PROCEDE ET ENSEMBLE D'ELIMINATION DES OXYDES D'AZOTE PRESENTS DANS DES GAZ D'ECHAPPEMENT, UTILISANT UN ECHANGEUR THERMIQUE

摘要

An apparatus for the elimination of nitrogen oxides (NOx) present in exhaust gases from an IC engine (1), incorporated in the exhaust line (2) from the engine, comprises a device for the conversion of NOx and a heat exchanger (4) situated in a shunt circuit (5) placed up-stream of the convertor (3), for cooling the exhaust gases. The convertor comprises several catalysts (3) arranged in the main exhaust line (2). The catalysts have disconnected temperature ranges over which the conversion of NOx is lower than a determined threshold (Cmin). A valve (6) is situated at the opening of the shunt line (5) to distribute the gas flow between the shunt line (5) and the main line (2) so that the exhaust gases pass over the catalysts at a temperature where at least one of the catalysts is active. Also claimed is a process for the elimination of the oxides.