Systems, apparatuses, and methods include an upstream exhaust analysis circuit structured to determine a characteristic of an exhaust gas stream entering a nitrous oxide (NOx) storage catalyst; a prediction circuit structured to predict a downstream NOx concentration of an exhaust gas stream exiting the NOx storage catalyst based on a model of a NOx storage capacity or a dynamic response of the NOx storage catalyst; a downstream exhaust analysis circuit structured to determine a downstream NOx concentration of the exhaust gas stream exiting the NOx storage catalyst; and a comparison circuit structured to compare the predicted downstream NOx concentration to the determined downstream NOx concentration, and determine a health of the NOx storage catalyst based on the comparison.

An exhaust gas catalyst system that includes at least one exhaust canister including an inlet separated from an outlet with catalytic components positioned between the inlet and outlet. The at least one exhaust canister receives a flow of exhaust gas. The at least one exhaust canister includes a pair of concentric passages formed therein including a central passage and an outer passage. A split flap valve is positioned in the inlet. An actuator is coupled to the split flap valve. A control unit is operably connected to the actuator and selectively moves the split flap valve closing one of the concentric passages and locally heating a portion of the catalytic components.

A scrubber system for cleaning exhaust gas from different engines. The scrubber system includes a scrubber, such as a wet scrubber, for removing a constituent from the gas and a housing having an inlet for receiving the gases into the scrubber and an outlet for discharging cleaned gas. An exhaust mixer has plural inlets for receiving exhaust gas from the different engines and an outlet for discharging the gases into the scrubber through the inlet. The exhaust mixer mixes the exhaust gases into a combined flow stream exiting the exhaust mixer outlet. The scrubber system can clean exhaust gases from different engines by connecting exhaust pipes from each engine to a respective inlet, mixing the exhaust gases in the mixer, and directing the mixed gases into the scrubber, which cleans and discharges the cleaned, mixed gases. The scrubber system can be provided to a marine vessel.

A sorption device for filtering evaporation emissions from a fuel tank, includes a vessel with a first opening connected to an air removal path of the fuel tank and a second opening opening to atmosphere, a middle annular space between a radial outer circumferential boundary of the middle annular space and a radial inner circumferential boundary thereof radially inwardly spaced apart from the outer boundary, a first annular space formed between a radial inner surface of a fluid tight circumferential outer shell of the vessel, the radial outer boundary being radially inwardly spaced from the inner surface, a sorbent material arranged in the middle annular space, and evaporation emissions from the fuel tank are guided through the first opening into the first annular space, through the sorbent material into a central space of the vessel in the radial direction, and through the second opening to atmosphere or another sorption device.

Methods and systems are provided for a low temperature NOx adsorber (LTNA). In one example, a method includes operating in a first mode, the first mode including storing exhaust NOx in an LTNA, heating the LTNA until an LTNA outlet temperature reaches a first threshold temperature, and then converting released NOx in a downstream selective catalyst reduction (SCR) device; and operating in a second mode, the second mode including heating the LTNA until the LTNA outlet temperature reaches a second threshold temperature, higher than the first threshold temperature, and converting exhaust NOx in the SCR device.

Methods and systems are provided for a low temperature NOx adsorber (LTNA). In one example, a method includes initiating a desulfation of an LTNA responsive to an estimated sulfur exposure exceeding a threshold, the desulfation including heating the LTNA to a first threshold temperature while maintaining an exhaust oxygen level above a threshold level throughout the entire desulfation.

An exhaust gas treatment apparatus is provided for use together with a diesel engine in an indoor environment, where the diesel engine is part of, e.g., a vehicle or other machinery. A method of controlling such an exhaust gas treatment apparatus is also provided.

An engine includes: an NOx catalyst and an SCR catalyst in an exhaust passage; an excess air ratio change device that changes an excess air ratio of an exhaust gas; and a reducing agent supply device that supplies a reducing agent for SCR including a material for NH.sub.3 or NH.sub.3 to a portion between the NOx catalyst and the SCR catalyst in the exhaust passages. The engine controls the reducing agent supply device in such a manner that a quantity of the reducing agent for SCR to be supplied from the reducing agent supply device to the exhaust passage 40 becomes small when the excess air ratio of the exhaust gas during regeneration control to regenerate the NOx catalyst is small, as compared to when the excess air ratio of the exhaust gas during regeneration control to regenerate the NOx catalyst is large.

A method for operating an exhaust gas post-treatment system of a diesel engine and associated exhaust gas post-treatment system are described. The system has two NOx sensors upstream and downstream of an SCR catalytic converter. The NOx sensor downstream of the SCR catalytic converter is used to divide the NOx information measured by the sensor upstream of the SCR catalytic converter into an NOx value and an NH.sub.3 value. Using this simple method, the SCR catalyst control and diagnosis can be carried out precisely and robustly.

An inorganic oxide material doped with nano-rare earth oxide particles that is capable of trapping one or more of NO.sub.x or SO.sub.x at a temperature that is less than 400 C. The nano-rare earth oxide particles have a particle size that is less than 10 nanometers. The catalyst support can trap at least 0.5% NO.sub.2 at a temperature less than 350 C. and/or at least 0.4% SO.sub.2 at a temperature less than 325 C. The catalyst support can trap at least 0.5% NO.sub.2 and/or at least 0.2% SO.sub.2 at a temperature that is less than 250 C. after being aged at 800 C. for 16 hours in a 10% steam environment. The catalyst support exhibits at least a 25% increase in capacity for at least one of NO.sub.x or SO.sub.x trapping at a temperature that is less than 400 C. when compared to a conventional rare earth doped support in a 10% steam environment.