Marine Installation Manual
2021-08
2-8
2 Engine Power and Speed
2.5 Power range limits
X72DF
Table 2
-
1
Line 5 coefficients
Formula 2
-
5
where:
P
............... = selected engine power [kW]
P
CMCR
....... = CMCR engine power [kW]
n
............... = selected engine speed [rpm]
n
CMCR
....... = CMCR engine speed [rpm]
C
2/
C
1/
C
0 .. = coefficients/constants
The area formed by Lines 1, 3, 5 and 9 is the range within which the engine
should be operated.
The area limited by Line 7, Line 9 and Line 3 is recommended for continuous op
-
eration.
The area between Line 7 and Line 5 is reserved for acceleration, shallow water
and normal operational flexibility. If a PTO is installed, then the operating char
-
acteristics of the engine will differ (see section
for further details re
-
garding PTO characteristics).
Overload Power Range
Line 6, Line 2 and Line 13 form the curve for the engine’s overload power limit,
as defined by
. Each component is governed by different coefficients
(see
).
Table 2
-
2
Line 6 coefficients
Line no.
Range (
n/n
CMCR
)
C2
C1
C0
Line 5
0.00 - 0.40
0.000
0.500
0.000
0.40 - 0.60
0.500
0.300
0.000
0.60 - 0.96
1.111
-0.067
0.000
Line 1
0.96 - 1.00
0.000
1.000
0.000
Line 9
1.00 - 1.08
0.000
0.000
1.000
2
2
1
0
CMCR
CMCR
CMCR
P
n
n
C
C
C
P
n
n
æ
ö
æ
ö
÷
÷
ç
ç
÷
÷
ç
ç
=
+
+
÷
÷
ç
ç
÷
÷
÷
÷
ç
ç
è
ø
è
ø
Line no.
Range (
n/n
CMCR
)
C2
C1
C0
Line 6
0.00 - 0.40
0.000
0.600
0.000
0.40 - 0.60
0.330
0.468
0.000
0.60 - 0.96
1.110
0.000
0.000
Line 2
0.96 - 1.032
0.000
1.066
0.000
Line 13
1.032 - 1.08
0.000
0.000
1.100
