Man B&W S50ME-B9.3-TII, Руководство по проекту

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MAN B&W 1.01
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MAN Diesel
MAN B&W ME-B-TII .5/.3 engines 199 01 13-7.0
The Fuel Optimised ME-B Tier II Engine
The ever valid requirement of ship operators is
to obtain the lowest total operational costs, and
especially the lowest possible specific fuel oil
consumption at any load, and under the prevailing
operating conditions.
However, lowspeed twostroke main engines
of the MC-C type, with a chain driven camshaft,
have limited flexibility with regard to fuel injection
to match the prevailing operating conditions.
A system with electronically controlled hydraulic
activation provides the required flexibility, this
system form the core of the ME-B ‘Engine Control
System’, described later in detail in Chapter 16.
Concept of the ME-B engine
The ME-B engine concept consists of a hydraulic
mechanical system for activation of the fuel injec-
tion. The actuator is electronically controlled by a
number of control units forming the complete En-
gine Control System.
MAN Diesel & Turbo has specifically developed
both the hardware and the software inhouse, in
order to obtain an integrated solution for the En-
gine Control System.
The fuel pressure booster consists of a simple
plunger powered by a hydraulic piston activated
by oil pressure. The oil pressure is controlled by
an electronically controlled proportional valve.
The exhaust valve is activated by a light camshaft,
driven by a chain drive placed in the aft end of the
engine. The closing timing of the exhaust valve is
electronically controlled for lower fuel consump-
tion at low load.
To have common spare parts, the exhaust valve
used for the ME-B is the same as the one used for
the MC-C. The exhaust valve is of the DuraSpin-
dle type with a W-seat bottom piece.
In the hydraulic system, the normal lube oil is used
as the medium. It is filtered and pressurised by
an electrically driven Hydraulic Power Supply unit
mounted on the engine.
The starting valves are opened pneumatically by
the mechanically activated starting air distributor.
By electronic control of the above valve according
to the measured instantaneous crankshaft posi-
tion, the Engine Control System fully controls the
combustion process.
System flexibility is obtained by means of different
‘Engine running modes’, which are selected either
automatically, depending on the operating condi-
tions, or manually by the operator to meet specific
goals. The basic running mode is ‘Fuel economy
mode’ to comply with IMO NO
x
emission limita-
tion.
The market is always moving, and requirements
for more competitive engines, i.e. the lowest pos-
sible propeller speed, lower fuel consumption,
lower lube oil consumption and more flexibility
regarding emission and easy adjustment of the
engine parameters, call for a re-evaluation of the
design parameters, engine control and layout.
Engine design and IMO regulation compliance
For MAN B&W ME-B-TII designated engines, the
design and performance parameters have been
upgraded and optimised to comply with the Inter-
national Maritime Organisation (IMO) Tier II emis-
sion regulations.
The potential derating and part load SFOC figures
for the Tier II engines have also been updated.
For engines built to comply with IMO Tier I emis-
sion regulations, please refer to the Marine Engine
IMO Tier I Project Guide.