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Particulate Filter Regeneration and NOx Catalyst Re-Activation

  • US 20080276602A1
  • Filed: 05/09/2007
  • Published: 11/13/2008
  • Est. Priority Date: 05/09/2007
  • Status: Active Grant
First Claim
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1. A method for operating a system having an engine with an emission control system, the emission control system including a lean NOx trap and a particulate filter, the method comprising:

  • after lean exhaust gas air-fuel ratio regeneration of the particulate filter at an elevated regeneration temperature, providing a rich or intermittently rich exhaust air-fuel ratio for a duration lasting until LNT temperature falls to a minimum threshold, where said rich or intermittently rich operation reactivates catalytic materials in the LNT and reverses deactivation caused by the elevated temperature lean operation associated with previous particulate filter regeneration.

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