In a competitive context of cost-cutting and delays, one of the carmakers strategies is to reduce the physical prototypes. Thus, the calculations are increasingly used and enable to anticipate the phenomena involved in the advanced study phase. Actually, the vibroacoustic calculations in low frequencies are already integrated in the design process to optimize the shape of the body in white (BIW). In medium and high frequencies (MF and HF), the numerical simulation is being more and more used thanks to the recent progress in the poroelastic materials models. In the high frequency band of interest, the absorbing parts in the engine compartment enable to reduce the engine noise by absorbing the radiated energy from the engine. The aim of this paper is to better understand the physical phenomena of such parts in this confined area. So, some numerical simulations were carried out taking into account the poro-elastic material effect. This paper is divided in two parts: first, the simulation is based on a simple geometry case to bring to light the essential phenomenon. Secondly, a complete FEM engine compartment is created to be closer to the car reality. The first part has explained how an almost double walls works. impervious film (isolation effect) and the absorbing part (absorption effect). The calculations were validated with measurements. In the second part, a real engine compartment model has been presented with a specific validated method to model the openings. Then, many insulating solutions were simulated. It appears that the absorbing parts on the wheels arches seem to be an interesting solution in order to reduce the vibrations of the dash panel. In fact, the correlation between the measurements and the simulations is quite good. The numerical tool enables to go much further in the physical phenomenon explanation. From this model, some further investigations have been carried out to help the project teams to elaborate proper specifications.
Numerical simulation of trim efficiency in engine compartment
2010
9 Seiten, 30 Bilder, 7 Quellen
Aufsatz (Konferenz)
Datenträger
Englisch
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Europäisches Patentamt | 2016
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