Experimental Investigations on Performance, Combustion, and Emission Characteristics of Niger (Guizotia abyssinica) Seed Oil Methyl Ester Blends with Diesel at Different Compression Ratios

In this study, the fuel performance, combustion, and emission characteristics were tested on four-stroke, multi-fuel variable compression research engine with different blends of Niger seed oil methyl ester (NSOME). Experiments were carried out at four test fuels of standard diesel, B10, B20, and B40 and at three different compression ratios (CRs) of 16, 17.5, and 18.5. Experimental results of the study revealed that the NSOME has alike characteristics of standard diesel oil. The brake thermal efficiency (BTE) of blend B20 was found to be nearer to standard diesel and decreased for blends B10 and B40. Brake-specific fuel consumption (BSFC) of the NSOME blends increased compared to standard diesel. Further, cylinder pressure and net heat release rate of NSOME blends increased significantly with blend ratio and B20 showed higher value as compared with standard diesel fuel. A notable reduction in CO, UHC, and smoke emissions was observed with all three blends of NSOME with an increase in NOx emissions. The same trend was continued for all three compression ratios. Among all three blends of NSOME, B20 has shown better results concerning performance, combustion, and emissions at CR 18.5. At CR 18.5, the BSFC, CP, NHRR, and NOx emissions of B20 were increased by 1.45%, 1.75%, 5.62%, and 10.76%, while BTE, CO, UHC, and smoke opacity were decreased by 1.65%, 58.40%, 38.93%, and 5.09%, respectively, at full load (12kgf).