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Viewing 61 to 90 of 9346
2016-06-15
Journal Article
2016-01-1784
Alessandro Fortino, Lutz Eckstein, Jens Viehöfer, Jürgen Pampel
Abstract Vehicles powered by electric machines offer the advantage to be more silent than vehicles equipped with an internal combustion engine. On the one hand, the reduced noise levels enable an improvement of the inner-city noise pollution. On the other hand, quiet vehicles entail risks not to be acoustically detected by surrounding pedestrians and cyclists in the lower speed range. The emitted noise can easily be masked by the urban background noise. Therefore, the UNECE has founded an informal working group which is currently developing guidelines in terms of an exterior noise required for detecting Quiet Road Transport Vehicles (QRTV). With the introduction of an Acoustic Vehicle Alerting System (AVAS), not only the exterior noise but also the perceived interior noise for an enhanced driving experience can be considered. Nevertheless, car manufactures have a big interest in maintaining their perceived brand identity.
2016-06-15
Technical Paper
2016-01-1782
Kyoung-Jin Chang, Dong Chul Park
Abstract This paper discusses approaches to emotionally improve the driving sound based on Active Sound Design (ASD). In the first step, target sound design methods are suggested in order to represent the vehicle’s concept and brand image via a driving sound. In this method, formant filter and musical chords are applied to the target sound synthesis. In the second step, a technique to make a target sound realistic in ASD system is discussed, which enables to stimulate the customers' emotion. In this technique, the process to simulate a musical instrument sound for a vivid driving sound and synthesize the sound with FIR filter is studied. Finally, the improved driving sound is demonstrated in ASD system.
2016-06-15
Technical Paper
2016-01-1787
Thomas Deighan, Graeme Maclean, Nozomu Kato, Kiyofumi Sato
Abstract A robust analytical process for evaluating the effects of engine component design on the powertrain NVH has been developed. The work presented focuses on design modifications for refinement of the NVH levels and sound quality of a 4 cylinder Boxer engine with automatic transmission. Assessment focuses on the powertrain structure, cranktrain, torque converter and valvetrain. Comparison of predicted mount vibrations with measurements on a fired engine are made. Through detailed post-processing of the analysis results, looking at modal contributions, modal excitations and loading contributions, the causes and contributions to the NVH are understood and used to direct potential modifications to the powertrain and component design. The models are used to quantify the relative benefit of these modifications in terms of both overall vibration levels and sound quality through implementation of a rumble metric.
2016-06-15
Journal Article
2016-01-1778
Gesche Fender, Steffen Marburg, Fabian Duddeck
Abstract One method to lower noise in a cabin is to position damping layers on vibrating panels, thereby reducing their radiated power. To assess the damping effect, criteria like the ERP (equivalent radiated power) are widely employed, which estimate the radiated sound power of a panel without taking into account the actual complex system. Advantageously only a part of the structure has to be modeled, but the optimal solution found on the simplified model then often fails for the complete, coupled system, especially if several variants of a cabin have to be considered. Hence, it is proposed to use the structure-only optimization for identification of a set of candidate solutions for optimal positioning of damping layers. These candidate solutions used as initial designs for the coupled investigations should be well distributed in the design space to avoid being wrongly stuck in an optimum with inferior coupled performance.
2016-06-15
Technical Paper
2016-01-1786
Per Alenius, Magnus Olsson, Thomas Lindbom
Abstract Highly refined NVH (Noise, Vibration and Harshness) is a key attribute for premium segment passenger cars. All noise sources such as powertrain, tires, wind, climate unit and etc. must be well balanced and at such a low level that the customer expectations are met or exceeded. However, not only are the NVH levels of importance but the character of the noise must also meet the high demands from premium car customers. This is especially true for diesel engines which historically have been more prone to have a less refined engine noise character than petrol engines. This paper will describe an investigation of what is defined as “engine presence” in four-cylinder diesel engine cars. The scope is to define a method for consistent subjective assessment of engine presence and to find the relationship and investigate the correlation between the “perceived loudness”, “perceived harshness” and the overall engine presence interior of the car.
2016-06-15
Technical Paper
2016-01-1781
Matthew Maunder, Phil Grant, Duncan Mawdsley
Abstract Engine sound quality is a key attribute for sporty cars - it powerfully conveys the brand image to the driver/passengers and onlookers, and provides driver involvement by giving instant feedback about how a car is operating. Providing this has become more difficult with tighter pass-by noise regulations and the near-universal adoption of turbocharging. In the last two decades, sporty sound inside the cabin has been regained using intake sound generator systems that transfer sound more directly to the vehicle interior. The high cost of these systems is more recently driving a move towards electronic Active Sound Design with systems delivering synthetic sound through loudspeakers. However, the purist sports car market perceives this approach to be fake or artificial. An alternative approach is provided by a system for Realistic Augmented Sound by Ricardo (RAS-R) that offers a choice of two realistic engine sound sources.
2016-06-15
Journal Article
2016-01-1777
Sebastian Oberst, Zhi Zhang, Joseph CS Lai
Abstract Despite significant progress made in the past 20 years in discovering some of the mechanisms of brake squeal, it remains difficult to predict the underlying friction-induced instabilities reliably. Most numerical analyses are based on linear deterministic analyses of structural vibrations such as the complex eigenvalue analysis (CEA). However, nonlinear multi-scale processes govern friction contact with high sensitivities to operating and/or environmental conditions. In addition, uncertainties in the material properties and boundary conditions such as contact and friction laws are rarely considered. Hence, it is quite common to underpredict or overpredict the number of instabilities and extensive brake noise dynamometer tests are still required in industry to ensure acceptable brake noise performance. In this paper, simplified finite element brake models are used to illustrate the role of nonlinearity in brake squeal.
2016-06-15
Technical Paper
2016-01-1779
Sergio Carvajal, Daniel Wallner, Reinhard Helfrich, Michael Klein
Abstract Numerical methods for brake squeal analysis are widely accepted in industry. The use of complex eigenvalue analysis is a successful approach to predict the appearance of squeal noise. Using simulation in an early design stage reduces time to market, saves costs, and improves the physical behavior and robustness of the brake system. State of the art of brake simulation comprises sampling for many parameter sets in a wide range of interesting values. Based on high performance, stability maps can be created in short time containing many results, which gives a deep insight into the brake behavior under varying parameters. An additional benefit of sampling is the possibility to detect parts with high potential for improving the NHV comfort. In the sequel, mathematical optimization methods like topology optimization or shape optimization are used for systematic improvements.
2016-06-15
Technical Paper
2016-01-1780
Francesca Ronzio, Theophane Courtois
Abstract In automotive acoustics, body NVH design is traditionally carried out without considering the acoustic trim parts. Nevertheless, the vibro-acoustic interaction of body structure and insulation trim cannot be neglected in the middle frequency range, where structure borne propagation might still be dominating and where classical statistical approaches are generally not able to represent the influence of local changes in stiffness and damping. This, together with the market requirement of lightweight and more efficient sound package solutions, is leading the CAE engineers to evaluate new design approaches dedicated to vehicle components such as dash or floor systems, for which the multi-physics interaction between damping, body stiffness and trim impedance is important.
2016-06-15
Technical Paper
2016-01-1783
Oliver Engler
Mercedes-AMG GmbH specializes in unique, high-performance vehicles. The image of AMG as the successful performance brand of Mercedes-Benz is reflected in its impressive successes in the world of motorsport and its unique vehicles. One of these vehicles is the SLS AMG Coupé Electric Drive. After an elaborate series of tests as well as numerous test drives, we have created the SLS eSound which captures the exceptional dynamism of this unique super sports car with electric drive. Starting with a characteristic start-up sound, which rings out on pressing the "Power" button on the AMG DRIVE UNIT, the occupants can experience a tailor-made driving sound for each driving situation: incredibly dynamic when accelerating, subdued when cruising and as equally characteristic during recuperation. The sound is not only dependent on road speed, engine speed and load conditions, but also reflects the driving situation and the vehicle's operating state with a suitable driving noise.
2016-06-15
Technical Paper
2016-01-1800
Xavier Carniel, Anne Sanon
Abstract The control of sound fields radiated by vibrating structures in a passenger compartment, (especially structures connected to different organs like the engine powertrain, the fan motor unit, seats, the steering column, electrical motors more and more, etc.) is among the functions of the automotive manufacturers. The absence of physical prototypes in the development phase systems led OEMs1 to use tests results obtained on benches following technical specifications from manufacturers. The transition "bench to vehicle" for vibro- acoustic behaviour sets many challenges that this standard intends to clear up. This standard specifies the experimental method to transpose the dynamic forces generated by the global movements of an active component between the vehicle and a test bench. The efforts are first measured on test benches and then transposed from test bench towards the vehicle. The standard is now a French standard (XP R 19-701) and is submitted to ISO process [1].
2016-06-15
Technical Paper
2016-01-1802
Mehdi Mehrgou, Franz Zieher, Christoph Priestner
Abstract Recently, hybrid and fully electric drives have been developing widely in variety, power and range. The new reliable simulation approaches are needed, in order to meet the defined NVH targets of these systems and implementing CAE methods for front loading, Design Validation Process (DVP). This paper introduces the application of a novel NVH analysis workflow on an electric vehicle driveline including both electromagnetic and mechanical excitations for an absolute evaluation of the NVH performance. At first, the electromagnetic field is simulated using FEM method to extract the excitations on the stator, rotor bearings as well as the drive torque. Then, the multibody dynamic model of the driveline is built-up, driven by this torque. The effect of eccentricity and skew angle of rotor in electromagnetic excitations are shown.
2016-06-15
Technical Paper
2016-01-1835
Albert Albers, Fabian Schille, Matthias Behrendt
Abstract In terms of customer requirements, driving comfort is an important evaluation criterion. Regarding hybrid electric vehicles (HEVs), maneuver-based measurements are necessary to analyze this comfort characteristic [1]. Such measurements can be performed on acoustic roller test benches, yielding time efficient and reproducible results. Due to full hybrid vehicles’ various operation modes, new noise and vibration phenomena can occur. The Noise Vibration Harshness (NVH) performance of such vehicles can be influenced by transient powertrain vibrations e.g. by the starting and stopping of the internal combustion engine in different driving conditions. The paper at hand shows a methodical procedure to measure and analyze the NVH of HEVs in different driving conditions.
2016-06-15
Technical Paper
2016-01-1836
Sylvestre Lecuru, Pascal Bouvet, Jean-Louis Jouvray, Shanjin Wang
The recent use of electric motors for vehicle propulsion has stimulated the development of numerical methodology to predict their noise and vibration behaviour. These simulations generally use models based on an ideal electric motor. But sometimes acceleration and noise measurements on electric motors show unexpected harmonics that can generate acoustic issues. These harmonics are mainly due to the deviation of the manufactured parts from the nominal dimensions of the ideal machine. The most recent VIBRATEC investigations have shown that the rotor eccentricities have the most relevant impact on acoustics of E-machines. Thus, the measurement of the rotor eccentricity becomes relevant to understand the phenomenon, quantify the deviation and then to use this data as an input in the numerical models.
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
Technical Paper
2016-01-1771
Manish Chhabra
Abstract By reducing overall noise emanating from Engine at design phase, permits to reduce both time-to-market and the cost for developing new engines. In order to reduce vibration and radiated noise in engine assembly, oil pan is one of the most critical components. This study explains the key-steps that are executed to optimize the oil pan design for 4-cylinder diesel engine by improving Normal Modes, modified Topology, reduced Forced Frequency Response and ATV analysis for reducing its noise radiation. Using Multi-body tool crankshaft forces were generated and the FE model of Base Design was analysed for its noise radiation and panel contribution was done for finding the most radiating panels using Boundary Element Method approach. A series of iterative optimization were carried out with commercial software.
2016-06-15
Technical Paper
2016-01-1776
Alexander Rabofsky, Alexander Koeck, Martin Mittermaier
Abstract Lightweight vehicle design causes special demands for functional NVH design. The reduction of weight by reducing material thickness, enabled by new alloys, the combination of materials and new materials increases the sensitivity of a vehicle body to the vibrational and acoustical response of external forces like powertrain or road and wind excitation. To be able to fully raise lightweight potentials design has to be driven closer to functional boundaries, putting higher demands on the accuracy of the prediction by simulation. For a robust design a very broad view on several loadcases is needed to make sure that by optimization on one target no other target is violated. In this paper, optimization strategies for complex NVH load-cases should be investigated in detail. In reality, load-cases, excitations as well as boundary conditions are very often complex and complicated.
2016-06-15
Journal Article
2016-01-1801
Jonathan Vaudelle, Florian Godard, Florian Odelot, Anne Sanon
Abstract Acoustic comfort inside the vehicle is required whenever a wiper system is in function: front wiper motor noise is of great influence on the global comfort and its perception inside the car is 100% due to transmission of vibrations through wiper system fixation points on the vehicle. As any active source, both car manufacturer and system supplier need to be involved, at early stages of project development, in order to master the vibroacoustic integration of the system into the vehicle. This paper presents an experimental methodology dedicated to the front wiper system that offers the possibility to estimate the acoustic comfort inside the vehicle during project deployment phase, when modifications can still be proposed. Based on the XP-R-19701 standard, the procedure allows to measure, on a bench, the dynamic forces transmitted via the fixation points and details how to transpose them to the vehicle, taking into account the different specificities of the wiper system.
2016-06-15
Technical Paper
2016-01-1796
Aurélien Cloix, Jean-Luc Wojtowicki
Paper for the session ('structure borne sound sources characterization'); TESSA Project Abstract: The current paper is based on the French research program TESSA (“Transfert des Efforts des Sources Solidiennes Actives”). A specific task within TESSA project consists in the characterization of the measurements variability between several laboratories, of the blocked forces on a water pump of a heat engine. This paper focuses only on the measurements carried out at Vibratec laboratory. Two kinds of measurements have been carried out: direct measurements, using force sensors, which is the target of the inter-laboratory measurements, and an inverse method without force sensor requirements. Reproducibility and repeatability tests have been done in order to quantify the measurement variability within the same laboratory, in preparation for the inter-laboratory disparity analysis.
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
Journal Article
2015-01-9152
André Lundkvist, Arne Nykänen, Roger Johnsson
Abstract Many of the information systems in cars require visual attention, and a way to reduce both visual and cognitive workload could be to use sound. An experiment was designed in order to determine how driving and secondary task performance is affected by the use of information sound signals and their spatial positions. The experiment was performed in a driving simulator utilizing Lane Change Task as a driving scenario in combination with the Surrogate Reference Task as a secondary task. Two different signal sounds with different spatial positions informed the driver when a lane change should be made and when a new secondary task was presented. Driving performance was significantly improved when both signal sounds were presented in front of the driver. No significant effects on secondary task performance were found. It is recommended that signal sounds are placed in front of the driver, when possible, if the goal is to draw attention forward.
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