Determination of the sustainability index along with energy–exergy–emission–economic analysis of a VCR diesel engine fuelled with diesel–bioethanol–Al2O3 nanoparticles

Abstract

One of the biofuels made from waste rice straw was mixed with diesel in different percentages [e-diesel (R10, R15, R20)] and diesel–bioethanol blends with 25 ppm Al₂O₃ nanoparticles [nanofuel (NF0, NF10, NF15, NF20)] were tested in a VCR CI engine under varying load intensities (0 kg-no load, 10 kg-full load) and at different compression ratios (CR: 14 and 18). Brake thermal efficiency in energy efficiency, exergy efficiency, brake specific fuel consumption (BSFC), heat release rate (HRR), peak cylinder pressure, and the emission of CO, HC, and NO_x are the output parameters of the current investigation. The cost of e-diesel and nanofuel was then predicted using economic analysis to compare them with regular diesel fuel. Except for BSFC, it was seen that other parameters rise when the load changes from zero to full. Similar to this, all metrics, except BSFC, CO, and HC emissions, increase when the CR is increased from 14 to 18 and drop as the fuel type is changed from diesel to e-diesel and nanofuel. For the maximum load and CR condition, the NF0 exhibits maximum energy efficiency of 30.42%, maximum exergy efficiency of 63.5%, an HRR of 61 J per degree, peak cylinder pressure of 84 bar, relative cost of −10.215%, and minimum BSFC of 0.463 kg kW⁻¹ h⁻¹, whereas the NF15 and F0 exhibit minimum emission of CO of 0.157%, HC of 43 ppm, and NO_x of 422 ppm. NF0 attains a higher sustainability index of 1.817 compared to other fuels due to a lower depletion rate, followed by NF10, F0, and NF15 of 1.803, 1.781, and 1.772, respectively. A higher waste energy ratio is observed for R20 of 0.751, followed by R15, NF20, and NF15 of 0.727, 0.704, and 0.651, respectively.