Interior Noise Problems of Small Diesel-Powered Buses

This paper discusses interior noise problems characteristic of the combination of diesel engines with typical small bus geometries.

One noise problem is the potential for low-frequency resonances. Natural air vibration modes for typical small bus interior dimensions are calculated and shown to give frequencies that can be stimulated by noise and vibration at engine firing frequencies. Measurements of noise and vibration at resonance are given. Other noise problems are associated with internal front engine covers, and leaks and low transmission loss paths in the console area.

Some practical suggestions, with examples, are given to reduce interior noise.