# US 11,306,638 B2 · Method for controlling an SCR catalytic converter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,638 B2 - Document ID: US11306638B2 - Status: Granted - Kind: B2 - Application number: 17/128,623 - Filed: 2020-12-21 - Published: 2021-06-24 - Granted: 2022-04-19 - Earliest claimed: 2019-12-20 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Frank Schweizer - Web page: https://patentgrep.com/patent/US11306638B2 ## CPC - F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent} - F01N 3/2073: {Means for generating a reducing substance from the exhaust gases} - F01N 9/005: {using models instead of sensors to determine operating characteristics of exhaust systems, e.g. calculating catalyst temperature instead of measuring it directly} - F01N 2560/021: for measuring or detecting ammonia NH3 - F01N 2560/026: for measuring or detecting NOx - F01N 2610/02: the substance being ammonia or urea - F01N 2900/0408: using a feed-back loop - F01N 2900/1402: Exhaust gas composition - F01N 2900/1411: Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate - F01N 2900/16: said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst - F01N 2900/1812: Flow rate - Y02T 10/12: Improving ICE efficiencies - Y02T 10/40: Engine management systems - 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 method for controlling an SCR catalytic converter (20, 30), comprising detecting (200) concentration values (314, 324; 414, 424) in the exhaust gas downstream of the catalytic converter (20), wherein at least one concentration value for NH3 and one concentration value for NOx is detected; calculating (202) modeled concentration values (316, 322; 416, 422) for NH3 and NOx downstream of the catalytic converter on the basis of a catalytic converter model, wherein the model comprises an aging parameter (342, 442) which at least partially describes aging of the modeled catalytic converter; comparing (208) the detected concentration values with the modeled concentration values; and, in a manner dependent on the result of the comparison, changing the aging parameter (342, 442) of the model and/or changing a predefined dosing quantity for a reducing agent in the SCR catalytic converter. ## Claims ### Claim 1 A method for controlling an SCR catalytic converter, comprising detecting concentration values in the exhaust gas downstream of the catalytic converter, wherein at least one concentration value for NH3 and one concentration value for NOx is detected; calculating modeled concentration values for NH3 and NOx downstream of the catalytic converter on the basis of a catalytic converter model, wherein the model comprises an aging parameter which at least partially describes aging of the modeled catalytic converter; comparing the detected concentration values with the modeled concentration values; and, in a manner dependent on the result of the comparison, changing the aging parameter of the model, changing a predefined dosing quantity for a reducing agent in the SCR catalytic converter, or both, wherein the predefined dosing quantity for a reducing agent is reduced if the comparison of the concentration values yields that a deviation between the detected concentration values and the modeled concentration values for NOx is lower than a predefined first threshold value and the deviation between the detected concentration values and the modeled concentration values for NH3 is higher than a predefined second threshold value, and wherein the predefined dosing quantity for a reducing agent is increased if the comparison of the concentration values yields that the deviation between the detected concentration values and the modeled concentration values for NOx is higher than a predefined third threshold value and the deviation between the detected concentration values and the modeled concentration values for NH3 is lower than a predefined fourth threshold value. ### Claim 2 (depends on 1) The method according to claim 1, wherein the aging parameter is changed if the comparison of the concentration values yields that the deviation between the detected concentration values and the modeled concentration values is both lower than a predefined first threshold value for NH3 and lower than a predefined second threshold value for NOx, wherein the first and the second threshold value are lower than or equal to zero, or if the comparison of the concentration values yields that the deviation between the detected concentration values and the modeled concentration values is both higher than a predefined third threshold value for NH3 and higher than a predefined fourth threshold value for NOx, wherein the third and the fourth threshold value are higher than or equal to zero. ### Claim 3 (depends on 1) The method according to claim 1, wherein the method further comprises: checking at least one acceptance condition for detected concentration values, and discarding detected concentration values if at least one acceptance condition for said detected concentration values is not met. ### Claim 4 (depends on 3) The method according to claim 3, wherein the at least one acceptance condition comprises at least one of the following: a lower and/or upper threshold value for the catalytic converter temperature, a status of a sensor for detecting concentration values, a threshold parameter for describing driving dynamics, a threshold value for a mass flow of the exhaust gas upstream of the catalytic converter. ### Claim 5 (depends on 1) The method according to claim 1, wherein, for the aging factor, a maximum value is predefined which corresponds to a fully functional catalytic converter, and a minimum value, which corresponds to a catalytic converter which is no longer adequately functional. ### Claim 6 (depends on 1) The method according to claim 1, wherein the comparison of detected and modeled concentration values comprises integrating the concentration values over a predefined period of time and calculating a difference between the modeled and the detected integrated concentration values. ### Claim 7 (depends on 6) The method according to claim 6, wherein the predefined period of time is determined in a manner dependent on a defined traveling distance, or wherein the predefined time period is determined in a manner dependent on a defined reference quantity of untreated NOx emissions through the internal combustion engine. ### Claim 8 (depends on 1) The method according to claim 1, further comprising: setting or predefining a step size by which the aging parameter of the model is increased or reduced. ### Claim 9 (depends on 1) The method according to claim 1, wherein the concentration values in the exhaust gas downstream of the catalytic converter are detected by means of a multi-gas sensor configured to output separate signals for NH3 and NOx. ### Claim 10 A processing unit which is configured to detect, via one or more sensors, concentration values in the exhaust gas downstream of a catalytic converter, wherein at least one concentration value for NH3 and one concentration value for NOx is detected; calculate modeled concentration values for NH3 and NOx downstream of the catalytic converter on the basis of a catalytic converter model, wherein the model comprises an aging parameter which at least partially describes aging of the modeled catalytic converter; compare the detected concentration values with the modeled concentration values; and, in a manner dependent on the result of the comparison, change the aging parameter of the model, change a predefined dosing quantity for a reducing agent in the SCR catalytic converter, or both, wherein the predefined dosing quantity for a reducing agent is reduced if the comparison of the concentration values yields that a deviation between the detected concentration values and the modeled concentration values for NOx is lower than a predefined first threshold value and the deviation between the detected concentration values and the modeled concentration values for NH3 is higher than a predefined second threshold value, and wherein the predefined dosing quantity for a reducing agent is increased if the comparison of the concentration values yields that the deviation between the detected concentration values and the modeled concentration values for NOx is higher than a predefined third threshold value and the deviation between the detected concentration values and the modeled concentration values for NH3 is lower than a predefined fourth threshold value. ### Claim 11 A non-transitory, machine-readable memory medium containing instructions that when executed by a computer cause the computer to detect, via one or more sensors, concentration values in the exhaust gas downstream of a catalytic converter, wherein at least one concentration value for NH3 and one concentration value for NOx is detected; calculate modeled concentration values for NH3 and NOx downstream of the catalytic converter on the basis of a catalytic converter model, wherein the model comprises an aging parameter which at least partially describes aging of the modeled catalytic converter; compare the detected concentration values with the modeled concentration values; and, in a manner dependent on the result of the comparison, change the aging parameter of the model, change a predefined dosing quantity for a reducing agent in the SCR catalytic converter, or both, wherein the predefined dosing quantity for a reducing agent is reduced if the comparison of the concentration values yields that a deviation between the detected concentration values and the modeled concentration values for NOx is lower than a predefined first threshold value and the deviation between the detected concentration values and the modeled concentration values for NH3 is higher than a predefined second threshold value, and wherein the predefined dosing quantity for a reducing agent is increased if the comparison of the concentration values yields that the deviation between the detected concentration values and the modeled concentration values for NOx is higher than a predefined third threshold value and the deviation between the detected concentration values and the modeled concentration values for NH3 is lower than a predefined fourth threshold value.