Patent ID: 6238525
Filing Date: 2001-05-29
Classification: B01D,F01N,F02B

Abstract:
A process for reducing a nitrogen oxides content of exhaust gas from an internal combustion engine, comprising: treating exhaust gas in an electric gas discharge such that at least one of nitrogen dioxide or nitric acid is formed from nitrogen oxides contained in the exhaust gas; storing the nitrogen dioxide or nitric acid as nitrates on a nitrogen oxides storage material during phases when the engine operates with greater than a stoichiometric air/fuel ratio, wherein the nitrogen oxides storage material is located within the gas discharge and is provided as a coating to walls of flow channels of a honeycomb structure, and the gas discharge is passed along the flow channels; decomposing the nitrates to nitrogen oxides during phases when the engine operates with less than the stoichiometric air/fuel ratio; and reducing the nitrogen oxides that are released from the storage material to nitrogen.