Abstract: An aftertreatment system for a diesel engine may include a diesel particulate filter configured for placement in fluid communication with the diesel engine to receive an exhaust flow. The system may also include a selective catalytic reduction system configured for arrangement downstream of the diesel particulate filter and a NOx sensor configured to measure a NOx concentration in the exhaust flow entering the selective catalytic reduction system. The system may also include a controller configured to estimate a ratio of NO2 to NOx downstream of the diesel particulate filter and based on a factor affecting the generation of NO2 upstream of the selective catalytic reduction system. The controller may also be configured to adjust the measured NOx concentration based on the ratio to provide an estimated actual NOx concentration and dose diesel exhaust fuel into the exhaust flow based on the estimated actual NOx concentration.

Abstract: An aftertreatment system for a diesel engine may include a diesel particulate filter configured for placement in fluid communication with the diesel engine to receive an exhaust flow. The system may also include a selective catalytic reduction system configured for arrangement downstream of the diesel particulate filter and a NOx sensor configured to measure a NOx concentration in the exhaust flow entering the selective catalytic reduction system. The system may also include a controller configured to estimate a ratio of NO2 to NOx downstream of the diesel particulate filter and based on a factor affecting the generation of NO2 upstream of the selective catalytic reduction system. The controller may also be configured to adjust the measured NOx concentration based on the ratio to provide an estimated actual NOx concentration and dose diesel exhaust fuel into the exhaust flow based on the estimated actual NOx concentration.

Abstract: An aftertreatment system is disclosed for use with a combustion engine. The aftertreatment system may have at least one exhaust passage, and a plurality of dosing circuits configured to inject reductant into the at least one exhaust passage. The aftertreatment system may also have a controller in communication with each of the plurality of dosing circuits. The controller may be configured to determine a failure of a first of the plurality of dosing circuits, and to selectively adjust operation of a second of the plurality of dosing circuits based on the failure.