Marine Installation Manual
2021-08
1-7
1 Engine Summary
1.3 Fuel operating modes
X72DF
1.3.1
Operation in gas mode
The engine operates in gas mode according to the Otto cycle with a pre-mixed
lean air-gas mixture, which is ignited by a small amount of pilot fuel. The
amount of injected pilot fuel used is approximately the same across the entire en
-
gine power range. This is equivalent to approximately 1-2 % of the total energy
consumption at 100% engine power (for the energy distribution during gas mode
see
).
Figure 1
-
4 Gas mode operation
Dynamic combustion control
Dynamic Combustion Control (DCC) allows full power output for gas mixtures
with a methane number of 65 and higher (see subsection
), independent of ambient condition and engine
rating. While DCC is active in combustion stabilising mode, a small amount of
liquid fuel is injected by the main fuel injectors, boosting the turbocharger to pro
-
vide sufficient combustion air, maintaining the intended air-gas mixture
(lambda).
NOTE
At any time, the gas operation can be stopped immediately by initiating
a gas trip.
NOTE
While DCC is active the engine remains Tier III compliant.
SM-0183
Engine power [%]
Total fuel
[power %]
Gas
100
50
0
0
50
100
Pilot fuel
(enlarged for visibility reasons, not scaled)
