FE-SEA model solves very rapidly on a desktop PC making iterative numerical design a realistic option. To validate the predictions, an experimental setup was created to directly measure the muffler insertion loss. This was done by using a broadband acoustic source piped into a hemi-anechoic chamber.
2009-05-19
Journal Article
2009-01-2043
Mikael Karlsson
The acoustic impedance of a circular, confined, side branch orifice subjected to grazing flow is studied. Two geometries are tested. In both geometries, the side branch dimension is of the same order as that of the main duct. The system is viewed as an acoustic three-port, whose passive properties are described by a system matrix. The impedance is studied with the acoustic field incident at different ports, which is shown to influence the results significantly. When excited from the leading edge or from the side branch, an interaction of the hydrodynamic and acoustic fields is triggered, while excitation from the trailing edge does not trigger such an interaction. For both the resistance and the reactance (here expressed as an end correction) the results vary in the three possible excitation cases. In the quasi-stationary limit the resistance is given by a loss coefficient times the Mach number, and the end correction collapses to a single value.
2009-05-19
Technical Paper
2009-01-2044
Chuanxi Ju, Sung Yoo
To facilitate the design and validation of exhaust system, quantification of tailpipe noise contribution to vehicle cabin is usually necessary. In this paper, transfer path analysis (TPA) concept has been applied to investigate the contributions from tailpipe and other noise sources as well as the interaction between tailpipe noise and its transmission path to vehicle cabin. An artificial acoustic source has been designed for transfer function measurement and an all-wheel-drive dynamometer located in anechoic chamber is used as a testing platform to collect operational data. A validation methodology has also been proposed and implemented by comparing the measured and predicted interior noise response with a big auxiliary muffler (BAM).
2009-05-19
Technical Paper
2009-01-2045
Hans Rämmal, Mats Åbom
In this paper experimental procedures to determine the sound transmission through automotive turbo-charger compressors are described. An overview of a unique turbocharger testing facility established at KTH CICERO in Stockholm is given. The facility can be used to measure acoustic two-port data for turbo-compressors. Results from measurements on a passenger car turbo-compressor are presented and the influence of operating conditions on the sound transmission is discussed.
2009-05-19
Technical Paper
2009-01-2038
Chulho Yang, John George, Thomas Wahl, Hao Jin
The muffler shell of an automotive exhaust system can cause significant NVH (noise/vibration/harshness) issues like shell vibration and radiated noise, buzzing, rattling, and implosion problems. Due to the complex relationship between the dynamic behavior of the muffler shell and many parameters like engine operating temperature, curvature of the shell, material density, shell thickness and baffle spacing, the NVH engineers have experienced difficulties identifying the root cause of problems and solutions to them. By considering all design parameters, a theoretical study on shell vibration has been conducted to investigate applicability of an analytical technique to predict and solve the NVH issues of an automotive muffler. We have identified the most promising shell vibration theories by comparing the solutions with the results from modal test and finite element analysis.
2009-05-19
Technical Paper
2009-01-2039
William E. Hill
A new passive muffler valve has been developed that offers the advantages of both the current passive and active valves without their major drawbacks. Like current passive valves this new valve provides high restriction at low to medium engine speeds for improved noise control. But with a near over-center spring action and unique flap shape, this high performance valve has minimal pressure drop at high engine speeds, closer to the active valve pressure drop performance. The in-line design of the valve makes it ideal for low restriction OE mufflers, resonators, and aftermarket performance mufflers. The new valve design is uncomplicated, with few components and has been tested extensively for durability utilizing both bench and vehicle level testing.
2009-05-19
Technical Paper
2009-01-2040
Axel Kierkegaard, Susann Boij, Gunilla Efraimsson
We present an efficient methodology to perform calculations of acoustic propagation and scattering by components in ducts with flows. In this paper a methodology with a linearized Navier-Stokes equations solver in frequency domain is evaluated on a two-dimensional geometry of an in-duct area expansion. The Navier-Stokes equations are linearized around a time-independent mean flow that is obtained from an incompressible Reynolds Averaged Navier-Stokes solver which uses a k-ε turbulence model and adaptive mesh refinement. A plane wave decomposition method based on acoustic pressure and velocity is used to extract the up and downstream propagating waves. The reflection of the acoustic waves by the induct area expansion is calculated and compared to both measurements and analytical models. Frequencies in the plane wave range up to the cut-on frequency of the first higher order propagating acoustical mode are considered.
2009-05-19
Technical Paper
2009-01-2041
J. Liu, D. W. Herrin
The source in an intake/exhaust system is commonly modeled as a source strength and impedance combination. Both the strength and impedance are normally measured and measurement accuracy depends on selecting an appropriate acoustic load combination. An incident wave decomposition method is proposed which is based on acoustic wave decomposition concepts instead of an electric circuit analogy providing a more straightforward approach to investigating the effect of acoustic load selection. Based on studying wave reflections in the system, the uncertainty for determining source impedance is estimated.
2009-05-19
Journal Article
2009-01-2034
Jae-Yeol Park, Rajendra Singh
Most of the prior work on active mounting systems has been conducted in the context of a single degree-of-freedom even though the vehicle powertrain is a six degree-of-freedom isolation system. We seek to overcome this deficiency by proposing a new six degree-of-freedom analytical model of the powertrain system with a combination of active and passive mounts. All stiffness and damping elements contain spectrally-varying properties and we examine powertrain motions when excited by an oscillating torque. Two methods are developed that describe the mount elements via a transfer function (in Laplace domain). New analytical formulations are verified by comparing the frequency responses with numerical results obtained by the direct inversion method (based on Voigt type mount model). Eigensolutions of a spectrally varying mounting system are also predicted by new models.
2009-05-19
Technical Paper
2009-01-2035
Shi Zheng, Chris Kleinfeld
The definition method and the two load/source method of a transmission loss test of an automotive tuning device are discussed in this paper. For the definition method, the accuracy penalty due to the imperfect anechoic termination quality is studied based on an empirical acoustic model of glass-wool and the best practice of constructing an anechoic termination is attempted. The conclusion is verified with numerical simulations. For the two load/source method, the difference in the two source/load impedances compounded with the error of measured acoustic pressures, as related to transmission loss accuracy, is discussed and demonstrated.
2009-06-15
Journal Article
2009-01-1980
Abhishek Vishwakarma, P. Chandramouli, V. Ganesan
A one-dimensional analysis was performed to analyze a three-pass muffler with perforated tubes for Transmission Loss, using numerical decoupling approach. Effect of mean flow on transmission loss inside the muffler was studied. To account for the three-dimensional nature of acoustic waves at higher frequencies, a three dimensional finite element analysis was done using SYSNOISE. The Transmission loss results of the three-dimensional analysis were compared with those of one-dimensional analysis for no flow case and shown to agree reasonably for lower frequency range.
2009-06-15
Technical Paper
2009-01-1984
Emiliano Pipitone
Internal combustion engine modeling is nowadays a widely employed tool for modern engine development. Zero and mono dimensional models of the intake and exhaust systems, combined with multi-zone combustion models, proved to be reliable enough for the accurate evaluation of in-cylinder pressure, which in turn allow the estimation of the engine performance in terms of indicated mean effective pressure (IMEP). In order to evaluate the net engine output, both the torque dissipation due to friction and the energy drawn by accessories must be taken into consideration, hence a model for the friction mean effective pressure (FMEP) evaluation is needed.
2009-05-19
Technical Paper
2009-01-2030
Filip De Coninck, Wim Desmet, Paul Sas, Eric Hansenne, Yvan Van Gucht, Luk Dedene
OEM's increase the pressure on their suppliers to design, develop and test their products within a short time period. This requires design ‘first-time-right’ philosophy and advanced numerical and experimental methods. Four steps are required to experimentally asses the durability of exhaust systems. Environmental loads and strain references are acquired on the test track. This data is analyzed and damaging are sections retained. These sections are then reproduced on a test rig. During this reproduction, strain is measured at the reference locations and the damage is calculated and compared with the test track data.
Viewing 271 to 300 of 58642

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