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MAN B&W 6.04
Exhaust Gas Amount and Temperature
Influencing factors
The exhaust gas data to be expected in practice
depends, primarily, on the following three factors:
a) The specified MCR point of the engine (point M):
P M : power in kW at SMCR point
n M : speed in r/min at SMCR point
and to a certain degree on the matching point O
with the percentage power P O% = % of SMCR
power:
P O% = (P O /P M ) x 100%
Calculation Method
To enable the project engineer to estimate the actual
exhaust gas data at an arbitrary service rating,
the following method of calculation may be used.
M exh : exhaust gas amount in kg/h, to be found
T exh : exhaust gas temperature in °C, to be found
M = M x exh L1 P ___ M
PL1 x 1 + ∆m ______ M%
100 x 1 + ∆M _______ amb%
100 x 1 + ∆m _____ s%
100 x P ⎧ ⎫ ⎧
⎫ ⎧ ⎫
____ S%
⎨ ⎬ ⎨
⎬ ⎨ ⎬
⎩ ⎭ ⎩
⎭ ⎩ ⎭ 100
Fig. 6.04.06: Summar<strong>is</strong>ing equations for exhaust gas amounts and temperatures
The partial calculations based on the influencing
factors are described in the following:
a) Correction for choice of specified MCR point
When choosing a specified MCR point ‘M’ other
than the nominal MCR point ‘L 1 ’, the resulting
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b) The ambient conditions, and exhaust gas
back�pressure:
T air : actual ambient air temperature, in °C
p bar : actual barometric pressure, in mbar
T CW : actual scavenge air coolant temperature,
in °C
∆p M : exhaust gas back�pressure in mm WC at
specified MCR
c) The continuous service rating of the engine
(point S), valid for fixed pitch propeller or controllable
pitch propeller (constant engine speed):
P S : continuous service rating of engine, in kW
The partial calculations based on the above influencing
factors have been summar<strong>is</strong>ed in equations
[4] and [5].
kg/h +/�5% [4]
T exh = T L1 + ∆T M + ∆T O + ∆T amb + ∆T S °C �/+15 °C [5]
where, according to ‘L<strong>is</strong>t of capacities’, i.e. referring to ISO ambient conditions and 300 mm WC
back�pressure and specified/matched in L 1 :
M L1 : exhaust gas amount in kg/h at nominal MCR (L 1 )
T L1 : exhaust gas temperature after turbocharger in °C at nominal MCR (L 1 )
changes in specific exhaust gas amount and
temperature are found by using as input in diagrams
the corresponding percentage values (of
L 1 ) for specified MCR power P M% and speed n M% :
P M% = P M /P L1 x 100%
n M% = n M /n L1 x 100%
MAN B&W ME-B, ME/ME�C, ME�GI engines 198 43 18�1.2
MAN Diesel