Laser particle sizing of diesel soots in two formulated oils after different engine tests

Soots of four types were extracted from two different formulated diesel oils, namely oil ‘A’, a 15W40, and oil ‘B’, a 20W40, after engine (50 h) and tribological (20 h + 20 h) tests. The soots were dispersed into four different model solvents and base oils, and analysed by Photon Correlation Technique. In a first study, soot particle size measurements were conducted after dilution in n-heptane, Kerdane solvent, 60N and 130N base oils. The influences of engine running-time and solvent nature have been particularly considered. The second study has been devoted to the aggregation kinetic of soots in these solvents. These data are important for a better understanding of soot dispersion stability and the rheology of used oils in diesel engines.