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Viewing 121 to 150 of 9398
2016-06-15
Journal Article
2016-01-1827
Giorgio Bartolozzi, Marco Danti, Andrea Camia, Davide Vige
Abstract The time to market in the automotive industry is constantly decreasing pushing the carmaker companies to increase the efforts in numerical simulations and to decrease the number of prototypes. In the NVH field, this time constraint reflects in moving the well-established finite element simulations towards the so called “full-vehicle simulations”. Specifically, the CAE techniques should be able to predict the complete behavior of the vehicles in mission conditions, so to reproduce some usual tests, such as the “coast down” test on different roads. The aim of this paper is to present a methodology to improve rolling noise simulations exploiting an integrated full-vehicle approach. An accurate modeling of all the subsystems is needed, with particular attention to the wheels and the suspension systems. Therefore, the paper firstly covers the modeling approach used to obtain the FE models of tires and suspension system.
2016-06-15
Journal Article
2016-01-1844
Jonathan Millitzer, Dirk Mayer, Roman Kraus, Matthias Schmidt
Abstract Current developments in the automotive industry such as downsizing, the use of cylinder deactivation and consistent lightweight construction increasingly enable the application of active control systems for the further reduction of noise and vibration in vehicles. In the past few years, different configurations of actuators and sensors for the realization of an active control system have been investigated and evaluated experimentally. Active engine mounts, inertial mass actuators and structural integrated actuators can be used to reduce either structural vibrations or the interior noise level. As a result, a variety of different topology concepts for the realization of an active control system arises. These can be divided into an active vibration control scenario, the direct influence of the sound field with loudspeakers or the application of structural actuators for the reduction of the interior sound pressure.
2016-06-15
Journal Article
2016-01-1808
Manfred Kaltenbacher, Andreas Hüppe, Aaron Reppenhagen, Matthias Tautz, Stefan Becker, Wolfram Kuehnel
Abstract We present a recently developed computational scheme for the numerical simulation of flow induced sound for rotating systems. Thereby, the flow is computed by scale resolving simulations using an arbitrary mesh interface scheme for connecting rotating and stationary domains. The acoustic field is modeled by a perturbation ansatz resulting in a convective wave equation based on the acoustic scalar potential and the substational time derivative of the incompressible flow pressure as a source term. We use the Finite-Element (FE) method for solving the convective wave equation and apply a Nitsche type mortaring at the interface between rotating and stationary domains. The whole scheme is applied to the numerical computation of a side channel blower.
2016-06-15
Journal Article
2016-01-1809
Alexander Schell, Vincent Cotoni
Abstract Prediction of flow induced noise in the interior of a passenger car requires accurate representations of both fluctuating surface pressures across the exterior of the vehicle and efficient models of the vibro-acoustic transmission of these surface pressures to the driver’s ear. In this paper, aeroacoustic and vibro-acoustic methods are combined in order to perform an aero-vibro-acoustic analysis of a Mercedes-Benz A-class. The exterior aero-acoustic method consists of a time domain incompressible Detached Eddy Simulation (DES) and an acoustic wave equation. The method is extended in this paper to account for convection effects when modelling the exterior sound propagation. The interior vibro-acoustic model consists of a frequency domain Finite Element (FE) model of the side glass combined with a generalized Statistical Energy Analysis (SEA) model of the interior cabin.
2016-06-15
Journal Article
2016-01-1815
Augusto Della Torre, Gianluca Montenegro, Angelo Onorati
Abstract In the last decades numerical simulations have become reliable tools for the design and the optimization of silencers for internal combustion engines. Different approaches, ranging from simple 1D models to detailed 3D models, are nowadays commonly applied in the engine development process, with the aim to predict the acoustic behavior of intake and exhaust systems. However, the acoustic analysis is usually performed under the hypothesis of infinite stiffness of the silencer walls. This assumption, which can be regarded as reasonable for most of the applications, can lose validity if low wall thickness are considered. This consideration is even more significant if the recent trends in the automotive industry are taken into account: in fact, the increasing attention to the weight of the vehicle has lead to a general reduction of the thickness of the metal sheets, due also to the adoption of high-strength steels, making the vibration of the components a non negligible issue.
2016-06-15
Journal Article
2016-01-1817
Juergen Veit, Paco Langjahr, Stephan Brandl, Bernhard Graf
Abstract Due to more challenging future emission legislations and the trend towards downsizing, the number of turbocharged (TC) engines, especially petrol engines, is steadily increasing. The usage of TC has high risk to cause different noise phenomena apparent in the vehicle interior which are often perceived as annoying for the passengers. In order to further improve consideration of TC topics in the development, objective judgment and monitoring of TC noise issues is of high importance. Therefore, objective parameters and corresponding tools that are especially focusing on TC noise phenomena have to be developed. One main target of these tools is to deliver an objective TC assessment in an efficient way and with minimum additional effort. Application of the criteria presented in this publication therefore allows acoustic engineers to judge the NVH behavior and annoyance of the TC with respect to its vehicle interior noise contribution.
2016-06-15
Journal Article
2016-01-1847
Olivier Robin, Celse Kafui Amedin, Alain Berry, Noureddine Atalla, Olivier Doutres, Franck Sgard
A method for estimating the sound absorption coefficient of a material under a synthesized Diffuse Acoustic Field was recently proposed, as an alternative to classical sound absorption measurements in reverberant rooms (Robin O., Berry A., Doutres O., Atalla N., ‘Measurement of the absorption coefficient of absorbing materials under a synthesized diffuse acoustic field’, J. Acoust. Soc. Am., 136 (1) EL13-EL19, 2014). Using sound field reproduction approaches and a synthetic array of acoustic monopoles facing the material, estimation of the sound absorption coefficient under a reproduced Diffuse Acoustic Field in a hemi-anechoic room was shown to be feasible. The method was successfully tested on a few samples of melamine foam of close thicknesses and areas, but the influence of several parameters such as the source height, or the samples dimensions together with the nature of the porous material was not fully investigated.
2016-06-15
Journal Article
2016-01-1855
Alastair Jay, Thomas Deighan, Nozomu Kato, Kiyofumi Sato
Abstract Requirements for reducing powertrain NVH drives the selection of low piston skirt to liner clearances contradicting the requirement to maintain larger skirt clearances for minimizing engine friction. Whilst this clearance trade-off between low friction and low NVH is fundamental, piston design features have a significant effect on where the trade-off curve sits on the friction/NVH map. Design features can therefore be viewed not by either friction or NVH improvement measures but a shift in the friction-NVH trade off curve. Specifically, some piston design features which may be targeted at reducing friction can be viewed as either a friction benefit for similar NVH or an NVH improvement for similar friction levels. The ability to realistically quantify the effect of the design changes on NVH is therefore critical to determining what design changes to recommend, the direction of the piston design being highly sensitive to the process by which the impact on NVH is assessed.
2016-05-31
Article
Stanford engineering professor David Lentink plans to use a new wind tunnel to learn the magic of bird flight and apply it to building better aerial robots.
2016-05-14
Article
Ann Arbor, Michigan is fast becoming the world capital of testing and research for connected cars, automated driving, and safety technology.
2016-05-13
Article
KTR has started up a test bench for large couplings that covers a performance range up to 500,000 N∙m at its headquarters in Rheine.
2016-05-13
Article
T/CCI Manufacturing’s Climatic Wind Tunnel in Decatur, IL allows customers to simulate any real-world condition by controlling humidity, wind, temperature, solar and road conditions up to100 mph.
2016-05-13
Article
A modular area view kit (AVK) from First Sensor aids in the setup of 360° all-around view systems for applications in special vehicles and machines.
2016-05-13
Article
Hermetic Seal Corporation (HSC), a unit of AMETEK Interconnect, has expanded its hermetic sealing capabilities to include state-of-the-art hermetic fiber-optic component manufacture.
2016-05-05
Magazine
New dawn at Honda R&D President Yoshiyuki Matsumoto aims to invigorate Honda's technology and product-development organization with 'full soul.' Automated driving meets regulation: NHTSA and the next 50 years The challenges and opportunities on the road to 'zero deaths' demand a new level of federal automotive safety technical standards, and a new safety-defect reporting and recall system. NHTSA and the U.S. Congress must act boldly and quickly to make it happen. Autonomous driving meets regulation: Hands off, eyes off, brain off Euro NCAP'S president warns that without coherent policies, the growing availability of automated technologies may result in piecemeal technology development-and unintentional consequences. Designer yin meets engineer yang Efficient and effective vehicle development means even closer collaboration between the two former sparring partners.
2016-04-29
Standard
J2531_201604
New methods are available to assist in evaluating the risk of impulse noise-induced hearing loss from inflatable devices, for example, airbags and seat belt pretensioners. This document presents some background on impulse noise measurement techniques and assessment criteria. Related information relative to test details, for example, preamplifier specifications and filtering methods and criteria, will be discussed in a future recommended practice.
2016-04-27
Article
Take-it-to-the-limit testing is typically reserved for vehicle development teams, but Jaguar's route and the sensational topography clearly gave Automotive Engineering good insight into F-Pace's dynamic capabilities and its four-year development.
2016-04-27
Standard
J3060_201604
This SAE Standard serves as a guide for vibration testing procedures of Automotive and Heavy Duty storage batteries.
2016-04-24
Article
Consortium of OEMs and suppliers worked on all fronts, while the SAE Interior Climate Control Committee reopened a suite of draft standards to prepare for possible importation of cars with R-744: CO2 as a refrigerant.
2016-04-20
Article
Experts say Phase Change Material (PCM) formulated for high latent heat capacity can provide cabin warmth for a typical U.S. daily commute, with residual capacity insulated for an EV parked during an eight-hour workday.
2016-04-20
Article
Ruetz System Solutions provides an interoperability test platform for Automotive Ethernet that constitutes a component of the test set-up for Open Alliance Layer 1 interoperability tests for ECUs.
2016-04-20
Standard
J3001_201604
This procedure is applicable to modes from 500 and 13,000 Hz. The parameters measured with this procedure are defined as the damping factor, ξ for first nine vibration modes of the beam. The measurement will be done in free-free conditions and with temperature.
2016-04-14
Article
Manufacturing and service teams are discovering ways to use AR technology to handle complex systems like wire harnesses.
2016-04-13
Article
The nCode brand of durability, test, and analysis software by HBM introduces nCode VibeSys, a new data processing system designed to help acoustics and vibration engineers.
2016-04-11
Article
Automakers are increasingly employing digital crash test dummies made of zeroes and ones to take the big hits in virtual vehicles.
2016-04-05
Technical Paper
2016-01-1058
Naoki Toyama, Takashi Hoshi
Abstract The subject is technology for damping forced vibration in the multiplate wet clutches used in hybrid vehicle transmissions. As a predictive technique for forced vibration caused by the structure of the clutch, three-dimensional simulation was used in the present study to anticipate the modes of vibration that occur. Next, a one-dimensional simulation was created as a predictive technique for drivetrain torsional vibration from the engine to the driveshaft. The one-dimensional simulation created was used to extract the modes of operation that are severe with regard to forced vibration from target values for vibration anticipated from the vehicle body. The results obtained were used with three-dimensional simulation to change the clutch structure to provide greater latitude with regard to the target for forced vibration.
2016-04-05
Technical Paper
2016-01-1060
Arnab Ganguly, Niket Bhatia, Vikas Kumar Agarwal, Ulhas Mohite
Abstract With ride comfort in a motorcycle gaining significance, it is important to minimize vibration levels at the customer touch points. The reciprocating piston imparts rotary motion to the crankshaft which in turn induces unbalance forces and produces vibration in the vehicle, thus influencing the ride quality. Generally, the primary inertial forces are balanced by a combination of balancer body and crank web. However, being a commuter bike, a balancer body could not be accommodated due to cost and space constraints. In such scenario, the first order unbalance force cannot be completely eliminated but can only be redistributed by adding counterweight to the crankshaft. Proper distribution of these forces is required for optimum vibration levels at motorcycle touch sensitive points (TSP) such as handle bar, footrest etc.
2016-04-05
Technical Paper
2016-01-1061
Guiping Yue, Wenbo Niu, Jian Zhao, Dandan Kong, Yun Li, Hangsheng Hou
Abstract Gear whine noise impacts customer perception of vehicle interior quietness in general and sound quality in particular. It has been a frequently occurred annoying phenomenon during vehicle development and much discussed topic regarding transmission NVH refinement in automotive industry. This work pertains to a transmission gear whine issue encountered in prototype evaluations during a vehicle program development process. The effort centers itself on the optimization of transmission gear macroscopic and microscopic parameters to fix the issue which is deemed unacceptable for customers. Specifically, by using multi-body dynamics approach, this work carries out a transmission system whine noise simulation based on optimal gear macro parameter selection and micro tooth flank modification. The obtained results show that the proposed design changes could successfully resolve the issue, which is verified by subsequent test measurement and confirmed by subjective evaluations.
2016-04-05
Technical Paper
2016-01-1053
TL Balasubramanian, Vigneshwara Raja Kesavan, V Lakshminarasimhan, Vamsi Krishna Balla, Suresh Palani
Abstract This paper discusses various noise sources of cylinder head assembly and focuses on design options developed to reduce the cylinder head noise in a single cylinder, 110cc scooter engine. Various experimental procedures were used for identification and ranking of different noise sources. In case of air-cooled small engines, temperature effects are dominant and as a consequence certain noises stand out in hot condition causing severe noise discomfort. After identifying the reasons for abnormal cylinder head noise, countermeasure mechanisms for reducing unintended impacts of valve train/ rocker arm in the layout were developed. The side-effects due to introduction of these additional mechanisms are studied using performance metrics. It is essential to limit noise deterioration over time to increase customer satisfaction. Simulation cycles were developed to quantify the cylinder head noise deterioration using accelerated testing procedures.
2016-04-05
Technical Paper
2016-01-1040
Rostislav Hadas, Rolf Sauerstein, Radúz Zahoranský, Michael Stilgenbauer, Matthias Ruh
Abstract A new generation of gasoline engine turbochargers has been developed with a focus on high performance and excellent NVH characteristics, especially with regards to the wastegate control system. With the recent introduction of EU6 emission standards, there is a clear demand to precisely control the flow of exhaust gas through the turbine wastegate. Engine operational duty cycles measured on EU6 compatible vehicles have shown increased stresses on wastegate parts due to a higher amount of regulation strokes during operation. Recent developments in the compact design of exhaust systems together with high pressure pulsation forces acting on wastegate flaps constitute the main challenges facing turbo engineers in the effort to achieve customer durability while meeting NVH requirements. For the development of a new generation of wastegate control systems a unique load prediction model was duly developed.
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