The consumption of crude oil has seen an increase of more than 40% worldwide in past few decades. In India, about 72% of crude oil is imported for fulfilment of requirements in coming years. The sources for crude oil are also limited and are bound to get depleted very soon. Apart from the shortage of fuel resources, emissions resulting from burning of fossil fuels in the engine is also a big problem. The gases emitted from the engine are very hazardous to human beings as well as animals. In the current global scenario,, it is necessary to find new fuels which are renewable and can be developed easily. A new alcohol-based fuel n- butanol, which is completely renewable, and which is made from lingo-cellulose, is used for the testing of a spark ignition engine.
In this paper, engine performance and emission parameters of single cylinder 4-stroke SI engine have been experimentally studied at various compression ratios (CRs) for petrol and petrol/n-butanol blends in a broad range of applied load without any tuning and modification of the engine. The performance
parameters such as brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) have been evaluated for petrol and blends of petrol/n-butanol such as B0 (100% petrol), B5 (95% petrol + 5% n-butanol by volume), B10, B15, B20 and B25 at compression ratios of 4.67:1, 6:1 and 8:1. Similarly emission parameters for CO, CO2 , HC and NOx have also been evaluated and analysed. Results of study show that, the BTE increases and BSFC reduces when blend of n-butanol is used, as a result of proper fuel combustion and higher oxygen content. As the compression ratio increased, the BTE also increased by 18.63% and by adding 25% n-butanol, it increased by 23.24%. The emissions of Carbon monoxide (CO), Carbon dioxide (CO2), Hydro Carbons (HC) and Nitrogen oxides (NOx ) were also found reduced by 92.18%, 23%, 38.14% and 18.29% respectively with the fuel B25 at a CR of 6:1 as compared with those of petrol at original CR.
SI engine, compression ratio, n-butanol, performance and emission characteristics