Use of Gasoline as an alternative fuel in Gasoline engine is becoming a need, looking at the scarcity of petroleum fuels in near future. This paper investigates the use of mathematical model to find effects of using gasoline and ethanol blends on SI engine performance at various compression ratios. This is done by first making a mathematical model of the engine and testing it for various operating conditions. The aim of this paper is to develop a simple, fast and accurate engine simulation model without the need of complex computational power or knowledge of precise engine geometrical data. The effectiveness of this model is verified by conducting trials on the engine. A four stroke, single cylinder, Kirloskar made Variable Compression Ratio SI engine is used for conducting this study. In this study the effects of adding ethanol to the unleaded gasoline on engine performance have been investigated numerically. The ethanol gasoline blends have been obtained by adding ethanol to a gasoline in different ratios by volume. Several parameters like BP, IP, Break Thermal Efficiency, Indicated Thermal Efficiency Mechanical Efficiency, BSFC, were calculated.. The performance of the engine was evaluated with gasoline and with the said fuels at varying speeds and different compression ratios. After running this mathematical model, it was observed that this model gives fairly close results and can be used to evaluate the performance of the engine for various speed, compression ratios and different combinations of gasoline- ethanol fuel blends. Errors were also calculated and it was observed that these errors are in the range of -0.12 % to 7.63% for BSFC & BP respectively

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Mathematical Model Gasoline Ethanol Blend VCR Engine