Modelling and acoustic optimization of an intake system for an internal combustion engine

The subject of the PhD thesis is represented by the modelling of the acoustic behavior of an air induction system for a four stroke, spark ignition engine with the help of computer aided engineering tools. More precisely, 1D/3D CFD analyses, 3D structural analyses have been executed in order to support the execution of 3D acoustic analyses aimed to reproduce the overall vibro-acoustic response of the system under investigation, in several conditions. Thus, the development of the thesis is divided in two parts. In the first part, the building up procedure of FE models of the intake system and their validation, thanks to a comparison with available experimental data in terms of Transmission Loss and emitted gas-dynamic noise in several engine running points, is described. Then, the realization of several localized geometric changes on the original device, aimed to enhance its acoustic performances in terms of both higher Transmission Loss and lower emitted gas-dynamic noise, is described in the second part of the thesis. From the presented results, it has been shown that opportunely realized geometric modifications may highly enhance the acoustic performance, without increasing the overall size of the original system.