Performance and emission characteristics of neem biodiesel-diesel blend with mango leaf extract additive in diesel engines

This study explores the performance and emission characteristics of neem biodiesel-diesel blends enriched with mango leaf extract (MLE) as a natural antioxidant. Neem biodiesel, known for its high viscosity and poor oxidative stability, was transesterified and blended with diesel in varying ratios (20–100%). A 1% concentration of MLE was added to the blends to enhance oxidative stability. Thermogravimetric analysis (TGA) assessed the oxidative stability, while engine tests evaluated brake thermal efficiency, fuel consumption, and emissions (HC, CO, NOx, smoke). The optimal blend, B20 + 1% MLE, showed a 14.3 °C increase in oxidation onset temperature, indicating improved stability. This blend also exhibited a 3.12% higher brake thermal efficiency and 3.84% lower fuel consumption than diesel. Additionally, it demonstrated a reduction in HC and CO emissions by 17.5% and 12.1%, respectively, but an increase in NOx and smoke emissions by 18.2% and 10.9%. The findings suggest that blending neem biodiesel with diesel and MLE can optimize fuel properties and performance. Further research is recommended to address the increased NOx and smoke emissions to enhance the viability of neem biodiesel as a renewable fuel alternative.