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2015-06-15
Technical Paper
2015-01-2216
Dong Chul Park, Eun Soo Jo, Seokgwan Hong, Michael Csakan
An important trend among vehicle NVH engineers is to produce the attractive engine sounds matching with a vehicle concept and engine performance. Recently customers have much more interests in their personal preferences and enjoying tuning their cars. The PESS(Personalized Engine Sound System) has been developed for making a unique and individual concept of a vehicle. The system helps customers make variety of engine sound in a single vehicle using active sound design technology. In this system, three different concept of engine sound has been defined-Dynamic, Sporty, and Extreme. Each of the engine sounds can be adjusted with a parameter that determines the timbre such as main orders, half orders, and high orders. In addition, the extent to the drivers stepping on the accelerator pedal has been used as a parameter to differ the sound response. An AVN application has been implemented that allows users to easily design those functions.
2015-06-15
Technical Paper
2015-01-2215
Thomas L. Lago
How to decrease noise and vibration exposure has been of interest for many years. Empirical data have verified that too high dose values can create multiple problems to a human body - often severe. Some years back, the European Machinery Directive has increased the responsibility for manufacturers and employers to make sure limits are complying with legislation. Classical technology often consists of passive solutions aiming at trying to cut back on noise and vibration levels. For low frequency, these methods are often lacking the needed performance especially if weight should be considered at the same time. A smart combination of passive and active techniques can make a real difference. Today, with possibilities for low cost and embedded electronics and the rapid development of new actuators, a vast range of applications are possible for this combined combat approach, with a financial advantage as well.
2015-06-15
Technical Paper
2015-01-2213
John Van Baren
The accumulated damage that a product experiences in the field due to the variety of vibration stresses placed upon it will eventually cause failures in the product. The failure modes resulting from these dynamic stresses can be replicated in the laboratory and correlated to end use environment to validate target reliability requirements. This presentation will discuss which random profile is needed to simulate end use environment, how to combine multiple vibration environments into one, and how to use FDS to accelerate the test.
2015-06-15
Technical Paper
2015-01-2218
Shuguang Zuo, Jun Zhang, xudong wu, jiajie HU, Guo Long
Title: Study on Active Noise Control of Blower in Fuel Cell Vehicle under Transient Conditions Authors: Zuo Shuguang, Zhang Jun, Wu Xudong, Hu Jiajie, Long Guo Abstract: Blower is one of the main noise sources of fuel cell vehicle. In this paper, a narrowband active noise control (ANC) model is established based on adaptive notch filter (ANF) to control the medium-high frequency noise produced by the blower. In actual application, the frequency of reference signal differs from the frequency of the noise signal inevitably. This difference is referred to as frequency mismatch (FM) which greatly degenerates the performance of the narrowband ANC algorithm. Under transient conditions, in order to reduce the FM of ANC for blower, a new Frequency Mismatch Filtered-Error Least Mean Square algorithm (FM-FELMS) is proposed to attenuate blower noise.
2015-06-15
Technical Paper
2015-01-2223
Rolf Schirmacher
Active Noise Control (ANC) and Active Sound Design (ASD) have long been seen as emerging technologies. During recent years, however, they became quite mainstream for new vehicle and infotainment platforms within a broad range of OEMs. This paper presents the current state-of-the-art of production ANC and ASD systems, including the lessons learned during the last years of bringing the technology from the lab into vehicles. Based on this current status, critical elements for an even broader application of the technologies are identified and developments to overcome them are discussed. In addition, as the integration of these technologies with other in-vehicle systems is crucial for a commercially viable application, trends of future IVI systems are discussed and integration scenarios for next generation IVI systems are shown.
2015-06-15
Technical Paper
2015-01-2230
Chatter vibrations are causing large monetary losses daily in industry. New materials have increased the challenges with harmful vibration levels. Since the vibrations, when observed as a final result, are chaotic and the vibration process nonlinear, it is a challenging task to deal with it. It is also a common “understanding” in the cutting industry that chatter is RPM (the rotational speed) dependent, since the behavior changes with RPM. Many attempts have been done over many years to mitigate and understand the vibrations. In our vast research on these topics, we have found that it is rewarding to classify the vibrations into categories, enabling a better understanding of its underlying physics and “source of vibrations,” and thus also the formulation of a possible remedy. An analysis approach has been developed where vibrations are analyzed and categorized and a GO/NOGO indicator is telling if the machine has the “right type of vibrations.”
2015-06-15
Technical Paper
2015-01-2277
Vishal Vaidya, Pravin Hujare
Recently quietness has become an important quality parameter for automotive vehicles and as a result various improvements have been brought to reduce noise at system and vehicle level. Due to stringent noise emission norms on automotive vehicles and increasing desire of quieter in-cab performance by users, reduction of air intake noise tends to be an area of explanation. Air intake noise, which was relatively considered as a minor source of noise in the past, is now gaining importance. This paper emphasizes the sound pressure level reduction through the increase in transmission loss at an air intake system. The intake noise of an automobile induced by firing of an engine accompanies acoustic resonance of ducts of an intake system. Conventionally, the adoption of an integrated type resonator was one of possible ways to eliminate the booming noise due to acoustic resonances of air ducts.
2015-06-15
Technical Paper
2015-01-2331
Alexander Schell, Vincent Cotoni
Aero-vibro-acoustic prediction of interior noise associated with exterior flow requires accurate predictions of both fluctuating surface pressures across the exterior of a vehicle and efficient models of the vibro-acoustic transmission of these surfaces pressures to the interior of a vehicle. The frequency range of interest varies depending on the region and source of interest. For noise transmitted through a sideglass the frequency range of interest is typically from 1-5kHz. The vibro-acoustic methods used to describe noise and vibration transmission also depend on the frequency range of interest. At higher frequencies methods like statistical energy analysis (SEA) are particularly well suited for describing the response of a trimmed cabin due to the short wavelength response of the interior acoustic space and sound package. An accurate prediction of fluctuating surface pressures also requires an accurate model of the flow over the exterior of the vehicle.
2015-06-15
Technical Paper
2015-01-2329
Paolo Di Francescantonio, Charles Hirsch, Piergiorgio Ferrante, Katsutomo Isono
The prediction of the broadband noise generated by the flow interaction with solid bodies such as for example side mirror noise, exhaust pipe noise, or ventilation and air conditioning noise require in principle the execution of extremely high demanding unsteady CFD simulations that nowadays cannot be afforded in an industrial environment. Therefore research efforts have been focused on alternative approaches that could permit to obtain engineering accurate results with much reduced computational efforts by stochastically reconstructing the turbulent velocity field starting from a steady RANS analysis. Two main families of methods have been introduced up to now, SNGR [1], and RPM[2], but applications in industrial environment are still limited mainly due to the lack of reliability of these methods and the need to introduce some tuning parameters.
2015-06-15
Technical Paper
2015-01-2224
Yong Xu
The purpose of this study was to develop an effective active control system for improving the sound quality of vehicle engine noise. The goal of the designed system was not to decrease the sound level of the residual noise, but to adjust its quality characteristics. The sound quality of vehicle engine noise was evaluated with both of subjective and objective evaluations. Then a linear regression analysis was performed in order to expressed the subjective sound quality with measureable objective parameters. Based on the periodic properties of vehicle engine noise, a waveform, synthesized with five sine waves, was used as a reference signal in the designed active control system. The primary noise at each reference frequency was controlled by an adaptive notch filter, the taps of which were updated by the FXLMS algorithm.
2015-06-15
Technical Paper
2015-01-2327
Wind noise is one of the important NVH attributes that impacts customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic door deflection under the pressure load due to fast movement of a vehicle plays an key roll. The excessive deflection could potentially cause opened sealing gap, a.k.a. aspiration leakage, which creates a path through which the exterior aerodynamically induced noise propagates into the vehicle cabin. The dynamic door deflection can be predicted using CFD and CAE tools. This work looks into the internal pressure issue associated with the dynamic load setup during the CAE analysis. The capability of predicting the internal pressure due to high wind speed outside of a vehicle still has not been developed, and the work is based on the wind tunnel measurement involving several vehicles.
2015-06-15
Technical Paper
2015-01-2323
Abdelhakim AISSAOUI, Ravindra S Tupake, Vilas Bijwe, Mohammed Meskine, Franck Perot, Alain BELANGER, Rohit J Vaidya
F or the automotive industry, acoustic comfort is of increasing importance and changes in the market make the HVAC system noise quality a question to be addressed as early as possible during the vehicle development process. On one hand, the so-called traditional sources of annoyance such as engine, road-tires contact, exhaust systems and wind-noise have been significantly reduced for most traditional combustion engine vehicles. On the other hand, the rapid expansion of hybrid and electric vehicles and idling stop systems increases the importance of sources such as HVAC systems considered in the past as secondary. At high mass flow rate, the flow-induced contribution from the ducts and registers is the main source of noise in the mid to high frequency ranges and is more important than the HVAC structure borne and blower engine contributions.
2015-06-15
Technical Paper
2015-01-2217
Guohua Sun, Tao Feng, JI XU, Mingfeng Li, Teik Lim
Current powertrain active noise control (ANC) system is not sufficient enough to track the fast engine speed variations, and yield consistent convergence speeds for individual engine order such that a balanced noise reduction performance can be achieved over a broad frequency range. This is because most of these ANC systems are configured with the standard filtered-x least mean squares (FxLMS) algorithm, which has an inherent limitation in the frequency-dependent convergence behavior due to the existing of secondary path model (electro-acoustic path from the input of control loudspeaker to the output of monitoring error microphone) in the reference signal path. In this paper, an overview is given first to compare several recently modified FxLMS algorithms to improve the convergence speed for harmonic responses such as eigenvalue equalization FxLMS (EE-FXLMS) and normalized reference LMS (NX-LMS) algorithms.
2015-06-15
Technical Paper
2015-01-2212
A. Elsawaf, H. Metered, T. Vampola, Z. Sika
This paper presents the particle swarm optimization (PSO) algorithm to search about the optimum feedback controller gains for the active mount suspension, for the first time, to reduce the transmitted vibrations to the suspended mass placed over a structure. A mathematical model and the equations of motion of the structure system with an active mount suspension are derived and simulated using Matlab/Simulink software. The proposed PSO algorithm aims to minimize the acceleration of the suspended mass as the objective function with constraint of the actuator force. System performance criteria are evaluated in both the time and frequency domains in order to count the effectiveness of the proposed controller. The simulation results reveal that the proposed feedback controller gains tuned by PSO algorithm offer a significant improvement of the vibration isolation compared with both the passive and active mount controlled using the linear quadratic regulator (LQR).
2015-06-15
Technical Paper
2015-01-2322
Bastien Ganty, Jonathan Jacqmot, Ze Zhou
At high cruising speed, the car A-pillars generate turbulent air flow. The resulting aerodynamic pressure applied on the windows significantly contributes to the total cabin noise. In order to predict this particular noise contribution, the physic of both the flow and the cabin needs to be accurately modeled. This paper presents an efficient methodology to predict the turbulent noise transmission through the car windows. The method relies on a two-step approach: the first step is the computation of the exterior turbulent field using an unsteady CFD solver (EXA PowerFlow); the second step consists in the computation of the acoustic propagation inside the cabin using a finite element vibro-acoustic solver (Actran). The simplified car cabin of Hyundai Motor Company, studied in this paper, involves aluminum skin, windows, sealant, inner air cavity and acoustic treatment (porous material, damping layer). A pure vibro-acoustic model with hammer shock excitation on a window is first built.
2015-06-15
Technical Paper
2015-01-2328
Barbara Neuhierl, Sivapalan Senthooran, Reinier Toppinga, Anke Jäger, Maarten Brink, Timo Lemke, Philippe Moron, Raghu Mutnuri
The object of the validation study presented in this paper is a generic vehicle, the so-called SAE body, developed by a consortium of german car manufacturers (Audi, Daimler, Porsche, Volkswagen). It consists of a simplified cabin whose interior can be equipped with either reverberant or partly absorbing walls. To obtain more realistic flow and pressure excitation typical for production vehicles, an a-pillar and a series rear view mirror were attached to the exterior surface. Furthermore the test object contains a glass side window, allowing noise transmission to the interior. Many experiments have been performed by the abovementioned consortium on this object in the past to investigate its behavior when exposed to fluid flow. Some of these experiments were used to validate the simulation results discussed in the present paper.
2015-06-15
Technical Paper
2015-01-2324
Hangsheng Hou, Guiping Yue
When a sunroof opens to let the fresh air in during driving, there might be several noise issues associated with it. The most common and important one is the wind throb issue, which is normally resolved by installing a wind deflector with sufficient height. However with the wind throb issue gone, other sound quality problems may surface. The most obvious one is the hissing noise, which occurs often in higher speed range. This work investigates a sunroof deflector deployment strategy considering wind throb, hissing noise and other psychoacoustic attributes that could be felt subjectively by a customer. The goal is to optimize sound quality associated with an open sunroof, potentially targeting the most NVH demanding customers in the premium vehicle segment.
2015-06-15
Technical Paper
2015-01-2325
Paul Bremner, Chris Todter, Scott Clifton
Title: Sideglass Turbulence and Wind Noise Sources Measured with a High Resolution Surface Pressure Array Authors: Paul Bremner – AeroHydroPLUS, Del Mar CA 92104 USA Chris Todter – Keppel Professional Services, San Diego CA 92107 Scott Clifton – c/o AeroHydroPLUS, Del Mar CA 92104 USA The authors report on the design and use of high resolution micro-electro-mechanical (MEMS) microphone arrays for automotive wind noise engineering. The arrays integrate both sensors and random access memory (RAM) chips on a flexible circuit board that eliminates high channel count wiring and allows the array to be deployed on automobile surfaces in a convenient “stick-on/peel-off” configuration. These arrays have application to the quantitative evaluation of interior wind noise from measurements on a clay model in the wind tunnel, when used in conjunction with a body vibro-acoustic model.
2015-06-15
Technical Paper
2015-01-2250
Masahiro Akei, Nobutaka Tsujiuchi, Akihito Ito, Takayuki Yamauchi, Daisuke Kubota
This paper describes the identification of the sound source model for the diesel engine installed on the agricultural machine by Inverse-Numerical Acoustic analysis (INA), and the noise prediction using the sound source model identified by INA. INA is a method to identify surface vibrations from surrounding sound pressures. This method is applicable for a complicated-shaped sound source like an engine. Although many studies about INA have been conducted, these past studies are the studies on improvement of the identified accuracy and noise prediction in the free sound field or hemi-free sound field. The authors predicted accurately sound pressure level of engine enclosure using sound source model identified by INA and boundary element method (BEM). However, we have not yet verified the effectiveness of sound source model against the enclosure which has an absorption material and an opening.
2015-06-15
Technical Paper
2015-01-2358
Rod Morris-Kirby, Evan Harry, Dirk Jaeger, Bernd Borgmann
Acoustic Diagnostic Network Algorithms (DNA) are experimental methods that extract airborne acoustic characteristics from a motor vehicle and decompose this information into a set of networks from which the source, path and receiver noise sources and paths can be determined. Unlike traditional transfer path analysis Acoustic DNA takes the problem into the fine detail and answers questions such as what, where and how does a vehicle system need to be changed in order to achieve any given objective. This paper describes the fundamental methodology and features together with how it has been implemented into a user friendly computer program that has been used successfully in over 50 vehicle projects within the Adler Pelzer group on a wide range of motor vehicles.
2015-06-15
Technical Paper
2015-01-2356
Huangxing Chen, David W. Herrin
The insertion loss of louvered terminations is determined using acoustic finite element analysis. The analysis is conducted in the plane wave regime and the source is anechoic. Insertion loss is determined by taking the difference between the sound power with and without the louvers at the termination. The effect of different louver configurations on insertion loss is examined. Parameters investigated include louver length, angle, spacing between louvers, and sound absorption thickness.
2015-06-15
Technical Paper
2015-01-2333
Brandon Sobecki, Patricia davies, J Stuart Bolton, Frank Eberhardt
Component sound quality is an important factor in the design of competitive diesel engines. One component noise source that causes complaints is the gear rattle that originates in the front-of-engine gear train which drives the fuel pump and other accessories. The rattle is caused by repeated tooth impacts resulting from fluctuations in differential torsional acceleration of the driving gears. These impacts generate a broadband, impulsive noise that is often perceived as annoying. In most previous work, the overall sound quality of diesel engines has been considered without specifically focusing on predicting the perception of gear rattle. Gear rattle level has been quantified based on angular acceleration measurements, but those measurements can be difficult to perform. Here, the emphasis was on developing a metric based on subjective testing of the perception of gear rattle.
2015-06-15
Technical Paper
2015-01-2248
Florian Pignol, Emiel Tijs, Daniel Fernandez Comesana, Daewoon Kim
It is important to determine the contribution of different engine components to the total sound perceived inside the cabin in order to apply an effective noise reduction treatment. Accelerometer or laser based vibration tests are usually performed, however, the radiated sound is not always captured accurately. Microphone based methods are strongly influenced by the many reflections and other sound sources inside the engine bay. Recently, it has been shown that engine radiation can be effectively measured using particle velocity sensors while the engine remains mounted in the car. Similar results were obtained as with a dismounted engine in an anechoic room. This paper is dedicated to the evaluation of the transfer path from the engine to the vehicle interior in order to calculate the sound pressure contribution of individual engine sections at the listener’s position. To achieve a good signal to noise ratio during acoustic transfer paths a novel monopole sound source was designed.
2015-06-15
Technical Paper
2015-01-2249
Saad Bennouna, Said Naji, Olivier Cheriaux, Solene Moreau, Boureima Ouedraogo, Jean Michel Ville
Passengers’ thermal comfort inside car cabin is mainly provided by the heating ventilation and air conditioning system (HVAC). The main part of HVAC modules is placed under the dash board. An HVAC module is a compact system composed of various elements which are subject to airflow. The interaction between airflow and these in-duct elements generates noise inside car cabin. Furthermore, the blower used to blow air inside the cabin must overcome the pressure generated by HVAC elements. Noise is created and its level is linked to flow and pressure. HVAC noise is an important issue for car makers and automotive suppliers wishing to reach passengers’ satisfaction. Furthermore thermal-engine cars are more and more silent. Also hybrid and electric car sells are expanding around the world. HVAC noise became a main issue for automotive actors. In order to reduce its HVAC noises, Valeo and partners worked to develop several methods.
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 each noise reduction technique. The noise reduction includes both a mechanically active quarter-wave resonator (MAQR) and mechanically active Helmholtz resonator (MAHR). Viability is given for both design types. These are presented with supporting implementation data. Control for both resonator platforms is discussed. The relative effect of each technology is compared based off cost and packaging.
2015-06-15
Technical Paper
2015-01-2261
Joseph Plattenburg, Jason Dreyer, Rajendra Singh
Combined active and passive damping is an emerging trend as it should be an effective solution to challenging NVH problems, especially for lightweight vehicle components that demand advanced noise and vibration treatments. Compact patches are of particular interest due to their small size and cost; however, improved modeling techniques are needed for such methods. This paper presents a refined modeling procedure for side-by-side active and passive damping patches applied to thin, plate-like powertrain casing structures. As an example, a plate with fixed boundaries is modeled as this is representative of real-life transmission covers which often require damping treatments. Further scientific studies include a bench experiment that determines frequency dependent properties of the viscoelastic damping material. The proposed model is then utilized to examine several cases of active and passive patch location, and vibration reduction is determined in terms of insertion loss for each case.
2015-06-15
Technical Paper
2015-01-2337
Gordon Ebbitt, Todd Remtema
Speech communication from the front seat to the rear seat in a passenger vehicle can be difficult. This is particularly true in a vehicle with an acoustically absorptive interior. Speech Transmission Index (STI) measurements can quantify the speech intelligibility, but they require specialized signal processing. The STI calculations can be simplified if it is assumed that reverberation and echoes play an insignificant role in an automobile. A simplification of a STI measurement is described that uses a stationary reference speech signal from a talker mannequin in the driver’s seat to create a signal at the rear passenger positions. On-road noise measurements are used for the noise level and the calculated signal to noise ratio is used to calculate a simplified STI value that tracks closely to a full implementation of the STI method for sedans. In fact, this method is very similar to the techniques described in the Articulation Index (AI) and Speech Interference Index (SII) standards.
2015-06-15
Technical Paper
2015-01-2321
Nicholas Oettle, Andrew Bissell, Sivapalan Senthooran, Mohammed Meskine
Car manufacturers put large efforts into reducing wind noise to improve the comfort level of their cars. Each component of the vehicle is designed to meet its individual noise target to ensure the wind noise passenger comfort level inside the vehicle is met. Sunroof designs are tested to meet low-frequency buffeting targets as well as broadband noise targets for the sunroof in vent position and any noise generated by deflectors. Experimentally testing designs and making changes to meet these design targets typically involves high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the use of a reliable numerical prediction capability early in the vehicle design process.
2015-06-15
Technical Paper
2015-01-2326
Denis Blanchet, Anton Golota
Recent developments in the prediction of the contribution of wind noise to the interior SPL have opened a realm of new possibilities. The main physical mechanisms related to noise generation within a turbulent flow and transmission through the vehicle greenhouse are nowadays better understood. Several simulation methods such as CFD, FEM, BEM, FE/SEA Coupled and SEA can be coupled together to represent the physical phenomena involved. The main objective being to properly represent the convective and acoustic component within the turbulent flow to ensure proper computation of the wind noise contribution to the interior SPL of a vehicle. This paper presents comparisons between simulations results and measurements for various configurations such as i) with and without mirror, ii) various A-Pillar shapes, iii) various vehicle speeds and finally iv) various yaw angles.
2015-06-15
Technical Paper
2015-01-2206
Glenn Yin, Alan Parrett, Nitish Wagh, Dennis Kinchen
In automotive noise control, the hood liner is an important acoustic part for mitigating engine noise. The random incidence absorption coefficient is used to quantify the component level acoustic performance. Generally, air gaps, type of substrate materials, density of the substrate materials and Air Flow Resistivity of the material or cover scrim are the dominant control factors in the sound absorption performance. This paper describes a systematic experimental investigation of how these control factors affect the part performance. The first stage of this study is based on current available solutions from sound absorber suppliers, the acoustic absorption of different hood liner constructions, with variations in materials, density, air gaps, and scrims were measured. Next, hood liners with these different constructions were installed in a vehicle, and Sound Power Based Noise Reduction (PBNR) from the engine compartment to the interior was measured to quantify in-vehicle effects.
Viewing 1 to 30 of 7459

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