Effects of micro-structure and components of diesel particulates on oxidation reactivity

Particulates emitted from a turbo-charged, intercooler engine with electronic control, high pressure common rail fuel injection system were collected. Particulates were characterized using thermo-gravimetric analyzer(TGA), high resolution transmission electron microscopy(HRTEM), energy dispersive spectroscopy(EDS), and elemental analyzer. Results show higher oxidation reactivity of particulates emitted from the engine fueled with GUO IV diesel fuel. DOC increases the volatile fraction in the diesel particulates, increases the size of crystallite consisting of primary particles, and arranges the carbon layers more orderly. Oxidation reactivity of particulates depends upon not only its microstructure, but also O/C ratios, specific surface area and the components of metals as well. Oxidation process of particulates is the one that nucleus is oxidized, and shell is rearranged in the primary particles. Furthermore, interior capsule structure is formed at the stage of post-oxidation, and finally collapsed. ©, 2015, Chinese Society for Internal Combustion Engines. All right reserved.