The present study details the enhancement in combustion, performance, and emission characteristics of SB fueled diesel engine by using water emulsion (10% and 20%) and CNT nanoparticle (100 ppm). The biodiesel was prepared from soybean crude oil by trans-esterification process, and the fuel properties were measured. Experiments were performed in a single cylinder, four-stroke, and natural aspirated stationary diesel engine under varying BMEP conditions. The measured fuel properties of SB, 10WSB, and 100CNT10WSB are at par with standard limits, whereas 20WSB and 100CNT20WSB viscosity values are not par with standard limits. Studies in the engine revealed that the combustion starts later for water/biodiesel blends, and ICP, NHR, and RPR are higher compared to pure SB. The nanoparticle inclusion with emulsion fuels reduces the peak ICP and NHR values. Emulsion fuels show a good improvement in BSFC, BSEC, and EGT when compared to pure SB, and the nanoparticle inclusion further improves the performance parameters. The emission characteristics of test fuels show that the water/biodiesel blends have a lower magnitude of NOx and smoke emissions, and 10WSB shows better HC and CO emissions when compared to SB and 20WSB. An inclusion of CNT nanoparticle further reduces the emissions level. (c) 2019 Elsevier Ltd. All rights reserved.