Exhaust system acoustic modeling

A combustion engine exhaust system prevents environment pollution and acts as a cascaded acoustic filter that removes most of the noise from the engine. That acoustic system is extremely nonlinear since temperature of the gasses and the geometry of the subsystems change along the structure, starting from the exhaust manifold to exhaust pipe tip. The main purpose of the investigation presented here was to find the system transfer function and use findings in the future exhaust system design. The whole nonlinear system is represented as a ladder network of linear subsystems, or physical networks. We show here that power spectrum characteristics of that complex system can be predicted, i.e., requirements in that domain could be fulfilled. One of the main objectives is to ensure better sound pollution protection for the environment.