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2014-06-30
Technical Paper
2014-01-2046
Matthias Frank, Franz Zotter, Alois Sontacchi, Stephan Brandl, Christian Kranzler
Abstract When employing in-car active sound generation (ASG) and active noise cancellation (ANC), the accurate knowledge of the vehicle interior sound pressure distribution in magnitude as well as phase is paramount. Revisiting the ANC concept, relevant boundary conditions in spatial sound fields will be addressed. Moreover, within this study the controllability and observability requirements in case of ASG and ANC were examined in detail. This investigation focuses on sound pressure measurements using a 24 channel microphone array at different heights near the head of the driver. A shaker at the firewall and four loudspeakers of an ordinary in-car sound system have been investigated in order to compare their sound fields. Measurements have been done for different numbers of passengers, with and without a dummy head and real person on the driver seat. Transfer functions have been determined with a log-swept sine technique. According to the measurements, the shape of the sound field produced by the shaker is more balanced than one produced by the loudspeakers, albeit the shaker's frequency response is limited to low frequencies.
2014-06-30
Technical Paper
2014-01-2075
Gregor Koners, Ralf Lehmann
Abstract Low interior noise levels in combination with a comfortable sound is an important task for passenger cars. Due to the reduction of many noise sources over the last decades, nowadays tire-road noise has become one of the dominant sources for the interior noise. Especially for manufactures of luxury cars, the reduction of tire-road noise is a big challenge and therefore a central part of NVH development. The knowledge of the noise transmission behavior based on the characteristics of the relevant sources is a fundamental of a modern NVH - development process. For tire-road noise the source characteristics can be described by wheel forces and radiated airborne noise. In combination with the related vehicle transfer functions it is possible to describe the noise transmission behavior in detail. A method for estimating wheel forces and radiated airborne noise is presented. The method is based on TPA (= Transfer Path Analysis) via matrix inversion and involves the measurement of the vehicle transfer functions.
2014-06-30
Technical Paper
2014-01-2087
Ashish Shah, David Lennström, Per-Olof Sturesson, William Easterling
Abstract The increased focus and demands on the reduction of fuel consumption and CO2 requires the automotive industry to develop and introduce new and more energy efficient powertrain concepts. The extensive utilisation of downsizing concepts, such as boosting, leads to significant challenges in noise, vibration and harshness (NVH) integration. This is in conflict with the market expectation on the vehicle's acoustic refinement, which plays an increasingly important role in terms of product perception, especially in the premium or luxury segment. The introduction of the twin charger boosting system, i.e. combining super and turbo charging devices, enables downsizing/speeding in order to achieve improved fuel economy as well as short time-to-torque, while maintaining high driving dynamics. This concept requires also extensive consideration to NVH integration. The NVH challenges when integrating a roots type supercharger are very extensive. The high frequency source characteristics of the supercharger result in complex wave propagation inside the intake duct system since exciting pulsation orders are well above duct cut-on frequencies.
2014-06-30
Technical Paper
2014-01-2088
Daniel Fernandez Comesana, Emiel Tijs, Daewoon Kim
Abstract 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.
2014-06-30
Technical Paper
2014-01-2048
Dirk Mayer, Jonathan Militzer, Thilo Bein
Abstract The automotive industry is aiming at both reducing the weight of the vehicles while improving a high level of comfort. This causes contradicting requirements for the systems used for noise and vibration control. Thus, active systems are investigated which may enhance the performance of passive noise and vibration control in vehicles without adding excessive weight. In this paper, basic principles for the implementations of those systems with a focus on the control systems are reviewed. Examples from implementations in automotive applications are presented, including control of engine vibrations, structure borne noise transmitted from the road into the passenger compartment and low-frequency chassis vibrations. Based on adaptive filter systems already widely used in active noise control adaptation of the control algorithms to the specific application scenarios are discussed. This includes different configurations for feedforward and feedback control, single- and multichannel control systems and the utilization of different actuator concepts like active mounts, inertial mass actuators and active tuned absorbers, as well as different control sensors like accelerometers and microphones.
2014-06-30
Technical Paper
2014-01-2080
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.
2014-06-30
Technical Paper
2014-01-2081
Rainer Stelzer, Theophane Courtois, Ki-Sang Chae, Daewon SEO, Seok-Gil Hong
Abstract The assessment of the Transmission Loss (TL) of vehicle components at Low-Mid Frequencies generally raises difficulties associated to the physical mechanisms of the noise transmission through the automotive panel. As far as testing is concerned, it is common in the automotive industry to perform double room TL measurements of component baffled cut-outs, while numerical methods are rather applied when prototype or hardware variants are not available. Indeed, in the context of recent efforts for reduction of vehicle prototypes, the use of simulation is constantly challenged to deliver reliable means of decision during virtual design phase. While the Transfer matrix method is commonly and conveniently used at Mid-High frequencies for the calculation of a trimmed panel, the simulation of energy transfer at low frequencies must take into account modal interactions between the vehicle component and the acoustic environment. After providing a brief review of the established approaches for TL simulation at LF, the article will present a new FE methodology for TL simulation and introduce the advantages of “in-situ” TL simulations by means of fluid-structure FE calculation.
2014-06-30
Technical Paper
2014-01-2095
Janko Slavic, Martin Cesnik, Miha Boltezar
Abstract 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.
2014-06-20
Article
Omega’s PR-21 series of RTD (resistance temperature detector) sensors with M12 connector feature a welded 316L stainless steel housing and an integral 4-pin M12 connector for easy connection.
2014-06-12
Article
The cause of the issue was an error in the process Ford engineers used to correlate wind-tunnel testing into their Total Road Load Horsepower (TRLHP) factor that is key to the vehicle fuel economy models that are ultimately submitted to the U.S. EPA.
2014-06-11
Article
Reaction Design worked with a German premium automotive company to build cylinder-combustion simulations for a high-performance diesel engine with the goal of accurately and quickly predicting combustion performance and the effects of varied operating conditions on soot emissions.
2014-06-06
Standard
J671_201406
Description of Material—The materials classified under this specification are: a. Mastic vibration damping materials used to reduce the sound emanating from metal panels. b. Mastic underbody coatings used to give protection and some vibration damping to motor vehicle underbodies, fenders, and other parts.
2014-06-03
Article
The LC411-USBH series high-speed USB load cells from Omega connect directly to your computer and offer up to 1000 readings per second.
2014-05-31
Article
Hexagon Metrology’s Leica T-Scan 5 handheld system for laser trackers is said to operate more than 15 times faster than the previous model.
2014-05-30
Article
PCB Piezotronics’ surface microphone for R&D testing features a low-profile design ideal for testing in confined spaces and windy environments.
2014-05-30
Article
Supercritical Fluid Technologies’ SFT-250 supercritical fluid extractor is designed to perform extractions in supercritical fluid and meets the rigors of the research lab.
2014-05-20
Article
ViCANdo from Zuragon is a multimedia software tool for development, physical testing, and validation of various applications such as vehicle fleets, hybrid-electric systems, active safety systems, autonomous vehicles, and HMI systems.
2014-05-16
Standard
J1207_201405
This SAE Recommended Practice sets forth the instrumentation, environment, and test procedures to be used in measuring the silencer system effectiveness in reducing intake or exhaust sound level of internal combustion engines. The system shall include the intake or exhaust silencer, related piping, and components. This procedure is intended for engine-dynamometer testing and is not necessarily applicable to vehicle testing (see Appendix A). The effect of the exhaust or intake system on the sound level of the overall machine must be determined using other procedures. This procedure may be successively applied to various silencer configurations to determine relative effectiveness for that engine. Insertion loss for individual silencers may be calculated through measurement of the silenced and unsilenced system.
2014-05-16
Standard
J1060_201405
This SAE Recommended Practice establishes a rating scale for subjective evaluations of noise and discomfort in motor vehicles. Through test procedures utilizing specific vehicles on specific roads, the scale may be utilized to assess the relative contributions of tires to noise and discomfort. The noise and ride comfort characteristics attributed to automotive tires have traditionally been estimated by subjectively assigning number designations (commonly on a 1 to 10 scale) to the audible and tactile sensations observed while traversing a given road course in a vehicle equipped with the tires under evaluation. Regardless of advances in objective measurements of tire properties related to noise and discomfort, subjective evaluation will continue to be necessary for the purpose of establishing the significance of such measurements. The rating scale of this recommendation is applicable to assessment of each of the wide variety of audible and tactile disturbances referred to by such terms as bump, thump, slap, shake, etc.
2014-05-16
Standard
J57_201405
This procedure provides for the measurement of the sound generated by a test tire, mounted on a single-axle trailer, operated at multiple speeds. The procedure describes test practices for both United States and International practices. Specifications for the instrumentation, the test site, and the operation of the test apparatus are set forth to minimize the effects of extraneous sound sources and to define the basis of reported sound levels.
2014-05-16
Standard
J1074_201405
This SAE Recommended Practice sets forth the equipment, environment, and test procedures to be used in measuring sound levels of engines. The purpose is to provide a uniform method of measuring the maximum acoustical radiation from the exterior surfaces of an engine under representative engine operating conditions. The measured sound levels will be useful in development of engines, comparison of engines, and installation of engines in various applications. The correlation of the measured engine sound levels to the various application sound levels will have to be developed.
2014-05-14
Article
Michael Duoba (SAE Member, 1993), Vehicle Test Engineer and team leader for the Advanced Powertrain Research Facility at Argonne National Laboratory, discuss his career progression and the type of work conducted at his lab.
2014-05-09
Technical Paper
2014-01-9126
Nikolina Samardzic
Values of the speech intelligibility index (SII) were found to be different for the same speech intelligibility performance measured in an acoustic perception jury test with 35 human subjects and different background noise spectra. Using a novel method for in-vehicle speech intelligibility evaluation, the human subjects were tested using the hearing-in-noise-test (HINT) in a simulated driving environment. A variety of driving and listening conditions were used to obtain 50% speech intelligibility score at the sentence Speech Reception Threshold (sSRT). In previous studies, the band importance function for ‘average speech’ was used for SII calculations since the band importance function for the HINT is unavailable in the SII ANSI S3.5-1997 standard. In this study, the HINT jury test measurements from a variety of background noise spectra and listening configurations of talker and listener are used in an effort to obtain a band importance function for the HINT, to potentially correlate the calculated SII scores with the measured speech intelligibility scores.
2014-05-09
Technical Paper
2014-01-9124
David Lennström, Roger Johnsson, Anders Agren, Arne Nykänen
In the vehicle development process, targets are defined to fulfill customers' expectations on acoustic comfort. The interior complete vehicle acoustic targets can be cascaded down to system and component targets, e.g. insulation properties and source strengths. The acoustic transfer functions (ATFs) from components radiating airborne noise play a central role for the interior sound pressure levels. For hybrid vehicles fitted with an electric traction motor, the contribution of high frequency tonal components radiated from the motor housing needs to be controlled. The interior sound pressure due to an airborne motor order can be estimated by surface velocities and ATFs. This study addresses the ATFs measured from a large number of positions located around an electric rear axle drive (ERAD) and their influence on estimated interior noise. First, the magnitude variation between the individual ATFs and how it clearly can be visualized was presented. Displaying all ATFs in a color map revealed the magnitude at each geometrical location of the respective microphone.
2014-05-08
Article
The first ever Airbus A350 XWB to visit the U.S., MSN2, arrived the second week in May at McKinley Climatic Lab at Eglin Air Force base in Florida. Over several weeks the aircraft and its various systems and cabin installations will be subjected to the extreme hot and cold temperatures that the facility can sustain in a testing environment.
2014-05-08
Article
CSEG has designed, and filed a patent for, a cooling pack and fan that would allow for extreme driving conditions while downsizing the cooling pack, increasing fuel economy, and reducing costs for the OEM as well as the customers who do the driving.
2014-05-05
Technical Paper
2014-01-9099
Lindsay J. Miller, Susan Sawyer-Beaulieu, Edwin Tam
Polyurethane (PU) foam is used for many automotive applications with the benefits of being lightweight, durable, and resistant to heat and noise. Applications of PU foams are increasing to include non-traditional purposes targeting consumer comfort. An example of this is the use of PU foam between the engine and engine cover of a vehicle for the purpose of noise abatement. This addition will provide a quieter ride for the consumer, however will have associated environmental impacts. The additional weight will cause an increase in fuel consumption and related emissions. More significant impacts may be realized at the end-of-life stage. Recycling PU foams presents several challenges; a lack of market for the recyclate, contamination of the foams, and lack of accessibility for removal of the material. PU foam pieces are likely to end up being landfilled after the vehicle is shredded, negating the benefit of choosing this material for its recyclability over another non-recyclable material.
2014-04-30
WIP Standard
J1598
This SAE Recommended Practice is applicable to all liquid-to-gas, liquid-to-liquid, gas-to-gas, and gas-to-liquid heat exchangers used in vehicle and industrial cooling systems. This document outlines the test to determine durability characteristics of the heat exchanger from vibration-induced loading.
2014-04-30
WIP Standard
J577
This SAE Recommended Practice provides procedures, and information to conduct vibration (impact) tests on lighting devices and their components as well as other safety equipment used on vehicles.
2014-04-28
Article
AB Dynamics’ updated suspension parameter measuring machine (SPMM), the SPMM5000, is a fixed ground plane kinetics and compliance test machine that measures suspension parameters and characteristics like the SPMM4000 on which it is based.
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