Investigation of performance and emissions of fuel blends formed by mixing JP8, JET A1, and nitromethane with gasoline using a piston engine

Abstract

This study investigates the impact of alternative fuel blends, including JP8, Jet-A1, and nitromethane, on the performance, combustion characteristics, and emissions of a single-cylinder gasoline engine at full load. A total of nine fuel blends were prepared, with gasoline (G100) serving as the baseline fuel. Engine performance was assessed in terms of thermal efficiency, brake-specific fuel consumption (BSFC), exhaust gas temperature (EGT), and emissions (CO₂, CO, HC, and NOx). The results showed that G100 exhibited the highest thermal efficiency (16.667%) and the lowest BSFC (487.57 g/kWh), reflecting its superior combustion characteristics. Blends containing nitromethane demonstrated the highest thermal efficiencies, with 90G5NM5JetA1 achieving 18.457% due to nitromethane's oxygen-rich composition enhancing combustion. However, blends with JP8 and Jet-A1 exhibited slightly reduced thermal efficiency and increased BSFC due to their lower energy density. Exhaust gas temperatures were elevated for all alternative fuel blends, with nitromethane-containing blends recording the highest values (up to 740.8°C), indicating more intense combustion. Emissions analysis revealed that nitromethane and Jet-A1 blends significantly reduced CO and HC emissions due to improved combustion efficiency. Conversely, CO₂ and NOx emissions increased, particularly for nitromethane blends, due to higher combustion intensity and oxygenation. The findings highlight that while G100 remains the most efficient fuel, alternative fuel blends, especially those containing nitromethane, offer enhanced thermal efficiency and reduced incomplete combustion emissions, making them suitable for performance-focused applications. However, the associated CO₂ and NOx emissions increase underscores the need for advanced after-treatment systems and fuel optimization. This study provides valuable insights into the trade-offs between performance, fuel efficiency, and environmental impact when adopting alternative fuel blends in combustion engines.