# US 9,517,437 B2 · Systems and methods for controlling aftertreatment systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,437 B2 - Document ID: US9517437B2 - Status: Granted - Kind: B2 - Application number: 14/635,816 - Filed: 2015-03-02 - Published: 2016-09-08 - Granted: 2016-12-13 - Earliest claimed: 2015-03-02 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Maruthi Narasinga Rao Devarakonda - Web page: https://patentgrep.com/patent/US9517437B2 ## CPC - B01D 53/9495: {Controlling the catalytic process} - B01D 53/90: Injecting reactants - B01D 53/9409: {Nitrogen oxides} - B01D 53/9431: {Processes characterised by a specific device} - B01D 53/9477: {with catalysts positioned on separate bricks, e.g. exhaust systems} - F01N 3/106: {Auxiliary oxidation catalysts} - F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent} - B01D 2251/2067: Urea - F01N 2240/40: a hydrolysis catalyst - F01N 2560/06: the means being a temperature sensor - F01N 2570/18: Ammonia - F01N 2900/1622: Catalyst reducing agent absorption capacity or consumption amount - Y02T 10/12: Improving ICE efficiencies - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A system includes a nitrogen oxide reduction catalyst fluidly coupled to an exhaust conduit of an engine system. The nitrogen oxide reduction catalyst is configured to reduce nitrogen oxides in an engine exhaust. The system also includes an ammonia oxidation catalyst fluidly coupled to the exhaust conduit downstream of the nitrogen oxide reduction catalyst and configured to reduce ammonia in the engine exhaust. Further, the system includes a reductant injection control system configured to control an injection of reductant into the exhaust conduit, determine a first nitrogen oxide conversion rate of the nitrogen oxide reduction catalyst, determine an ammonia storage value of the nitrogen oxide reduction catalyst, and determine a first temperature of the engine exhaust upstream of the ammonia oxidation catalyst. The reductant injection control system is also configured to increase or decrease the injection of reductant based on the first nitrogen oxide conversion, the ammonia storage value, and the first temperature. ## Claims ### Claim 1 A system comprising: a nitrogen oxide reduction catalyst fluidly coupled to an exhaust conduit of an engine system and configured to reduce nitrogen oxides in the engine exhaust; an ammonia oxidation catalyst fluidly coupled to the exhaust conduit downstream of the nitrogen oxide reduction catalyst and configured to reduce an ammonia in the engine exhaust; and a reductant injection control system configured to: read a first temperature of an exhaust exiting the nitrogen oxide reduction catalyst; if the first temperature is less than an upper temperature value and greater than a lower temperature value then to: a) determine a nitrogen oxide conversion rate of the nitrogen oxide reduction catalyst; b) determine an ammonia storage value of the nitrogen oxide reduction catalyst; and c) increase, decrease, or a combination thereof, the injection of reductant based on the nitrogen oxide conversion rate, and the ammonia storage value. ### Claim 2 (depends on 1) The system of claim 1, wherein the reductant injection control system is configured to determine an ammonia oxidation catalyst temperature window increase based on one of or both of the first temperature and an ammonia oxidation catalyst temperature window. ### Claim 3 (depends on 2) The system of claim 2, wherein the reductant injection control system is configured to determine a second temperature of the engine exhaust downstream of the ammonia oxidation catalyst and to determine the ammonia oxidation catalyst temperature window based on the first and the second temperatures. ### Claim 4 (depends on 3) The system of claim 3, wherein the reductant injection control system is configured to determine the ammonia oxidation catalyst temperature window to increase an ammonia selectivity of the ammonia oxidation catalyst. ### Claim 5 (depends on 1) The system of claim 1, wherein the reductant injection control system is configured to use a model of the aftertreatment system, a model of the engine system, or a combination thereof, to determine the nitrogen oxide conversion rate, the ammonia storage, the first temperature, or any combination thereof. ### Claim 6 (depends on 1) The system of claim 1, wherein the reductant injection control system is configured to increase the injection of reductant when the nitrogen oxide conversion rate is below a reference value. ### Claim 7 (depends on 1) The system of claim 1, wherein the reductant injection control system is configured to start a diagnostic evaluation of the nitrogen oxide reduction catalyst, the ammonia oxidation catalyst, or any combination thereof, based on the nitrogen oxide conversion rate and the first temperature. ### Claim 8 (depends on 7) The system of claim 7, wherein the reductant injection control system is configured to start the diagnostic evaluation of the nitrogen oxide reduction catalyst based on the ammonia storage value. ### Claim 9 (depends on 1) The system of claim 1, wherein the engine system comprises a lean-burn engine system. ### Claim 10 A method, comprising: reading a first temperature of an exhaust exiting a nitrogen oxide reduction catalyst, wherein an ammonia oxidation catalyst is fluidly coupled to the nitrogen oxide reduction catalyst, and the ammonia oxidation catalyst is positioned downstream of the nitrogen oxide catalyst and configured to reduce ammonia in the engine exhaust; if the first temperature is less than an upper temperature value and greater than a lower temperature value then: a) determining a nitrogen oxide conversion rate of a nitrogen oxide reduction catalyst configured to receive the engine exhaust and reduce nitrogen oxides in the engine exhaust; b) determining an ammonia storage value of the nitrogen oxide reduction catalyst; and c) increasing or decreasing the reductant injection based on the nitrogen oxide conversion rate, the ammonia storage value, and the first temperature. ### Claim 11 (depends on 10) The method of claim 10, comprising receiving a second input corresponding to an amount of nitrogen oxides in the engine exhaust downstream of the nitrogen oxide reduction catalyst and determining the nitrogen oxide conversion rate based on the amount of nitrogen oxides. ### Claim 12 (depends on 10) The method of claim 10, comprising adjusting a temperature window of the ammonia oxidation catalyst based on the nitrogen oxide conversion rate and the first temperature. ### Claim 13 (depends on 12) The method of claim 12, comprising adjusting the temperature window to maximize the ammonia selectivity of the ammonia oxidation catalyst. ### Claim 14 (depends on 10) The method of claim 10, comprising starting a diagnostic evaluation of the nitrogen oxide reduction catalyst, the ammonia oxidation catalyst, or a combination thereof, based on the ammonia storage value. ### Claim 15 A non-transitory computer-readable medium comprising computer executable code comprising instructions configured to: read a first temperature of an exhaust exiting a nitrogen oxide reduction catalyst, wherein an ammonia oxidation catalyst is fluidly coupled to the nitrogen oxide reduction catalyst, and the ammonia oxidation catalyst is positioned downstream of the nitrogen oxide catalyst and configured to reduce ammonia in the engine exhaust; if the first temperature is less than an upper temperature value and greater than a lower temperature value then to: a) determine a nitrogen oxide conversion rate of a nitrogen oxide reduction catalyst configured to receive the engine exhaust and reduce nitrogen oxides in the engine exhaust; b) determine an ammonia storage value of the nitrogen oxide reduction catalyst; and c) increase or decrease the reductant injection based on the nitrogen oxide conversion rate, the ammonia storage value, and the first temperature. ### Claim 16 (depends on 15) The non-transitory computer-readable medium of claim 15, comprising instructions configured to start the diagnostic evaluation of the ammonia oxidation catalyst based on the nitrogen oxide conversion rate, the first temperature, or any combination thereof. ### Claim 17 (depends on 15) The non-transitory computer-readable medium of claim 15, comprising instructions configured to determine an amount of nitrogen oxide in the engine exhaust downstream of the ammonia oxidation catalyst and increase the injection of urea based on the amount of nitrogen oxide. ### Claim 18 (depends on 15) The non-transitory computer-readable medium of claim 15, comprising instructions configured to adjust a temperature window of the ammonia oxidation catalyst based on the nitrogen oxide conversion rate and the first temperature. ### Claim 19 (depends on 18) The non-transitory computer-readable medium of claim 18, comprising instructions configured to adjust the temperature window to maximize an ammonia selectivity of the ammonia oxidation catalyst. ### Claim 20 (depends on 15) The non-transitory computer-readable medium of claim 15, comprising instructions configured to increase the injection of reductant when the nitrogen oxide conversion rate is below a reference value.