Reduction of NOx and Particulate Emissions by Using Oxygen-Enriched Combustion Air in a Locomotive Diesel Engine

Abstract

This paper discusses operational and emissions results obtained with a locomotive (two-cylinder, EMD 567B) research diesel engine when oxygen-enriched combustion air is used. An operating regime was identified in which particulates and NOx could be reduced simultaneously when the concentration of intake air oxygen, fueling rate, and injection timing were optimized. Using oxygen from an external source, particulates were reduced by approximately 60% and NOx emissions were reduced by 15–20% with the optimal operating strategy. Higher gross power, lower peak cylinder pressures, and lower brake-specific fuel consumption were also observed. Gross power was increased by about 15–20% at base peak combustion pressure, and gross brake-specific fuel consumption was decreased by 2–10% with load. The effect of achieving oxygen enrichment by means of an air separation membrane is beyond the scope of the current study.