The microcrystal structure of soot particulates in diesel engines.

Abstract

It is considered that the oxidation of soot particulates in the combustion chamber of diesel engines is influenced by their microcrystal structure. The microcrystal structure of a soot particulate is not clear however, and this investigation attempted to determine the microcrystal structure of soot particulates in the combustion chamber and exhaust by means of a high-resolution electron microscope. The results were as follows : the typical layer plane structure which characterizes graphite carbon is not observed in the exhaust of diesel engines, but some particulates display a somewhat similar layer plane structure. The structure of soot particulates is turbostratic because the electron diffraction patterns of soot particulates are patterns of polycrystals. The structure of soot particulates in the combustion chamber is similar to that of exhaust soot particulates. In the initial stage of combustion, a similar layer plane structure is observed, but after the heat release there is no clear layer plane structure.