Biodiesel soot incandescence and NO emission studied in an optical engine

High-speed imaging and thermodynamical characterization are applied to an optically accessible, heavy-duty diesel engine in order to compare soot incandescence and NO emission behaviour of four bioderived fuels: rapeseed-methylester, Jatropha oil (pure), Jatropha-methylester and a 50/50 blend of cyclohexanone with a Fischer-Tropsch synthetic fuel. Regular diesel fuel is used as a reference. Soot incandescence is observed at 0.3° crank angle resolution (200 images/cycle). The heat release rate and exhaust NO concentrations are used as indicators of average and peak temperatures, respectively, which are combined with soot incandescence signal to get a relative measure for a fuel's sooting propensity.