Performance analysis of a VCR SI engine using petrol alcohol blends

Due to the sharp rise in population and industrial and technological growth there has been a rapid rise in the need for fossil fuels like petrol. Hence there is a need to develop alternate fuels. One such alternate fuel can be petrol alcohol blends. These fuels will not only meet the fuel requirements of today and future but also increase the performance of IC engine and reduce emissions. In this study, the performance of a variable compression ratio S.I. engine has been analyzed. The engine used is a four stroke VCR(Variable compression ratio) engine with electrical loading and air cooling. No modifications on the engine and its parts have been made. The blends tested in this study are butanol and ethanol with proportions 10, 20, 30 and 40 percent in petrol. The Brake Thermal Efficiency and Brake Specific Fuel Consumption (BSFC) has been found out and are compared for the above mentioned blends for different compression ratios and loads. It has been observed that the Brake Thermal Efficiency increases and the BSFC decreases. Moreover no major problems like knocking were encountered during the engine operation. Results show that engine runs smoothly up to 40 percent blends in each case without modification to the engine and parts. The maximum efficiency was found at 40 percent blend.