Acoustic optimization of an intake system by means of geometry CAD modifications

The intake system of internal combustion engines represents the most prominent noise source at high load and low vehicle speeds because of the de-throttling strategies which are realized in order to maximize the cylinders filling. Therefore, a good acoustic performance of intake systems represents a very important challenge in order to respect the overall noise emission, according to the more strict European standards. In general, the most used method for characterizing the acoustic performances of a system is represented by the Transmission Loss computation. In this study, a 3D numerical analysis by using the Finite Element Method onan intake system for a commercial spark ignition engine has been exploited for the Transmission Loss calculation. The numerical findings of the finite element model have been validated by means of experimental investigations. A very good agreement between numerical and experimental data has been reached. For this reason, an optimization procedure, by implementing different CAD modifications on the system, has been investigated, as well. All the foreseen geometry changes do not modify the overall size of the original system.