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US 8,281,578 B2Granted
Method for correcting an estimate of NH3 stored within a selective catalyst reduction system
AssigneeFord Global Technologies, LLC
InventorsDevesh Upadhyay, Michiel J. Van Nieuwstadt
Life of this patent
Estimating the term…
Abstract
A method for correcting an estimated amount of NH3 store within a SCR is described. In one example, SCR efficiency is determined from a NOx sensor output and the estimated amount of NH3 is corrected based on the SCR efficiency. Engine emissions may be reduced via improving the estimated NH3 storage level, at least during some conditions.
Claims20
A method for correcting an estimate of NH3 stored within a SCR, comprising:
- correcting an estimated amount of NH3 stored within the SCR in response to an indication of NH3 slip, the indication of NH2 slip determined via a metric based on a convolution;
- and
- adjusting an amount of NH3 delivered to the SCR in response to the corrected estimated amount of NH3 stored within the SCR.
A method for correcting an estimate of NH3 stored within a SCR, comprising:
- correcting an estimated amount of NH3 stored within the SCR based on an expected storage amount of NH3, the expected storage amount related to an efficiency and temperature of the SCR, the estimated amount of NH3 stored within the SCR corrected in response to an absence of indication of NH3 slip past the SCR and an indication of NOx slip past the SCR greater than a threshold level, absence of NH3 slip indication and presence of NOx slip provided via at least one NOx sensor, and a metric based on convolution;
- and
- adjusting an amount of NH3 delivered to the SCR in response to the corrected estimated amount of NH3 stored within the SCR.
A method for correcting an estimate of NH3 stored within a SCR, comprising:
- estimating an amount of NH3 stored within the SCR;
- correcting an estimated amount of NH3 stored within the SCR in response to an indication of NH3 slip, the indication of NH3 provided via a metric based on convolution of one or more NOx sensors;
- and
- adjusting an amount of NH3 injected to the SCR in response to the corrected amount of NH3 stored within the SCR.
1 more element
Dependencies are inferred from the claim text.