Optimization of exhaust systems to meet the acoustic regulations and the enginespecifications
2011 (English)Conference paper (Other academic)
Mufflers for internal combustion engines should be carefully designed. The main objective of a muffler is to reduce the engine noise while maintaining the back pressure below a certain limit. A specific target acoustic performance has to be met under space constraints and allowable engine back pressure limit. Usually, the insertion loss of the exhaust system is required to satisfy a certain target performance curve. The insertion loss is most appropriate to describe the exhaust system acoustic performance since it is dependent on the engine acoustic impedance, which varies with the engine loading and rotational speed. In this paper, a muffler optimization problem is formulated so that several shape parameters are optimized under some space constraints with flow. Any combination of linear space constraints can be imposed. The allowable engine back pressure is introduced as a non-linear constraint so that the optimum shape design will meet the engine back pressure specifications. The interior point optimization algorithm, which is available as a built-in MATLAB function "fmincon", is used in this paper. The formulated problem is applied to a real case study, where a truck exhau stsystem consists of a diesel engine, two mufflers, intermediate pipes, and a tailpipe. The first muffler is a typical EU-regulation compliant. The dimensions and location of the second muffler are to be optimized. A limit for the system back pressure is imposed by the engine manufacturer. An optimum design was investigated for different engine speeds and loadings. It was found that using the suggested formulation in this paper; one can obtain an applicable design of a muffler to meet both the acoustic regulations and the engine specifications.
Place, publisher, year, edition, pages
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-103698ScopusID: 2-s2.0-84871490374OAI: oai:DiVA.org:kth-103698DiVA: diva2:561282
18th International Congressof Sound and Vibration, Rio De Janeiro (2011)
QC 201210182012-10-182012-10-182016-09-20Bibliographically approved