The objective of this investigation was to improve the performance of a diesel engine by adding oxygenated fuel additives of known percentages. The fuel additives di-methoxy-methane (DMM) and di-methoxy-propane (DMP) were separately blended with diesel fuel in proportions of 1 ml, 3 ml and 5 ml. The experimental study was carried out on a single cylinder DI diesel engine. The result showed an appreciable reduction of emissions such as smoke density, particulate matter and marginal increase in the performance when compared with normal diesel run. The same engine was employed with diesel particulate trap (DPT) in the exhaust pipe to study its influence on the emission analysis. (C) 2007 Elsevier Ltd. All rights reserved.