Marine Installation Manual
2021-08
4-55
4 Ancillary Systems
4.4 Fuel gas system
X72DF
Figure 4
-
34 The GVU-ED
™
from Wärtsilä
Location of the GVU
The fuel gas supply pipe length between the GVU and the engine inlet should be
kept as short as possible (maximum length 30 m) to ensure optimal engine re
-
sponse to transient conditions.
The GVU consists of the following main components:
Fuel gas pressure
regulating valve
The fuel gas feed pressure to the engine must be adjusted within a narrow,
load-dependent pressure range. This adjustment will ensure that the fuel gas
pressure in the engine’s common-rail piping fits to the load command. This is
done by means of a pressure regulating valve that is controlled by the PCS. A
smaller gas volume between the pressure control valve and the engine improves
the response time of the system in transient conditions, such as engine load fluc
-
tuations.
Valve block
The ‘Interim guidelines on safety for natural gas-fuelled engine installations in
ships’ (IGF Code) state that each item of gas-consuming equipment must be pro
-
vided with a set of valves to form a double block-and-bleed function and thus en
-
sures reliable and safe operation on fuel gas.
G
V
U
Forced engine room ventilation
Engine room: gas safe area
GVU enclosure
Annular pipe / GVU enclosure venting
Piston underside gas detection
Gas detector
Gas venting pipe
Double-wall fuel gas pipe
GVU venting pipe
from fuel gas
supply system
SM-0075
