Marine Installation Manual
2021-08
4-80
4 Ancillary Systems
4.6 Fuel oil system
X72DF
4.6.5
Pressurised fuel oil system
The fuel is supplied from the heated heavy fuel oil service tank or the unheated
diesel oil service tank to the low-pressure feed system.
Fuel changeover
For changing over from one fuel type to the other it was common to have a
simple, manually operated three-way valve. This arrangement is not recom
-
mended any longer, as with the introduction of different Emission Control Areas
(ECA), fuel changeover is quite frequently required, even at high engine load.
(In the past it was needed in rare cases only, for instance due to maintenance or
before stopping the engine, i.e. at relatively low loads.)
Automatic
changeover unit
Consequently, a well proven automatic changeover unit is nowadays recom
-
mended, which ensures:
•
A maximum temperature gradient of 2K/min during changeover
•
A maximum viscosity of 20cSt
•
A minimum viscosity of 2cSt; this minimum limit is most challenging
during changeover from HFO to distillate fuel.
Attention:
Not all changeover units guarantee keeping the minimum vis
-
cosity limit, as viscosity is not controlled.
•
A best-practice automatic control of diesel oil cooler activation
4.6.6
Fuel oil specification
The validated fuel oil qualities are published in the document
Diesel engine
fuels
provided on the WinGD webpage under the following link:
