Abstract: An engine exhaust gas treatment system includes an oxidation catalyst, a NOX adsorber, and a turbine. The oxidation catalyst and the NOX adsorber are fluidly connected to an exhaust manifold of the engine. The turbine is fluidly connected to, and downstream of the oxidation catalyst and the NOx adsorber.

Abstract: A hydrocarbon selective catalytic reduction (HC-SCR) catalyst is regenerated using a nitrogen-based reductant agent. The HC-SCR catalyst is in communication with a power system such as an internal combustion engine and receives exhaust gasses from the internal combustion engine. Sulfur in the exhaust gasses may deactivate the HC-SCR catalyst by sulfur oxides forming thereon. To remove the sulfur oxides, a nitrogen-based reductant agent is introduced to the exhaust gasses. The nitrogen-based reductant agent decomposes to nitrogen oxides and hydrogen. The hydrogen reacts with the sulfur oxides to form hydrogen sulfides thereby removing the sulfur oxides from the HC-SCR catalyst.