# US 2021/0277816 A1 · After-Treatment System For Repower Locomotives > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0277816 A1 - Document ID: US20210277816A1 - Status: Published application - Kind: A1 - Application number: 16/813,215 - Filed: 2020-03-09 - Published: 2021-09-09 - Earliest claimed: 2020-03-09 - Assignees: Progress Rail Services Corporation - Applicants: Progress Rail Services Corporation - Inventors: Ajay Patel; Arun Kumar - Web page: https://patentgrep.com/patent/US20210277816A1 ## CPC - F01N 3/28: Construction of catalytic reactors - F01N 13/017: {the purifying devices are arranged in a single housing} - B61C 5/04: Arrangement or disposition of exhaust apparatus - F01N 3/206: {Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents} - F01N 3/2066: {Selective catalytic reduction [SCR]} - F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent} - F01N 3/2892: {Exhaust flow directors or the like, e.g. upstream of catalytic device} - F01N 13/1816: {the pipe sections being joined together by flexible tubular elements only, e.g. using bellows or strip-wound pipes} - F01N 2340/00: Dimensional characteristics of the exhaust system, e.g. length, diameter or volume of the exhaust apparatus; Spatial arrangements of exhaust apparatuses - F01N 2590/08: for heavy duty applications, e.g. trucks, buses, tractors, locomotives - F01N 2610/02: the substance being ammonia or urea - Y02T 10/12: Improving ICE efficiencies - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - B61C: LOCOMOTIVES; MOTOR RAILCARS (vehicles in general B60; frames or bogies B61F; special railroad equipment for locomotives B61J, B61K) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An SCR after-treatment system for a locomotive engine includes 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, and a side channel located between the mixing tube and the plurality of catalyst cells. The enclosure is configured to create low back pressure and an even distribution of the exhaust flow path across the plurality of catalyst cells. ## Claims ### Claim 1 An after-treatment system for a locomotive engine, comprising: 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. ### Claim 2 (depends on 1) The after-treatment system of claim 1, wherein the low back pressure and even distribution are created by controlling key dimensions, the key dimensions including: a length of the mixing tube, a distance from the end of the mixing tube to the back wall of the enclosure, and a width of the side channel from the plurality catalyst cells to the mixing tube. ### Claim 3 (depends on 2) The after-treatment system of claim 2, wherein the length of the mixing tube is 60 inches, the distance from the end of the mixing tube to the back wall of the enclosure is 38 inches, and the width of the side channel is 8.6 inches. ### Claim 4 (depends on 1) The after-treatment system of claim 1, further comprising a mixer located at the end of the mixing tube. ### Claim 5 (depends on 4) The after-treatment system of claim 4, wherein the mixer is a two-stage mixer. ### Claim 6 (depends on 1) The after-treatment system of claim 1, wherein the plurality of catalyst cells contain vanadium. ### Claim 7 (depends on 1) The after-treatment system of claim 1, wherein the enclosure is configured to fit between an engine and an envelope meeting Plate C clearance standards. ### Claim 8 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. ### Claim 9 (depends on 8) The locomotive of claim 8, wherein the low back pressure and even distribution are created by controlling key dimensions, the key dimensions including: a length of the mixing tube, a distance from the end of the mixing tube to the back wall of the enclosure, and a width of the side channel from the plurality of catalyst cells to the mixing tube. ### Claim 10 (depends on 9) The locomotive of claim 9, wherein the length of the mixing tube is 60 inches, the distance from the end of the mixing tube to the back wall of the enclosure is 38 inches, and the width of the side channel is 8.6 inches. ### Claim 11 (depends on 8) The locomotive of claim 8, further comprising a mixer located at the end of the mixing tube. ### Claim 12 (depends on 11) The locomotive of claim 11, wherein the mixer is a two-stage mixer. ### Claim 13 (depends on 8) The locomotive of claim 8, wherein the plurality of catalyst cells contain vanadium. ### Claim 14 (depends on 8) The locomotive of claim 8, wherein the envelope meets Plate C clearance requirements. ### Claim 15 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. ### Claim 16 (depends on 15) The method of claim 15, wherein the low back pressure and even distribution are created by controlling key dimensions, the key dimensions including: a length of the mixing tube, a distance from the end of the mixing tube to the back wall of the enclosure, and a width of the side channel from the plurality of catalyst cells to the mixing tube. ### Claim 17 (depends on 16) The method of claim 16, wherein the length of the mixing tube is 60 inches, the distance from the end of the mixing tube to the back wall of the enclosure is 38 inches, and the width of the side channel is 8.6 inches. ### Claim 18 (depends on 15) The method of claim 15, further comprising a mixer located at the end of the mixing tube. ### Claim 19 (depends on 15) The method of claim 15, wherein the plurality of catalyst cells contain vanadium. ### Claim 20 (depends on 15) The method of claim 15, wherein the reductant is urea.