Iveco Marine Diesel Engines, Installation Handbook

Page: 103 / 132

MARCH 2004 AUXILIARY SERVICES
10.103
MARINE ENGINES INSTALLATION
ven by the engine, in relation to the torsional vibrations. Thus, it is worth remembering that the most
qualified joint manufacturers can provide adequate professional advice.
The driving belts of the engine water pump and alternator must be changed periodically; it is advis-
able to have a proper number of spare joints in the driving area and to attach them on fixed parts so
that they can be easily reached and installed in place without intervention to engine connexion and
the driven parts.
Lateral with belt transmission
IVECO engines for professional applications can be supplied with front pulleys with supplementary
throats for belt transmission.
Supplementary pulleys other than the ones supplied by IVECO can be used as long as balance, cen-
tring, alignment, and maximum inertial limits are ensured.Thus, the dockyard personnel will be in charge
of mounting the application correctly.
The power and the torque used are lower than the values admitted by the power inlets in the motor
shaft, due to the greater stress exerted on the motor shaft and the corresponding bearings and as a
consequence of the lateral stress caused by the belts tension.
Thus, the belt transmission should be adjusted so that the tension does not produce a very strong lat-
eral strain that may produce a bending moment over the admitted values.
These types of power inlets are appropriate to drive accessories that require power input limited to a
few kW; however, it is necessary to pay maximum attention to the rotation rate acted upon them:
A limited power input required for low rotation rates can be incompatible with the engine capacity
since it may imply a high bending moment, and to be transmitted the belts should be tightly tensed,
which may produce an excessive bending moment upon the engine shaft.
In the case of two different available transmissions, they should be installed in such a way to balance
the lateral stress produced thus reducing to the minimum the resultant.
When the engine is supported on elastic parts, and therefore subjected to oscillations, the belt-driven
element must have a supplementary support; otherwise, its oscillations may cause additional stress on
the engine.
10.4 BUILT-IN POWER TAKE-OFF ON TIMING OR FLYWHEEL HOUSING
Some engine versions are fitted with hydraulic pump drive devices that take the driving force from the
gear assembly to move the camshaft and the injection pump. The connexion is made using a rigid
grooved joint or collar, and the rotation speed of the driven element can be increased or reduced in
relation to the engine rotation speed.
The usable power is indicated in each engine manual, and it is figured out during the pump working
cycle.The continuous power inputs should be lower than the occasional ones.
The manufacturer is responsible for verifying that the usable power are below the maximum admitted
values, which can be ensured by timely adjustments to the operating pressure of the pumps hydraulic
systems. It should be remembered that hydraulic pumps have frequently a maximum power performance
higher than admissible, in such cases it must be installed a valve limiting the fluid pressure/flow rate.
The dockyard personnel must connect the pump for proper use.