Effect of early injection strategy on spray atomization and emission reduction characteristics in bioethanol blended diesel fueled engine

This study is to investigate the emission reduction characteristics of bioethanol blended diesel fuel at early injection condition including spray, atomization and evaporation characteristics. The spray atomization and evaporation characteristics were investigated using spray visualization system and KIVA-3V code, respectively. In this work, the effect of ethanol blending on the spray behavior is more evident at early injection condition. In the calculation results, the droplet size of bioethanol blended fuel was smaller than that of diesel, and bioethanol blended diesel droplets firstly evaporated by its volatility and superior atomization characteristics. In early injection condition, the bioethanol blending caused an increase in indicated mean effective pressure with an extension of the ignition delay. The cooling effect of the bioethanol fuel reduced NOx. The HC emission increased and the CO emission decreased because of the ethanol blending. The geometry mean diameter and total number density increased as a result of ethanol blending, the particle number in the nuclei mode decreased, and the particle number in the accumulation mode increased in early injection condition.

► The overall spray, combustion and emission characteristics of bioethanol-blended diesel fuel are measured.
► Experimental results are compared in the early injection- and the conventional injection cases.
► Atomization and evaporation characteristics of diesel-bioethanol blended fuel were numerically analyzed using KIVA-3V.
► In the early injection cases, the cooling effect of bioethanol fuel is clearer compared to the conventional injection.
► By the early injection strategy with bioethanol blended diesel fuel, the exhaust emissions can be significantly reduced.