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Diesel engine manufacturers have succeeded in developing engines with high power concentration and thermal efficiency without disregarding to comply with the continuous stringent emission regulations. Nowadays, several techniques such as injection control strategies, EGR and exhaust after treatment devices have been used to reduce diesel emissions. However, emission control alternatives are often accompanied by fuel consumption or cost penalties and also, the request for improving the pollutant emissions behavior of the existing diesel vehicle fleet has become mandatory. Thus, research scientists and engineers have focused also on the area of fuel composition for the reduction of pollutant emissions. Of major importance seems to be the use of oxygenated additives to reduce particulate emissions. According to recent studies, soot emissions are decreased following the increase of oxygen percentage.

In the present work a multi-zone combustion model, initially developed for naturally aspirated, high-speed, direct injection diesel engines, is used for studying the performance and emission characteristics of large scale, slow-speed marine diesel engines. Up to now pollutant emissions was not considered a problem in the field of marine engines, since no specific legislation existed. However, the International Maritime Organization (IMO) is forwarding a legislation that will be applicable in the next years concerning soot and nitric oxide (NO) emissions. This legislation will make it impossible for vessels to enter the native waters into countries where this legislation applies. Due to this fact, engine manufacturers are making serious efforts to design new engine builds with reduced soot and nitric oxide emissions using new designs and exhaust gas aftertreatment systems.