Use of LIF image acquisition and analysis in developing a calibrated technique for in-cylinder investigation of the spatial distribution of air-to-fuel mixing in direct injection gasoline engines

The carefully considered scene illumination, image acquisition and image analysis techniques described in this paper play key roles in facilitating the advancement of the LIF technique to a point that permits examination of cycle-to-cycle variability of the injection process, for example. A new approach to coping with the fluorescence dependency on pressure and temperature, the issues related to the choice of a fluorescence tracer, the careful determination of the optimum tracer concentration, and the complete calibration methodology are described. The paper concludes with some examples of calibrated measurements, which validate the design assumptions.