Chemical and Physical Characterization of Organic Particulate Matter from Last Generation Exhaust Aftertreatment System of Medium Duty Diesel Engine 2019-24-0053
Particulate Matter from Euro 6 Medium Duty diesel engine was analyzed from engine-out, downstream of particulate filter (DPF), and up to the exit of a selective catalytic reactor (SCR) to characterize its chemical and physical nature. Particular attention was devoted to the analysis of particles down to 23 nm.
An array of chemical, physical and spectroscopic techniques (Gas chromatography coupled with mass spectrometry (GC-MS), mobility analyzer, UV-visible absorption and fluorescence spectroscopy) was applied for characterizing the organic particulate matter (PM, constituted of polycyclic aromatic hydrocarbons (PAH), heavy aromatic compounds, soot) in the exhaust.
The engine was operated at “full-load” (100% of the total power, representing the best performance of the engine operation) condition, and at different engine speeds.
Results showed that the DPF efficiency was greater than 96% in the reduction of the sub 23 nm particles across the speeds range. Soot concentration in the exhaust after the DPF did not undergo any significant further concentration decrease after SCR. By contrast, PAH concentration was found decreasing of about 30 % after the SCR. Also, the heavy aromatic compounds, with molecular weights over the detectability range of GC-MS (300 u), were mitigated by SCR. Therefore, SCR resulted not effective in causing a further soot reduction, whereas it was able to largely reduce PAH and heavy aromatics emissions. Moreover, SCR system seems to support an agglomeration of particles, with beneficial effect on the harmfulness to human health.
Ezio Mancaruso, Bianca Maria Vaglieco, Wolfgang Gstrein, Konstantinos Priftis, Antonio Tregrossi, Carmela Russo, Anna Ciajolo, Barbara Apicella
Istituto Motori-CNR, FPT Motorenforschung AG, Istituto Ricerche Sulla Combustion
14th International Conference on Engines & Vehicles