Concept Of The Me Engine; Me Advantages - Man B&W S80ME-C7 Project Manual

MAN B&W
The ME 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 type, with a chain driven camshaft, have
limited flexibility with regard to fuel injection and
exhaust valve activation, which are the two most
important factors in adjusting the engine to match
the prevailing operating conditions.
A system with electronically controlled hydraulic
activation provides the required flexibility, and
such systems form the core of the ME 'Engine
Control System', described later in detail in Chap­
ter 6.

Concept of the ME engine

The ME engine concept consists of a hydraulic­
mechanical system for activation of the fuel injec­
tion and the exhaust valves. The actuators are
electronically controlled by a number of control
units forming the complete Engine Control Sys­
tem.
MAN Diesel has specifically developed both the
hardware and the software inhouse, in order to
obtain an integrated solution for the Engine Con­
trol 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 opened hydraulically, just
as on the MC engines, but the camshaftdriven
mechanical actuator has been replaced by a
twostage exhaust valve actuator activated by the
control oil from an electronically controlled pro­
portional valve. The exhaust valves are closed by
the 'air spring', just as on the MC engines.
MAN B&W ME/MEC/MEGI engines
In the hydraulic system, the normal lube oil is
used as the medium. It is filtered and pressurised
by a Hydraulic Power Supply unit mounted on the
engine (4 40 60) or placed in the engine room,
option 4 40 660.
The starting valves are opened pneumatically by
electronically controlled 'On/Off' valves, which
make it possible to dispense with the mechani­
cally activated starting air distributor.
By electronic control of the above valves accord­
ing to the measured instantaneous crankshaft
position, 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, such as 'Fuel economomy mode' to com­
ply with IMO NO
emission mode'.

ME Advantages

The advantages of the ME range of engines are
quite comprehensive, as seen below:
• Lower SFOC and better performance param­
eters thanks to variable electronically controlled
timing of fuel injection and exhaust valves at any
load
• Appropriate fuel injection pressure and rate
shaping at any load
• Improved emission characteristics, with lower
NOx and smokeless operation
• Easy change of operating mode during opera­
tion
• Simplicity of mechanical system with well­
proven simple fuel injection technology familiar
to any crew
MAN Diesel
emission limitation or 'Low NO
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