Man B&W S80ME-C7, Project Manual

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MAN B&W 1.06
Page of 5
MAN Diesel
MAN B&W ME/MEC engines 198 46 139.4
Connecting Rod
The connecting rod is made of forged or cast
steel and provided with bearing caps for the
crosshead and crankpin bearings.
The crosshead and crankpin bearing caps are se-
cured to the connecting rod with studs and nuts
tightened by means of hydraulic jacks.
The crosshead bearing consists of a set of
thinwalled steel shells, lined with bearing metal.
The crosshead bearing cap is in one piece, with
an angular cutout for the piston rod.
The crankpin bearing is provided with thinwalled
steel shells, lined with bearing metal. Lube oil is
supplied through ducts in the crosshead and con-
necting rod.
Piston
The piston consists of a piston crown and piston
skirt. The piston crown is made of heatresistant
steel and has four ring grooves which are
hardchrome plated on both the upper and lower
surfaces of the grooves.
The uppermost piston ring is of the CPR type
(Controlled Pressure Relief), whereas the other
three piston rings are with an oblique cut. The up-
permost piston ring is higher than the others. The
piston skirt is of cast iron with a bronze band.
Piston Rod
The piston rod is of forged steel and is surface-
hardened on the running surface for the stuffing
box. The piston rod is connected to the cross-
head with four screws. The piston rod has a cen-
tral bore which, in conjunction with a cooling oil
pipe, forms the inlet and outlet for cooling oil.
Crosshead
The crosshead is of forged steel and is provided
with cast steel guide shoes with white metal on
the running surface.
The telescopic pipe for oil inlet and the pipe for oil
outlet are mounted on the guide shoes.
Scavenge Air System
The air intake to the turbocharger takes place
directly from the engine room through the turbo-
charger intake silencer. From the turbocharger,
the air is led via the charging air pipe, air cooler
and scavenge air receiver to the scavenge ports
of the cylinder liners, see Chapter 4.
Scavenge Air Cooler
For each turbocharger is fitted a scavenge air
cooler of the monoblock type designed for sea-
water cooling at up to .0  .5 bar working pres-
sure, alternatively, a central cooling system can
be chosen with freshwater of maximum 4.5 bar
working pressure.
The scavenge air cooler is so designed that the
difference between the scavenge air temperature
and the water inlet temperature at specified MCR
can be kept at about °C.
Auxiliary Blower
The engine is provided with electricallydriven
scavenge air blowers. The suction side of the
blowers is connected to the scavenge air space
after the air cooler.
Between the air cooler and the scavenge air re-
ceiver, nonreturn valves are fitted which auto-
matically close when the auxiliary blowers supply
the air.