Synergy effects analysis on CDPF regeneration performance enhancement and NOx concentration reduction of NH3–SCR over Cu–ZSM–5

To improve the synergy effects of post-processing equipment and decrease diesel engine emissions, the after-treatment synergy model is established to analyze the soot regeneration combustion of catalytic diesel particulate filter (CDPF) passive and active regeneration and downstream selective catalytic reduction (SCR) by NH 3 (NH 3 –SCR) over Cu–ZSM–5. Kinetic models of nitric oxide oxidation on platinum-based catalyst, passive and active regeneration of CDPF and nitrogen oxide conversion in SCR are verified. Results show that the CDPF passive regeneration weakens the SCR performance with small inlet NO 2 /NO X ratio while enhances the SCR performance with large inlet NO 2 /NO X ratio, and active regeneration deteriorates SCR performance. Of all the factors, except temperature, the SCR NO X conversion varies with the NO 2 concentration at the outlet of the CDPF during the CDPF passive regeneration, and the CDPF outlet oxygen concentration mainly affects downstream SCR performance under active regeneration conditions. • An after-treatment synergy model of post-processing equipment is established. • Kinetic models of nitric oxide oxidation and soot regeneration are verified. • Soot regeneration combustion of the post-processing equipment are investigated. • Key parameters affecting soot regeneration performance are summarized.