Evaluation of Exhaust Gas Recirculation and Fuel Injection Strategies for Emission Performance in Marine Two-Stroke Engine.

Abstract IMO issued latest environmental regulations Tier Ⅲ has strengthened the emission standards, in which the NOx emission should be less than 3.4g/(kWh) for marine two-stroke engines (engine speed lower than 130r/min) in NOx ECAs. In order to meet the strengthened emission regulations, EGR and fuel injection strategies have been used in marine two-stroke engines to reduce emissions. In this paper, a full cycle computation fluid dynamics (CFD) simulation model has been established in GT-Power software to study the effects of EGR rate, post-injection and pilot-injection on emissions and overall performance of a low speed two-stroke marine engine. By changing the EGR rates and the degree and mass of the post-injection and pilot-injection, an optimal combination among different fuel injection strategies and EGR rates is proposed in this paper. The results indicate that the degree and mass of injection strategies with EGR play an important role in NOx and soot emissions. The trade-off relationship between NOx and soot is improved by changing the fuel injection strategies with different EGR rates. [ABSTRACT FROM AUTHOR]