Performance, emission, vibration and noise characteristics of gasoline-based fuel blends with JP-8, Jet A-1, and nitromethane mixtures in a single-cylinder gasoline engine

Abstract

This study investigates the performance, fuel consumption, and emission characteristics of various gasoline-based fuel blends, including JP-8 (Jet Propellant 8), Jet A-1, and nitromethane mixtures, in a single-cylinder, air-cooled, four-stroke gasoline engine. The engine was operated at a constant speed of 2500 RPM under varying torque loads (0 Nm, 2.5 Nm, 5 Nm, 7.5 Nm, and 10 Nm), and key performance indicators such as brake specific fuel consumption (BSFC), thermal efficiency, exhaust gas temperature (EGT), noise, vibration and exhaust emissions (CO, CO₂, NO_x, HC, O₂) were measured. The results revealed that blended fuels containing JP-8 and nitromethane exhibited improved thermal efficiency, especially under higher torque conditions. The highest thermal efficiency of 18.46 % was observed for the 90G5NM5JP8 blend at 10 Nm, compared to 16.67 % for pure gasoline (G100). Similarly, BSFC values significantly decreased with increasing load for all fuel blends, with 90G5NM5JP8 demonstrating the lowest BSFC at 458.17 g/kWh under 10 Nm load. In terms of emissions, NO_x levels increased with increasing load, with 90G5NM5JP8 reaching 2000 ppm at 10 Nm, indicating more combustion temperature. CO and HC emissions, on the other hand, decreased with higher loads for all blends, with 90G5NM5JP8 showing the lowest CO emissions at 3.026 % and HC emissions at 76 ppm. CO₂ emissions were higher for fuel blends containing Jet A-1 and nitromethane, reflecting more complete combustion. The study concludes that JP-8 and nitromethane blends significantly improve engine performance and efficiency but result in higher NO_x emissions. Experimental findings indicate that as engine load increases, vibration and noise levels rise across all fuel types. For G100 fuel, vibration increased by 191 %, from 33.49 m/s² at 0 Nm to 97.49 m/s² at 10 Nm. This increase was more pronounced in JP-8- and nitromethane-containing blends, with 90G10JP8 experiencing a 224 % rise, from 33.82 m/s² to 108.5 m/s² over the same load range. A similar trend was observed in noise levels, where G100′s noise increased by 8.2 %, from 90.01 dBA at 0 Nm to 97.37 dBA at 10 Nm. In contrast, the high-energy 90G5NM5JP8 blend exhibited a 9.1 % increase, reaching 99.13 dBA at 10 Nm. On the other hand, Jet A-1-based fuels demonstrated a relatively lower increase; for instance, 95G5JetA1′s vibration levels rose by 165 %, from 36.16 m/s2 to 95.83 m/s2. These findings suggest that these blends hold promise for high-performance applications, though further work is needed to manage emissions for broader practical use.