Marine Diesel Engines - Decreasing Fuel Consumption and Exhaust Gas Emissions in Transportation - page 154

Chapter 11
Marine Diesel Engines
Marine diesel engines are very similar to the self-ignition engines in heavy-duty
vehicles, but they are generally larger, more complex, and operate with higher
efficiency. About 75% of all marine diesel engines are four-stroke engines; how-
ever, 75% of the installed power is produced by two-stroke engines. Four-stroke
marine diesel engines are gaining importance not only in inland, but also in marine
shipping, primarily in smaller container and bulk carrier ships. Fuel consumption
and exhaust gas emissions of ship engines depend not only on the principle of
operation, but also on the type, the size, the power, the load, the speed, etc. [ 1 ].
On the one side, fuel saving and exhaust gas after treatment technology in ship-
ping will gain more importance in the next years because fleet management will
focus on fuel and exhaust gas emission saving. On the other side, fuel saving is
directly combined with environment and climate protection. Higher costs of fuel
intensively support developing fuel saving technologies. Fuel saving also contributes
to innovations in climate protection technology and to development in legislation [ 2 ].
11.1 Fuel Consumption in Marine Diesel Engines
Modern marine diesel engines with direct injection have a maximum brake effi-
ciency of 40-43%. Further improvement of the direct injection technology is
possible. Although improvements will continuously go on, they will be carried out
in small steps.
Retrofitting older engines has often high costs, particularly in larger ships. This
is one of the reasons why quality of retrofitting measures must always have a high
level. The attempts to improve engines include:
• Controlling and reducing the friction of the main and auxiliary parts with
lubrication;