6.5
Gas valve unit and external gas supply system
6.5.1
External gas supply
The external gas supply system upstream of the gas valve unit (GVU) contains the gas supply
pipes and the pressurized gas supply.
NOTE:
Your gas valve units can look different.
NOTE:
Your engine could have iGPR instead of GVU. In that case, refer to the chapter:
Integrated gas pressure regulation.
6.5.2
Gas supply pipes
The gas supply pipes between the gas storage area and the engine room are in a closed area.
The supply pipes have double walls or are installed in a closed, ventilated duct. This duct has a
gas detector to detect the gas and monitor the gas flow.
6.5.3
Shut-off valve
The propulsion control system (PCS) controls the shut-off valve. During usual operation, the
shut-off valve for the GVU shuts-off the gas supply to the engine room. The shut-off valve can
be closed from the engine room, the engine control room or the bridge. In some conditions, the
shut-off valve is automatically closed.
6.5.4
Gas valve unit (GVU)
It is necessary for dual fuel engines to have accurate control of the gas pressure and the
changes of the load conditions.
The GVU has three primary functions:
1
Gas pressure control
a
The gas pressure depends on the engine load.
b
The signal for the applicable gas pressure comes from the Engine Control System.
2
Leak test sequence
a
The leak test sequence is done before the engine changes from diesel to gas
mode.
b
The leak test sequence makes sure that the valves of the GVU operate correctly
and that there is no internal leakage.
3
Inert gas function
a
The GVU uses inert gas and runs pressure release sequences automatically.
b
The pressure release sequence is safe during usual operation.
Your GVU is on of these two variants:
1
2
GVU-OD (Open Design see )
X92DF
AA00-8014-00AAA-042A-A
Operation Manual
Gas valve unit and external gas supply system
Winterthur Gas & Diesel Ltd.
- 278 -
Issue 002 2020-08
