Exhaust Emission Measurements from a Spark-Ignition Engine Using Fuels with Different Ethanol Content for Aircraft Applications

[Image: see text] To have more sustainable aviation, ways to reduce lead and gaseous emissions are important and currently large research topics. As further efficiency improvements for internal combustion engines (ICE) have reached a limit, and the research and development of certifiable full and hybrid electric aircrafts are still ongoing, it becomes increasingly important to investigate the use of alternatives to conventional fuels, such as bioethanol. In this study, a state-of-the-art turbocharged 104 kW flight piston engine (BRP Rotax 915 iS) was tested with fuels containing various amounts of ethanol to assess the influence on the engine’s performance and emissions. Emission and performance maps covering the full range of engine operation from 4500 to 5800 RPM and about 40 to 110 kW output power were obtained using the standard fuel AvGas 100 LL, its current alternative Super 98 E5, and higher ethanol content fuels Super 98 E10 and Super 95 E20. With 20% ethanol in the fuel blend, a general decrease in CO and unburned hydrocarbon (UHC) emissions and an increase in CO(2) and NO(x) were observed compared to the other fuels. Differences in the performance and emissions of the engine were also observed with different manifold air temperatures (MAT).