Exhaust treatment methods and systems

摘要

A control method for monitoring a selective catalytic reduction ("SCR") device is provided. A control method includes adjusting an existing efficiency threshold based on a dosing adaptation value to determine an efficiency threshold. The dosing adaptation value represents an adjusted value of a supply of reductant based on a determined deviation of a downstream NOx concentration value to an expected NOx concentration. The control method includes comparing the efficiency threshold with a determined efficiency of the SCR device. The control method includes generating a message based on comparing the efficiency threshold with the determined efficiency of the SCR device.