Abstract: An exhaust treatment system is disclosed that can diagnose the performance of an exhaust treatment oxidation catalyst in converting NO to NO2. The exhaust treatment system is fluidly coupled to an internal combustion engine, and includes an oxidation catalyst disposed in an engine exhaust stream; a reductant source for injecting a reductant into the exhaust stream downstream of the oxidation catalyst; an SCR catalyst disposed in the exhaust stream downstream of the reductant source; and a gas sensor, disposed in the exhaust stream downstream of the oxidation catalyst and upstream of the reductant source, comprising a plurality of sensing or pumping cells that measures NO concentration in the exhaust gas and NO2 concentration in the exhaust gas.

Abstract: In an exemplary embodiment of the invention an exhaust gas after treatment system for an internal combustion engine comprises an exhaust gas conduit configured to transport exhaust gas from the internal combustion engine to exhaust treatment devices of the exhaust gas treatment system. A controller in signal communication with the exhaust gas aftertreatment system is configured to monitor the temperature of a selective catalytic reduction device, wherein the controller is operable to move a valve assembly to an open position when the selective catalytic reduction device is at or above an operating temperature and to move the valve assembly to a closed position when the selective catalytic reduction device is below the operating temperature for entrainment of NOx constituents from the exhaust gas.

Abstract: An exhaust treatment system is disclosed that can diagnose the performance of an exhaust treatment oxidation catalyst in converting NO to NO2. The exhaust treatment system is fluidly coupled to an internal combustion engine, and includes an oxidation catalyst disposed in an engine exhaust stream; a reductant source for injecting a reductant into the exhaust stream downstream of the oxidation catalyst; an SCR catalyst disposed in the exhaust stream downstream of the reductant source; and a gas sensor, disposed in the exhaust stream downstream of the oxidation catalyst and upstream of the reductant source, comprising a plurality of sensing or pumping cells that measures NO concentration in the exhaust gas and NO2 concentration in the exhaust gas.

Abstract: An exhaust gas after treatment system for an engine comprises an oxidation catalyst NOx adsorber wherein an oxidation catalyst compound and a NOx adsorber compound are disposed. A fuel injector is connected to and is in fluid communication with the oxidation catalyst NOx adsorber device for delivery of a hydrocarbon fuel thereto and an air pump is connected to and is in fluid communication with the oxidation catalyst NOx adsorber device for delivery of air thereto. The fuel injector and the air pump supply fuel and air to the oxidation catalyst NOx adsorber device for oxidation thereof and heating of the NOx adsorber compound to a NOx release temperature following shut down of the internal combustion engine.

Abstract: In an exemplary embodiment, an internal combustion engine includes an oxidation catalyst configured to receive an exhaust gas flow from the internal combustion engine, a urea injector positioned downstream of the oxidation catalyst to inject a urea flow into the exhaust gas flow and a mixer positioned downstream of the urea injector to mix the exhaust gas flow and the urea flow to form a mixed exhaust gas and urea flow. The engine also includes a particulate filter and catalytic reduction assembly positioned downstream of the mixer to receive the mixed exhaust and urea flow from the mixer to form a treated exhaust gas flow and an exhaust gas recirculation system coupled to the particulate filter to receive a portion of the treated exhaust gas flow and recirculate the portion of the exhaust gas flow to be mixed with a fresh air flow for the internal combustion engine.

Abstract: An exhaust gas treatment system for an internal combustion engine is provided, including an exhaust gas conduit, a pressurized vessel, a selective catalytic reduction (“SCR”) device, and a control module. The internal combustion engine has a plurality of pistons and an engine off condition that indicates that the pistons are generally stationary. The exhaust gas conduit is in fluid communication with, and configured to receive an exhaust gas from the internal combustion engine. The pressurized vessel stores a solid ammonia gas producing material. The pressurized vessel is selectively activated to heat the solid ammonia gas producing material into an ammonia gas. The ammonia gas is released into the exhaust gas conduit. The SCR device is in fluid communication with the exhaust gas conduit and is configured to receive the ammonia gas.

Abstract: An exhaust system is provided. The exhaust system includes a first sensor that senses a level of nitrous oxide (NOx) in exhaust gas and generates a first sensor signal. A second sensor senses a level of ammonia (NH3) in the exhaust gas and generates a second sensor signal. A control module receives the first sensor signal and the second sensor signal, determines a desired reductant dosage based on the first sensor signal and the second sensor signal, and generates an injector control signal based on the desired reductant dosage.

Abstract: In an exemplary embodiment of the invention an exhaust gas after treatment system for an internal combustion engine comprises an exhaust gas conduit configured to transport exhaust gas from the internal combustion engine to exhaust treatment devices of the exhaust gas treatment system. A controller in signal communication with the exhaust gas aftertreatment system is configured to monitor the temperature of a selective catalytic reduction device, wherein the controller is operable to move a valve assembly to an open position when the selective catalytic reduction device is at or above an operating temperature and to move the valve assembly to a closed position when the selective catalytic reduction device is below the operating temperature for entrainment of NOx constituents from the exhaust gas.

Abstract: An exhaust gas after treatment system for an engine comprises an oxidation catalyst NOx adsorber wherein an oxidation catalyst compound and a NOx adsorber compound are disposed. A fuel injector is connected to and is in fluid communication with the oxidation catalyst NOx adsorber device for delivery of a hydrocarbon fuel thereto and an air pump is connected to and is in fluid communication with the oxidation catalyst NOx adsorber device for delivery of air thereto. The fuel injector and the air pump supply fuel and air to the oxidation catalyst NOx adsorber device for oxidation thereof and heating of the NOx adsorber compound to a NOx release temperature following shut down of the internal combustion engine.