Emma, A.F.Sathyabhama, A.Yadav, A.K.2026-02-042023International Journal of Energy for a Clean Environment, 2023, 24, 6, pp. 19-4021503621https://doi.org/10.1615/InterJEnerCleanEnv.2022043949https://idr.nitk.ac.in/handle/123456789/22120This study investigates the suitability of coffee husk (CH) and spent coffee ground (SCG) as the biomass energy source to produce biodiesel. The chemical composition was determined using the field emission gun scanning electron microscope (FEG-SEM). The carbon and oxygen concentration in CH was 49.84% and 48.06%, respectively, by weight. The SCG had 67.72% of carbon and 26.18% of oxygen by weight. The oil extracted from CH was converted into biodiesel using the transesterification process. The properties of the biodiesel, such as flashpoint, fire point, viscosity, calorific value, and density, were measured. The engine's performance and emission characteristics were investigated by blending the produced biodiesel with regular diesel. It was found that by using CHOME biodiesel-diesel blends, exhaust gas emissions such as HC, CO, and smoke opacity were considerably reduced, while CO2 and NOx emissions increased. The brake thermal efficiency (BTE) of the engine was slightly reduced, and brake specific energy consumption (BSFC ) was increased. © 2023 by Begell House, Inc.BlendingBrakesCarbonDiesel enginesEnergy utilizationGas emissionsOxygenScanning electron microscopySmokeThermal efficiencyTransesterificationCoffee husksDiesel engine emissionsDiesel engine performanceEmissionEmission characteristicsPerformancePerformance and emissionsPerformance characteristicsSpent coffee groundsTransesterificationsBiodieselbiofuelbiomasschemical reactioncrop residuediesel engineenergy efficiencyexhaust emissionextraction methodperformance assessment