SCR-Catalyzed Diesel Particulate Filter (SDPF)

SCR-Catalyzed Diesel Particulate Filters (SDPFs) filter particulate matter, convert them periodically, and reduce NOx in the exhaust gas.  Two important reactions are:

• Without NO₂: Standard SCR: 

4 NH₃ + 4 NO + O₂ → 4 N₂ + 6 H₂O

• With NO₂: Fast SCR: 

4 NH₃ + 2 NO + 2 NO₂ → 4 N₂ + 6 H₂O