In the paper, combustion and emissions of a multi-cylinder Cl (compression-ignition) engine fueled with DMF-diesel, n-butanol-diesel and gasoline-diesel blends were experimentally investigated, and fuel characteristics of DMF, n-butanol and gasoline were compared. Diesel was used as the base fuel. And 30% of DMF, n-butanol and gasoline were blended with the base fuel by volume respectively, referred to as D30, B30 and G30. Results show that compared to B30 and G30, D30 has longer ignition delay because of lower cetane number, which leads to faster burning rate and higher pressure rise rate. With increasing EGR (exhaust gas recirculation) rate, D30 gets the lowest soot emissions, and extended ignition delay and fuel oxygen are two key factors reducing soot emissions, and ignition delay has greater effects than fuel oxygen on soot reduction. In addition, D30 and B30 improve the trade-off of NOx-soot remarkably and extend low-emission region without deteriorating fuel efficiency by utilizing medium EGR rates (<40%). As diesel additive, DMF is superior to n-butanol and gasoline for reducing soot emissions due to its prolonged ignition delay and atomic oxygen. Using DMF-diesel blends combined with medium EGR may be a better choice for diesel engine to meet future emissions regulations with high fuel efficiency. (c) 2013 Elsevier Ltd. All rights reserved.