Performance, Emission, Energy, and Exergy Assessment of Gasoline–1-Decanol, Gasoline–DIPE, and JP-8 Fuels Toward Sustainable Two-Stroke UAV Propulsion

This study experimentally investigates the performance, emission, energy, and exergy characteristics of six fuels in a two-cylinder, air-cooled, two-stroke unmanned aerial vehicle (UAV) engine, using neat gasoline (G100) as the reference fuel. The test matrix comprised G100, neat JP-8, gasoline–1-decanol blends containing 10 and 20 vol.% decanol (G90D10 and G80D20), and gasoline–diisopropyl ether blends containing 10 and 20 vol.% DIPE (G90E10 and G80E20). Experiments were conducted at shaft speeds of 3250, 3750, 4500, 5250, and 6250 rpm under matched speed–load conditions. Fuel consumption, exhaust-gas temperature, excess-air ratio, gaseous emissions, and first- and second-law thermodynamic performance were evaluated. The inclusion of G100 enabled the effects of the oxygenated additives to be quantified directly. At 5250 rpm, G90E10 reduced BSFC by 0.73% relative to G100 while increasing energy and exergy efficiencies by 1.69% and 1.61%, respectively. G80E20 produced larger reductions in brake-specific CO and HC emissions, 6.63% and 14.58%, respectively, and increased energy and exergy efficiencies by 2.43% and 2.27%, respectively, although both DIPE blends increased NOx. In contrast, increasing the decanol fraction increased BSFC and reduced thermodynamic efficiency relative to G100 despite moderate reductions in CO. JP-8 showed the strongest operating-point dependence; at 5250 rpm its BSFC was 9.52% lower than G100 and its energy and exergy efficiencies were 12.33% and 12.84% higher, respectively, whereas its advantage diminished markedly at the highest speed. Overall, the results demonstrate that oxygenate type and concentration produce distinct trade-offs between fuel utilization and gaseous emissions, while the suitability of JP-8 for gasoline-oriented two-stroke UAV propulsion is strongly dependent on operating conditions. From an operational-sustainability perspective, the results show that improvements in fuel utilization and incomplete-combustion emissions are strongly fuel and operating-point dependent. However, fuel production pathways, life-cycle greenhouse-gas emissions, durability, economic impacts, and mission-level environmental effects were outside the scope of this study and should be addressed before broader sustainability conclusions are drawn.