Experimental Studies of the Impact of CETANER™ on Diesel Combustion and Emissions

Oxygenated fuels have been used successfully as blending agents to improve combustion and reduce emissions from spark-ignition fuels. For compression-ignition engines, similar benefits may accrue from the use of oxygenated fuels and blending agents, however, the combustion and physical properties of the oxygenates appropriate for diesel applications are significantly different. In this study, a blend of 20% monoglyme and 80% diglyme, referred to as CETANER^™, has been examined as a reformulating agent in a single-cylinder IDI diesel engine and a 4-cylinder DI turbodiesel engine. Gaseous and particulate emissions measurements, as well as pressure trace analyses, have been used to examine how this additive affects diesel combustion and emissions. This blend of glycol ethers has both a high cetane number and a high oxygen content; its performance stems from both characteristics. Blend ratios were considered that provided approximately 2, 4 and 6 wt.% oxygen to a premium diesel fuel. The results demonstrate that the oxygenated fuel provides significant reduction in particulate matter emissions and mixed effects on NO_x, CO and HC emissions. Ignition delay was not significantly altered in the IDI engine, although only the main chamber pressure was monitored. The impact of this blend of glycol ethers is to provide greater than 5 wt.% particulate matter emissions reduction for each 1 wt.% oxygen addition, although the effectiveness of particulate mass reduction decreases with increasing oxygen addition and is affected by engine configuration.