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The investigations performed serve to develop a 2D measurement technique for dynamic mixture formation analysis of fuel and air with almost standard gasoline (Euro Super colorless, without the low volatile bitumen constituents). A measurement concept for fuel-air-ratio detection by laser-induced fluorescence (FARLIF) is validated. The concept is based on 266nm Nd-YAG-laser excitation of the self-fluorescing gasoline and is validated for mixture pressures above 2.5 bar, sufficient air-fraction λ ≥ 0.4 and temperatures at least up to 548 K. The mixture temperature is shown to affect the FARLIF-intensities. The technical feasibility of FARLIF-imaging with almost standard gasoline is successfully demonstrated. Single-shot measurements of transient mixing fields of gasoline and air at engine relevant gas conditions are performed and quantitative fuel-air-ratio maps are generated.

Quantitative 1-D spatially-resolved NO LIF measurements in the combustion chamber of a mass-production SI engine with port-fuel injection using a tunable KrF excimer laser are presented. One of the main advantages of this approach is that KrF laser radiation at 248 nm is only slightly absorbed by the in-cylinder gases during engine combustion and therefore it allows measurements at all crank angles. Multispecies detection turned out to be crucial for this approach since it is possible to calculate the in-cylinder temperature from the detected Rayleigh scattering and the simultaneously acquired pressure traces. Additionally, it allows the monitoring of interfering emissions and spectroscopic effects like fluorescence trapping which turned out to take place. Excitation with 248 nm yields LIF emissions at shorter wavelengths than the laser wavelength (at 237 and 226 nm).