Experimental studies on variable compression ratio engine fuelled with cottonseed oil methyl ester biodiesel

This research work investigates the effects of compression ratio on engine performances, combustion characteristics and emission of exhaust gases of variable compression ratio engine fuelled with biodiesel. The cottonseed oil methyl ester is blended with standard diesel and used as fuel in the variable compression ratio single cylinder four stroke multi fuel engine at 1,440 rpm of 80% load with different compression ratios i.e., 18:1, 19:1, 20:1, 21:1 and 22:1. The analyses of engine performances, combustion characteristics and emission of exhaust gases were carried out for different proportions of cottonseed oil methyl ester blends (b15%, b30%, b45%, b60%, b75%, b90% and b100%). The investigation reveals that at higher compression ratios, heat release rate, combustion pressure and brake thermal efficiency is higher. The investigation also reveals that the brake power and mechanical efficiency are found to have increased with increase in compression ratios. It is also found that the higher blend proportions with standard diesel reduce the emission of HC and CO2 but increase the emission of NOX.