Patent ID: 8661797

Claim:
An exhaust gas after treatment system for an internal combustion engine comprising: an exhaust gas conduit in fluid communication with, and configured to receive an exhaust gas from, the internal combustion engine; an oxidation catalyst NOx adsorber device having an inlet and an outlet in fluid communication with the exhaust gas conduit; an oxidation catalyst compound disposed in the oxidation catalyst NOx adsorber device; a NOx adsorber compound disposed in the oxidation catalyst NOx adsorber device for storage and release of NOx constituents in the exhaust gas; a hydrocarbon delivery system connected to and in fluid communication with the exhaust gas conduit upstream of the oxidation catalyst NOx adsorber device for delivery of a hydrocarbon fuel thereto; an air pump connected to and in fluid communication with the exhaust gas conduit upstream of the oxidation catalyst NOx adsorber device for delivery of air thereto, wherein the hydrocarbon delivery system and the air pump supply fuel and air to the exhaust conduit and the oxidation catalyst NOx adsorber device; a selective catalytic reduction device disposed downstream of the oxidation catalyst NOx adsorber device in fluid communication with exhaust gas conduit and the oxidation catalyst NOx adsorber device; a selective catalytic reduction catalyst composition in the selective catalytic reduction device; and a controller in signal communication with the internal combustion engine, the exhaust gas treatment system, the reductant delivery system and the air pump and configured to operate the reductant delivery system and the air pump following a shut down of the internal combustion engine.