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MAN B&W 7.00
Air
intake
Inert gas
(N 2) inlet
Sealing oil outlet
Sealing oil inlet
1. High pressure pipe from gas compressor
2. Main gas valve
3. Main venting valve
Engine side
Fig. 7.00.03: Layout of double�wall piping system for gas
The layout of double�wall piping system for gas <strong>is</strong>
shown in Fig. 7.00.03. The high�pressure gas from
the compressor�unit flows through the main pipe
via narrow and flexible branch pipes to each cylinder’s
gas valve block and large�volume accumulator.
The narrow and flexible branch pipes perform
two important tasks:
• They separate each cylinder unit from the rest in
terms of gas dynamics, util<strong>is</strong>ing the well�proven
design philosophy of the ME engine’s fuel oil
system.
• They act as flexible connections between the
stiff main pipe system and the engine structure,
safeguarding against extra�stresses in the main
and branch pipes caused by the inevitable differences
in thermal expansion of the gas pipe
system and the engine structure.
6
Outside engine room
5
4. Main gas pipe (double pipe)
5. Main venting pipe (double pipe)
6. Inert gas valve in main gas pipe
Pilot oil outlet
Pilot oil inlet
Air outlet
Gas fuel
inlet
Page 3 of 4
MAN B&W ME/ME-C/ME-B/-GI 198 48 84-6.2
MAN Diesel
10
4
2
1
8
9
7
3
7. Suction fan
8. Flow control
9. HC sensors in double wall pipes
178 53 62�1.0
The large�volume accumulator, containing about
20 times the injection amount per stroke at MCR,
also performs two important tasks:
• It supplies the gas amount for injection at only a
slight, but predetermined, pressure drop.
• It forms an important part of the safety system
(as described later).
Since the gas supply system <strong>is</strong> a common rail
system, the gas injection valve must be controlled
by another system, i.e. the control oil system. <strong>Th<strong>is</strong></strong>,
in principle, cons<strong>is</strong>ts of the ME hydraulic control
(servo) oil system and an ELGI valve, supplying
high�pressure control oil to the gas injection valve,
thereby control�ling the timing and opening of the
gas valve.