Exhaust Noise Modelling for Muffler Design

The design of mufflers for motor vehicles has traditionally been trial and error based. This is still true of much of the vehicle exhaust industry. In an attempt to improve upon trial and error methods a computer model of the exhaust system was developed and used to assist in the acoustical aspects of exhaust system design. The computer model is based on a linear acoustic analysis of the pulsating gas flow in the exhaust system and sound radiation at the tailpipe outlet. In using the computer model the insertion loss or muffling effect caused by making a particular change to any part of the complete exhaust system may be predicted. As comparisons between calculations and measurements from an actual vehicle exhaust design project show, accuracy is very good.