Insight into exhaust systems optimization techniques

Abstract

Exhaust system mufflers should be carefully designed for different applications. The main objective of an exhaust system is to reduce the engine noise. Maximum acoustic performance is usually desired under the limit of space constraints. Therefore obtaining the muffler optimum design is very crucial. In this paper, the muffler optimization problem is formulated allowing getting the optimum muffler design through calculating the acoustic properties conjugated with the optimization technique using a function "fmincon" from the MATLAB optimization tool-box that finds the minimum of a constrained nonlinear multivariable function. There are several possibilities to evaluate the acoustic performance of a muffler such as the sound transmission loss, the insertion loss, and the acoustic pressure measured by a receiver outside the exhaust system opening. By selecting one of these design targets, the optimum design of a specific muffler configuration in the frequency range of interest can be obtained. In this paper, a shape optimization approach is presented for different mufflers configurations, and the results of transmission loss, insertion loss, and the outside acoustic pressure are compared against optimum designs from the literature obtained using different optimization methods as well as design targets.