Iveco Marine Diesel Engines, Installation Handbook

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Light service
Boat
Light boats for tourist, professional or military use subject to frequent speed variations. For example,
yachts, charters, light passenger boats, fast patrol boats, police boats, civil protection boats, rescue boats,
special squads.
Engine
Use of the maximum power below 10% of the time, cruising speed with engine rpm < 90% of the set
rated rpm, use limit 1500 hours/year.The definition of setting and use limits for military and state bod-
ies is based on the contractual specifications.
Power classification according to ISO 3046-7 (IOFN).
Medium service
Boat
Boats for commercial, military, work and light fishing use with variable speed. For example,
patrols, pilot boats, light fishing boats, seasonal medium-range passenger taxi boats, fire boats.
Engine
Use of the maximum power below 25% of the time, cruising speed with engine rpm < 90% of the set
rated rpm, use limit from 1500 to 3000 hours/year. The definition of setting and use limits for military
and state bodies is based on the contractual specifications.
Power classification according to ISO 3046-7 (IOFN).
Continuous service
Boat
Fishing boats, work and load boats, passenger boats where it is possible to use the maximum power.
For example fishing boats, work boats, load boats, tug-boats, passenger boats.
Engine
Maximum usable power up to 100% of the operating time, without limiting the number of hours
per year.
Power classification according to ISO 3046-7 (IOFN).
2.3 ENGINE PERFORMANCE
The diagram of the typical curves of an engine illustrates the maximum engine power and torque
according to the rotation speed and provides the engine specific consumption. The engine power and
torque values will be different according to the position of the accelerator lever.
On the basis of the power and torque curves, which bound the engine operating range when the accel-
erator is in limit switch position, it is possible to derive other important parameters for the choice of
the engine:
■
Maximum idling speed (n
v
) : it is the maximum rotation reached by the engine without load, with
the accelerator in limit switch position.This limit is set by the speed regulator of the injection pump,
or by the engine electronic control system EDC, which limits the fuel inlet to the quantity needed
to keep the engine running, thus preventing overspeed.This parameter must be taken into consid-
eration for the choice of the engine when there are limitations to the maximum rotation speed
bearable by the drive system.
■
Maximum power speed (n
p
) : it is the speed where the maximum power is supplied, called also
rated speed. It corresponds to the rotation speed at which the regulator - mechanical or electron-
ic - with the accelerator in limit switch position, starts to reduce the fuel inlet to control the speed
as the torque required by the engine drops. During the bench tests it is possible to detect the max-
MARCH 2004 ENGINE/BOAT CHOICE FACTORS
2.26
MARINE ENGINES INSTALLATION