MULTI-DIMENSIONAL CFD-TRANSMISSION MATRIX MODELLING OF IC ENGINE INTAKE AND EXHAUST SYSTEMS

A method able to investigate the overall performances of internal combustion engine intake and exhaust systems is proposed. Such a method is based on the combination between a time domain non-linear model (used to perform fluid and thermodynamic analysis in cylinders, valves and manifolds) and a linear acoustic method (used to predict the spectral characteristics of the remainder of the system). The time domain approach is based on the simultaneous use of zero-, one- and three-dimensional fluid dynamic models, applied to different regions of the same geometry. The frequency domain approach is based on acoustic theory and uses the transfer matrix technique. Both the procedures used to couple the different calculation domains analyzed by time domain models and to interface fluid dynamic and linear acoustic models have been developed. In this paper, the comparison between the obtained results and the predictions of another simulation technique and experimental measurements, is shown, proving that the developed method is a reliable tool for the prediction of complete intake and exhaust systems.