Abstract: A testing device is capable of testing a NOx sensor in an environment that does not have dew point detection capability. The testing device includes a connector configured to be coupled to the NOx sensor, an output indicator, and circuitry. The circuitry is configured to send an unverified dew point signal to the NOx sensor via the connector and receive a sensor signal from the NOx sensor via the connector. The unverified dew point signal includes an indication that a temperature of the environment is at or above the dew point. The sensor signal includes an indication of operation of the NOx sensor in the environment. The circuitry is further configured to determine a status of the NOx sensor based on the received sensor signal and indicate, via the output indicator, the status of the NOx sensor.

Abstract: Exhaust after treatment systems for internal combustion engine powered vehicles are provided. One system includes logic in the form of one or more routines implemented by one or more of the system's components for determining the quantity of certain combustion products present in the exhaust that exits an oxidation catalyst, such as a diesel oxidation catalyst (DOC), without the use of a specific sensor for each combustion product. Results from such a determination may then be used to estimate the amount of soot present in the particulate filter. This estimated value of soot present in the particulate filter can then be subsequently used to determine when the particulate filter should be actively regenerated.

Abstract: A testing device is capable of testing a NOx sensor in an environment that does not have dew point detection capability. The testing device includes a connector configured to be coupled to the NOx sensor, an output indicator, and circuitry. The circuitry is configured to send an unverified dew point signal to the NOx sensor via the connector and receive a sensor signal from the NOx sensor via the connector. The unverified dew point signal includes an indication that a temperature of the environment is at or above the dew point. The sensor signal includes an indication of operation of the NOx sensor in the environment. The circuitry is further configured to determine a status of the NOx sensor based on the received sensor signal and indicate, via the output indicator, the status of the NOx sensor.

Abstract: Exhaust after treatment systems for internal combustion engine powered vehicles are provided. One system includes logic in the form of one or more routines implemented by one or more of the system's components for determining the quantity of NO2 present in the exhaust that exits an oxidation catalyst, such as a diesel oxidation catalyst (DOC), without the use of an NO2 sensor. Results from such a determination may then be used to estimate the amount of soot present in the particulate filter. This estimated value of soot present in the particulate filter can then be subsequently used to determine when the particulate filter should be actively regenerated.

Abstract: A mixer for pulsed exhaust gas recirculation (EGR) includes a fresh intake air conduit having an inlet opening configured to be placed into fluid communication with a fresh intake air source, an EGR pocket having an upstream opening in fluid communication with an upstream air source and a downstream opening in fluid communication with the fresh intake air conduit, and an EGR conduit configured to introduce pulsed EGR into the EGR pocket.

Abstract: Systems and methods are provided for controlling the amount and timing of nitrogen oxide reductant injected during a given injection cycle into an exhaust system of a vehicle as part of a selective catalytic reduction system. The amount of reductant injected is determined by at least one computational model that accounts for the growth of liquid and/or solid reductant film growth on the interior of the exhaust system. The model determines reductant injection characteristics (e.g., amount, timing, etc.) that reduce and/or eliminate reductant films on the interior of the exhaust system. Exemplary inputs into the model include exhaust temperature, exhaust flow, and the amount of reductant injected in a previous injection cycle.

Abstract: Exhaust after treatment systems for internal combustion engine powered vehicles are provided. One system includes logic in the form of one or more routines implemented by one or more of the system's components for determining the quantity of NO2 present in the exhaust that exits an oxidation catalyst, such as a diesel oxidation catalyst (DOC), without the use of an NO2 sensor. Results from such a determination may then be used to estimate the amount of soot present in the particulate filter. This estimated value of soot present in the particulate filter can then be subsequently used to determine when the particulate filter should be actively regenerated.

Abstract: Exhaust after treatment systems for internal combustion engine powered vehicles are provided. One system includes logic in the form of one or more routines implemented by one or more of the system's components for determining the quantity of NO2 present in the exhaust that exits an oxidation catalyst, such as a diesel oxidation catalyst (DOC), without the use of an NO2 sensor. Results from such a determination may then be used to estimate the amount of soot present in the particulate filter. This estimated value of soot present in the particulate filter can then be subsequently used to determine when the particulate filter should be actively regenerated.

Abstract: A fixed positive displacement exhaust gas recirculation (EGR) system includes an intake manifold in fluid communication with a fresh intake air source, an exhaust manifold, and an engine having at least one EGR cylinder and at least one non-EGR cylinder. The at least one EGR cylinder is in fixed fluid communication with the intake manifold such that substantially all of the exhaust gas flows from the at least one EGR cylinder to the intake manifold, and the at least one non-EGR cylinder is in communication with the exhaust manifold such that exhaust gas flows from the at least one non-EGR cylinder into the exhaust manifold.

Abstract: A mixer for pulsed exhaust gas recirculation (EGR) includes a fresh intake air conduit having an inlet opening configured to be placed into fluid communication with a fresh intake air source, an EGR pocket having an upstream opening in fluid communication with an upstream air source and a downstream opening in fluid communication with the fresh intake air conduit, and an EGR conduit configured to introduce pulsed EGR into the EGR pocket.

Abstract: Systems and methods are provided for controlling the amount and timing of nitrogen oxide reductant injected during a given injection cycle into an exhaust system of a vehicle as part of a selective catalytic reduction system. The amount of reductant injected is determined by at least one computational model that accounts for the growth of liquid and/or solid reductant film growth on the interior of the exhaust system. The model determines reductant injection characteristics (e.g., amount, timing, etc.) that reduce and/or eliminate reductant films on the interior of the exhaust system. Exemplary inputs into the model include exhaust temperature, exhaust flow, and the amount of reductant injected in a previous injection cycle.

Abstract: Exhaust after treatment systems for internal combustion engine powered vehicles are provided. One system includes logic in the form of one or more routines implemented by one or more of the system's components for determining the quantity of NO2 present in the exhaust that exits an oxidation catalyst, such as a diesel oxidation catalyst (DOC), without the use of an NO2 sensor. Results from such a determination may then be used to estimate the amount of soot present in the particulate filter. This estimated value of soot present in the particulate filter can then be subsequently used to determine when the particulate filter should be actively regenerated.

Abstract: Systems and methods are provided for controlling the amount and timing of nitrogen oxides reductant injected during a given injection cycle into an exhaust system of a vehicle as part of a selective catalytic reduction system. The amount of reductant injected is determined by at least one computational model that accounts for the growth of liquid and/or solid reductant film growth on the interior of the exhaust system. The model determines reductant injection characteristics (e.g., amount, timing, etc.) that reduce and/or eliminate reductant films on the interior of the exhaust system. Exemplary inputs into the model include exhaust temperature, exhaust flow, and the amount of reductant injected in a previous injection cycle.

Abstract: Systems and methods are provided for controlling the amount and timing of nitrogen oxides reductant injected during a given injection cycle into an exhaust system of a vehicle as part of a selective catalytic reduction system. The amount of reductant injected is determined by at least one computational model that accounts for the growth of liquid and/or solid reductant film growth on the interior of the exhaust system. The model determines reductant injection characteristics (e.g., amount, timing, etc.) that reduce and/or eliminate reductant films on the interior of the exhaust system. Exemplary inputs into the model include exhaust temperature, exhaust flow, and the amount of reductant injected in a previous injection cycle.

Abstract: Systems and methods are provided for measuring the thickness of a film on an interior surface of an exhaust pipe system of a vehicle. The film is typically a layer of a nitrogen-oxides reductant, such as urea, deposited during operation of a selective catalytic reduction system for eliminating pollutants in an exhaust stream. The methods and systems are directed to optical measurements that directly probe the interior surfaces of the exhaust system to determine the thickness of a urea film built up during operation of the engine and the selective catalytic reduction system.