Biodiesel and ethanol can be blended with diesel fuel at various ratios, resulting in what is called diesohol, and can exhibit distinct behaviors. In some cases, nanoparticles can mix with fuels to improve their performance and emission characteristics. In this study, the carbon nanotubes were combined with the diesohol fuel (Ethanol + diesel) and B2 to evaluate the performance of a CI single-cylinder engine. Carbon nanotubes with concentrations of 20, 60, and 100 ppm were used for D100, B2, B2E2, B2E4, and B2E6 fuel blends. Measured characteristics were torque, power, brake thermal efficiency (BTE), specific fuel consumption (SFC), exhaust gas temperature, and exhaust gases of CO, CO2, UHC, NO, O-2, and smoke. The engine was run under full load at three speed levels of 1700, 2300, and 2900 rpm. The results for B2E4C60 fuel showed that the torque, power, and BTE were increased by 15.52%, 15.52%, and 13.97% respectively, compared to pure diesel fuel. Additionally, the specific fuel consumption and engine exhaust gas temperature were reduced by 11.73% and 1.86%, respectively. The CO, UHC, and soot emissions were decreased by 5.47%, 31.72%, and 6.96% respectively. However, the NO emission was increased by 12.22%, and a high correlation was observed between CO-NO and CO2-O-2 contents. (C) 2017 Elsevier Ltd. All rights reserved.