Prospect of reduced CO and NOx emissions in diesel dual fuel engines
ASME 2003 Internal Combustion Engine and Rail Transportation Divisions Fall Technical Conference, ICERT2003
A numerical analysis of homogeneous natural gas/diesel/air mixture, that could be formed when small amounts of diesel pilot are used in a diesel dual fuel engine or when using natural gas/diesel dual fuel homogeneous charge compression ignition combustion, was studied to provide insight on future experimental investigations to be conducted by the institution. Use was made of Curran's normal-heptane mechanism in CHEMKIN to deduce its effects on lean fuel/air mixtures with respect to ignition timing and carbon monoxide (CO) and oxides of nitrogen (NOx) emissions. For the cases considered, increase in the amount of n-heptane addition resulted in advanced ignition closer to TDC thereby increasing peak cylinder pressure and gross IMEP. Increase in the amount of n-heptane addition also resulted in early decomposition of the fuel consequently advancing the production of OH radicals that oxidised the CO. For the same fuel/air mixture strength, increase in the amount of n-heptane addition increased NOx production due to increased peak temperature, residence time and availability of O2. When using leaner mixtures and small amounts of n-heptane to promote/advance ignition, however, peak cylinder temperatures were reduced and hence comparatively reducing engine-out NOx emissions. Copyright © 2003 by ASME.
Mulenga, Mwila C.; Reader, Graham T.; Ting, David S.K.; and Zheng, Ming. (2003). Prospect of reduced CO and NOx emissions in diesel dual fuel engines. ASME 2003 Internal Combustion Engine and Rail Transportation Divisions Fall Technical Conference, ICERT2003, 303-311.