Evaluation and optimization of engine performance and exhaust emissions of a diesel engine fueled with diestrol blends

Biofuel is a nontoxic and renewable fuel and could be used in diesel engines in combination with diesel to reduce emissions. The effects of various biodiesel–ethanol–diesel (BED) blends were investigated on the engine power, specific fuel consumption (SFC), engine vibration, and pollutant emissions. The engine experiments were performed using nine castor biodiesel and ethanol blends under five different engine speeds. The engine power was not influenced by different BED blends while B5E4, and B5E6 fuel blends had the highest SFC. The engine vibration slightly increased when fueled with BED blends. Hydrocarbon emission diminished by increasing biodiesel percentage in the blends, whereas it increased by substituting more ethanol in BED blends. NO_x emission was increased by adding more biodiesel into BED blends, while ethanol performed vice versa. The results showed that CO emission was enhanced by increasing ethanol percentage, while it decreased with more biodiesel addition. There was not a remarkable difference in CO₂ emissions between different treatments. A novel combination of an Adaptive Neuro-Fuzzy Inference System (ANFIS) modeling and Honeybee Mating Optimization (HBMO) method was adopted to find a global optimum BED blend considering various output parameters. The selected ANFIS model satisfactorily predicted the engine efficiency and exhaust emissions with R², mean absolute percentage error (MAPE), and root-mean-squared error (RMSE) of 0.99, 0.02, and 0.11, respectively. Consequently, using the HBMO algorithm, the BED blend with 15% of biodiesel, 6% of ethanol, and 79% of pure diesel was found to be the most optimal BED blend for a diesel engine at an engine speed of 950 rpm.