Engine room, ventilation and sound proofing
75
Location of air ducts
The channels or ducts for the engine air supply
should be routed up as close as possible to the air
filters, but with a minimum distance of 20–30 cm
(8–2"), to definitely prevent water from entering the
engine. See figures in chapter
Location of ventila-
tors and air intakes.
For diesel engines the incoming ventilation air duct
should open out low down in the engine room, but not
so low that any bilge water can block the air supply.
The outlet ducts should be located diagonally across
on the other side of the engine.
All channels and ducts must be routed so that the
least possible flow resistance is obtained. The bends
must not be sharp, but softly rounded. The smallest
radius is twice the diameter.
Restrictions must al-
ways be avoided.
The ducts should be cut obliquely at the ends to get
the best flow.
In certain countries there are regulations in this re-
spect, which must be followed.
Soundproofing
The drive package must be installed in such a way
as to minimise noise and vibration. The noise that oc-
curs is airborne noise and structural noise (vibration).
Structural noise
Vibration from the engine is transmitted via the en-
gine mountings and the engine bed to the hull. Other
routes are via the transmission and propeller sys-
tems, exhaust pipe, coolant pipes, fuel pipes, electri-
cal cables and control cables.
Pressure pulses from the propeller are transmitted
through the water and into the hull. Pulsed force on
the propeller enters the hull via support blocks, bear-
ings and seals.
Airborne noise
This section refers to airborne noise from the engine
bay. The most important measure to lower airborne
noise from the engine room is to seal the room prop-
erly. Further improvements in noise level reduction
can be achieved by sound insulation material and by
designing sound traps for the air inlets.
The engine installation should be soundproofed in or-
der to obtain a noise level that is as low as possible.
Build the engine compartment with sound traps. Dif-
ferent types of sound traps can be selected. The fig-
ure reflects a type that is also provided with drainage.
Furthermore, due consideration must be given to the
thickness of the insulation material.
Summary of Contents for D11 series
Page 1: ...Marine Propulsion Diesel Engines Installation 1 1 D E D5 D16 series ...
Page 2: ......
Page 208: ...206 References to Service Bulletins Group No Date Concerns ...
Page 209: ...207 Notes ...
Page 210: ...208 Notes ...
Page 212: ...7748655 English 11 2007 ...