SCR catalyst ammonia surface coverage estimation and control

摘要

Described herein are various embodiments of an apparatus, a system, and a methods for reducing NOx emissions using ammonia storage on an SCR catalyst. For example, according to one embodiment, an apparatus for controlling an SCR system of an internal combustion engine system includes an ammonia storage module and a reductant dosing module. The ammonia storage module determines an ammonia storage surface coverage on an SCR catalyst of the SCR system and an ammonia compensation value based on one of an excess ammonia flow rate entering the SCR catalyst and an excess NOx flow rate entering the SCR catalyst. The reductant dosing module that generates a reductant dosing command based on the ammonia compensation value.

主权项

1. A controller for controlling a selective catalytic reduction (SCR) system of an internal combustion engine system comprising:
a reductant dosing module configured to generate a reductant command based, at least in part, on a determined ammonia compensation value and output the generated reductant command to a reductant delivery system, the reductant delivery system injecting reductant into an exhaust gas stream at a rate based on the generated reductant command; and an ammonia storage module comprising:
a mode determination module configured to determine an operating mode of the SCR system as one of an adsorption mode, a desorption mode, or a neutral mode;an ammonia adsorption mode module or an ammonia desorption mode module configured to receive a first ammonia storage surface coverage value and calculate a second ammonia storage surface coverage value based, at least in part, on the determined operating mode of the SCR system; andan ammonia storage control module configured to determine the ammonia compensation value based, at least in part, on the calculated second ammonia storage surface coverage value and output the determined ammonia compensation value to the reductant dosing module.