At this year's CIMAC conference Wärtsilä presented a paper on noise reduction of medium speed engines. Changes made to the crankcase covers and camshaft covers brought the emitted sound level down by approximately 6dB(A). A multi-layer sandwich solution applied to the turbocharger casing and charge air cooler reduced noise levels 5dB(A). Engine noise emanating from th was reduced by placing an additional covering on top of the existing cylinder head valve covers. It is proposed that these optional parts will be available for current and future Wärtsilä medium speed engines providing a noise reduction of approximately 5dB(A).
At this year's CIMAC conference Wärtsilä presented a paper following a five year research program on noise reduction of medium speed engines. The test engine used was a seven cylinder 32 series engine of 3.5MW at 750 rpm with 320 mm bore and stroke of 400 mm.
Changes made to the crankcase covers and camshaft covers included replacing the one piece cast aluminum covers by a two piece cast aluminum frame with bonded and bolted 2mm steel cover plate, giving greater rigidity and reducing noise radiation that brought the emitted sound level down by approximately 6dB(A). A multi-layer sandwich solution of fireproof fabric, mineral wool, aluminium plate and finally more fireproof fabric applied to the turbocharger casing and charge air cooler reduced emitted noise levels from these parts by 5dB(A).
Tests showed that 27 per cent of engine noise emanates from the top of the engine. Noise level from this area was reduced by placing an additional covering comprising a a 2 mm vibro-acoustically treated steel plate with a 1mm corrugated micro-perforated plate on top of the existing cylinder head valve covers.
It is proposed that these optional parts will be available for current and future Wärtsilä medium speed engines providing a noise reduction of approximately 5dB(A).