Selective catalytic reduction device monitoring system

An internal combustion (IC) engine comprising:

• an engine including an exhaust gas conduit;
• a selective catalytic reduction (SCR) device fluidically connected to the exhaust gas conduit;
• and
• an SCR device monitoring system including:
• an engine out NOx monitoring module;
• an SCR out NOx monitoring module configured and disposed to monitor NOx released from the SCR device;
• a NOx storage model module operatively connected to the engine out NOx module and the SCR out NOx monitoring module, the NOx storage model module being configured and disposed to determine an amount of NOx stored in the SCR device;
• and
• a consumed ammonia correction model module operatively connected to the NOx storage model module, the consumed ammonia correction model module being configured and disposed to calculate a corrected consumed ammonia prediction factor.

A method of monitoring a selective catalytic reduction (SCR) device comprising:

• calculating an amount of NOx entrained within exhaust gases passing from an internal combustion engine;
• determining an amount of NOx entrained within exhaust gases passing from the SCR device;
• calculating an amount of NOx stored in the SCR device;
• calculating a corrected consumed ammonia correction factor;
• and
• determining a corrected amount of ammonia consumed in the SCR device.