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2015-06-15
Journal Article
2015-01-2223
Rolf Schirmacher
Abstract Active Noise Control (ANC) has long been seen as emerging technology. During recent years, however, it became popular in new vehicle and infotainment platforms within a broad range of OEMs. This paper summarizes the current status and lessons learned of production systems (as well as those entering production soon) and gives an outlook on how ANC and related technologies will integrate in future vehicles and audio/infotainment architectures.
2015-06-15
Technical Paper
2015-01-2219
Al Ganeshkumar, Shinichi Fukuhara
Abstract Active Noise Cancellation (ANC) technology is widely used in automobiles to reduce engine harmonic noise [3]. ANC systems require one or more microphones mounted in the cabin to monitor the harmonic noise level and provide feedback to the DSP algorithm. The ideal locations for the microphones are as close as possible to the passenger seating locations and away from any wind turbulence that can impact the diaphragm of the microphone. Excessive wind turbulence on the diaphragm can cause the ANC adaptive filter weights to be perturbed enough resulting in audible ‘pumping’ type artifacts. For several practical reason it's not always possible to control the location of the microphones and hence a DSP software and/or mechanical solution needs to be incorporated in the system. This paper will primarily address the DSP software solutions to detect wind turbulence noise in ANC microphones so appropriate counter measures can be applied to eliminate the unwanted artifacts.
2015-06-15
Technical Paper
2015-01-2296
Seunghyun Lee, Sungmoon Lee, Kyoungdoug Min, Insoo Jung
Abstract Diesel engine noise is classified into mechanical noise, flow dynamic noise and combustion noise. Among these, combustion noise level is higher than the others due to the high compression ratio of diesel combustion and auto ignition. The injected fuel is mixed with air in the ignition delay process, followed by simultaneous ignition of the premixed mixture. This process results in a rapid pressure rise, which is the main source of combustion noise. The amount of fuel burned during premixed combustion is mainly affected by the ignition delay. The exhaust gas recirculation (EGR) rate has an impact on ignition delay, and thus, it influences the combustion noise characteristics. Therefore, during the transient state, the combustion noise characteristics change as the EGR rate deviates from the target value. In this study, the effect of the EGR rate deviation during the transient state of the combustion noise is examined.
2015-06-15
Journal Article
2015-01-2226
Shishuo Sun, David W. Herrin, John Baker
Abstract Transmissibility is the most common metric used for isolator characterization. However, engineers are becoming increasingly concerned about energy transmission through an isolator at high frequencies and how the compliance of the machine and foundation factor into the performance. In this paper, the transfer matrix approach for isolator characterization is first reviewed. Two methods are detailed for determining the transfer matrix of an isolator using finite element simulation. This is accomplished by determining either the mobility or impedance matrix for the isolator and then converting to a transfer matrix. It is shown that results are similar using either approach. In both cases, the isolator is first pre-loaded before the transfer matrix is determined. The approach to find isolator insertion loss is demonstrated for an isolator between two plates, and the effect of making changes to the structural impedance on the machine side of the isolator by adding ribs is examined.
2015-06-15
Technical Paper
2015-01-2317
Zhenlin Ji, Yiliang Fan
Abstract A simulative program named as MAP (Muffler Analysis Program) is developed for the rapid calculation and analysis of acoustic characteristics of duct muffling systems. The program is based on the plane wave theory and uses the Visual Basic 6.0 to create a friendly GUI (Graphic User Interface) for input of the geometrical and physical parameters to build and modify the duct muffling systems quickly. The relations among the acoustic elements are established by using the transfer matrix method, the transmission loss (TL) and insertion loss (IL) may be calculated, and then the results are plotted in terms of curves. Map allows designer to change parameters of the duct muffling systems expediently, in order to examine the effects of design changes on the acoustic attenuation characteristics and finally to get an acceptable solution.
2015-06-15
Journal Article
2015-01-2216
Dong Chul Park, Eun Soo Jo, Seokgwan Hong, Michael Csakan
Abstract An important trend among vehicle NVH engineers is the production of attractive engine acceleration sound quality for the enhancement of a vehicle's image and performance. In addition, customers have increasing interest and enjoyment in customizing their cars to reflect their personal taste and preferences. The PESS (Personalized Engine Sound System) has been developed for making a unique and individually customizable vehicle concept. The system allows the customers an opportunity to create a variety of engine sounds in a single vehicle using active sound design technology. In this system, three different engine sound concepts are pre-defined, Dynamic, Sporty, and Extreme. Each of the engine sounds can then be adjusted with parameters that determine the timbre, such as main order, rumble, and high order. In addition, the pedal position during acceleration has also been used as a parameter to further personalize the experience.
2015-06-15
Journal Article
2015-01-2281
Shrirang Deshpande, Randall Allemang
Abstract Spectral maps and order tracks are tools which are susceptible to improper sensor location on rotating machinery and to measurement noise. On a complex/large rotating system, the major behavior in a particular direction cannot be observed by using standard digital signal processing averaging techniques on different sensor outputs. Also, measurement noise cannot be reduced by applying averaging - due to the slew rate of the system. A newly developed technique tested on experimental data, is presented which uses singular value decomposition (SVD) as its basis to improve the observability of rotating systems. By using data acquired from multiple accelerometers on a machine, singular values - obtained from a SVD of the cross-power matrix at each 2-D point in the frequency-RPM domain - can be plotted in a color-map format similar to a RPM spectral map.
2015-06-15
Journal Article
2015-01-2282
Roland Sottek, Wade Bray
Abstract For many years in vehicle and other product noise assessments, tonality measurement procedures such as the Tone-to-Noise Ratio, Prominence Ratio and DIN 45681 Tonality have been available to quantify the audibility of prominent tones. Especially through the recent past as product sound pressure levels have become lower, disagreements between perceptions and measurements have increased across a wide range of product categories including automotive, Information Technology and residential products. One factor is that tonality perceptions are caused by spectrally-elevated noise bands of various widths and slopes as well as by pure tones, and usually escape measure in extant tools. Near-superpositions of discrete tones and elevated narrow noise bands are increasingly found in low-level technical sounds.
2015-06-15
Journal Article
2015-01-2284
Chris Hocking, Simon Antonov, Arsham Shahlari
Abstract The higher cylinder peak pressure and pressure rise rate of modern diesel and gasoline fueled engines tend to increase combustion noise while customers demand lower noise. The multiple degrees of freedom in engine control and calibration mean there is more scope to influence combustion noise but this must first be measured before it can be balanced with other attributes. An efficient means to realize this is to calculate combustion noise from the in-cylinder pressure measurements that are routinely acquired as part of the engine development process. This publication reviews the techniques required to ensure accurate and precise combustion noise measurements. First, the dynamic range must be maximized by using an analogue to digital converter with sufficient number of bits and selecting an appropriate range in the test equipment.
2015-06-15
Journal Article
2015-01-2173
Srikumar C Gopalakrishnan, Teik Lim
Abstract Modeling of elastohydrodynamic lubrication phenomena for the spiral bevel gears is performed in the present study. The damping and the friction coefficient generated from the lubricated contact area will have profound effects on the dynamics of spiral bevel gears. Thus the damping value generated from this friction model will be time varying. This makes the use of constant and empirical damping value in the dynamics of spiral bevel gears questionable. The input geometric and kinematic data required for the elastohydrodynamic lubrication (EHL) simulations are obtained using Tooth Contact Analysis. A full numerical elastohydrodynamic lubrication simulations are carried out using asymmetric integrated control volume (AICV) algorithm to compute the contact pressures. The fast Fourier transform is used to calculate the elastic deformations on the gear surfaces due to contact load.
2015-06-15
Journal Article
2015-01-2265
Murali Balasubramanian, Ahmed Shaik
Abstract Automotive manufacturers are being challenged to come up with radical solutions to achieve substantial (30-35%) vehicle weight reductions without compromising Safety, Durability, Handling, Aero-thermal or Noise, Vibration and Harshness (NVH) performance. Developing light weight vehicle enablers have assumed foremost priority amongst vehicle engineering teams in order to address the stringent Fuel Economy Performance (FEP) targets while facilitating lower CO2 emissions, downsizing of engines, lower battery capacities etc. Body sheet metal panels have become prime targets for weight reductions via gage reduction, high strength steel replacement, lighter material applications, lightening holes etc. Many of these panel weight reduction solutions are in sharp conflict with NVH performance requirements.
2015-06-15
Technical Paper
2015-01-2344
Murteza T. Erman
Abstract In today's world, automotive manufacturers are required to decrease CO2 emissions and increase the fuel economy while assuring driver comfort and safety. To achieve desired acoustic performance targets, automotive manufacturers use various Noise-Vibration-Harshness (NVH) materials which they apply to the vehicle Body-In-White structures either in the body or paint shop. Beside the sound deadening coatings applied onto the underbody of vehicles, they have historically used either constrained or free-layer sheets. The majority of these damping pads/sheets, so called asphalt sheets, are applied onto the floor pan inside the vehicle. These pre-manufactured and vehicle specific die-cut sheets are typically highly metal-carbonate, sulfate or silicate filled asphalt systems with a high specific gravity. Depending on the size of vehicle, the amount of these sheets can reach application weights of 10∼20 kg/vehicle. This paper will document the technical path that Dr. H.
2015-06-15
Technical Paper
2015-01-2202
Catheryn Jackson, Justin E. Gimbal, Dhara Metla
Abstract Over the past decade damping materials have contributed major improvements to passenger comfort. Noise Vibration and Harshness (NVH) engineers have further shaped material specifications to reflect key targeted properties that improve vehicle design. The specified damping material is then applied to the formed surfaces of the vehicle body to provide optimal performance and achieve the required results. This paper describes how liquid dampers have advanced to meet increased performance requirements through improved loss modulus of the final coating. Data generated by dynamic mechanical analysis shows that this viscoelastic behavior is what drives the performance in damping materials. Through the correlation of loss moduli to damping performance of Oberst bars, the mechanism can be further quantified and explained.
2015-06-15
Journal Article
2015-01-2288
Abdelkrim Zouani, Joseph Stout, Salah Hanim, Changshen Gan, Gabriela Dziubinschi, William Baldwin, Zhi Fu
Abstract A new turbocharged 60° 2.7L 4V-V6 gasoline engine has been developed by Ford Motor Company for both pickup trucks and car applications. This engine was code named “Nano” due to its compact size; it features a 4-valves DOHC valvetrain, a CGI cylinder block, an Aluminum ladder, an integrated exhaust manifold and twin turbochargers. The goal of this engine is to deliver 120HP/L, ULEV70 emission, fuel efficiency improvements and leadership level NVH. This paper describes the upfront design and optimization process used for the NVH development of this engine. It showcases the use of analytical tools used to define the critical design features and discusses the NVH performance relative to competitive benchmarks.
2015-06-15
Journal Article
2015-01-2183
Thomas Wellmann, Kiran Govindswamy, Jeff Orzechowski, Sudharsan Srinivasan
Abstract Integration of automatic engine Stop/Start systems in “conventional” drivetrains with 12V starters is a relatively cost-effective measure to reduce fuel consumption. Therefore, automatic engine Stop/Start systems are becoming more prevalent and increasing market share of such systems is predicted. A quick, reliable and consistent engine start behavior is essential for customer acceptance of these systems. The launch of the vehicle should not be compromised by the Stop/Start system, which implies that the engine start time and transmission readiness for transmitting torque should occur within the time the driver releases the brake pedal and de-presses the accelerator pedal. Comfort and NVH aspects will continue to play an important role for customer acceptance of these systems. Hence, the engine stop and re-start behavior should be imperceptible to the driver from both a tactile and acoustic standpoint.
2015-06-15
Journal Article
2015-01-2298
Stephen Chittick, Mark Swindell, Samir Raorane
Abstract Jaguar Land Rover (JLR) has designed and developed a new inline 4 cylinder engine family, branded Ingenium. In addition to delivering improved emissions and fuel economy over the outgoing engine, another key aim from the outset of the program was to reduce the combustion noise. This paper details the NVH development of the lead engine in this family, a 2.0 liter common rail turbo diesel. The task from the outset of this new program was to reduce the mass of the engine by 21.5 kg, whilst also improving the structural attenuation of the engine by 5 dB in comparison to the outgoing engine. Improving the structural attenuation by 5 dB was not only a key enabler in reducing combustion noise, but also helped to achieve a certified CO2 performance of 99 g/km in the all-new Jaguar XE model, by allowing more scope for increasing cylinder pressure forcing without compromising NVH.
2015-06-15
Journal Article
2015-01-2289
Joseph L. Stout, Vincent Solferino, Simon Antonov
Abstract Powerplant NVH decisions are sometimes made looking only at how the change impacts either the source radiated noise level or the source vibration. Depending on the engine configuration, those can be good approximations, but they can also be very misleading. By combining both noise sources into a vehicle equivalent noise level a much better analysis can be made of the impact of any proposed design change on the customer perceived loudness. This paper will investigate several different scenarios and identify how the airborne and the structureborne paths combine for I4, V6 and V8 engine configurations. Similar relationships will be shown for path as well as the source contributions.
2015-06-12
Article
Small, electrically driven propellers spaced along wing leading-edges could benefit both small and medium-size aircraft
2015-06-09
Article
New surface scanning technology is being utilized by rFpro to produce digital road models with unprecedented accuracy and speed to help make autonomous driving safer.
2015-06-09
Article
To reduce cost and improve performance in engines, Honeywell is offering a software tool to embed virtual sensors in engines, using first-principles models that resides in the engine control unit.
2015-06-09
Article
The AUTOSAR standard is all about improving embedded electronic systems in vehicles, but did you know that it also promotes the early testing of software code? The early testing and validation of embedded software reduces the number of ECU prototypes and additional test systems needed down the road, and it benefits the whole development process.
2015-06-09
Article
For the design process of the class of aircraft known as an efficient supersonic air vehicle, particular attention must be paid to the propulsion system design as a whole, including installation effects integrated into a vehicle performance model.
2015-05-14
Article
The newly named Johnson Controls Vehicle Engineering Laboratory, on the Lawrence Technological University campus in Michigan, will serve the energy-storage-system supplier and benefit LTU engineering students.
2015-05-13
Technical Paper
2015-36-0004
Patric Daniel Neis, Ney Francisco Ferreira, Luciano Tedesco Matoso, Diego Masotti, Jean Carlos Poletto
Abstract The present paper addresses an investigation about the definition of a parameter for quantifying the creep-groan propensity in brake pads. Creep-groan is a self-excited vibration caused by stick-slip phenomenon [1, 2, 3]. For the definition of the creep-groan propensity parameter, extensive experimental work was performed on a laboratory-scale tribometer. The experiments are divided in two main parts: (i) study of correlation between accelerometer signal with physical and operating parameters. (ii) validation of the chosen parameter, which was based on stick-slip tests performed with three different materials, one low-metallic (low-met) and two non-asbestos organic (NAO 1 and 2). From the first study, it was found that both the slip power and mean torque multiplied by torque variation showed a slightly higher correlation with the acceleration signal.
2015-05-13
Technical Paper
2015-36-0002
Keshav Sundaresh, Felipe Moretti Leila
Abstract The level of noise transmitted to the passengers of a vehicle can drastically impact a passenger's comfort. Brake noise will give the customer an impression of poor product quality and can thus damage the quality image of the company. Within the automotive industry, the study of mode coupling instability by the use of FEM and modal complex analysis is widespread to reduce this phenomenon. In this paper an alternative method is presented, where potential brake noise issues are predicted by the use of a time transient integration using multi-body system analysis. The simulation model contains a nonlinear contact description, bushing, flexible bodies and the axis kinematics of the vehicle. Transient results are transformed by Fourier for a frequency domain study. The parameters that can be varied for the prediction analysis are brake pressure, vehicle speed, friction laws, system damping and bushing properties.
2015-05-13
Technical Paper
2015-36-0026
André G. L. Suetti, Robson Pederiva
Abstract In the field of engineering, there is a well known phenomenon called “stick-slip” a specific type of vibration in a mechanical system where friction is involved, it is qualified as non-linear, auto-excited and generally stable within a limited cycle. During stick-slip, the behavior of the friction coefficient as a function of the sliding velocity has big influence on the wave pattern, wherein various models can be found in the literature. Besides affecting wave patterns, this behavior affects significantly the amount of damping necessary to reach an asymptotic level of stability. The objective of this work is to study various friction models found in literature, for example: constant transition between coefficients, linear and exponential and apply these models in mechanical systems that represent brake systems.
2015-05-05
Article
At Intermat, LiuGong announced that it was in a 60-day countdown before its new Global Research and Development Center opens in June at Liuzhou, also home to the company's global headquarters.
2015-05-01
Journal Article
2015-01-9106
Magnus Löfdahl, Arne Nykänen, Roger Johnsson
Abstract In the automotive industry, tire noise is an important factor for the perceived quality of a product. A useful method to address such NVH problems is to combine recordings with measurements and/or simulations into auralizations. An example of a method to create structure-borne tire noise auralizations is to filter recordings of hub forces and moments through binaural transfer functions experimentally measured from the hub of the car to an artificial head in the car cabin. To create authentic auralizations of structure-borne sound, all six degrees of freedom (DOFs) of hub forces and moments and transfer functions should be included. However, rotational DOFs are often omitted due to measurement difficulty, complexity, time, and cost. The objective was to find which DOF (or DOFs) is perceived as most prominent in structure-borne tire noise. An auralization model of interior structure-borne tire noise was used.
2015-04-30
Article
New AWD systems from BorgWarner and Honda deliver significant improvements in efficiency, as well as vehicle dynamic performance.
2015-04-30
Standard
J1174_201504
This SAE Recommended Practice establishes the instrumentation and procedure to be used in measuring the operator ear sound level for engine powered equipment under 30 kW (40 bhp). The sound levels obtained by using this procedure are representative of the sound levels generated by the equipment under typical operating conditions. It is intended to include equipment such as lawn mowers, snow blowers, and tillers. It is not intended to include equipment designed primarily for operation on highways or within factories or buildings, or vehicles such as motorcycles, snowmobiles, and pleasure motorboats that are covered by other SAE Standards or Recommended Practices. This procedure does not cover handheld equipment such as chainsaws, leaf blowers, and trimmers. This SAE Recommended Practice may also be used when measuring the operator ear sound level of similar equipment powered by electricity or other power sources.
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