Steyer Motors 4 Cylinders, Руководство по установке

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Z001007/0_4_September 2007 Page NOISE ATTENUATION-3
NOISE ATTENUATION INSTALLATION INSTRUCTION
14. NOISE ATTENUATION
14. 1. GENERAL
In most cases a low noise level is required, which implies an insulation of the machine unit. The disturbing engine
noise is transmitted through the hull - i.e. engine base and body - and by the air.
To avoid a propagation of the engine noise through the hull, as first step engine and reversing gear are to be
provided with elastic suspensions and elastic propeller shaft coupling (see chapter 3) which results in a reduction
of the hull-latent noise.
In addition, the acoustic source is to be shielded as far as possible, to reduce the air-latent noise. This measure
above all is a very simple way to reduce the high-frequency noise. However, a small opening in the shielding may
already cause a considerable noise leakage. Therefore, insulating material should also be provided below the
engine bed, down to the hull, and all inlets are to be sealed with rubber bellows.
14. 2. NOISE REDUCTION
Equip the unit with a noise insulation to keep the sound level as low as possible. Provide noise catchers in the
engine compartment. Various type are available.
Ill. 14/1 shows a construction with a water drain.
If a water drain is not possible, the air tubes may be bent like a swanneck (ill. 14/2), to avoid the entering of water.
Design of the engine compartment should consider enough space for maintenance of the engine. In addition,
thickness of the noise-absorbing material is to be considered.
ill. 14/2
ill. 14/1
Carefully shield the acoustic source.
Shielding should go down to the hull.
Gaps on hatches and bench covers to be
sealed with insulating material (see ill. 14/3)
If the engine is under the bottom plate, cover
all bulkheads and sheets.
ill. 14/3