Production and evaluation of engine performance and emission characteristics of composite biodiesel from Michelia Champaca and Amoora Rohituka oils in a CRDI VCR diesel engine

• Composite biodiesel was produced from Michelia Champaca and Amoora Rohituka seed oils. • Engine testing showed MCARME5 achieved a BTE of 30.1%, closest to diesel. • MCARME20 reduced CO and HC emissions by 12.65% and 13.79%, respectively. • Higher NO emissions (5.18% increase) were observed due to oxygenated fuel properties. • MCARME blends offer a sustainable alternative to diesel, reducing fossil fuel reliance. The rising global energy demand and environmental concerns have accelerated the search for renewable fuel alternatives. This study investigates the performance and emission characteristics of biodiesel produced from Michelia Champaca and Amoora Rohituka methyl ester (MCARME). A two-step transesterification process was used to synthesize MCARME, which was tested in a single-cylinder, four-stroke, CRDI diesel engine at a constant speed of 1500 rpm under varying loads (25%, 50%, 75%, and 100%). Results showed that at 100% load, MCARME5 achieved a brake thermal efficiency (BTE) of 30.1%, whereas MCARME20 exhibited a 19.32% reduction in BTE compared to diesel, due to its higher viscosity and lower calorific value. Brake-specific fuel consumption (BSFC) increased by 31.03% for MCARME20, indicating higher fuel consumption compared to diesel. Emission analysis revealed that MCARME20 reduced CO and HC emissions by 12.65% and 13.79%, respectively, at 100% load, due to its oxygenated nature. However, NO emissions decreased by 5.18% compared to diesel, attributed to lower combustion temperatures. These findings highlight the feasibility of MCARME as a renewable biofuel, supporting carbon neutrality and sustainable energy solutions.