The purpose of this study was to analyze the exhaust emissions of DME fuel through experimental and numerical analyses of in-cylinder spray behavior. To investigate this behavior, spray characteristics such as the spray tip penetration, spray cone angle, and spray targeting point were studied in a re-entrant cylinder shape under real combustion chamber conditions. The combustion performance and exhaust emissions of the DME-fueled diesel engine were calculated using KIVA-3V. The numerical results were validated with experimental results from a DME direct injection compression ignition engine with a single cylinder. The combustion pressure and IMEP have their peak values at an injection timing of around BTDC 30 degrees, and the peak combustion temperature, exhaust emissions (soot, NOx), and ISFC had a lower value. The HC and CO emissions from DME fuel showed lower values and distributions in the range from BTDC 25 degrees to BTDC 10 degrees at which a major part of the injected DME spray was distributed into the piston bowl area. When the injection timing advanced to before BTDC 30 degrees, the HC and CO emissions showed a rapid increase. When the equivalence ratio increased, the combustion pressure and peak combustion temperature decreased, and the peak IMEP was retarded from BTDC 25 degrees to BTDC 20 degrees. In addition, NOx emissions were largely decreased by the low combustion temperature, but the soot emissions increased slightly. (C) 2009 Elsevier B.V. All rights reserved.