Abstract: A system including a pump fluidly connected to a fluid reservoir, the pump configured to direct diesel exhaust fluid (DEF) from the fluid reservoir to an injector fluidly connected to the pump via a flow line. The system also includes a first pressure sensor configured to determine fluid pressure at a first location in the flow line between the pump and the injector and a second pressure sensor configured to determine fluid pressure at a second location in the flow line between the pump and the injector. The system further includes an air source coupled to the injector via an air flow line, the air source configured to direct air to the injector via the air flow line and a controller communicatively coupled to the first pressure sensor, the second pressure sensor, and the air source, the controller configured to diagnose the system.

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: A system including a pump fluidly connected to a fluid reservoir, the pump configured to direct diesel exhaust fluid (DEF) from the fluid reservoir to an injector fluidly connected to the pump via a flow line. The system also includes a first pressure sensor configured to determine fluid pressure at a first location in the flow line between the pump and the injector and a second pressure sensor configured to determine fluid pressure at a second location in the flow line between the pump and the injector. The system further includes an air source coupled to the injector via an air flow line, the air source configured to direct air to the injector via the air flow line and a controller communicatively coupled to the first pressure sensor, the second pressure sensor, and the air source, the controller configured to diagnose the system.