Combustion and emission characteristics of diesel engine fueled with biodiesel/PODE blends

Abstract

Polyoxymethylene Dimethyl Ethers (PODE), with excellent volatility and oxygen content of up to 49%, have great potential to improve engine performance and emission characteristics, especially for soot reduction. In this study, experiments were carried out in a single-cylinder engine fueled with diesel, biodiesel and BP15 (15% PODE and 85% biodiesel by volume). The effects of CA50 and EGR rates on the combustion and emission characteristics have been carefully examined. As CA50 was retarded, diesel always had the shortest ignition delay and longest combustion duration, while BP15 had similar ignition delay, but shorter combustion duration in contrast to biodiesel. As EGR rate varied from 20% to 40%, diesel still presented the shortest ignition delay and longest combustion duration, while BP15 had shorter ignition delay and combustion duration than biodiesel. Regarding to the emissions, BP15 showed the lowest soot emissions and can break the trade-off between NOx and soot emissions. Notably, emissions of NOx and soot can reach 0.05g/kWh and 0.0009g/kWh, respectively. In addition, BP15 had the highest thermal efficiency over the test conditions.