Engine Compartment Ventilation - FNM HPEP 225 Installation Manual

Engine Compartment Ventilation

IMPORTANT: This section does not cover the design of the ventilation system as it
pertains to ventilation of fumes from the engine compartment. The requirements for
ventilation of fumes varies considerably from one boat design to the next, as well as
from country to country, and therefore, the boat manufacturer is responsible for
ensuring their application is in compliance with the appropriate industry regulations
and standards.
GENERAL INFORMATION
According to boating standards and Coast Guard regulations the engine compartment
ventilation system has multiple tasks. Included are the following:
1. To supply the engine with combustion air.
2. To maintain a low temperature in the engine compartment.
Fresh air should enter the engine compartment as low as possible and the heated air should
be discharged from the highest point.
If a separate air shaft (or similar) is used to provide engine compartment ventilation, or
additional ventilation, care must be taken to prevent seawater and spray from entering it.
COMBUSTION AIR REQUIREMENTS
Engine compartments with natural draft ventilation must have vent openings of sufficient
size and location to accomplish the tasks previously outlined.
IMPORTANT: The size of ventilation openings must be increased if any auxiliary
equipment is located in the engine compartment.
The combustion air requirement (per engine) for the specified engines at wide open
throttle are shown in the chart below:
:
Model
HPEP 225 - 250
IMPORTANT: Follow regulations and boating standards for engine compartment ventilation.
In order to guarantee the optimum engine temperature (30-40°C), it is necessary to make sure that the
engine compartment ventilation meets the following requirements:
Inlet (combustion air): the surface must not be lower than 228 cm
•
the air inlets are positioned in such a way as to favor a continuous air flow towards the engine's air
filter.
Hot air outlet: the surface must not be less than 100 cm
•
positioned in the upper part of the engine compartment.
For all those applications that do not allow for these requirements to be fully met, it is required that the
air inlets must be connected directly from the outside of the engine compartment with an appropriate
water system and also we require that a ventilation system must be installed so that the hot air flow is
forced from the engine compartment to the outside. All the components must meet the European
Community standards and regulations.
If the temperature at the engine air inlet exceeds 40°, the engine may be seriously damaged.
Combustion Air Requirements (Per Engine)
CAUTION!
Engine Air Requirements at WOT
3
10 m / min. (353 ft
2
per engine. We recommend that
2
per engine and the air outlets must be
13
3
/ min.)