MAN B&W S65ME-C8.2-GI-TII, Project Manual

Page: 49 / 395

MAN B&W 2.08
Page 2 of 2
MAN Diesel MAN B&W ME-GI TII .2 engines 198 86 34-1.0
Examples of Graphic Calculation of related SFOC for -GI engines
The following diagrams a (a1, a2 and a3), b (b1
and b2) and c (c1 and c2), valid for fixed pitch
propeller (b) and constant speed (c), respectively,
show the reduction of related SFOC in g/kWh,
relative to the SFOC of fuel oil operated engine for
the nominal MCR L
1
rating.
Mep influence
The solid mep lines in b1 and c1 show the SFOC
reduction, and are valid at 100%, 70% and 50%
of SMCR point (M), and refer to derated engines
operation on fuel oil.
Point M is drawn into the abovementioned Dia-
grams b1 or c1. A straight line along the constant
mep curves (parallel to L
1
L
3
) is drawn through
point M. The intersections of this line and the
curves indicate the reduction in specific fuel oil
consumption at 100, 70 and 50% of the SMCR
point, related to the SFOC stated for the nominal
MCR L
1
rating, when operating on fuel oil.
Rpm influence
The straight vertical lines in b2 and c2 along the
engine speed (rpm) lines show the extra SFOC re-
ductions, and are valid at 100%/90%/80%, 75%,
65% and 50%/35% of SMCR point (M), and refer
to -GI engines operating on LNG.
Point M is already drawn into the above men-
tioned diagram b2 or c2. A straight vertical line
along the constant rpm curves (parallel to L
1
-L
2
is drawn through point M. The intersections of
this line and the curves indicate the extra SFOC
reduction at 100%/90%/80%, 75%, 65% and
50%/35% of SMCR, for -GI engines operating on
LNG, compared to the SFOC valid for engine op-
erating on fuel oil.
An example of the calculated SFOC curves
are shown in Diagram a (a1, a2 and a3), and is
valid for an engine with fixed pitch propeller, see
Fig. 2.10.01.