Abstract: A system for the treatment of exhaust gases from an internal combustion engine with a combustion chamber includes an upstream DEF injector disposed to introduce DEF to the combustion chamber and a close-coupled SCR catalyst downstream of and in close-coupled relation to the internal combustion engine. Downstream of the close-coupled SCR catalyst may be a primary SCR catalyst and a primary DEF injector. The system may operate to reduce NO2 in the close-coupled SCR catalyst during low-load conditions of the internal combustion engine and reduce NO2 in the primary SCR catalyst during loaded conditions.

Abstract: A system for the treatment of exhaust gases from an internal combustion engine with a combustion chamber includes an upstream DEF injector disposed to introduce DEF to the combustion chamber and a close-coupled SCR catalyst downstream of and in close-coupled relation to the internal combustion engine. Downstream of the close-coupled SCR catalyst may be a primary SCR catalyst and a primary DEF injector. The system may operate to reduce NO2 in the close-coupled SCR catalyst during low-load conditions of the internal combustion engine and reduce NO2 in the primary SCR catalyst during loaded conditions.

Abstract: A compression ignition internal combustion engine system includes an engine and an exhaust system with an upstream exhaust conduit, and an oxidation catalyst device (DOC). Systems and methods of desulfating the oxidation catalyst by the injection of a lightoff fluid to promote ignition of uncombusted fuel in the exhaust stream are disclosed.

Abstract: An aftertreatment system for an engine system is disclosed. The aftertreatment system may comprise an optical sensor mounted on the aftertreatment catalyst. The optical sensor may include a light source configured to illuminate the aftertreatment catalyst with light and a detector configured to measure an amount of the light absorbed by the aftertreatment catalyst upon illumination with the light. The measured amount of the light absorbed by the aftertreament catalyst may correlate with a condition parameter (e.g., hydrocarbon loading, oxidation state, etc.) of the aftertreatment catalyst.

Abstract: A compression ignition internal combustion engine system includes an engine and an exhaust system with an upstream exhaust conduit, and an oxidation catalyst device (DOC). Systems and methods of desulfating the oxidation catalyst by the injection of a lightoff fluid to promote ignition of uncombusted fuel in the exhaust stream are disclosed.

Abstract: An aftertreatment system for an engine system is disclosed. The aftertreatment system may comprise an optical sensor mounted on the aftertreatment catalyst. The optical sensor may include a light source configured to illuminate the aftertreatment catalyst with light and a detector configured to measure an amount of the light absorbed by the aftertreatment catalyst upon illumination with the light. The measured amount of the light absorbed by the aftertreament catalyst may correlate with a condition parameter (e.g., hydrocarbon loading, oxidation state, etc.) of the aftertreatment catalyst.

Abstract: A reactor assembly is provided. The reactor assembly includes a substrate and a first catalytic layer provided on the substrate. The first catalytic layer further includes a first temperature zone configured to operate at a first temperature. The first catalytic layer further includes a second temperature zone extending from the first temperature zone. The second temperature zone is configured to operate at a second temperature. The second temperature is lower than the first temperature. The reactor assembly also includes a diffusion barrier coating provided on the first catalytic layer. The diffusion barrier coating is configured to regulate a diffusion of gas phase oxygen therethrough for controlling the first temperature with respect to the second temperature.

Abstract: A method for testing a condition of a catalyst is provided. The method includes providing a gas source in communication with the catalyst. The method also includes passing compressed gas from the gas source over the catalyst at normal operating temperature. The method further includes invoking a reaction with the catalyst based on the passage of the compressed gas. The method includes measuring a performance of the catalyst based on the reaction.