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Training / Education
2014-10-27
This Engineering Academy covers a variety of vehicle noise control engineering principles and practice. Two specialty tracks are available: Vehicle Interior Noise and Powertrain Noise. While the Vehicle Interior Noise track focuses on the understanding and application of acoustical materials to optimize NVH in the passenger or operator compartment of a vehicle, the Powertrain Noise track focuses on NVH issues generated by powertrain noise sources and the design strategies to minimize them. Noise sources include engines, transmissions/transfer cases, accessories, exhaust, gears, axles, joints, and couplings. Considerable attention is given to current measurement and instrumentation technologies and their effective use.This Engineering Academy covers a variety of vehicle noise control engineering principles and practice. Two specialty tracks are available: Vehicle Interior Noise and Powertrain Noise. While the Vehicle Interior Noise track focuses on the understanding and application of acoustical materials to optimize NVH in the passenger or operator compartment of a vehicle, the Powertrain Noise track focuses on NVH issues generated by powertrain noise sources and the design strategies to minimize them.
Training / Education
2014-10-27
This Engineering Academy covers a variety of vehicle noise control engineering principles and practice. Two specialty tracks are available: Vehicle Interior Noise and Powertrain Noise. While the Powertrain Noise track focuses on NVH issues generated by powertrain noise sources and the design strategies to minimize them, the Vehicle Interior Noise track focuses on the understanding and application of acoustical materials to optimize NVH in the passenger or operator compartment of a vehicle. Considerable attention is given to current measurement and instrumentation technologies and their effective use. Practical Component This Academy includes several equipment demonstrations and hands-on lab sessions. Specific instrumentation suppliers have been selected for an instrumentation workshop on one evening. There is also a field trip to one of the OEM’s noise and vibration facility in the metro Detroit area. Through these activities, you become acquainted with relevant instrumentation, measurement protocols, and problem solving strategies.
Event
2014-10-20
This session sets out to reflect the recent advances on the research, development and practices of Powertrain NVH treatment. The technical papers are of interest to powertrain system designers, testing specialists, NVH experts, and other individuals who evaluate and develop technologies to control powertrain NVH. The coverage includes: engine, engine subsystem and components noise and vibration; powertrain systems noise measurement and instrumentation; powertrain systems noise analysis.
Event
2014-10-20
This session sets out to reflect the recent advances on the research, development and practices of Powertrain NVH treatment. The technical papers are of interest to powertrain system designers, testing specialists, NVH experts, and other individuals who evaluate and develop technologies to control powertrain NVH. The coverage includes: engine, engine subsystem and components noise and vibration; powertrain systems noise measurement and instrumentation; powertrain systems noise analysis.
Event
2014-10-05
This session focuses on innovations for improving brake NVH (Noise, Vibration and Harshness) performance. Papers and presentations involving new methods, theories, techniques, and application examples are welcome.
Training / Education
2014-09-10
This four-session webinar provides a detailed understanding of the source – path-receiver relationship for developing appropriate sound package treatments in vehicles, including automobiles, commercial vehicles, and other transportation devices. The webinar provides a detailed overview of absorption, attenuation (barrier), and damping materials and how to evaluate their performances on material, component, and vehicle level applications. A significant part of this course is the case studies that demonstrate how properly designed sound package materials successfully address vehicle noise issues. Note: A similar course is available as a classroom seminar.
Training / Education
2014-08-05
This webinar provides an in-depth overview of diesel engine noise including combustion and mechanical noise sources. In addition, the instructor will discuss a system approach to automotive integration including combining sub-systems and components to achieve overall vehicle noise and vibration goals.
Technical Paper
2014-06-30
Kasper Steen Andersen, Fuyang Liu
Keywords Aftertreatment system, Exhaust, Silencer, Transfer Matrix, Coupling Introduction The tailpipe noise from an aftertreatment system must comply with legislation and meet customer expectations. The approach to capture the influence of complicated geometries and the ceramic substrates included in full aftertreatment systems is possible by coupling the 1D analytical solution of the substrates with the 3D FEM solution. The originality of the paper This paper present simulation and measurement results for a complete aftertreatment system including DOC, DPF, SCR, mixers and acoustic features with and without mean flow, where the transfer matrix of the aftertreatment system founds the basis for both transmission loss, insertion loss and tail pipe noise calculations. The transfer matrix of the aftertreatment system is extracted after solving the finite element model only once, when applying the appropriate boundary conditions and taking advantage of a symmetric transfer matrix with a determinant of one.
Technical Paper
2014-06-30
Koen Vansant, Hadrien Bériot PhD, Claudio Bertolini, Giuseppe Miccoli
As the legislation for pass-by-noise (PBN) has recently become more stringent, it is clear that car manufacturers face again a challenging task to reach the new SPL objective (70dB(A)). Following the well-known scheme of source-transmission-receiver, we can see how a good design of the engine bay is required to sufficiently attenuate the noise coming from sources as the engine and the intake. This involves proper design of the engine bay’s panels including apertures, and a good selection of the type and location of acoustic treatments. Such optimization or redesign can be inspired by a new target SPL, but can also be initiated by a change in source: the radiated noise from an electric motor differs from that of a conventional IC engine. For a given engine bay design, the PBN SPL results can be obtained with a PBN test or by an equivalent simulation. The conditions for a good PBN test setup are well described but not always easy to obtain. Using simulation models however it is possible to create the perfect test environment virtually and moreover to obtain acoustic results for a large number of designs upfront of any actual testing or prototype.
Technical Paper
2014-06-30
Albert Albers, Jan Fischer, David Landes, Matthias Behrendt
Albert Albers 1, *Jan Fischer 1, David Landes 1, Matthias Behrendt 1 1 IPEK - Institut für Produktentwicklung am Karlsruher Institut für Technologie (KIT) * Contact author: Kaiserstr. 10, 76131 Karlsruhe; jan.fischer@kit.edu The driving comfort is an important factor for buying decisions. Especially for battery electric vehicles (BEV) the acoustic quality is an elementary distinguishing feature, since the masking of an internal combustion engine (ICE) is no longer present. Opposing the importance of the acoustic quality is the lack of knowledge of how to measure and interpret the high frequency noise generated by an electric powertrain with respect to the NVH behavior influencing the passengers [1, 2]. In this contribution a method for measuring and interpreting the transfer path of acoustic phenomena from the drivetrain of a battery electric vehicle into the passenger cabin is presented. Due to the lack of masking by the ICE in case of BEV, high frequency phenomena must be considered as well.
Technical Paper
2014-06-30
Ze Zhou, Jonathan Jacqmot, Gai Vo Thi, ChanHee Jeong, Kang-Duck Ih
Abstract: The NVH study of trimmed vehicle body is essential in improving the passenger comfort and optimizing the vehicle weight. Efficient modal finite-element approaches are widely used in the automotive industry for investigating the frequency response of large vibro-acoustic systems involving a body structure coupled to an acoustic cavity. In order to accurately account for the localized and frequency-dependant damping mechanism of the trim components, a direct physical approach is however preferred. Thus, a hybrid modal-physical approach combines both efficiency and accuracy for large trimmed body analysis. Dynamic loads and exterior acoustic loads can then be applied on the trimmed body model in order to evaluate the transfer functions between these loads and the acoustic response in the car compartment. The scenario study of installing different trim components into the vehicle provides information on the acoustic absorption and dynamic damping with regard to added vehicle weight by the trim.
Technical Paper
2014-06-30
Daniel Fernandez Comesana, Emiel Tijs, Daewoon Kim
For (benchmark) tests it is not only useful to study the acoustic performance of the whole vehicle, but also to assess separate components such as the engine. Reflections inside the engine bay bias the acoustic radiation estimated with sound pressure based solutions. Consequently, most current methods require dismounting the engine from the car and installing it in an anechoic room to measure the sound emitted. However, this process is laborious and hard to perform. In this paper, two particle velocity based methods are proposed to characterize the sound radiated from an engine while it is still installed in the car. Particle velocity sensors are much less affected by reflections than sound pressure microphones when the measurements are performed near a radiating surface due to the particle velocity's vector nature, intrinsic dependency upon surface displacement and directivity of the sensor. Therefore, the engine does not have to be disassembled, which saves time and money. An array of special high temperature particle velocity probes is used to measure the radiation simultaneously at many positions near the engine of a compact class car.
Technical Paper
2014-06-30
Hiromichi Tsuji, Kimihiko Nakano PhD
In the early stage of digital phase and prototype experimental phase, the identification of the operational force on the components and the most important paths of the vibration correlated to the one of the evaluation points, such as steering, seats, and passenger ears, is required for optimizing the dynamic characteristics of the subsystem components of the vehicle. The transfer path analysis (TPA) with the impedance matrix of the component joints is widely used and reliable method to identify the force and the paths of the noise and vibration. However, the conduction of this TPA costs a lot of times. In addition, the estimated force includes not contributing to the evaluation responses. The uncorrelated force to the evaluation responses causes the design errors of the dynamic characteristics in the digital development phase when it has high value at the certain frequency range. To solve the problems, a new force estimation technique is presented in this paper. The proposed technique is based on TPA with the impedance matrix in the frequency domain.
Technical Paper
2014-06-30
Mahdi Mohammadpour, Ramin Rahmani, Homer Rahnejat
The over-riding objective in modern engine development is fuel efficiency. This has led to a host of pursued measures, including down-sizing (a lower number of cylinders), high output power-to-weight ratio, variable valve activation or cylinder de-activation (CDA) as well as a gradual trend towards mild or micro-hybrid technology. Furthermore, The main aim is to combine a suitable combination of the aforementioned methods with various driving conditions in order to reduce thermal and frictional losses as well as meeting the ever stringent emission directives as outlined in the NEDC. Another imperative is to ensure good NVH refinement which can be adversely affected by application of the above trends, such as light weight constructions and exacerbated power torque variations with CDA. The highlighted issues affect all the load bearing conjunctions in an engine. In particular, increased load fluctuations with CDA can also affect the whirl stability of big-end bearings. Therefore, the current paper concentrates on the issues that affect the big-end bearing thermo-frictional characteristics and dynamic stability in NEDC cycle.
Technical Paper
2014-06-30
Roland Sottek, Bernd Philippen
In the engine development process, the ability to judge NVH comfort as early as possible is a great benefit. The prediction of engine noise on the basis of a prototype engine without the need to install it in a real car significantly speeds up the development process and leads to a cost reduction, as prototype modifications can be evaluated faster. Meaningful predictions of the perceived NVH comfort cannot be achieved just by comparing order levels, but require listening to an auralization of the engine noise at the driver’s position. With the methods of Transfer Path Analysis and Synthesis (TPA/TPS) a prototype engine can be virtually installed in a car using test-bench data. The interior noise can be estimated by combining source signals containing near-field airborne radiation and mount forces together with transfer functions describing the transmission to the target position in the cabin. Even the transfer functions of a predecessor car could be used if the new car body is not yet available.
Technical Paper
2014-06-30
Sameh AFFI
In order to face new standards restrictions (ex: EURO6, CAFE), car manufacturers are looking for reducing both fuel consumption and toxic emission. That's why, they are heading much more for hybrid technology with preferably simple and low cost solutions. In this case, Stop & Start system may be adopted without heavy modifications of existent architecture (12V board system and conventional ring gear starter). Such technology results in higher ICE (internal combustion engine) restart occurrence, which impacts customers' acceptance of its NVH aspect. Indeed, engine restart should be imperceptible especially when it steps in without driver's will because it may surprise or even annoy. Besides, noise perception is directly related to engine restart duration. Therefore, the shorter the restart, the better the perception will be at equal noise level. This paper provides NVH analysis of engine restart sequence with conventional ring gear starter. Some optimized solutions for hybrid application was tested and their contribution on reducing restart noise and duration was quantified by a test bench.
Technical Paper
2014-06-30
Rujia Wang, Diange Yang, Ziteng Wang
Identification and quantitative measurement of the pass-by noise radiated by moving vehicles exterior sources correctly and quickly is very important in controlling vehicle noise. In the recent years, acoustical holography has been widely applied for noise sources location and sound field quantitative measurement. Based on this theory, we developed several methods which can effectively achieve identification of moving sound sources and improve the accuracy of quantitative measurement: the diffraction acoustical holography method, dynamic wave super position method, and hybrid acoustical holography method which is the acoustical holography based on wave superposition (WSAH). In this paper, the theoretical analysis and simulations of the comparative study of the above methods were taken; experiments were also carried out based on these methods. With the comparison among these methods, the research conclusions are drawn that the hybrid acoustical holography method performs best in quantitative measurement, which not only provide better identification results for locating sound sources accurately but also reduce the side lobe significantly and solve the ghost sources problem successfully.
Technical Paper
2014-06-30
Ennes Sarradj, Thomas Geyer, Christoph Jobusch, Sebastian Kießling, Alexander Neefe
The development of energy-efficient and lightweight vehicles is a major challenge for researchers and engineers in the automotive industry, with one solution being the use of micro gas turbines in serial hybrid vehicles. Among other advantages, the use of a micro gas turbine instead of a reciprocating engine, enables a high reliability and low emissions. What makes the concept of using a gas turbine even more interesting are its special NVH characteristics, which are quite different from those of a reciprocating engine. Besides the fact that a gas turbine in general produces less noise and vibration than a diesel engine of the same power, the characteristic noise spectrum is also very different. In this paper, the noise characteristics of a micro gas turbine are compared to those typical for a common reciprocating engine and the sources of the noise are considered. The data that form the basis for these analyses were obtained using measurements on a 70 kW micro gas turbine that is designed to be used in a serial hybrid concept for buses.
Technical Paper
2014-06-30
Barry M. James, Andreas Hofmann
The noise performance of electric vehicles is essential to ensure that they gain market acceptance. This can be a challenge for several reasons. Firstly, there is no masking from the internal combustion engine. Next, there is pressure to move to motor designs such as Switch Reluctance Motors, which have worse dynamic properties than their Permanent Magnet counterparts. Finally, there is the drive towards higher speed motors with their greater power density. Experience has shown that this challenge is frequently not met. It is known that reputable motor suppliers reputable transmission suppliers have designed and developed their "quiet" sub-systems to conventional, state of the art levels, only to discover that the assembled E-powertrain is unacceptably noisy. This paper follows an EU-funded project that is part of the FP7 programme that is focussed on the design of a highly integrated driveline for a passenger car. The consortium is led by Bosch but includes the likes of Renault, Romax Technology, Fuchs and GKN Driveline.
Technical Paper
2014-06-30
Vishal Parmar, Daniele Di Rocco, Martin Sopouch, Philippe Albertini
Over the past 30 years simulation of the N&V (Noise and Vibration) behavior of automotive drivelines became an integral part of the powertrain development process. With current and future HEVs (Hybrid-Electrical Vehicles) additional phenomena and effects have been entered the scene and need to be taken into account during layout/design as well as optimization phase. Beside effects directly associated with the e-components (namely electric whistle and whine), torque changes caused by activation/deactivation of the e-machine give rise to vibration issues (e.g. driveline shuffle or clonk) as well. This is in particular true for transient operation conditions like boosting and recuperation. Moreover, aspects of starting the Internal Combustion Engine (ICE) using the built-in e-machine in conjunction with the dynamic behavior of torsional decoupling devices become increasingly important. In order to cope with above mentioned effects a multi-physics simulation approach is required. The following paper proposes a simulation approach which incorporates the domains of the ICE thermodynamics, the mechanical driveline system, the electric components, the vehicle, as well as the fundamental control functions.
Technical Paper
2014-06-30
Janko Slavic, Martin Cesnik, Miha Boltezar
Car components are exposed to the random/harmonic/impact excitation which can result in component failure due to vibration fatigue. The stress and strain loads do depend on local stress concentration effects and also on the global structural dynamics properties. Standardized fatigue testing is long-lasting, while the dynamic fatigue testing can be much faster; however, the dynamical changes due to fatigue are usually not taken into account and therefore the identified fatigue and structural parameters can be biased. In detail: damage accumulation results in structural changes (stiffness, damping) which are hard to measure in real time; further, structural changes change the dynamics of the loaded system and without taking this changes into account the fatigue load in the stress concentration zone can change significantly (even if the excitation remains the same). This research presents a new approach for accelerated vibration testing of real structures. The new approach bases on phase locked harmonic excitation and can be used for identification of natural frequencies and damping while the damage due to vibration is being accumulated.
Technical Paper
2014-06-30
Jean-Baptiste Dupont, Racha Aydoun, Pascal BOUVET
The noise radiated by an electrical motor is very different from the one generated by an internal combustion engine. It is characterized by the emergence of high frequency pure tones that can be annoying and badly perceived by future drivers, even if the overall noise level is lower than that of a combustion engine. A simulation methodology has been proposed, consisting in a multi-physical approach to simulate the dynamic forces and noise radiated by electric motors. The principle is first to calculate the excitation due to electromagnetic phenomena (Maxwell forces) using an electromagnetic finite element solver. This excitation is then projected onto the structure mesh of the stator in order to calculate the dynamic response. Finally, the radiated sound power is calculated with the aid of a standard acoustic finite element method. The calculation methodology assumes a weak coupling between the different physical levels. It has been validated by comparison with the experiment. This simulation only considers the excitation generated by a perfect machine.
Viewing 1 to 30 of 8686

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