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US 8,739,517 B2Granted
Vehicle-based strategy for removing urea deposits from an SCR catalyst
AssigneeFord Global Technologies, LLC
InventorsLifeng Xu, Williams Lewis Henderson Watkins, Shane Elwart, George Wade Graham
Life of this patent
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Abstract
A method is provided for controlling regeneration of an SCR catalyst. The method includes coordinating the regeneration duration and temperature (e.g., longer/shorter regenerations and/or lower/higher temperatures) to the urea deposit loading. In this way, improved regeneration may be achieved due to the particular nature of urea deposits on SCR catalysts.
Claims12
A method, comprising:
- directing engine exhaust to a urea-based selective catalyst reduction (SCR) catalyst and then to a particulate filter;
- regenerating the particulate filter;
- and
- adjusting operating parameters to regenerate the SCR catalyst, including varying each of a SCR regeneration duration (longer/shorter) and a SCR regeneration temperature (lower/higher) based on an accumulated urea deposit amount on the SCR catalyst prior to its regeneration.
1 more element
A method, comprising:
- directing engine exhaust to an oxidation catalyst, then a urea-based selective catalyst reduction (SCR) catalyst, and then to a particulate filter;
- regenerating the particulate filter;
- completing the particulate filter regeneration;
- and then
- regenerating the SCR catalyst, including varying each of a SCR regeneration duration (longer/shorter) and a SCR regeneration temperature (lower/higher) based on an accumulated urea deposit amount on the SCR catalyst prior to its regeneration.
2 more elements
A method, comprising:
- directing engine exhaust to an aftertreatment device coupled downstream of the engine, the aftertreatment device including an oxidation catalyst, a urea-based selective catalyst reduction (SCR) catalyst, and a particulate filter;
- establishing a threshold urea deposit accumulation for regeneration of the SCR catalyst;
- determining that the threshold urea deposit accumulation in the SCR catalyst has been met;
- in response to the determination, regenerating the SCR catalyst by maintaining the SCR catalyst at a predetermined regeneration temperature for a predetermined interval, and
- after determining that the threshold urea deposit accumulation in the SCR catalyst has been met, delaying the SCR regeneration until a regeneration performed in the particulate filter is completed.
2 more elements
Dependencies are inferred from the claim text.