An experimental study of engine combustion, performance and emission characteristics using diesel-ethanol blends along with investigation of tribological effects of ethanol on engine oil was done in present work using 1-butanol as emulsifier. Thorough observations of diesel ethanol miscibility resulted that 25% v/v ethanol is miscible with diesel using only 3% v/v emulsifier. Tribological effects of ethanol on engine oil were investigated by analyzing the engine oil samples through FT-IR (Fourier Transform Infrared Spectroscopy). Overall experimentation re-evaluated the potential of ethanol in reduction of NOx, Soot and in-cylinder temperature with slight penalty for HC, CO and BSEC prominently at low load. All fuels produced more NO but lesser NO2 at higher load satisfying Zeldovich mechanism. A comparative trade-off analysis was done in between NHC, Soot and BSEC to reflect the performance and emission characteristics at a time. Trade-off study revealed D78E20B02 (78% diesel 20% ethanol 2% butanol) as optimal blend among all fuels used in present work. FT-IR analysis depicted negligible variation in the compounds in engine oil samples for the specified operational period. Statistical analysis showed larger Coefficient of variation for D78E20B02 blend due to higher absorbance of a particular compound. (C) 2015 Elsevier Ltd. All rights reserved.