Optimization of neem biodiesel blends and hydrogen addition to improve compression ignition engine performance

This research investigates the effects of Neem biodiesel and hydrogen-enriched air on the emissions and performance of a common-rail direct-injection diesel engine operating under variable load conditions of 25%, 50%, 75%, and 100%. The aim is to improve engine efficiency and promote sustainable energy solutions. Several Neem biodiesel blends (B10-B30) were initially evaluated, and B15 was selected for comprehensive analysis due to its optimal performance. Hydrogen as a gaseous fuel was subsequently inducted into the inlet air at rates of 3.34 to 9.27 liters per minute to assess its influence on engine behavior. Key parameters, including Brake Thermal Efficiency (BTE), Brake Specific Fuel Consumption (BSFC), and emissions of carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx), were analyzed. The B15 blend exhibited a BSFC of 0.27 kg/kWh and a BTE of 31.38% at full load. With hydrogen supplementation at 5.19 liters per minute, BTE increased to 33.31%, and BSFC decreased to 0.25 kg/kWh. NOx and CO emissions were reduced to 488 ppm and 0.04%, respectively, while HC emissions remained unchanged. Hydrogen’s high flame speed and broad flammability range contributed to emission reductions; however, higher hydrogen levels led to higher NOx emissions, necessitating ongoing monitoring to comply with regulations. The artificial neural network model, trained on experimental data, was very good at predicting performance and emissions, suggesting it could be used for real-time combustion diagnostics and fuel optimization. In summary, adopting dual-fuel systems utilizing hydrogen and Neem biodiesel offers significant potential to reduce the environmental impact of diesel engines.