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MAN B&W 16.01
• Continuous running control of auxiliary functions
handled by the ACUs
• Alternative running modes and programs.
Gas Control System
The gas control system for the -GI prime mover
<strong>is</strong> an ‘interaction’ between the traditional boil�off
gas (BOG) handling, the well�known high�pressure
compressor and the engine technology.
Tanks Oxid<strong>is</strong>er Compressor Engine ME-GI
Fig. 16.01.03: System configuration
178 52 63�8.0
When the gas evaporates, the boil�off gas increases
the pressure in t he gas tanks and therefore
has to be removed. <strong>Th<strong>is</strong></strong> gas contains methane
and nitrogen.
In order to boost the pressure for further working,
a turbo compressor <strong>is</strong> used to activate a pressure
at approximately 2 bar.
The above�mentioned flow of the boil�off gas <strong>is</strong>
the traditional flow which has been used in gas
carriers for years.
In order to burn the boil�off gas in a high�pressure
gas engine, a reciprocating compressor has to be
installed.
These compressors are well�known and used with
various kinds of gases, delivered in units including
all internal control of the system, which operates
together with engines. Futher the control system
has sufficient ability to adjust optimal flow to engines
if the condition of the boil�off gas, to the
compression or requirements for the engine be
changed. These gas compressors use control of
by�pass at engine part load, all depending of the
application necessary; please see the gas supply
systems, Section 7.07.
Page 3 of 11
The compressors are capable of operating at engine
shutdown and of manoeuvring the system
without any delay or other difficulties, may appear
for the operator. The operator will, in practice,
operate the -GI engine as an ordinary HFO ME
engine.
Engine control and safety system
The -GI control and safety system <strong>is</strong> built as an
add�on system to the ME control and safety system.
It hardly requires any changes to the ME
system, and it <strong>is</strong> consequently very simple to
implement.
The principle of the gas mode control system <strong>is</strong>
that it <strong>is</strong> controlled by the error between the wanted
d<strong>is</strong>charge pressure and the actual measured
d<strong>is</strong>charge pressure from the compressor system.
Depending on the size of th<strong>is</strong> error the amount of
fuel�gas (or of pilot oil) <strong>is</strong> either increased or decreased.
If there <strong>is</strong> any variation over time in the calorific
value of the fuel�gas it can be measured on the
rpm of the crankshaft. Depending on the value
measured, the amount of fuel�gas <strong>is</strong> either increased
or decreased.
The change in the calorific value over time <strong>is</strong> slow
in relation to the rpm of the engine. Therefore the
required change of gas amount between injections
<strong>is</strong> relatively small.
To make the engine easy to integrate with different
suppliers of external gas delivering systems,
the fuel gas control system <strong>is</strong> made almost ‘stand
alone’. The exchanged signals are limited to Stop,
Go, ESD, and pressure set�point signals.
MAN B&W ME/ME-C/ME-B/-GI engines 198 49 28-03
MAN Diesel