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Vehicle manufacturers are facing increasing legislative pressure to reduce vehicle emissions and achieve zero tailpipe CO2 emissions within the coming decade. The focus on techniques to reduce the tailpipe CO2 emissions, rather than vehicle lifecycle emissions, naturally dictates electrified solutions. However, this will not address the increased emissions resulting from vehicle manufacture, the emissions of the legacy fleet, or enable niche or classic applications, to be decarbonised for future use. The use of bio-derived fuels, and fully synthetic fuels, can provide a technical solution to these challenges, but it is beneficial if these can be used as a drop-in replacement to existing fossil derived fuels, as this would enable straight-forward backward compatibility with existing vehicles and avoid the need to re-engineer future engine designs or upgrade existing hardware.

The performance of a direct injection gasoline engine (G-DI) is highly dependent on the quality of the air-fuel mixture preparation. This is of particular importance when operating at a stratified charge condition, where the ideal mixture distribution would be a stoichiometric region around the spark plug, surrounded by air. To achieve this ideal situation over a wide range of speeds and loads is extremely difficult, requiring an understanding of the fuel spray, the in-cylinder air motion and their interactions. This paper presents the results of Phase Doppler Anemometry (PDA) and Laser Induced Fluorescence (LIF) measurements made both within an optically accessed direct injection gasoline engine and under atmospheric conditions. The experimental results are compared with those of a VECTIS Computational Fluid Dynamics (CFD) simulation of the same engine.