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Training / Education Classroom Seminars
Most muffler design in the automotive industry is accomplished by using "cut-and-try" methods that rely on what has worked in the past and/or extensive full-scale testing on engines for validation. New computer software aimed at muffler design can shorten the design cycle and yield more effective results. This four hour seminar provides an introduction to the behavior of mufflers and silencers including a description of the two-port approach to muffler design. This seminar covers the acoustic simulation of muffler and silencer systems and the use of experimental methods to measure muffler performance.
2018-11-05 ...
  • November 5, 2018 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
Training / Education Classroom Seminars
The influx of different hybrid and electric vehicle configurations has brought about unique NVH challenges from a variety of sources. NVH refinement is an important aspect of powertrain development and the vehicle integration process. While developing the NVH behavior of the vehicle is critical to satisfy customer expectations, it is also important to consider the influence of reduced exterior noise levels on pedestrian safety.
2018-10-01 ...
  • October 1-5, 2018 (8:00 a.m. - 8:00 p.m.) - Troy, Michigan
Training / Education Classroom Engineering Academies
This Engineering Academy covers a variety of vehicle noise control engineering principles and practices. 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.
2018-10-01 ...
  • October 1-5, 2018 (8:00 a.m. - 8:00 p.m.) - Troy, Michigan
Training / Education Classroom Engineering Academies
This Engineering Academy covers a variety of vehicle noise control engineering principles and practices. 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.
2018-06-11 ...
  • June 11-22, 2018 (6 Sessions) - Live Online
  • November 28-December 10, 2018 (6 Sessions) - Live Online
Training / Education Online Web Seminars
Finite Element Analysis (FEA) has been used by engineers as a design tool in new product development since the early 1990's. Until recently, most FEA applications have been limited to static analysis due to the cost and complexity of advanced types of analyses. Progress in the commercial FEA software and in computing hardware has now made it practical to use advanced types as an everyday design tool of design engineers. In addition, competitive pressures and quality requirements demand a more in-depth understanding of product behavior under real life loading conditions.
2018-06-05 ...
  • June 5-7, 2018 (2 Sessions) - Live Online
Training / Education Online Web Seminars
This web seminar 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.
2018-05-10 ...
  • May 10-11, 2018 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
Training / Education Classroom Seminars
The sound package materials for vehicle noise control seminar provides a detail and thorough analysis of three different classes of acoustical materials – namely absorbers, barriers, and dampers, how they are different from each other, and acoustical properties that materials should possess for optimum vehicle noise control. The seminar addresses new advances in acoustical materials, primarily in absorption materials that impact the vehicle acoustics. The seminar covers ways to evaluate the acoustical performance of these materials using different test methods, including material, component, and vehicle level measurements.
2018-03-23 ...
  • March 23, 2018 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
  • October 19, 2018 (8:30 a.m. - 4:30 p.m.) - Palm Desert, California
Training / Education Classroom Seminars
Brake noise is one of the highest ranked complaints of car owners. Grunts, groans, squeaks, and squeals are common descriptions of the annoying problem which brake engineers spend many hours trying to resolve. Consumer expectations and the high cost of warranty repairs are pushing the optimization of brake NVH performance. This course will provide you with an overview of the various damping mechanisms and tools for analyzing and reducing brake noise. A significant component of this course is the inclusion of case studies which will demonstrate how brake noise squeal issues have been successfully resolved.
2018-03-22 ...
  • March 22, 2018 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
  • October 18, 2018 (8:30 a.m. - 4:30 p.m.) - Palm Desert, California
Training / Education Classroom Seminars
Brake Noise, Vibration, and Harshness (NVH) is recognized as one of the major problems currently faced by the automotive manufacturers and their suppliers, with customers warranty claims of more than $100 million per year for each manufacturer. With increasing consumer braking performance expectations, automotive OEM’s and suppliers need the ability to predict potential problems and identify solutions during the design phase before millions of dollars have been spent in design, prototyping, and manufacturing tooling.
2018-03-06 ...
  • March 6-13, 2018 (3 Sessions) - Live Online
  • November 13-20, 2018 (3 Sessions) - Live Online
Training / Education Online Web Seminars
This web seminar will provide an introduction to the characteristics of sound waves, human perception of sound, sound and vibration measurements, measurement facilities, and various noise sources and noise control principles. It will include an overview of sound pressure, power, intensity, decibels, and frequencies. Practical examples will be used to familiarize participants with the acoustic fundamentals for solving noise and vibration problems and the associated solution principles.
2018-01-10 ...
  • January 10-19, 2018 (4 Sessions) - Live Online
  • August 21-30, 2018 (4 Sessions) - Live Online
Training / Education Online Web Seminars
This four-session web seminar 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 course 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.
2010-10-25
Technical Paper
2010-01-2162
Patricia Anselmi, Julian Kashdan, Guillaume Bression, Edouard Ferrero-Lesur, Benoist Thirouard, Bruno Walter
Latest emissions standards impose very low NOx and particle emissions that have led to new Diesel combustion operating conditions, such as low temperature combustion (LTC). The principle of LTC is based on enhancing air fuel mixing and reducing combustion temperature, reducing raw nitrogen oxides (NOx) and particle emissions. However, new difficulties have arisen. LTC is typically achieved through high dilution rates and low CR, resulting in increased auto-ignition delay that produces significant noise and deteriorates the combustion phasing. At the same time, lower combustion temperature and reduced oxygen concentration increases hydrocarbon (HC) and carbon oxide (CO) emissions, which can be problematic at low load. Therefore, if LTC is a promising solution to meet future emission regulations, it imposes a new emissions, fuel consumption and noise trade-off. For this, the injection strategy is the most direct mean of controlling the heat release profile and fuel air mixture.
2010-09-28
Technical Paper
2010-32-0028
Daniela Siano, Fabio Auriemma PhD, Fabio Bozza
Automotive exhaust systems give a major contribution to the sound quality of a vehicle and must be properly designed in order to produce acceptable acoustic performances. Obviously, noise attenuation is strictly related to the used materials and to its internal geometry. This last influences the wave propagation and the gas-dynamic field. The purpose of this paper is to describe advantages and disadvantages of different numerical approaches in evaluating the acoustic performance in terms of attenuation versus frequency (Transmission Loss) of a commercial two perforated tube muffler under different conditions. At first, a one-dimensional analysis is performed through the 1D GTPower® code, solving the nonlinear flow equations which characterize the wave propagation phenomena. The muffler is characterized as a network of properly connected pipes and volumes starting from 3D CAD information. Then, two different 3D analyses are performed within the commercial STS VNOISE® code.
2010-09-28
Technical Paper
2010-32-0027
Darrell A. Wiatrowski, Peter E. Lucier
Advances in motorized vehicle vibration control have increased consumer expectations to feel minimal vibration when operating vehicles in any environment; on and off road. Small outboard marine engines have a heightened need for vibration isolation, since the user often steers using a tiller arm connected to the outboard. Traditional engine mount systems allow the mount reaction loads to create a periodic torque about the steering axis and result in significant tiller arm shaking forces. This paper presents a novel mount arrangement that minimizes the shaking couple about the steering axis and isolates the tiller from engine vibration. The concept was first modeled using rigid body dynamics software to predict vibration of the tiller arm. Testing confirmed the simulation, and demonstrated a significant reduction of vibration transmitted to the tiller arm and boat seat compared with a traditional focused mount system.
2010-09-28
Technical Paper
2010-32-0025
Masao Ishihama
This paper reports development of a measuring device built in a camshaft drive chain sprocket for detecting precise torque fluctuation with minimum change on the valve drive system dynamical characteristics. This torque measuring device (TMD) was designed to measure torque with minimum cross-talk with bending force or lateral force. To realize these functions, the disc portion of a chain sprocket that connects the teeth and the camshaft was carved to make thin plate area so that the strain gages placed on the area may have enough sensitivity to torque fluctuation. The signal from the circuit goes through frequency modulation and is transmitted to demodulation circuit via coil antennas. By this arrangement, almost perfect linearity was observed in the relationship of the TMD output voltage and the applied torque. Using a model cylinder head unit of an in-line four cylinder gasoline engine driven by a variable speed electric motor, the TMD performance was evaluated.
2010-09-28
Technical Paper
2010-32-0023
Toshiaki Taguchi, Makoto Aoki, Youta Katsukawa, Masahiro KOGA, Tohru Koshimizu, Masahito Saitou
Motorcycle exhaust mufflers are important devices which influence not only exhaust noise and engine performance but also appearance of motorcycle. Since the improvement of engine performance often contradicts the attenuation of exhaust noise in designing mufflers, it is necessary that both the exhaust noise and the engine performance are predicted simultaneously. Recently, unsteady-state one-dimensional computational fluid dynamics (1-D CFD) analysis is being applied to this problem. We have developed the technique to predict engine performance and exhaust pulsating sound by adopting unsteady-sate 1-D CFD analysis (here, we treat the exhaust pulsating sound which is a discrete frequency component of exhaust noise). In this paper, firstly, as a result of a preliminary study, it is shown that our prediction technique can predict the acoustic transmission loss of a muffler.
2010-09-28
Technical Paper
2010-32-0022
Jüri Lavrentjev, Hans Rämmal
Today, catalytic converters are widely used in small engine exhaust systems to reduce pollutants. Besides reducing harmful pollutants, these devices have a significant effect on the acoustical performance and the pressure drop of the engine exhaust system. A catalytic converter is known to have two distinct acoustic effects: the reactive effect originating from the acoustic wave reflections caused by cross-sectional area changes within the unit and the resistive effect which results in the acoustic wave dissipation caused by viscous losses. The pressure drop in the narrow tubes in the catalytic converter element results in frequency dependent resistive effects on the transmitted sound. In this paper the passive acoustic effect which treats the sound attenuation in the catalytic converters has been investigated. An experimental investigation on small engine catalytic converters treated as acoustic two-ports is carried out.
2010-09-28
Technical Paper
2010-32-0021
Shital Shah, Saisankaranarayana Kuppili, Kalyankumar Hatti, Dhananjay Thombare
Exhaust noise from engines is one of component noise pollution to the environment. Exhaust systems are developed to attenuate noise meeting required db (a) levels and sound quality, emissions based on environment norms. Hence this has become an important area of research and development. Most of the advances in theory of acoustic filters and exhaust mufflers have been developed in last two decades. Mufflers are important part of engine system and commonly used in exhaust system to minimize sound transmissions caused by exhaust gases. Design of mufflers is a complex function that affects noise characteristics, emission and fuel efficiency of engine. Therefore muffler design becomes more and more important for noise reduction. Traditionally, muffler design has been an iterative process by trial and error. However, the theories and science that has undergone development in recent years has given a way for an engineer to cut short number of iteration.
2010-04-12
Technical Paper
2010-01-0586
Avoki Michel Omekanda, Todd Geib, Dan Buehler, Kirk Wan, Lucille G. Lavan
Gasoline Direct Injection (GDi) system is a relatively new technology. In early implementations, its major components, i.e. high pressure fuel pump, injectors, and fuel rails, emit objectionable acoustic noise during normal operation. This paper will focus on making an objective comparison (assessment) of acoustic noise emitted by several cam-driven high pressure fuel pumps during their normal operation, especially at engine idle. Taguchi robust engineering methods will be used to conduct the robust assessment study of six GDi high-pressure pumps. A-weighted total sound pressure level (SPL), processed from two free-field microphones around each pump, will be used as the main function in the Taguchi design of experiments (DOE).
2010-04-12
Technical Paper
2010-01-0414
Avnish Gosain, Mugundaram Ravindran
One of the most common NVH refinement areas of a vehicle is the cabin booming noise. The current study discusses the improvement of the low frequency booming noise in the cabin of a small passenger car. The practice of reinforcing experimental evaluation results with the extensive use of computer aided engineering tools in the development process is presented in this paper. The structural changes executed in the vehicle, to reduce noise contribution, are iterated and optimized using simulation and validated using experimental analysis methods like operational modal analysis, linear frequency response functions and actual run-up measurements. Additionally, the interesting variation of the NVH characteristics of a vehicle due to the changeover from a 4-cylinder inline to a 3-cylinder inline powertrain, while inheriting the similar body structure, is discussed in this study.
2010-04-12
Technical Paper
2010-01-0416
Weiguo Zhang, S. T. Raveendra, Moohyung Lee, J Stuart Bolton
The identification of the propulsion noise of turbofan engines plays an important role in the design of low-noise aircraft. The noise generation mechanisms of a typical turbofan engine are very complicated and it is not practical, if not impossible, to identify these noise sources efficiently and accurately using numerical or experimental techniques alone. In addition, a major practical concern for the measurement of acoustic pressure inside the duct of a turbofan is the placement of microphones and their supporting frames which will change the flow conditions under normal operational conditions. The measurement of acoustic pressures on the surface of the duct using surface-mounted microphones eliminates this undesirable effect. In this paper, a generalized acoustical holography (GAH) method that is capable of estimating aeroacoustic sources using surface sound pressure is developed.
2011-04-12
Technical Paper
2011-01-0436
Alejandra Paola Polanco, Luis Munoz
In this paper the comfort sensitivity to the variation of the inertia parameters is studied. For the theoretical approach, two computational models that predict the comfort response of a vehicle are developed and verified. These models are used to study the effect of a change on the inertial properties of the car on its comfort response. The models are developed on a commercial multi-body package and also implementing handwritten equations with a numerical integration algorithm. The influence of the inertial properties on comfort is also experimentally studied. Both approaches use two different road patterns as input generating a roll and pitch excitation. An allowed uncertainty on the inertia properties is proposed, based on the sensitivity to those properties.
2011-04-12
Technical Paper
2011-01-0397
Hiromichi Kawamura, Ken Ito, Takaaki Karikomi, Tomohiro Kume
This paper describes a shaking vibration suppression approach for electric vehicles to support their quick and smooth acceleration response. Applied to the Nissan LEAF that has been specifically designed as a mass-market EV, the shaking vibration control system achieves a balance between highly responsive acceleration obtained with the electric drive motor, producing maximum torque of 280 Nm and maximum power of 80 kW, and a comfortable ride. A vehicle powered by an electric motor can provide quick acceleration response, thanks to the motor's fast torque response. However, the fast rate of increase in motor torque causes an uncomfortable shaking vibration that originates in the torsional torque of the drive shaft. The unique shaking vibration control system has been developed to achieve a balance between vehicle acceleration performance and ride comfort. Driving test results have confirmed that highly responsive acceleration is obtained without any shaking vibration.
2010-04-12
Technical Paper
2010-01-1141
Yong Woo Park, Hyo Seok Kim, Kwangjin Joo, Namil Jeon
The purpose of this paper is to identify and reduce the suspension rattle noise. First, the characteristics of the rattle noise are analyzed experimentally in the time and frequency domain. It was found that the rattle noise and vibration at shock absorber mounting point are strongly correlated. Second, the sensitivity analysis of design parameters is performed using a half car model in ADAMS. The result of the simulation model is verified by comparison with test. Finally, the influence of design parameters for the rattle noise is investigated. The study shows that the shock absorber mounting bushing is the most sensitive parameter to affect the suspension rattle noise. This paper shows how the suspension rattle noise can be improved.
2010-04-12
Technical Paper
2010-01-1094
Shin Nishimura, Takashi Tetsuka, Yukihiro Asada, Tomoya Kono, Makoto Tsuyuguchi, Satoru Nojima
Honda R&D has developed a throttle-by-wire (TBW) system that meets the needs of motorcycles where the attitude of the vehicle body is controlled by operation of the throttle. To gain high response and following for the throttle valve, we employed a new adaptive control algorithm. The newly developed system has an idling combustion stabilization function and a three-dimensional control function for the throttle-opening map based on running gear and engine speed. With those functions, we improved the controllability of the motorcycle, especially for small throttle openings. Furthermore, we improved the feeling of the limiter control used in maximum-speed limitation. For the overall system, intake system related devices are consolidated to improve the layout flexibility and expand the mounting options on the motorcycle.
2010-10-10
Technical Paper
2010-01-1685
Eric Denys, James K. Thompson
The development and validation of a brake pad insulator damping measurement procedure by the SAE Brake NVH Standards Committee is described in this paper. The details of the test procedure, test set-up and recommendations for proper test practices are described. The description provides an excellent foundation for evaluating the damping properties of a shim over a range of frequencies and temperatures. To document the repeatability of the measurement process, a Gage R&R study was conducted. The results show that a high level of repeatability is achieved over a range of temperatures and damping properties. An example application is described to illustrate the usage of the procedure. This example provides an excellent illustration of how this procedure can be used to select the best shim for a specific application. Conclusions as to the applicability of this procedure and its value to brake noise control are provided in the final section.
2010-10-10
Technical Paper
2010-01-1686
Carmen Parra, Jose Luis Olazagoitia, Jorge Biera
Coalescence of natural frequencies among different brake components is one of the main causes for squeal noise appearance under some specific operating conditions. Many publications have dealt with the study of squealing under different situations. However, in most cases this knowledge has not been transferred to the companies by means of easy to use software. This paper is focused on the development of a practical tool to provide brake pad manufacturers with an instrument to reduce the probability to suffer squeal noises at the design stage of the product. It can also be used as a problem solving tool to interactively find the optimum design to a specific problem.
2010-10-10
Journal Article
2010-01-1687
Georg P. Ostermeyer, Matthias Graf
To predict and minimize squeal propensity in brake systems, numerous models, which perform friction induced vibration, are available. However, today there is no model that can explain satisfactorily the dynamic behavior of brake systems. We argue that this is - among other effects - because existing models are based on decaying or constant coefficient of friction, although many investigations indicate rich dynamics of the coefficient of friction. Stability analysis of linear differential equations with periodic coefficients shows that instability regions change with rising amplitude of the periodic coefficients. If the periodic coefficient corresponds to the coefficient of friction, its periodicity can lower the stability of a minimal model.
2010-10-10
Technical Paper
2010-01-1688
Mohamed Khalid Abdelhamid, Eric Denys
As part of the development of a new SAE Recommended Practice for brake rotor modal frequencies measurement and control, the SAE Brake NVH Standards Committee developed detailed recommendations for such measurement, data reporting and use in quality control. This paper addresses the need for formalizing measurement techniques of rotor modal frequencies and documenting the proper set up and measurement parameters. Additionally, a rotor mode classification system is proposed so that important rotor modes may be tracked. Statistical control of modal frequencies is presented and practical limits are defined
2010-10-10
Technical Paper
2010-01-1684
Mohamed Khalid Abdelhamid
NVH development is an important part of modern brake product development plans. This paper analyzes a typical NVH development process and identifies gaps in available development technologies and processes that when filled can improve the brake NVH development effort. The paper also discusses how the disciplines of simulation, component testing, dynamometer testing, and vehicle testing are currently integrated and proposes more effective processes of development. The paper identifies opportunities for contributions from professional societies and standardization organizations, vendors of test equipment and software, test laboratories, university research centers as well as brake suppliers' engineering centers to improve the engineering toolbox and fill the gaps in brake NVH development.
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