WÄRTSILÄ WARTSILA 50DF, Product Manual

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2.3 Operation at low load and idling
Absolute idling (declutched main engine, disconnected generator):
●
Maximum 10 minutes if the engine is to be stopped after the idling. 3-5 minutes idling
before stop is recommended.
●
Maximum 2 hours on HFO if the engine is to be loaded after the idling.
●
Maximum 8 hours on MDF or gas if the engine is to be loaded after the idling.
Operation below 20 % load on HFO or below 10 % load on MDF or gas:
●
Maximum 100 hours continuous operation. At intervals of 100 operating hours the engine
must be loaded to min. 70% of the rated output for 1 hour.
●
If operated longer than 30h in liquid fuel mode, the engine must be loaded to minimum
70% of rated output for 1 hour before transfer to gas.
● Before operating below 10% in gas mode the engine must run above 10% load for at least
10 minutes. It is however acceptable to change to gas mode directly after the engine has
started, provided that the charge air temperature is above 55°C.
Operation above 20 % load on HFO or above 10 % load on MDF or gas:
●
No restrictions.
2.4 Low air temperature
The minimum inlet air temperature of 5°C applies, when the inlet air is taken from the engine
room.
Engines can run in colder conditions at high loads (suction air lower than 5°C) provided that
special provisions are considered to prevent too low HT-water temperature and T/C surge.
For start, idling and low load operations (Ch 2.3), suction air temperature shall be maintained
at 5°C.
If necessary, the preheating arrangement can be designed to heat the running engine (capacity
to be checked).
For further guidelines, see chapter Combustion air system design.
2-6 Wärtsilä 50DF Product Guide - a16 - 9 September 2016
Wärtsilä 50DF Product Guide 2. Operating Ranges