Enhancing diesel engine thermal efficiency with candlenut biodiesel and acetylene fumigation: A dual‐fuel approach to performance improvement and emission reduction

Abstract This research investigates the use of acetylene (C 2 H 2 ) gas to improve operational efficiency and reduce emissions of a diesel engine fueled by candlenut seed oil biodiesel (CSOB), a renewable and non‐edible energy source. Experimental evaluations were performed at a fixed engine speed of 1500 rpm under varying load conditions (0%–100%), with C 2 H 2 introduced into the intake at flow rates of 3 and 6 liters per minute (LPM). The selection of C 2 H 2 was predicated on its substantial energy density (48.22 MJ/kg) and rapid flame propagation, which facilitated improved combustion characteristics. The findings revealed that brake thermal efficiency increased by 27.32% at 3 LPM and 44.76% at 6 LPM compared to diesel fuel. Emissions of carbon dioxide, carbon monoxide, and hydrocarbons were diminished by 26.49%, 71.32%, and 34.66%, respectively, signifying a cleaner combustion process. However, nitrogen oxide emissions escalated by as much as 55.98%, underscoring the necessity for the implementation of emission control measures. In summary, this investigation demonstrates that integrating C 2 H 2 with CSOB can enhance engine performance while simultaneously reducing detrimental pollutants. This dual‐fuel approach presents a feasible and economically viable alternative for agricultural and off‐grid energy applications, necessitating only minimal adaptations to conventional diesel engine configurations.