An off-line approach for the evaluation of particle size distribution emitted from a modern Diesel engine

The present paper is dedicated to the study of the soot particle emissions at the exhaust of an automotive diesel engine. An off-line approach was employed and compared with a consolidated on-line method for particulate emissions characterization (Differential Mobility Spectrometer Cambustion DMS 500). The evolution of the particles molecular weight (MW) distribution was studied offline as a function of the UV-Visible absorption by means of Size Exclusion Chromatography (SEC) [5, 6]. The SEC methodology was applied for the first time to study the particulate emission of a real engine running at different low/partial load operative points. The adopted engine was a EURO5 diesel engine, running in three low, medium and high speed/load operative points, representative of the New European Driving Cycle (NEDC) procedure. The analysis of particle emission upstream the particulate filter was performed taking into account the presence of the Exhaust Gas Recirculation (EGR).