Investigation of the effect of barium-based additive on smoke and NO_x emissions of a diesel engine fueled with conventional and biodiesel fuels

Abstract

Nowadays, increasing energy demand and environmental and air pollution issues have spread the use of alternative fuels such as biodiesel in diesel engines. While the advantages of biodiesel that are comparable to petroleum-based diesel fuels and low unburned HC, carbon monoxide and smoke (soot) emissions make the use of this fuel environmentally significant; high NO_x emissions are still a problem to be solved. The formation of decreased smoke reducing radiative heat transfer from combustion chamber in biodiesel engines and increase in formation of NO_x due to rise in flame temperature are among the reasons reported for high NO_x in the literature. In this study, in a diesel engine using biodiesel, soot emissions produced by petroleum diesel fuel were reduced to biodiesel level by using metallic additive (Ba), and NO_x emissions were compared. When the amount of Ba in the fuel was increased, there was a significant decrease in the smoke emissions, but in this case, NO_x emissions decreased slightly, while they were expected to increase. When NO_x emissions of diesel and biodiesel were compared for the same or similar smoke emissions, it was seen that high NO_x emissions were achieved with biodiesel. As a result, although Ba additive reduced smoke emissions, it was seen that its effect on NO_x formation was not very clear.

Graphic abstract