Preliminary studies confirm the assumption that existing soot formation models have to be revised, or more detailed, phenomenological soot formation models must be established - especially in regard of the precalculation of the soot emission of combustion engines at extreme parameters (high pressure injection, high EGR, high pressure supercharging). In order to generate the necessary basic knowledge, the Chair of Combustion Engines (LVK) developed a novel gas sampling probe which permits the time-resolved gathering of small soot samples from the combustion chamber. Compared to common gas sampling probes, the new probe features several particularities [6], such as a novel injection process of a probe head into the inner flame core for the sampling. The LVK's new gas sampling probe rendered extensive sampling series possible that show the formation and modification of soot during the combustion cycle. It was possible to take samples out of the combustion chamber at a time resolution of 1 ms. After the analysis of a first series of soot samples taken directly from the combustion chamber of the LVK diesel engine, the Department of Materials Science and Engineering (Institute of Microcharacterization WW7) has verified the formation, growth and oxidation of the primary soot particles. Furthermore it was possible to discern characteristic modifications, from compact to fissured shapes, of generated soot agglomerates during combustion. These results enabled a first modelling of the soot formation during a combustion process.
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