Browse Topic: Noise pollution

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Noise Reduction of Construction Equipment Vehicle Through Structure-borne and air-borne Noise Reduction Strategy2026-26-03181/16/2026
One can witness the constant development and redevelopment of cities throughout the world. Construction equipment vehicles (CEVs) are commonly used on the construction site. However, the noise pollution from construction sites due to the use of CEV has become a major problem for many cities. The construction equipment employed is one of the main causes of these elevated noise levels. The construction workers face a potential risk to their auditory health and well-being due to the noise levels they are exposed to. Different countries have imposed exterior and operator’s ear noise limits for construction equipment vehicles, enabling them to control noise pollution. In this study, three vehicles were selected and checked for NVH performance and found that the operator ear noise level of the identified vehicle is 6 dB(A) higher than the benchmark vehicle level in dynamic conditions, when tested as per ISO 6396. Similarly, there was another vehicle having exterior noise 2 dB(A) higher than
Shinde, Gaurav, Jawale, Pradeep, Jain, Sachinkumar, Harishchandra Walke, Nagesh
Understanding Takeoff and Landing Noise for Small Multirotor VehiclesF-0080-2024-11575/7/2024
Small multirotor vehicles, for example, designed for package delivery, are expected to operate in close proximity to populated areas, raising concerns about noise pollution. This study utilizes acoustic flight tests and computational modeling of an instrumented research hexacopter developed at Penn State to investigate noise generation during takeoff and landing maneuvers, considering varying flight path angles and vehicle speeds. Flight tests were conducted at Mid-State Regional Airport and corresponding predictions were made using the Penn State Noise Prediction System. The predicted vehicle states and noise levels are first validated against the flight test data. The validated model and flight test data are then utilized to study the noise emissions of the aircraft. Measurements and predictions of the acoustic characteristics of the vehicle are analyzed using conventional noise metrics, frequency content, and directivity features. Descent maneuvers are found to be noisier than climb
Chaudhary, Rupak, Greenwood, Eric, S. Brentner, Kenneth, Jue, Andrew, Mukherjee, Bhaskar, T. Valente, Vitor
Achieving New Pass-By Noise Regulatory Norms R51.3 (Method B) - An Analysis of Acceleration and Noise Source Contribution2024-26-01991/16/2024
Worldwide automotive sector regulatory norms have changed and become more stringent and complex to control environmental noise and air pollution. To continue this trend, the Indian Ministry of Road Transport is going to impose new vehicle exterior pass-by noise regulatory norms R51.3 (Method B) in the upcoming year to control urban area noise pollution. This paper studies the synthesis of M1 category vehicle driving acceleration, dominant noise source, and frequency contribution in exterior PBN level. A vehicle acceleration analysis study was carried out to achieve an optimized PBN level based on the vehicle’s PMR ratio, reference, and measured test acceleration data. Based on the analysis, the test gear strategy and acceleration were changed to achieve a lower PBN level. Improved engine calibration resulted in a 20% increment of ith gear acceleration. This increased acceleration surpassed the upper limit of the reference acceleration range; hence, the vehicle was tested in a
kalsule cEng., Shrikant Balasaheb, Titave, Uttam, Patil, Jitendra, Jadhav, Kamalakar, Naidu, Sudhakara
Challenges for Indian Road Traffic with Sound Alert Devices on Electric Vehicles2024-26-02111/16/2024
Challenges for Indian Road Traffic with Sound Alert Devices on Electric Vehicles For safety towards pedestrians and other road-vehicles, sound alert systems (horns) have been in use since development of Automobiles. On the same line but with special purpose of preventing a Driver to sleep in a running vehicle, a Driver Monitoring System [DMS] is recently developed. For Electric Vehicles which are very quiet during starting and driving till 20 km/hr, Acoustic Vehicle Alert System (AVAS) is deployed in Europe and likely to be implemented in India soon. For all these Alert Devices, there are Standard Regulations across the world: ECE R-28 for Horns and ECE R-138 for AVAS. They, however, define only lower and upper dBA limits of the sound radiated by them. For DMS, no such regulation exists till today. With this, there has been a long time debate on what an optimal dBA level should be there, for all road-users as well as for vehicle- users inside the cabin. It would be adequate, on one
A, Milind Ambardekar
Development of Advanced Signal Analysis Technique for Pass-by Noise Source Identification of Light Commercial Vehicle2024-26-02011/16/2024
The Auto industry, particularly goods-moving trucks, is heavily responsible for noise pollution in cities. From a noise pollution control perspective, the noise produced, which is subject to regulation (IS 3028:1998), requires immediate action. This noise is mainly contributed by various vehicle systems like engine, exhaust, intake, tires etc. Identifying the major contributing source is a challenge when the pass-by noise levels does not comply with regulatory norms. The existing methods of source identification like windowing sources or swapping sub-systems sequentially are time consuming and needs more resources. Acquiring noise data using data acquisition system at vehicle level and pass-by noise measurement location can be carried out for contribution analysis, but currently being measured by two separate data acquisition systems. There exists no process/method to synchronize the measurements in two individual data acquisition systems without external exclusive synchronising
Suresh, Vineeth, Choudhari, Yogeshwar, Kalsule, Dhanaji, Athavale, Prasad
Sound Design for Electric Vehicles: Enhancing Safety and User Experience Through Acoustic Vehicle Alerting System (AVAS)2025-01-00685/5/2023
Silent engines are an excellent strategy to combat noise pollution. Still, they can pose risks for pedestrians who rely on auditory cues for safety and reduce driver awareness due to the absence of the familiar sounds of combustion engines. Sound design for silent engines not only tackles the above issues but goes beyond safety standards towards a user-centered approach by considering how users perceive and interpret sounds. This paper examines the evolving field of sound design for electric vehicles (EVs), focusing on Acoustic Vehicle Alerting Systems (AVAS). The study analyzes existing AVAS, classifying them into different groups according to their design characteristics, from technical concerns and approaches to aesthetic properties. Based on the proposed classification, an (adaptive) sound design methodology, and concept for AVAS are proposed based on state-of-the-art technologies and tools (APIs), like Wwise Automotive, and integration through a functional prototype within a
Esteves, Raquel, Campos Magalhães, Eduardo Miguel, Bernardes, Gilberto
Interior Noise Reduction of Construction Equipment Vehicle Through Structure-borne Noise Reduction Strategy2025-01-00635/5/2023
One can witness the constant development and redevelopment of cities throughout the world. Construction equipment vehicles (CEVs) are commonly used on the construction site. However, the noise pollution from construction sites due to the use of CEV has become a major problem for many cities. The construction equipment employed is one of the main causes of these elevated noise levels. The construction workers possibly are face a potential risk to their auditory health and well-being due to the noise levels they are exposed to. Different countries have imposed exterior and operator noise limits for construction equipment vehicles, enabling them to control noise pollution from CEVs. In this study, the operator ear level noise of the identified vehicle is 6 dB(A) higher than the regulatory limit in dynamic conditions, when tested as per ISO 6396. It was a tough time for the NVH engineer to reduce the interior noise level of the vehicle. Surprisingly, the steering unit and radiator fan were
Jawale, Pradeep
SAE TOMORROW TODAY: Mark Moore's New Start-Up Making Noise with Quieter Electric Aircraft1316810/22/2021
A new age of flight is taking shape from brilliant engineers who are redefining how lower carbon emissions, minimal noise pollution and reduced maintenance costs can work together. Mark Moore's newest venture, Whisper Aero, is combating busier skyways with a new electric thruster design that reduces noise to a near-imperceptible level. Moore, a former NASA engineer and Uber Elevate executive, discusses the need for sustainable eVTOL, eCTOL and eSTOL aircraft, how eliminating noise will aid public adoption, and why he decided to set up camp in Crossville, Tenn. Stay updated on the latest news from Whisper Aero: https://www.whisper.aero/
Hineman, Marcie
Reduction of Aeroacoustics Tonal Noise for a Tractor Cooling Fan2021-26-02999/22/2021
Currently, noise pollution has become one of the major environmental concerns. To address this, new noise standards and regulations are being introduced and mandate the tractor OEM's to meet the defined noise levels. Fan noise from the cooling fan is one of the key contributors to the overall vehicle noise. Hence, the reduction of fan noise at the source is a very important and critical task. Even though fan noise is broadband in nature its aerodynamic noise sources are most dominant at the higher harmonics of the blade pass frequency (BPF). Aerodynamic noise of a fan can be varied by changing the fan geometry viz. blade profile, fan width & diameter, no. of blades, and ring on its periphery. Cooling fan is an important component of the cooling system which ensures adequate airflow for radiator cooling and avoids engine overheating with uniform heat dissipation. The important parameters that need to be considered while designing a cooling fan are noise level, airflow, and power
Avinash, D., Shankar, M, Maller, Rathish, V, Ravindran
DESIGN AND ANALYSIS OF A MUFFLER FOR ENGINE EXHAUST NOISE AND HEAT REDUCTION2021-28-01289/15/2021
Exhaust noise and heat from engines is one of component noise pollution to the environment. Exhaust systems are developed to attenuate noise meeting required db levels and sound quality, emissions based on environment norms. Mufflers are important part of engine system and commonly used in exhaust system to minimize sound transmissions caused by exhaust gases and reduction of heat. Attaching a muffler in the exhaust pipe is the most effective means of reducing noise and heat. The aim of our project is to design and analyse a muffler for engine exhaust noise reduction. The suitable design and development will help to reduce the noise level and heat level, but at the same time the performance of the engine should not be hampered by the backpressure caused by the muffler. In this analysis 3D models are constructed using Solid Works software before exporting to ANSYS FLUENT CFD software for analysis. At ANSYS/FLUENT, pressure conditions will be specified as the inlet and outlet boundary
Deepan Kumar, Sadhasivam, Praveenkumar, Nagarajan, S, Arulkumar, N, Boopalan, PRAVEENKUMAR, S
Integration of VTOL Air-taxis into an Existing Infrastructure with the Use of the Model-Based System Engineering (MBSE) Concept CUBEF-0076-2020-1635810/5/2020
One major problem of big cities is the congested traffic situation and the noise pollution generated by the traffic participants, i.e., cars, busses, and trams. Those ground-bound transport systems are already reaching their limits. The use of aerial taxi services has the potential to use the third, vertical dimension. Vertical take-off and landing systems, shortened to VTOL systems, possibly autonomous and electrified, with low noise emission and little ground space requirements are preferred. Applying an MBSE-based approach like our methodology called 'Compositional Unified system-Based Engineering', in short CUBE, enables to control the complexity of the challenge to develop appropriate VTOLs. This methodology has already proven itself in the automotive industry and its system development processes. In this paper the CUBE methodology will be transferred to the aerospace system development process to demonstrate its general usability. The fully systematical and model-based
Jäckel, Nicolas, Fischer, Maximilian, Andert, Jakob, Grotenrath, Malte, Orth, Philipp, Schaller, Robert, Granrath, Christian
Equivalent damping added by Sound package2020-01-13974/14/2020
In Automotive and Aerospace industries, sound package has an important role to help identify and control vehicle noise in order to improve passenger comfort and reduce environmental noise pollution. The well-known used approaches to model the sound package are Transfer Matrix Method (TMM) combined with Statistical Energy Analysis (SEA). The effect of sound package on the sound radiation can be summarized in three points. (i) Interact with the non-resonant response of the panel to modify the mass law. (ii) Act as a barrier and modify the radiation efficiency of the panel. (iii) Acts as a multilayer damping treatment on the panel. To the best of our knowledge, the equivalent damping due to the multilayer has not been done by earlier researchers and it's a novel approach. In this paper, an experimental study will be conducted to assess the add-on damping by sound package for different configurations. The decay rate method will be used to measure the damping indicator on a flat samples
Rhazi, Dilal, Mathur, Kunal, Nulkar, Abhishek
Reducing Vehicle Interior NVH by Means of Locally Resonant Metamaterial Patches on Rear Shock Towers2019-01-15026/5/2019
Stringent regulations for CO2 emissions and noise pollution reduction demand lighter and improved Noise, Vibration Harshness (NVH) solutions in automotive industries. Designing light, compact and, at the same time, improved NVH solutions is often a challenge, as low noise and vibration levels often require heavy and bulky additions, especially to be effective in the low frequency regime. Recently, locally resonant metamaterials have emerged among the novel NVH solutions because of their performant NVH properties combined with lightweight and compact design. Due to the characteristic of stop band behavior, frequency ranges where free wave propagation is inhibited, metamaterials can beat the mass law, be it at least in some tunable frequency ranges. Previously the authors demonstrated how metamaterials can reduce the vibrations in a simplified shock tower upon shaker excitation. In this work, the authors apply the metamaterial concept on the real rear shock towers of a vehicle. In order
Sangiuliano, Luca, Claeys, Claus, Deckers, Elke, De Smet, Jasper, Pluymers, Bert, Desmet, Wim
Impact of “Break In” Running on Exhaust Emissions and Fuel Consumption of a Portable Genset2017-01-10123/28/2017
In developing countries like India, large numbers of portable gensets are used as a power source due to the scarcity of grid power supply. The portable gensets, ranging from 0.5 kW to 5 kW are very popular in the residential areas, for example, small restaurants, and shopping complexes, etc. These gensets are using various fuels like gasoline, diesel, LPG, and kerosene in small internal combustion engines. Such engines are the significant source of air pollution, as these are running in the vicinity of populated areas and higher human exposure to these pollutants.Theses gensets are regulated by exhaust and noise emissions norms, set by statutory bodies like the ministry of environment and forest and central pollution control board of India. The gaseous emissions of carbon monoxide (CO), total hydrocarbon (THC) and nitrogen oxides (NOx) and particulate matter (PM)-diesel only, are regulated, and emission testing is performed as per three mode cycle as specified in the regulation.The
Pathak, Sunil Kumar, sood, Vineet, Singh, Yograj, Channiwala, Salim Abbasbhai
Bistatic DIAL for Multi-Species Aviation Pollutant Measurements from RPAS2015-01-24779/15/2015
This paper presents the conceptual design of a new low-cost measurement system for the determination of pollutant concentrations associated with aircraft operations. The proposed system employs Light Detection and Ranging (LIDAR) and passive electro-optics equipment installed in two non-collocated components. The source component consists of a tuneable small-size and low-cost/weight LIDAR emitter, which can be installed either on airborne or ground-based autonomous vehicles, or in fixed surface installations. The sensor component includes a target surface calibrated for reflectance and passive electro-optics equipment calibrated for radiance, both installed on an adjustable support. The proposed bistatic system determines the column-averaged molecular and aerosol pollutant concentrations along the LIDAR beam by measuring the cumulative absorption and scattering phenomena along the optical slant range. The molecular column densities are measured by means of Differential Absorption LIDAR
Gardi, Alessandro, Sabatini, Roberto
Vibration Reduction of Single Cylinder Diesel Engine used for Agricultural Water Pumping2015-01-22916/15/2015
There are many environmental issues in India. Air pollution, water pollution, garbage, vibration, noise pollution and pollution of the natural environment are all challenges for India. India has a long way to go to reach environmental quality similar to those enjoyed in developed economies. Pollution remains a major challenge and opportunity for India. The review of trends in farm practices and machinery development suggests that vibration & noise problems are still prevalent in agricultural situations, even though there has been a steady increase in the availability of materials and equipment for vibration & noise control over recent years. Diesel engine is the main source of power for agricultural equipments, such as water pump set, compressor, electric generator and tractor. Even it is one of the sources of vibration & noise in agricultural field. There is reluctance of the agricultural sector to use of vibration & noise control methods. It is difficult to estimate the number of
Jadhav, Pandurang Maruti, Dunung, Sandesh A, Nitnaware, Pravin T
Measurement of Minimum Noise Emitted by Road VehiclesJ2889/1_201205 (Historical)5/14/2012
This SAE Standard is derived from SAE J2805 and specifies an engineering method for measuring the minimum noise emitted by road vehicles. The specifications reproduce the level of noise which is generated by the principal vehicle noise sources consistent with minimal noise emission in urban traffic. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustic environment which is only obtained in an extensive open space. Such conditions usually exist during: Measurements of vehicles for regulatory certification Measurements at the manufacturing stage Measurements at official testing stations The results obtained by this method give an objective measure of the noise emitted under the specified conditions of test. It is necessary to consider the fact that the subjective appraisal of the annoyance, perceptibility, and/or detectability of
Safety and Human Factors Standards Steering Committee
Acoustic Characterization of Automotive Mufflers - Part II: Validation of the Numerical Models by Means of Experimental Data2012-01-08014/16/2012
Increasing interest is being paid to noise pollution of internal combustion engines and as a result, recent international standards imposed more severe limitations to acoustic emissions on engine manufacturers. In particular, the noise coming from gas-dynamic interactions has an important influence in determining the final noise level of the engine; as a consequence, the muffler design is currently being considered as one of the most important research threads for engine companies. Within this context, the 1D approach to numerical simulations, which has been successfully applied by industrial designers to the fluid-dynamic design of the engine, is considered to be inaccurate in the evaluation of the acoustic behavior of the muffler for medium-high frequencies. On the other hand, an extension of the applicability of these codes in the medium-high frequencies would be desirable. The direct advantage would be the use of the same software for the simulation of both the fluid-dynamic and
Ferrara, Giovanni, ferrari, Lorenzo, Vichi, Giovanni, Lenzi, Giulio, Biliotti, Davide
Muffler Design, Development and Validation for Acoustic Advantages on Automotive Vehicles2011-01-22159/13/2011
Noise pollution has become one of the major environmental concerns in present era. With the ever tightening laws and increasingly straight regulations for controlling noise pollution of automotive vehicles, mufflers are important part of engine system and commonly used in exhaust system to minimize noise caused by exhaust gases. Design of mufflers is a complex function that affects the noise characteristics and fuel efficiency of the vehicle. Traditionally, muffler design has been an iterative process by trial and error method. However theories and science that has undergone development in recent years has given a way for an engineer to cut short number of iterations. In today's competitive world market, it is important for a company to shorten product development cycle time and thereby cost. The objective of this paper is to propose a practical approach to design, develop and validate muffler practically which will give advantage over conventional method. This paper also emphasis on
Ramesh Shah, Shitalkumar, GS, Gangadhar
Intake System Design Approach for Turbocharged MPFI SI Engine2011-26-00011/19/2011
The automotive industry is currently facing the challenge of significantly stringent requirements regarding CO₂ emission and fuel economy coming from both legislations and customer demand. Advanced engine technologies play a vital role for downsizing of gasoline engine. The development of key design technologies for high efficiency gasoline engines is required for the improvement of competitive power in the global automobile industry. This paper focused on effect of geometry of intake manifold of gas exchange process and consequently the performance of the engine. Specially, the optimal design technologies for the intake manifold and intake port shape must be established for high performance, increasingly stringent fuel economy and emission regulations. Space in vehicle or packaging constraints and cost are also important factors while consideration of the design. Two models of intake manifolds discussed in this paper, such as short runner intake manifold and long runner intake
Jagtap, Harishchandra, Vinayak, Chavan, Koli, Ravindra
Propulsion challenges10AEMD0428_014/28/2010
Universities and research institutes in the U.K. are playing an ever-growing role in EU aerospace development projects as well as maintaining an independent industry workload. In aerospace and beyond, there are a lot of human activities now being challenged to become more environmentally friendly. As a result, there is a lot of impetus to change the way we do things to protect the environment. Aerospace is doing its fair share and, in some ways, a lot more than its fair share because many applications developed in aerospace are finding their way into other sectors, one example being reducing pollutants. The roots of some of these developments can be traced back to universities, with those in the U.K. having a particularly strong presence. Within the department of Power and Propulsion School of Engineering at Cranfield University, for example, the efforts made within aerospace can be categorized in three areas.
Challen, John
Acceptability of OHM and ATV Noise-Case Studies of Environmental Noise Produced by OHM and ATV Riding Areas2009-01-22445/19/2009
Acceptability of Off-Highway Motorcycle (OHM) and All Terrain Vehicle (ATV) noise is increasingly becoming an issue. Increasing numbers of riders combined with a decrease in available riding areas, due to liability concerns and increasing rural development, has raised issues with land compatibility. Lack of clear noise regulations in typical rural Midwestern communities makes enforcement difficult or subjective. This paper reviews two case studies of OHM and ATV riding area noise at neighboring residential property lines. One study was performed as part of the defense for nuisance tickets, for excessive noise, issued to a group of riders at a new private riding area. The other study was performed to help an established riding club obtain a conditional use permit for their land, which they had been legally riding on for decades, due to noise and dust complaints from new residential development next to their property. An issue immediately raised with both of these studies was determining
pierson, Richard G.
Combining acoustic imaging techniques to localize and identify sources2008-36-05953/30/2008
This paper deals with recent advances in acoustic experimental methods and especially acoustic imaging. The paper covers two areas of interest to acousticians. In the first part, it is explained how near-field acoustic holography (NAH) can be extended with beamforming in the near-field, focalization. The combination of the two methods is providing now a source localization solution with a good spatial resolution over the complete frequency range without the burden of measuring a large number of points as would be required if only NAH was used. In the second part of the paper, a method is described that goes one step beyond source localization. In this part is explained how source localization techniques in conjunction with artificial excitation of the structure can provide information on the internal sources of the structure.
Deblauwe, Filip, Beguet, Bernard, Robin, Maxime
Proposals of Exposure Criteria to Prevent Annoyance Due to Low Frequency Noise at Workplaces2007-01-24075/15/2007
The aim of the study was to recommend methods for assessing low frequency noise (LFN) in the occupational environment to prevent annoyance and its effects on work performance. Three different evaluating methods and corresponding admissible values were proposed: (i) method I - frequency analysis in 1/3-octave bands 10250 Hz, (ii) method II - consisting in 1/3-octave band measurements and determination of low frequency equivalent-continuous A-weighted sound pressure level (SPL) in the frequency range of 10250 Hz, and (iii) method III - based on equivalent-continuous A-weighted SPL corrected due to the presence of low frequencies and tonal character of LFN. Separate noise limits were recommended for workplaces in control rooms and office-like areas. The proposed criteria were verified in laboratory and field studies on subjective noise annoyance rating.
Pawlaczyk-Luszczynska, Małgorzata, Dudarewicz, Adam, Sliwinska-Kowalska, Mariola, Szymczak, Wieslaw
ECoustics -- Vehicle Sound Package Inspired by Environmental Design2007-01-24055/15/2007
The environmental issues are mounting for a global automotive industry associated with ever-increasing output. Major issues include fuel consumption, vehicle emissions, consumption of non-renewable materials, and recycling of waste materials. This paper provides an overview of recent advances in new acoustic materials based on recycled and sustainable sources for “environmental” vehicle sound packages that address NVH and trim acoustics requirements. Thanks to new eco-design standards, both the OEM and suppliers can increase and improve eco-friendly aspects such as recycling end of life vehicles. The use of end of life materials in a new car includes: automotive shredded residue (ASR) such as tire fibers included in damping materials, chips foam from seats for acoustical shields, and automotive shredded residue for acoustical dash insulators.
Boyer, Aureli, Casulli, Jean, Horak, Jan, Khan, Hameed, Berdine, Michael D.
Model-Based Synthesis of Noise in Aircrafts2005-01-340410/3/2005
Aircraft noise modeling aims to provide designers with computational tools that allow exploring the design parameters domain early in the design and development process. A number of modeling techniques are available for acoustics and vibration prediction, but in order to define objective targets for sound quality perception, dedicated tools are still needed to correlate structural models and design modifications with human perception of sounds. This paper presents a model-based sound synthesis concept for interior and exterior aircraft noise that allows interactive, real-time sound reproduction and replay. The proposed approach is presented through two application cases: jet flyover noise and turboprop interior noise.
Janssens, Karl, Van de Ponseele, Patrick, Vecchio, Antonio, Van der Auweraer, Herman, Flynn, Bill, Berckmans, Dries
Pass-by Noise Analysis in a Commercial Vehicle Homologation2003-01-365211/18/2003
NVH (Noise, Vibration and Harshness) is an important vehicle attribute and focus in every Product Development at OEM'S (Original Equipment Manufacturers). Pass-by Noise is one of these aspects in order to improve noise vehicle as a whole. As a result, this paper will show opportunities that Pass-by Noise test can get in a new development of Commercial Vehicles, presenting the methodology, NVH improvements, Quiet Truck and Frequency Analysis as well as Robustness of Noise Package Development. Moreover, the presentation will consider all the requirements and the advantages that Pass-by Noise can accomplish in a new Sound Package Development to meet a new Conama Resolution. The focus on this topic is to meet a new Governmental Regulation (CONAMA 272/2000) and consequently improve overall noise quality showing procedures that will accomplish targets of NVH. Conclusions will present the advantages of the proposed method regarding to timing and cost and real cases examples will be mentioned.
Martins, Rogério, Pinto, Márcio Gonçalves, Mendonça, Carlos Magno, Morais, André Ribeiro
Application of Machinery Diagnostic Techniques for Identifying and Elimination of Annoying Whistling Noise of Two-Wheeler Gear Box2003-26-00321/18/2003
This paper discusses the methodology and techniques, which are used to investigate and reduce noise generation by gearbox. The aim of this paper is to investigate the root causes and to eliminate a uniquely identified gear noise. Steps presented illustrate a logical process, which begins with identification of gear whistle frequency of a two-wheeler gearbox through narrow band analysis and subsequent elimination by design improvement. The specific examples discussed here involve the successful elimination of an intolerable high dB (A) whistle noise produced by gearbox.
Reddy, P. V., Shirode, Satish V.
Improved Mufflers for General AviationTBMG-298921/1/1999
Innovative designs of mufflers for engines of small airplanes have been investigated in an effort to satisfy conflicting demands to maximize the reduction of exhaust noise while minimizing back pressure, size, and weight. Automotive-type muffler designs are not suitable for this purpose because they entail excessive back pressures, sizes, and weights.
Noise Attenuation for Polyamide Intake Manifold9502322/1/1995
Noise Attenuation for Polyamide Intake Manifolds Since the stiffness of polyamide is lower than aluminum, special techniques have been developed to increase local and global stiffnesses of polyamide intake manifolds. The increased stiffness results in parts with noise emissions equal to or less than equivalent aluminum intake manifolds with twice the wall thickness. These special techniques enable engineers not only to attenuate noise, but to “tune” the remaining noise emissions for a desirable sound quality.
Sattler, Eric, Abboud, I.
U.S. Vehicle Noise Regulations and the Effects of Vehicle Condition91270911/1/1991
This paper reviews the history of heavy truck noise legislation in the U.S. Both legislative activity and the response of vehicle and engine manufacturers are described. The cost cycle experienced by manufacturers is also described. Over a period of time, the costs involved in meeting noise regulations are reduced without increasing truck noise levels. Data is presented which shows that public complaints about truck noise are often related to modified vehicle exhaust systems. The data shows that modified exhaust systems have an especially severe effect on compression brake noise. Additional results suggest that some trucks with extensively modified exhaust systems may be able to pass the in-use noise standard.
Reinhart, Thomas E.
Urban Transport and the Environment in the Asia-Pacific Region91259611/1/1991
Across the entire globe, motor vehicle usage has increased tremendously. One result is that many areas of the world have been experiencing serious motor vehicle pollution problems. To deal with them, significant motor vehicle pollution control programs have become increasingly common, leading to tremendous advances in petrol car control technologies. At present, similar technologies are under intensive development for diesel cars and trucks and significant breakthroughs are starting to appear with production diesel vehicles. The purpose of this paper is to survey what is presently known about the transportation related environmental problems in Asian cities, to summarize the adverse impacts which result, to review actions underway or planned to address these problems, and to estimate future trends. Potential strategies for ameliorating transportation related environmental problems will be assessed.
Walsh, Michael P.
Motor Vehicle Air Pollution in Greece—Programs and Policies8710798/1/1987
The purpose of this paper is to survey the environmental problems in Greece caused by road vehicles, to review the actions taken and planned in the last decade by the competent authorities against pollution and to identify the effectiveness of these actions to prevent and reduce atmospheric pollution caused by road vehicles. The major reference is to Athens where the environmental problems were firstly experienced. Where it is possible reference is made to the country as a whole. Setting environmental standards, application of vehicle inspection programs, development of public transport and infrastructure, traffic management schemes, 5-years environmental plans, urban planning and research are the main sectors of action and concern.
Vasilakos, Evangelos K.
The Program of Greece to Address - Motor Vehicle Air Pollution8503922/1/1985
A series of measures are developed in Greece, in order to face and solve the complex problems of environmental pollution caused among other sources by motor vehicles. These measures are basically aiming at reducing air pollution in Athens Area where the basic source of a number of pollutants is traffic and where fleet has increased very rapidly in the past twenty years. Setting environmental standards, application of vehicle inspection programs, development of public transport and infrastructure, new traffic management schemes and integrated urban planning are the main sectors of actions and planning which are expected to reduce pollution and prevent the deterioration of the human and material environment. Research on the interaction between transport and the environment is in progress.
Vasilakos, E. K.
Status Report of Italy - 19858560051/1/1985
This report outlines Italian safety concerns. Domestic statistics have shown a slight decrease in casualties due to road accidents and a stable situation with regard to injuries. Italy has adopted approximately 55 ECE regulations and 46 Community Directives. Active and passive safety measures are outlined. Emission limits and noise pollution legislation are under consideration.
Rossi, Franco
Status Report of the Federal Republic of Germany - 19858560041/1/1985
The report reviews safety priorities in Germany. Accidents have increased by 9.3 percent. In 1984 the Federal Government presented a comprehensive program for improving road safety. An accident research database has been established and studies on active safety, driver training and the rating of safety of driver groups has become increasingly important. Environmental problems, especially noise pollution and exhaust emissions are a major EEC concern.
Praxenthaler, Heinrich
Traffic Noise Measurements in the City of Bandung, Indonesia83095211/7/1983
Traffic noise measurements have been done at several locations representing urban area, center and periphery of the city. The traffic consists of cars, motor cycles, trucks and buses. The percentage of motor cycles is relatively high (30-50%). The flow of vehicles is not uniform with a 24 hour average of more than 1000 vehicles per hour. The noise levels to be measured were L10, L50 and L90. The noise indices to be calculated were Traffic Noise Index (TNI), Equivalent Energy Level (Leq) and Noise Pollution Level (LNP). Evaluation of the noise indices based on the corresponding limit values show that at most of the streets the values have been exceeded. Predictions of L10 (18 hr) compared with the measured values were also discussed.
Noise Pollution From Road Traffic in Urban Environment7850691/1/1978
In the 1970's, the noise of road traffic was investigated in Budapest and in five rural towns /Gyðr, Szeged, Debrecen, Szombathely and Dunaujváros/ of Hungary. 650 measurements were made at 348 points of the towns. Relations among the equivalent A-weighted noise level and certain statistical levels were analyzed on grounds of the measurement results. The regional distribution and fluctuations in time of road traffic were evaluated. In parallel to the measurements, also a census of road traffic was taken. Relations among the various characteristics of traffic noise and traffic density were analyzed by mathematical-statistical methods. In addition to the simple first-degree relation also the second-degree relations considered to be more precise were determined. The relations thus obtained could be used for forecasting the noise of road traffic. The measurement results were compared with the data of similar investigations conducted in Budapest /1959/ and in Szeged /1961/. On grounds of
Czabalay, Lázló
The Evolution of Contemporary Concerns in Mobile Hydraulics7404182/1/1974
The growth of hydraulics applied to construction equipment has been qualitatively and quantitatively dramatic in the past 25 years. The purpose of this paper is to review the past, view the present, and speculate on the future hydraulic systems with particular focus on the evolution of operator comfort and safety, air, and noise pollution control and energy conservation.
Link, John R.
The Environment and The Bus7206072/1/1972
The ecology of our environment has recently been of great concern to all of us. In the bus business, we have gone from horse drawn carriages, to electric, to steam power to diesel power to obtain an efficient, clean operating vehicle. A great deal of effort has been expended in determining the components of the emissions of the diesel engine. Great strides have been made in reducing these emissions. GMC Truck & Coach has developed and released an Environmental Improvement Program that reduces smoke to the invisible range and meets Federal standards for HC, CO and NOx. Odor also is eliminated as a problem.
Field, Robert E.
Application of Lead-Vinyl Noise Barriers in Transportation Equipment7202222/1/1972
Lead vinyl coated fabrics, new composite vinyl films, and molding compounds have been developed that have application as flexible sound barriers in transportation and recreational equipment. The material consisting of fine lead particles disbursed in PVC compounds for coating, casting films, extrusion, injection molding, thermal form sheets, and rotational casting combines the high mass of lead and the properties and formability of vinyl. These composites provide a limp high mass sound barrier material.
Meteer, Charles L.
Sound Attenuation After the Fact7207512/1/1972
The noise levels of earthmoving equipment, in the operator's cab and outside the machine, are discussed. Ways and means of lowering the dB ratings for increased operator and by-stander comfort are taken into account. Suggestions are made for ways of mounting the cab itself and lessening vibratory reactions from the engine, including rubber engine and cab mounts, plus acoustical material for reducing inside the cab noise.
Giovanetto, James, Kacynski, Carl
Are Present Horns, Whistles and Sirens Necessary for Communications?7206402/1/1972
Horns, whistles and sirens are commonly used to convey information concerning time, location or warning. Of major concern to the community are the audible warning systems used on emergency vehicles and trains. The various types of existing audible warning systems and their historical development are discussed in this paper, together with an analysis of their effectiveness in fulfilling their prime function - namely, to warn people of imminent danger. It is concluded that such systems perform adequately in many situations, but not when the recipient of the warning signal is inside another vehicle. It is suggested that alternative means be developed for warning the occupants of vehicles of immediate danger so that audible warning systems of reduced acoustic power can be used to warn the pedestrian or other persons outside vehicles.
Eldred, K. M., Sharp, B. H.
The Engineer and Man's Environment - Academe's Response to the Challenge7100062/1/1971
The increasing levels of affluence in the highly industrialized western societies have resulted in a drastic and increasing deterioration of the quality of man's environment. The economic facts in these societies are such that it actually “pays to pollute.” Air and water pollution, solid waste disposal, and noise pollution have become areas of major concern for the institutions of higher learning. Through instruction and research, knowledge toward the alleviation and control of environmental pollution must be disseminated and advanced. One of the major contributors to the present state of environmental deterioration is the almost absolute lack of well-defined control criteria. Much needs to be done in this area and the academic community has the know-how and economic remoteness to tackle this problem. One of the most fascinating facets of the environmental pollution problem is its interdisciplinary nature. In this paper, the Pennsylvania State University's programs on air pollution
Reethof, Gerhard
The Challenge Facing the Automotive Industry in the Next Decade7108772/1/1971
Brock, Harold L.
Effects of Air Pollution on Man and His Environment7103262/1/1971
Air pollutants emitted from turbine engine aircraft may have adverse effects on man and his environment. Carbon monoxide, nitrogen oxides, various organic compounds, and particulate matter are the primary pollutants produced by jet engines. Carbon monoxide at low levels may cause impairment of both time interval discriminations and of visual acuity. Nitrogen dioxide has been associated with reduced ventilatory performance and an increase in acute respiratory illness. Some organic compounds, such as formaldehyde and acrolein, may cause eye irritation, and excess of particulate matter in the atmosphere has been associated with increased chronic respiratory disease. In addition to effects on human health, pollutants emitted from turbine engines may adversely affect plants, animals, soil, water, and man-made materials. Much more research is needed before effects on health and welfare can be specifically related to aircraft emissions.
Barth, Delbert S.
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