MAN B&W 2.04
Page 9 of
MAN Diesel
MAN B&W ME/ME-C/ME-GI engines
198 38 97-3.6
Example 4:
Special running conditions. Engine coupled to xed pitch propeller (FPP) and with shaft generator
M Specied MCR of engine
S Continuous service rating of engine
O Matching point of engine
A Reference point of load diagram
MP Specied MCR for propulsion
SP Continuous service rating of propulsion
SG Shaft generator
Point A of load diagram is found:
Line Propeller curve through matching point (O)
or point S
Point A Intersection between line and line L
– L
3
Point M Located on constant power line 7
through point A and with MP’s speed.
Example 4. Layout diagram for special running conditions,
engine with FPP and with shaft generator
Example 4. Load diagram for special running conditions,
engine with FPP and with shaft generator
178 55 85-0.1
Also for this special case in example 4, a shaft
generator is installed but, compared to example 3,
this case has a specied MCR for propulsion, MP,
placed at the top of the layout diagram.
This involves that the intended specied MCR of
the engine M’ will be placed outside the top of the
layout diagram.
One solution could be to choose a larger diesel
engine with an extra cylinder, but another and
cheaper solution is to reduce the electrical power
production of the shaft generator when running in
the upper propulsion power range.
In choosing the latter solution, the required speci-
ed MCR power can be reduced from point M’ to
point M as shown. Therefore, when running in the
upper propulsion power range, a diesel generator
has to take over all or part of the electrical power
production.
However, such a situation will seldom occur, as
ships are rather infrequently running in the upper
propulsion power range.
Point A, having the highest possible power, is then
found at the intersection of line L
– L
3
with line
and the corresponding load diagram is drawn.
Point M is found on line 7 at MP’s speed.
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