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Inventories of emissions of GHGs and other relevant substances 109
Figure 72: Impact of engine control tuning (ECT) to specific fuel oil consumption during low load operation
of MAN 6S80ME-C8.2. Standard tuning is shown by the solid black line, part load optimization by the solid
blue line and low load tuning by the broken line (from MAN, 2012)
The changes in specific fuel oil consumption (SFOC) for a specified maximum continuous rating (SMCR) of a
large two-stroke engine are illustrated in Figure 72. It is possible to achieve a lower optimum load range for the
purpose of slow steaming, but this will make the engine less efficient in the high load range.
SFOC assumptions used in this study for marine diesel engines
Engines are classified as SSD, MSD and HSD and assigned SFOC or BSFC in accordance with the Second
IMO GHG Study 2009.
Table 49 – Specific fuel oil consumption of marine diesel engines (ll values in g/kWh)
Engine age SSD MSD HSD
before 1983 205 215 225
1984–2000 185 195 205
post 2001 175 185 195
Table 49 gives the values used in this study. Main engines are typically SSD and MSD while auxiliary engines
are typically MSD and HSD. The SFOC data for turbine machinery, boilers and auxiliary engines are listed in
Table 50.