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Possibilities of Active Noise Supression for Diesel Engines
Technical Paper
785131
Sector:
Language:
German
Abstract
90% of noise from Diesel-powered vehicles originates from the
engine, exhaust, and cooling system. The paper investigates means
of reducing this noise.
Straightforward approaches to noise reduction of exhaust and
cooling systems are reviewed. However, improvements of the greatest
noise source, the engine, is more problematic. Modification of
engine processes themselves is not promising. Engine coverings
encompass serious drawbacks involving weight, cost, accessibility,
and fire hazard. Improvement guidelines suggest two areas where
efforts should be concentrated: the points of noise transfer from
engine to the vehicle body, and the noise-emitting body surfaces
themselves.
Specific improvements to meet both of these requirements were
developed through laboratory tests; they included stiffening of the
clutch housing, inclusion of an oil pan brace, and redesign of the
intake pipe. These specific improvements offered 3.5 to 4dB(A)
noise reductions; further inclusion of exhaust and cooling
improvements provided 4 to 6dB(A) total improvements. However,
progressive cost increases of noise reductions require better
measurement techniques of noise perception in order to target
future design work.