FUEL CHARACTERIZATION AND COMPATIBILITY ASSESSMENT OF BERGAMOT PEEL OIL–DIESEL BLENDS FOR CI ENGINE APPLICATIONS

Source abstract

The present study explores the feasibility of utilizing Bergamot Peel Oil (BPO) as a renewable alternative to conventional diesel fuel in a compression ignition engine. Before engine testing, the physicochemical properties of BPO were tested. FTIR analysis confirmed the presence of oxygenated functional groups such as esters and carbonyl compounds, while CHNS analysis revealed a significant oxygen content, supporting improved combustion characteristics. GC-MS analysis identified major fatty acid methyl esters contributing to the high volatility and calorific value of BPO. Experimental investigations were conducted at varying blending ratios (BPO10, BPO20, BPO30, BPO40, and BPO50) without any engine modifications, evaluating performance, combustion, and emission parameters against baseline diesel. Results indicated an improvement in brake thermal efficiency (BTE) by 3–6% for BPO30–BPO40 blends, while brake specific fuel consumption (BSFC) reduced by up to 9% for higher blends, attributed to better energy content and oxygenation. In-cylinder analysis revealed increased peak pressure and rate of pressure rise (RoPR) with BPO addition, with BPO50 recording the highest peak due to superior oxidation and localized high temperatures. Ignition delay showed a slight increase for higher blends due to lower cetane number, though overall combustion duration remained comparable to diesel. On the emissions front, smoke opacity was significantly reduced by 14–17% for BPO50 owing to enhanced soot oxidation. Carbon monoxide (CO) and unburned hydrocarbons (HC) decreased by 8–12% across all blends, while NOx emissions exhibited a 6–10% rise for higher blends due to an increase in in-cylinder temperatures and oxygen availability. The findings suggest that BPO, with its oxygenated nature and favorable volatility, can partially replace diesel fuel without major engine modifications, particularly in blends up to BPO40, ensuring improved efficiency and cleaner combustion.