Man B&W S50ME-B9.3-TII, Project Manual

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MAN B&W 1.06
Page 4 of 7
MAN Diesel
MAN B&W ME-B9.5/.3 engines 199 01 20-8.0
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.
The auxiliary blowers will start operating con-
secutively before the engine is started in order to
ensure sufficient scavenge air pressure to obtain a
safe start.
The auxiliary blower design is of the integrated
type.
Further information is given in Chapter 14.
Exhaust Gas System
From the exhaust valves, exhaust gas is led to the
exhaust gas receiver where the fluctuating pres-
sure from the individual cylinders is equalised,
and the total volume of gas is led further on to the
turbocharger(s). After the turbocharger(s), the gas
is led to the external exhaust pipe system.
Compensators are fitted between the exhaust
valves and the receiver, and between the receiver
and the turbocharger(s).
The exhaust gas receiver and exhaust pipes are
provided with insulation, covered by galvanised
steel plating.
A protective grating is installed between the ex-
haust gas receiver and the turbocharger.
Exhaust Turbocharger
Three turbocharger makes are available for the
ME-B engines, i.e. MAN, ABB and MHI. As an op-
tion, MAN TCA turbochargers can be delivered
with variable nozzle area technology that reduce
the fuel consumption at part load by controlling
the scavenge air pressure.
The turbocharger selection is described in Chap-
ter 3, and the exhaust gas system in Chapter 15.
Camshaft and Cams
The camshaft is made in one piece with exhaust
cams.
The exhaust cams are made of steel, with a hard-
ened roller race, and are shrunk onto the shaft.
They can be adjusted and dismantled hydrauli-
cally.
The camshaft bearings consist of one lower half-
shell fitted in a bearing support. The camshaft is
lubricated by the main lubricating oil system.
Chain Drive
The camshaft is driven from the crankshaft by a
chain drive, which is kept running tight by a manu-
ally adjusted chain tightener. The long free lengths
of chain are supported by rubber-clad guidebars
and the chain is lubricated through oil spray pipes
fitted at the chain wheels and guidebars.
2nd Order Moment Compensators
The 2nd order moment compensators are rel-
evant only for 5 or 6-cylinder engines, and can be
mounted either on the aft end or on both fore and
aft end. The aft-end compensator consists of bal-
ance weights built into the camshaft chain drive.
The fore-end compensator consists of balance
weights driven from the fore end of the crankshaft.
The 2nd order moment compensators as well as
the basic design and options are described in
Section 17.02.