Marine Installation Manual
2021-08
7-1
7 Engine Emissions
7.1 Exhaust gas emissions
X72DF
7
Engine Emissions
In 1973 an agreement on the International Convention for the Prevention of Pol
-
lution from Ships was reached. It was modified in 1978 and is now known as
MARPOL 73/78.
Annex VI to MARPOL 73/78, entered into force in 2005, contains regulations
limiting or prohibiting certain types of emissions from ships, including limita
-
tions with respect to air pollution. Following the entry into force of the annex, a
review process was started, resulting in an amended Annex IV, which was
adopted by the International Maritime Organization (IMO) in October 2008 and
entered into force in July 2010.
This amended Annex IV includes provisions for the further development of emis
-
sions regulations until 2020.
7.1
Exhaust gas emissions
7.1.1
Regulation regarding NO
x
emissions
Regulation 13 of Annex IV specifies a limit for the nitrogen oxides (NO
x
) emis
-
sions of engines installed on ships, which has a direct implication on the design
of propulsion engines.
Depending on the rated speed of the engine and the date of keel-laying of the
vessel, the weighted average NO
x
emission of that engine must not exceed the
maximum allowable value as indicated by the respective curves in the following
diagram.
Figure 7
-
1 Speed dependent maximum allowable average of NO
x
emissions
NO
x
Technical Code
The rules and procedures for demonstrating and verifying compliance with this
regulation are laid down in the NO
x
Technical Code, which is part of Annex VI
and is largely based on the latest revision of ISO 8178.
SM-0084
0
0
2
4
6
8
10
12
14
16
18
20
200
A
B
C
400
600
800
1000
1200
1400
1600
1800
2000
Engine speed [rpm]
NO
X
emission [g/kWh]
A
B
C
Tier I: 1
st
January 2000 global
Tier II: 1
st
January 2011 global. After 2016 outside emission control areas
Tier III: 2016 in emission control areas
