Influence of Cabin Modal Density on Vehicle Interior Noise

The increasing trends towards smaller power units running at high speeds together with the increasing use of diesel engines in passenger vehicles have resulted in higher vehicle interior noise and vibration levels. The customer awareness towards comfort of vehicle specifically with reference to perceived noise levels has become a selling point for vehicle manufacturers. In this paper experimental and analytical techniques used to study the influence of cabin related parameters on interior noise are presented. These techniques were applied to study interior noise of truck cabins.

The noise and vibration signals were measured at body panels and at Operators Ear Location (OEL) for different engine speeds. The natural frequencies of body panels were identified by using frequency response function measurements. The modal analysis of acoustic cavity was carried out using finite element technique.