Acoustic Modelling and Measurements of Engine Mufflers

1998 ◽  
Vol 5 (1) ◽  
pp. 27-38
Author(s):  
Samir N.Y. Gerges ◽  
Márcio R. Kimura ◽  
J.L. Bento Coelho
Keyword(s):  
Internal Combustion Engines ◽  
Transmission Loss ◽  
Noise Source ◽  
Internal Combustion ◽  
Industrial Applications ◽  
Combustion Engines ◽  
Acoustic Modelling ◽  
Exhaust Noise ◽  
Ic Engines ◽  
Diesel Motors

Most buildings such as hospitals, hotels, governmental offices, data processing rooms, etc, are equipped with internal combustion engines, diesel motors and generators to supply energy in emergencies. These same IC engines are used for industrial applications, building services and transportation. Exhaust noise are the predominant noise source with most internal combustion engines and thus exhaust systems incorporating mufflers have been designed to reduce the noise. This paper describes the analysis of several configurations of mufflers and also presents comparisons between the results for the transmission loss obtained by numerical modelling (FEM), Transfer Matrix Method (TMM) and measurements.

Calculation of Acoustic Efficiency of Exhaust Silencers for Automotive Internal Combustion Engines

2021 ◽  
pp. 41-47
Author(s):  
Vladimir Tupov ◽  
O. Matasova
Keyword(s):  
Acoustic Waves ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Control Point ◽  
Plane Waves ◽  
Exhaust System ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Exhaust Noise ◽  
Insertion Losses

Insertion losses as the main characteristic that mathematically describes the acoustic efficiency of a noise silencer has been considered. This characteristic shows the reduction of noise generated by its source, in particular by the internal combustion engine’s exhaust system, at the control point as a silencer use result. Has been presented a mathematical description of the insertion losses, and have been considered parameters necessary for calculating this characteristic. Has been demonstrated the analytical dependence of impedance for the sound emission by the exhaust system’s end hole from the coefficient of acoustic waves reflection by this hole. The performed analysis of the widely used formulas for calculating the coefficient of sound reflection by the end hole has showed their insufficient accuracy for project designs performing. Have been proposed calculation dependences providing high accuracy for calculations of the reflection coefficient modulus, and the attached length of the channel end hole without a flange in the entire range of the existence of plane waves in it. It has been shown that the end correction of this hole at ka = 0 is 0.6127, and not 0.6133, as it was mistakenly believed until now in world acoustics. Has been proposed a method for calculation the exhaust noise source internal impedance. This method more accurately, in comparison with the already known ones, describes the acoustic processes in the internal combustion engine’s exhaust manifold, thanks to increases the accuracy of calculation the silencer acoustic efficiency, that allows develop the silencer at the early stages of the design of an automotive internal combustion engine.

scholarly journals Alternative Fuels for Internal Combustion Engines

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4086 ◽  
Author(s):  
Jorge Martins ◽  
F. P. Brito
Keyword(s):  
Greenhouse Gases ◽  
Co2 Emissions ◽  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Pollutant Emissions ◽  
Co2 Production ◽  
Combustion Engines ◽  
Synthetic Fuels ◽  
Ic Engines

The recent transport electrification trend is pushing governments to limit the future use of Internal Combustion Engines (ICEs). However, the rationale for this strong limitation is frequently not sufficiently addressed or justified. The problem does not seem to lie within the engines nor with the combustion by themselves but seemingly, rather with the rise in greenhouse gases (GHG), namely CO2, rejected to the atmosphere. However, it is frequent that the distinction between fossil CO2 and renewable CO2 production is not made, or even between CO2 emissions and pollutant emissions. The present revision paper discusses and introduces different alternative fuels that can be burned in IC Engines and would eliminate, or substantially reduce the emission of fossil CO2 into the atmosphere. These may be non-carbon fuels such as hydrogen or ammonia, or biofuels such as alcohols, ethers or esters, including synthetic fuels. There are also other types of fuels that may be used, such as those based on turpentine or even glycerin which could maintain ICEs as a valuable option for transportation.

scholarly journals Research of the acoustic efficiency of chamber cells of ICE exhaust silencers

2020 ◽  
Vol 320 ◽  
pp. 00016
Author(s):  
Olga Matasova ◽  
Vladimir Tupov
Keyword(s):  
Internal Combustion Engines ◽  
Theoretical Study ◽  
Internal Combustion ◽  
Wide Frequency Range ◽  
Combustion Engines ◽  
Cell Design ◽  
Frequency Range ◽  
Highly Efficient ◽  
Exhaust Noise

To reduce the exhaust noise of internal combustion engines, exhaust silencer containing chamber cells are widely used. Cell design largely determines its acoustic efficiency as a function of frequency. Therefore, in this work, a theoretical study of the most frequently used chamber noise-suppressing cells of various designs is carried out. Designs with high acoustic efficiency in a wide frequency range have been determined. The results of the study will allow the designer, using these structures, to synthesize highly efficient ICE exhaust silencers.

Ammonia and Gasoline Fuel Blends for Spark Ignited Internal Combustion Engines

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Shehan Omantha Haputhanthri ◽  
Timothy Taylor Maxwell ◽  
John Fleming ◽  
Chad Austin
Keyword(s):  
High Pressure ◽  
Liquid Fuel ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Liquid Equilibrium ◽  
High Pressure Cell ◽  
Fuel Blends ◽  
Composite Fuel ◽  
Ic Engines

Ammonia, when blended with hydrocarbon fuels, can be used as a composite fuel to power existing internal combustion (IC) engines. Feasibility of developing ammonia gasoline liquid fuel blends and the use of ethanol as an emulsifier to enhance the solubility of ammonia in gasoline were studied using a small thermostated vapor liquid equilibrium (VLE) high-pressure cell. Engine dynamometer tests were conducted for developed fuel blends to measure the performance. Gasoline with 30% ethanol can retain 17.35% of ammonia in the liquid phase by volume basis. Engine dynamometer results show ammonia-rich fuels result in an increased torque and power output especially at higher engine speeds.

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