Model-based monitoring for selective catalytic reduction device in aftertreatment assembly

An aftertreatment assembly includes a selective catalytic reduction (SCR) device having a catalyst and configured to receive an exhaust gas. A controller is operatively connected to the SCR device. The controller has a processor and a tangible, non-transitory memory on which is recorded instructions for executing a method of model-based monitoring of the SCR device. The method relies on a physics-based model that may be implemented in a variety of forms. The controller is configured to obtain at least one estimated parameter, and at least one threshold parameter based at least partially on a catalyst degradation model. The catalyst degradation model is based at least partially on a predetermined threshold storage capacity (Theta T). A catalyst status is determined based on a comparison ofthe estimated and threshold parameters. The operation of the assembly is controlled based at least partially on the catalyst status. 后处理组件包括选择性催化还原(SCR)装置，其具有催化剂并且被配置为接收排气。控制器可操作地连接到SCR装置。该控制器具有处理器和有形非暂时性存储器，该存储器上记录有用于执行对SCR装