In the present study, the results of an investigation on a Perkins A63544 direct injection diesel engine using water in diesel emulsion (2, 5, 8 and 10% water) was reported. For noise emission evaluation, 1600 to 1900 rpm engine speed in steps of 100 rpm were selected. No modification or change in engine components and systems was made. Two factors completely randomized design was used for statistical analysis of the effects of engine speeds and fuel blend. According to analysis of variance, engine speeds had statistically significant effects at 1% probability level (P < 0.01) on the mean values of the engine noise emission. The engine noise emission increased with the increase in engine speed. The presence of water in neat diesel fuel generally increased ignition delay and engine noise emission
