Design of Experiment - Application of a Statistical Evaluation Method to Optimize the Tailpipe Noise of an Exhaust System

This paper describes the application of a “Design of Experiment”-Method (Taguchi-Method) to reduce the tail-pipe noise of an exhaust system.

The aim of this work was to find out how effective and useful this method is in developing the acoustic behavior of an exhaust system. For that purpose the Taguchi-Method [1] was applied to three different exhaust systems. Several geometric parameters, such as pipe diameter and length or muffler volume, have been changed at each exhaust system. The time domain engine/exhaust simulation code WAVE was used to calculate the tail-pipe noise.

The benefit of Taguchi's Method is, that only a slight number of parameter combinations is necessary to measure, in order to obtain the optimal configuration of a vast number of possible combinations. In addition one gets also the response intensity of each parameter. These informations lead to an optimum combination of the parameters according to the desired target.

One of the most critical steps during a DoE Investigation is the validation of a test result. The process to find the best test result function for tailpipe noise in this case will be described. With a good test results it was possible to obtain the optimal tailpipe noise just from a few WAVE simulations. The tailpipe noise could be reduced by 5 - 10 dB compared to an initial design.