Investigation of electronic controlled direct water injection for performance and emissions of a diesel engine running on sunflower oil methyl ester

摘要

Among alternative fuels with low emission profiles used in diesel engines, biodiesels are renewable, biodegradable and non-toxic, but cause higher NOx emission than diesel fuelled engines. In this study, direct water injection (DWI) with electronical control is used for reducing NOx emissions from a diesel engine running on sunflower oil methyl ester (SOME). DWI is applied during compression stroke through a separate water injector on cylinder head. Using 20% SOME blend (B20) as fuel the effects of water ratios, 40%, 60%, 80%, and 100% (W100), on performance, combustion and emissions are investigated. As water is injected directly into diesel engines running on B20 blend, slight decline in engine performance parameters compared to B20 blend. And, to distinguish the effect of DWI and B20 blend, standard engine data (diesel fuel) are presented in accompany. Besides, with direct water injection, a distinctive reduction (56%) in NOx emissions and increases in HC, CO, and smoke emissions are observed, compared to B20 blend results. It has been found that the ignition delay period is shortened using B20 blend, while prolonged in direct water injection case at the same operating conditions. Since it is possible to achieve a significant reduction in all direct water injection rates compared to standard NOx values, it would be optimal to keep the water spray rate around W80 for all engine parameters. As a result, utilizing direct water injection on diesel engines running on biodiesel blends has been found a useful tool to reduce NOx emissions.