WinGD X72DF, Installation Manual

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Marine Installation Manual 2021-08 4-51
4 Ancillary Systems
4.4 Fuel gas system
X72DF
Figure 4 - 30 Fuel gas supply pressure control at the GVU inlet (engines with GVU)
Pressure control of the
engine’s operational gas
pressure
The operational gas pressure at the engine’s internal Gas Admission Valves
(GAVs) is controlled by the iGPR (see section
4.4.6,  4-52 ) or the GVU (see
section 4.4.7,

4-54 ). Both the iGPR or the GVU are connected to the ECS (ei -
ther by means of the PCS, or directly). The iGPR or the GVU preferably just pro -
vide fine adjustments of the gas supply pressure to compensate for fluctuating
pressure demands. These varying pressure demands may be caused by fluctua
-
tions of the engine power demand. At the same time, the FGSS provides the gas
supply pressure as requested by the PCS. However, the iGPR or the GVU have
the capacity to handle any gas supply pressure up to the maximum design gas
supply pressure of 16 bar(g).
Overview of steps for ac -
quiring the FGSS delivery
pressure
Figure 4 - 31 provides an overview of the gas pressure from the FGSS input by way
of the iGPR or the GVU inlet to the final pressure level at the engine’s gas admis -
sion valves.
Figure 4 - 31 Fuel gas pressure level definitions
SM-0276
P
set-point
+ P
offset
Control signals
P
set-point
Fuel Gas
Supply System
(FGSS)
Propulsion
Control System
(PCS)
GVU
Engine
Control System
(ECS)
P
set-point
- Set-point of the fuel gas supply pressure at the GVU inlet
P
offset
- Fuel gas supply pressure offset to compensate for:
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SM-0773
On-engine
(GAV inlet)
GVU or iGPR
inlet
FGSS
input
Pressure at the GVU
or iGPR inlet, includes
margin for fluctuating
engine power demand Adapted gas pressure
as required for
engine operation Fuel gas supply pressure,
includes margin for system
pressure drop and properties
Minimum pressure
definition provided
by a graph in the
MIM and GTD
Pressure controlled
by the ECS
Project-specific, depending
on the FGSS pressure
drop and the system’s
ability to compensate for
pressure fluctuations caused
by variations of flow rates