scholarly journals Calculation of the required noise reduction of a engine exhaust system

2020 ◽  
Vol 320 ◽  
pp. 00017
Author(s):  
Olga Matasova ◽  
Vladimir Tupov
Keyword(s):  
Noise Reduction ◽  
Combustion Engine ◽  
Early Stage ◽  
Power Level ◽  
Exhaust System ◽  
Vehicle Design ◽  
Engine Exhaust ◽  
Sound Power Level ◽  
Initial Stage ◽  
Theoretical Assessment

The problem of reduction of internal combustion engine (ICE) noise is most urgent at present when the fleet of vehicles has significantly expanded and their power has increased. Reactive mufflers are often used to solve it. The initial stage in the design of mufflers is a theoretical assessment of the frequency spectrum of sound power level (SPL) of an unmuffled ICE noise source, comparing it with the calculated maximum permissible spectrum and determining the required amount of its reduction in standard frequency bands. The paper presents a method for calculating the required noise reduction of a transport engine exhaust using the example of a two-stroke ICE of the class of 125 cm3. Thus, the designer has the opportunity to develop mufflers, the acoustic efficiency of which meets the calculated required noise reduction values, already at an early stage of the vehicle design.

scholarly journals Experimental Study of Pipes Shape Effect on Noise Reduction

2017 ◽  
Vol 5 (1) ◽  
pp. 71-86
Author(s):  
Muna S. Kassim ◽  
Ammar Fadhil Hussein Al-Maliki
Keyword(s):  
Experimental Study ◽  
High Pressure ◽  
Noise Reduction ◽  
Power Plants ◽  
Combustion Engine ◽  
Exhaust System ◽  
Noise Pollution ◽  
Shape Effect ◽  
Pipe Length ◽  
Exhaust Noise

Internal combustion engine is a major source of noise pollution. These engines are used for various purposes such as, in power plants, automobiles, locomotives, and in various manufacturing machineries. The noise is caused by two reasons; the first reason is the pulses which created when the burst of high pressure gas suddenly enters the exhaust system, while the second reason is the friction of various parts of the engine where the exhaust noise is the most dominant. The limitation of the noise caused by the exhaust system is accomplished by the use of silencers and mufflers. The aim of this study is the reduction of the noise by changing its inlet and outlet pipe length and shape. Also the losses in noise for different length and shapes have been investigated experimentally. The results show that the corrugated pipe is preferable for noise reduction.

The Design and Analysis of Closed-Coupled Exhaust Manifold

2012 ◽  
Vol 215-216 ◽  
pp. 1241-1245
Author(s):  
Rang Shu Xu ◽  
Xiang Feng Yan ◽  
Ling Niu ◽  
Zhi Wei Dong
Keyword(s):  
Combustion Engine ◽  
Catalytic Converter ◽  
Exhaust System ◽  
Flow Distribution ◽  
Engine Exhaust ◽  
Business Software ◽  
Field Uniformity ◽  
Calculation Results ◽  
Cfd Method ◽  
Volume Method

The layout of closed-couple catalyst converter in internal combustion engine exhaust system is one of important way to reduce vehicle emission. CFD method based on finite volume method is adopted to numerical simulate flow distribution in the entrance of closed-coupled catalytic converter and applying business software of FLUENT to clarity the flow uniformity of inlet to ensure catalytic converter work efficiently and meet regulations. The flow field uniformity of entrance were studied and analyzed. Research finds that the shape of manifold has effect on dispersion of velocity in entrance and dispersion of velocity has a relatively strong correlation with pulsation flow. The flow reverse in junction deflect the air flow that flow into the entrance of closed-couple catalyst converter. Calculation results indicate that the uneven rate coefficient is 0.266 and volatility is 0.515 in the entrance of closed-couple catalyst.

scholarly journals Environmental Performance of Noise Reduction System in Cogeneration Plants—A Life Cycle Assessment Study

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1324
Author(s):  
Andrzej Marcinkowski ◽  
Joanna Kopania
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Noise Reduction ◽  
Environmental Performance ◽  
Background Noise ◽  
Power Level ◽  
Health Indicators ◽  
Sound Power ◽  
Sound Power Level ◽  
Environmental Loss

Although one of the most harmful factors to health is noise, it is often ignored in life cycle assessment (LCA) studies. Most researches regarding noise inclusion in LCA focus on the problem of transport noise, and very few works consider the impact of noise emitted by other sources. This study addresses the effects of noise generated by cogeneration plants. The main objective is to assess the environmental performance of the noise reduction system by considering the health effects of noise due to steam discharge as well as to compare the environmental loss associated with the production and disposal of a steam silencer with the benefits resulting from its application for noise reduction. A method to determine midpoint and endpoint human health indicators for a composition of noise emitted by intermittent stationary source and background noise is developed. The results indicate that the health benefit due to noise reduction is six orders of magnitude greater than the environmental loss. Human health indicators attributable to noise reduction in the residential zones under consideration span a wide range of disability adjusted life years (DALY)—0.16–136 DALY. The greatest values occur in the densely populated areas located close to the noise source. A formula is proposed to express annoyance of the residents of individual zones depending on their distance to the steam discharge source, its sound power level, and existing background noise level. Uncertainty and sensitivity analyses have been carried out assuming other conditions. Modifications of sound power level, noise reduction efficiency, steam discharge duration, and the silencer lifetime have not affected the overall conclusion drawn.

Paper 10: A Computer Program for Calculating the Performance of an Internal Combustion Engine Exhaust System

1967 ◽  
Vol 182 (12) ◽  
pp. 91-108 ◽  
Author(s):  
R. S. Benson
Keyword(s):  
Computer Program ◽  
Internal Combustion Engine ◽  
Method Of Characteristics ◽  
Combustion Engine ◽  
Exhaust System ◽  
Theoretical Background ◽  
Experimental Measurements ◽  
Design Calculation ◽  
Exhaust Pipe ◽  
Engine Exhaust

The paper describes the method of presenting data for a computet program, based on the method of characteristics, which calculates the pressure and temperature in the exhaust system and cylinders in two- or four-stroke engines with valves or ports. The program is arranged so that the performance of an exhaust pipe can be assessed for a number of pipe configurations. A brief description of the theoretical background and program format is given, followed by a suggested design calculation procedure. Examples are then given of the application of the program to both two- and four-stroke supercharged engines. The results of the calculation are compared with experimental measurements. A description of the subroutines and the organization of a calculation on the computer, together with the data order are given in two of the appendices.

Analysis for effect of pores on acoustic performance of reactive muffler

2021 ◽  
pp. 095745652110307
Author(s):  
Pravin P Hujare ◽  
Vishal R Mote ◽  
Ashok R Mache ◽  
Deepak P Hujare ◽  
Sandeep S Kore
Keyword(s):  
Numerical Analysis ◽  
Transmission Loss ◽  
Combustion Engine ◽  
Exhaust System ◽  
Noise Pollution ◽  
Engine Exhaust ◽  
Target Frequency ◽  
Acoustic Performance ◽  
Outlet Pipe ◽  
Exhaust Noise

The major source of noise pollution was an internal combustion engine. Henceforth, the design of the engine exhaust system was a tough challenge for automotive industries. The mufflers have been used to moderate the exhaust noise from the engine to the neighboring atmosphere. So in domestic as well as the industrial application, it is required to reduce noise levels to prevent human hazards. The performance of muffler is measured in terms of transmission loss. The transmission loss of reactive muffler is depending on its geometry. This article describes the effects of pores at the inlet pipe and outlet pipe of the reactive muffler on its performance capacity at a target frequency. It is found that the muffler performance is dependent on the number and position of pores. The single chamber and double chamber reactive mufflers are used for the study. The numerical analysis is performed by COMSOL Multiphysics software. The numerical analysis result of the different models of the muffler is compared with experimental analysis. The purpose of the study is to investigate the effect of pores in inlet and outlet pipe to maximize the TL at the target frequency of reactive muffler.

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