Investigation of EGR With EGB (Exhaust Gas Bypass) on Low Speed Marine Diesel Engine Performance and Emission Characteristics

Abstract

In 2016, the International Maritime Organization (IMO) has enforced stricter nitrogen oxide (NOx) emission standards. Exhaust gas recirculation (EGR) technology is an effective way to achieve IMO Tier III standards for two-stroke marine diesel engines. This paper selected the 6S50ME-C8.2 diesel engine for research, by making use of GT-POWER simulation software. In this paper, three different types of EGR systems were built to investigate the effects of EGR on engine performance and NOx emissions. The results show that both the high pressure EGR system and the low pressure EGR system can reduce NOx emissions with the power drop and BSFC risen. While in the high pressure EGR system combined with CB (cylinder bypass) and EGB (exhaust gas bypass), more NOx emissions can be reduced with less power drop and BSFC risen. What is more, the running points of the compressor are still in the efficient areas and away the surge margin. Based on the conclusions, the results obtained in this paper can provide reference for turbocharged diesel engines with EGR systems to reduce NOx emissions and improve engine performance.