Cummins Inc.
Systems and methods for using oxygen to diagnose in-range rationality for NOx sensors

Abstract:

An apparatus includes an exhaust analysis circuit and a sensor diagnostics circuit. The exhaust analysis circuit is structured to interpret first oxygen data acquired by a first sensor indicative of a first amount of oxygen in an exhaust flow at a first location along an exhaust aftertreatment system, and interpret second oxygen data acquired by a second sensor indicative of a second amount of oxygen in the exhaust flow at a second location along the exhaust aftertreatment system. The sensor diagnostic circuit is structured to determine at least one of the first sensor and the second sensor are faulty based on the first amount of oxygen and the second amount of oxygen differing more than a threshold value.