The Use of Exhaust Gas Recirculation for Ensuring the Environmental Performance of Marine Diesel Engines

The article deals with the operational features of internal combustion engines of marine vessels during their operation in special environmental areas -Nitrogen Oxide Emission Control Areas. According to the requirements of Annex VI MARPOL, during the operation of marine diesel engines in these areas the content of nitrogen oxides in the exhaust gases should be less than 3.4 g/(kWh). The article touches upon the possible technical measures to ensure the maintenance of the required level of nitrogen oxide emissions in the exhaust gases of marine diesel engines. The authors propose to use an exhaust gas recirculation system, with a certain amount of gases supplied back to the cylinder after preliminary cooling and mixing with air, which reduces the maximum combustion temperature to values that prevent the formation of nitrogen oxides. The experiment proved that the recirculation of exhaust gases in the 4.7 ... 18.8% range helps to reduce the concentration of nitrogen oxides in exhaust gases by 19.5 ... 48.8%. At the same time, it is necessary to ensure values that meet the requirements of international organizations aimed at protecting the air from pollution and allowing the use of marine vessels in areas of increased environmental control.