Modelling of NOx reduction from old generation diesel engine by nitrogen enriched air

Abstract

   This paper presents the study results of NOx reduction on diesel engines by providing nitrogen enriched air (NEA) to the engine. NEA is provided to the engine by a nitrogen injector which is placed on the intake manifold after the intercooler. The mass flow of nitrogen injected to intake air was controlled to archive the proportion of nitrogen in intake air greater than 77% by mass. The results show that NEA could decrease NOx emission at low and medium load conditions. The brake power of the engine could be enhanced slightly with the supplied ratio of nitrogen less than 80%. CO emission was decreased, and soot was constant. It can be concluded that using nitrogen-enriched air is a feasible solution for NOx
reduction while the effects on other exhaust pollutants and engine performance are eligible.