Abstract: Increasing industrialization and motorization led to a significant rise in demand for petroleum products. As these are the non renewable resources, it is difficult to predict the availability of these resources in the future resulting in uncertainty in its supply and price and impacting growing economies like India, importing 80% of the total demand of the petroleum products. Many attempts have been made by different researchers to find out alternate fuels for Internal Combustion engines. Many alternate fuels like Biodiesel, LPG (Liquefied Petroleum Gas), CNG (Compressed Natural Gas) and Alcohols are being used nowadays by different vehicles. In this context pyrolysis of scrap tyres can be used effectively to produce oil, thereby solving the problem of waste tyre disposal. In the present study Experimental investigations were carried out to evaluate the performance and emission characteristics of a single cylinder diesel engine fuelled by TPO10, TPO15, and TPO20 keeping the blend quality by controlling density and viscosity of tyre pyrolysis oil within permissible limit of euro IV diesel requirement to study its replace ability. The investigation involves three parameters such as blend proportion, injection timing and injection pressure, a simultaneous optimization method called Taguchi was used in this work. This method requires fewer numbers of trials for fixing optimum levels. As per this method nine experiments were required to be conducted and the results were used for optimization. This is the primary advantage as well as disadvantage of this method. In order to eliminate this difficulty and improve the quality of the research work, twenty-seven experiments were conducted in this work and the results were used for optimization. In addition, an ANOVA was also performed for the parameters to evaluate its percentage contribution over the desired output. Using the optimum levels, a full range experiment was conducted to compare its performance and emission behaviour with standard diesel operation. Keywords: Operating parameters, Diesel Engine, Tyre Pyrolysis Oil (TPO), Performance, Emission