Influence of Treated Waste Engine Oil into diesel ethanol blends on the Performance in Compression Ignition Engine - An Experimental Study B.Prabakarana P.Vijayabalanb a,b School of Mechanical Sciences, Hindustan Institute of Technology and Science, Chennai Tamil Nadu India Diesohol blends (diesel and ethanol) can be utilized as fuel for CI engine up to 15% of ethanol (E15) content to reduce the consumption of diesel a fossil fuel. This work is to investigate the effects of addition of treated wasted engine oil (TWEO) as property improver to enhance the properties of diesohol and study the characteristics of the blend in CI engine. Waste engine oils are not utilized as of now and this spoils the land as well as the groundwater by contamination. To utilize waste engine oil to a certain extent, waste engine oil was taken as property enhancer in this work. Waste engine oil is treated in a novel method of treatment having four steps. The steps were Initial filtration, acid treatment with acetic acid, clay contraction using fuller`s earth and neutralization cum decolorization. The treated oil was blended with E15 in various proportions. The blends were tested for essential properties as per ASTM standards. The addition of TWEO to E15 enhanced the energy content, kinematic viscosity, density and cetane number. Properties of an Optimal blend of E15 and TWEO OF 10% were found closer to the properties of diesel was taken for analysis of performance in a diesel engine. At full load condition, the performance parameters were found better than diesel and the emissions produced by the blends were found better compared to diesel. This enhanced the opportunity for the utilization of ethanol and waste engine oil to prevent the emissions and pollution of the environment to a certain extent.