Man L27/38

5) Correction for exhaust gas back
pressure
Increased negative intake pressure before com-
pressor leads to increased fuel oil consumption,
calculated as increased air temperature before tur-
bocharger:
U = (-20 [mbar] – p
Air before compressor
[mbar] ) x 0.25 [K/
mbar] with U ≥ 0
Increased exhaust gas back pressure after turbine
leads to increased fuel oil consumption, calculated
as increased air temperature before turbocharger:
O = (p
Exhaust after turbine
[mbar] – 30 [mbar] ) x 0.25 [K/
mbar] with O ≥ 0
Charge air blow-off for exhaust gas temperature
control (ex. plants with catalyst) leads to increased
fuel oil consumption:
For every increase of the exhaust gas temperature
by 1° C, due to activation of charge air blow-off
device, an addition of 0.05 g/kWh to be considered.
6) Correction for MGO (+2 g/kWh)
When engine is running MGO the fuel consumption
can be increased by up to +2 g/kWh due to lower
energy content and longer injection duration.
SFOC can in some case also be reduced by inver-
ted fuel values of MGO.
MAN Diesel & Turbo
B1101 0
Calculation of specific fuel oil consumption (SFOC)
3700405-6.2
Page 4 (4)
V28/32S-DF, L28/32S-DF, L28/32DF, L23/30S-DF, L23/30DF, V28/32S, L28/32S,
L27/38S, L23/30S, L21/31S, L16/24S, L16/24, L21/31, L23/30H, L27/38, L28/32H