After-Treatment System For Repower Locomotives

A locomotive, comprising:

• a frame;
• an envelope supported by the frame;
• at least one set of drive wheels supporting the frame;
• an engine supported by the frame and providing power to the drive wheels;
• and
• an aftertreatment system supported by the frame and located between the engine and the envelope, the aftertreatment system having:
• an enclosure defining an exhaust flow path from an inlet to at least one outlet, the inlet being flexibly connected to an exhaust outlet of the engine;
• an injector located in the inlet and configured to provide an aerosolized reductant into the exhaust flow path;
• a mixing tube extending from the inlet into the enclosure towards a back wall of the enclosure, the mixing tube having an end opposite the inlet;
• a plurality of catalyst cells extending parallel to the mixing tube;
• the exhaust flow path traveling through the catalyst cells between the mixing tube and the outlet, the enclosure being configured to create low back pressure and an even distribution of the exhaust flow path across the plurality of catalyst cells;
• and
• a side channel located between the mixing tube and the plurality of catalyst cells.

A method of reducing nitrogen oxides in locomotive engine exhaust, comprising:

• providing an aftertreatment system, the aftertreatment system having an enclosure defining an exhaust flow path from an inlet to an outlet, the inlet being flexibly connected to an exhaust outlet of the engine, an injector located in the inlet and configured to provide an aerosolized reductant into the exhaust flow path, a mixing tube extending from the inlet into the enclosure towards a back wall of the enclosure, a plurality of catalyst cells extending parallel to the mixing tube, the exhaust flow path traveling through the plurality of catalyst cells between the mixing tube and the outlet, the enclosure being configured to create low back pressure and an even distribution of the exhaust flow path across the plurality of catalyst cells, and a side channel located between the mixing tube and the plurality of catalyst cells;
• injecting the aerosolized reductant into the exhaust flow path;
• mixing the reductant with exhaust from the engine in the mixing tube;
• and
• passing the mixture of reductant and exhaust over the plurality catalyst cells such that nitrogen oxides in the exhaust decompose into diatomic nitrogen and water.