Oxygen correction for engine-out NOx estimates using a NOx sensor of an aftertreatment system

A method for controlling operations of an aftertreatment system, comprising:

• determining an estimated engine NOx amount in exhaust gas produced by an engine fluidly coupled to the aftertreatment system;
• interpreting an output value indicative of a first amount of oxygen in the exhaust gas downstream of a selective catalytic reduction system;
• determining an adjusted engine NOx amount in response to the output value;
• and
• controlling an operation of the selective catalytic reduction system based upon the determined adjusted engine NOx amount.

A controller for use with an aftertreatment system, comprising:

• an estimated engine NOx amount determining circuit configured to determine an estimated engine NOx amount in an exhaust gas produced by an engine fluidly coupled to the aftertreatment system;
• a first oxygen amount determining circuit configured to receive a signal from a NOx sensor disposed downstream of a selective catalytic reduction system and interpret the signal to determine an output value indicative of a first amount of oxygen in the exhaust gas downstream of the selective catalytic reduction system;
• and
• an adjustment module configured to:
• determine an adjusted engine NOx amount from the estimated engine NOx amount in response to the output value, and
• generate a signal corresponding to the adjusted engine NOx amount.