Air-fuel mixing and combustion behavior of gasoline-ethanol blends in a GDI wall-guided turbocharged multi-cylinder optical engine

Finally, E85 and E50 showed higher values of the integral flame luminosity in the first phase of combustion due to the higher flame speed with respect to gasoline one. Moreover, the chemiluminescence imaging confirmed a lower number of diffusive flames with respect gasoline and E10 in the late combustion phase, when the flame burns the fuel film on the piston crown. These results validated the lower emission of UHC and smoke of E50 and E85 with respect to gasoline and E10.