Oxidation Reactivity Changes of Diesel Particulate Matter After Being Pre-treated

To evaluate the accuracy of the commonly used method based on thermogravimetric analysis in calculation of the thermal kinetic parameters, particulate matter (PM) was sampled at different engine loads and pre-treated in N₂ atmosphere. Indirect evaluation on the influence of pre-treatment on PM kinetic parameters was made based on the analysis of microstructure morphology and nanostructure parameters. Onion-like structures of raw PM and PM aggregation sampled at 80% engine load converted to core-shell like structures, however, it was almost no change for raw PM sampled at 100% load. The diameter of raw PM sampled at 80% load decreased greatly. The mean lattice fringe separation distance decreased for all the three samples and raw PM sampled at 80% load had the largest decrease. For PM aggregation sampled at 80% load and raw PM sampled at 100% load, the mean fringe length changed slightly and mean fringe tortuosity increased greatly, while it was the opposite for raw PM sampled at 80% load. The analysis indicated indirectly that the thermal kinetic parameters of pre-treated samples was different from raw samples.