SCR catalyst heating control
AssigneeFord Global Technologies, LLC
InventorsEric Matthew Kurtz, Paul Joseph Tennison
Life of this patent
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Abstract
Various systems and methods are described for controlling a selective catalytic reduction system coupled to an exhaust system of an engine, the selective catalytic reduction system including a catalyst and a diesel particulate filter. One example method comprises, before regeneration of the diesel particulate filter, adjusting an operating parameter to decrease an amount of ammonia stored in the SCR catalyst to a desired amount of stored ammonia, where the desired amount of ammonia storage is varied based on operating conditions, and initiating regeneration of the catalyst when the desired amount of stored ammonia is reached.
Claims19
A method for controlling a diesel aftertreatment system including an SCR catalyst and a particulate filter coupled to an engine, comprising:
- before regenerating the particulate filter, reducing exhaust gas recirculation to decrease a stored ammonia amount in the SCR catalyst to a desired pre-regeneration amount of stored ammonia, the desired pre-regeneration amount varied based on an anticipated peak regeneration temperature;
- and
- initiating particulate filter regeneration when the desired pre-regeneration amount is reached.
A method for an aftertreatment system including an SCR catalyst and a particulate filter, comprising:
- first, increasing SCR catalyst temperature to a first threshold while decreasing stored ammonia without increasing engine NOx generation;
- then
- increasing engine NOx generation while increasing SCR catalyst temperature to a second threshold;
- and
- when SCR catalyst temperature is above the second threshold and the stored ammonia has reached a desired pre-regeneration value, initiating a particulate filter regeneration.
A system for a diesel aftertreatment device coupled to an exhaust system of an engine in a vehicle, the system comprising:
- an SCR catalyst;
- a diesel particulate filter;
- a control system comprising a computer readable storage medium, the medium including instructions thereon, the control system receiving communication from a selective catalytic reduction device, the medium comprising:
- instructions for, before a regeneration of the diesel particulate filter and during a first phase, increasing SCR catalyst temperature to a first threshold value and decreasing an amount of stored ammonia without increasing engine NOx generation;
- instructions for, before regeneration of the diesel particulate filter and during a second phase, increasing engine NOx generation while increasing the SCR catalyst temperature to a second threshold value based on the amount of stored ammonia;
- and
- instructions for initiating a regeneration of the diesel particulate filter during a third phase when the SCR catalyst temperature is above the second threshold value and the amount of stored ammonia has reached a desired pre-regeneration value.
Dependencies are inferred from the claim text.