Detailed characterization of particulate emissions of an automotive catalyzed DPF using actual regeneration strategies

The study aimed to perform detailed dynamic characterization of the particulate emission in mass and size from a modern Euro 5 automotive engine employing real regeneration strategies. The experimental tests were performed with a 2 l engine installed on a dyno chassis while the PM emissions where measured in mass and size by means of dynamic instruments. Different engine operating conditions in load and speed were selected. The regeneration strategies were composed of multiple in-cylinder post-injections calibrated in order to generate a defined warm-up of the DPF and guarantee the completion of the regeneration. Results highlighted that such regeneration strategies affect DPF performance during regeneration. In particular, the thermal behavior of the DPF controlled by the post-injections produces and emits a high number of small particles. The analysis of data seems to support the hypothesis that the high small particle number is generated by soot cake fragmentation when the maximum oxidation temperature inside the filter is reached.