In this investigation, CB (Carbon black) was doped with diesel by following certain sequential processes and the mixture was commonly referred to as Carbodiesel. The mixture containing 5% CB was denoted as Carbodiesel5. Similarly, 10%, 15% and 20% CB in Carbodiesel were denoted as Carbodiesel10, Carbodiesel15 and Carbodiesel20 respectively. All the four Carbodiesels were used as alternative fuels in a single cylinder, four stroke, air cooled, DI (direct injection) diesel engine. The engine behaviour in terms of combustion, performance and emissions of the engine fuelled with the four Carbodiesels was evaluated and compared with those of diesel operation. The results indicated that Carbodiesel10 gave better performance and lower emissions compared to those of Carbodiesel15 and Carbodiesel20 at full load. The nitric oxide (NO) emission for Carbodiesel10 was found to be lower by about 6.2% than that of diesel at full load, while the smoke density was found to be higher by about 11.5% than that of diesel at full load. The engine can run on Carbodiesels without any major engine modification. (C) 2015 Elsevier Ltd. All rights reserved.