Converting an Automobile Engine to an Aircraft Engine

Abstract: This project evaluates the opportunity to convert a three-cylinder automobile piston engine (the Tiny Friendly Giant) to an aircraft engine from an environmental and practical point of view. The problem of increased emissions from aviation calls for technical and socioeconomic solutions, which is the reason why this report is written. The main goals are to choose the best fuel for the piston engine in aviation, as well as to study emissions, engine cooling and practical challenges with conversion. The structure resembles a feasibility study where the problem is solved using literature in a trade study, together with emission estimations using The Greenhouse gases, Regulated Emissions, and Energy use in Technologies Model framework and Boeing Fuel Flow Method 2. An estimation for engine cooling is done using a semiemprical method from Lycoming, showing air cooling can be sufficient for the Tiny Friendly Giant in aviation. The results furthermore show that none of the alternative automobile fuels are appropriate for use in aviation and that alternative pathways to jet fuel are more suited for high altitude. The conclusion is thus that the engine should be converted to jet fuel compatibility. To avoid large turning moment fluctuations, two-stroke can be applied. Conversion and use of the engine in aviation is not considered to be feasible because of practical limitations - instead the study concludes designing a new engine from scratch is easier and most likely quicker. The study shows that reducing carbon dioxide emissions also lead to reductions in water and sulfur- and nitrous oxides. However, the same mitigation strategy leads to increase in carbon monoxide and hydrocarbons. In general, the conclusion is that alternative fuels can significantly reduce aircraft emissions.