LAUSR

Five different lubricating oils with three different sulfur contents (0.182%, 0.583%, and 1.060%) and three different ash contents (0.48%, 1.21%, and 1.99%) were used in this study to investigate their effects on the morphology of diesel particulate matter (PM). The aggregate morphology and nanostructure of primary particles in diesel PM were analyzed using transmission electron microscopy. The primary morphological parameters were determined using an advanced image-processing method. The results show that, with increasing sulfur content and ash content, the macroscopic structure of the primary particles can transform from chainlike to more complex and disordered agglomerated structures, whereas the inner cores change little, the shell thickness decreases, and the thickness of the amorphous materials attached to the outer shell increases. The fractal dimension (Df) of the PM aggregate morphology varies from 1.656 to 1.811, and the mean primary-particle diameter (dp) of the PM is mainly in the range of 10–...