# US 2019/0376428 A1 · Systems and methods for idle fuel economy mode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0376428 A1 - Document ID: US20190376428A1 - Status: Published application - Kind: A1 - Application number: 16/550,501 - Filed: 2019-08-26 - Published: 2019-12-12 - Earliest claimed: 2016-10-14 - Assignees: Cummins Inc. - Applicants: Cummins Inc. - Inventors: Minming Zhao; Josh Si Shao; Sriram Madhavan; Matthew John Zanker - Web page: https://patentgrep.com/patent/US20190376428A1 ## CPC - F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent} - F01N 3/2066: {Selective catalytic reduction [SCR]} - 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 11/00: Monitoring or diagnostic devices for exhaust-gas treatment apparatus - F01N 2550/02: Catalytic activity of catalytic converters - F01N 2560/026: for measuring or detecting NOx - F01N 2610/02: the substance being ammonia or urea - F01N 2900/0422: measuring the elapsed time - F01N 2900/1602: Temperature of exhaust gas apparatus - F01N 2900/1622: Catalyst reducing agent absorption capacity or consumption amount - F01N 2900/1814: Tank level - F02D 41/08: for idling (F02D41/06, F02D41/16 take precedence) - 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) - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An apparatus includes a stored reductant determination circuit structured to determine an amount of stored reductant in a component of an exhaust aftertreatment system, and a fuel mode economy circuit structured to control an amount of reductant added to the exhaust aftertreatment system during an engine idle mode of operation based on the amount of stored reductant. ## Claims ### Claim 1 An apparatus comprising: a stored reductant determination circuit structured to determine an amount of stored reductant in a selective catalytic reduction (SCR) component of an exhaust aftertreatment system; a fuel mode economy circuit structured to control an amount of reductant added to the exhaust aftertreatment system during a standard engine idle mode of operation based on the amount of stored reductant, wherein the fuel mode economy circuit is structured to enter a fuel efficient engine idle mode in which the fuel mode economy circuit is inhibited from adding reductant during the fuel efficient engine idle mode in response to determining that a temperate in the SCR component is above a temperature threshold and in response to determining that an amount of time that the engine is in at least one of the standard engine idle mode and the fuel efficient engine idle mode is less than a fuel efficient idle time threshold. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the fuel mode economy circuit is further structured to control the amount of reductant added based on operation data regarding exhaust gas flowing through the exhaust aftertreatment system, wherein the operation data includes an indication of an amount of nitrogen oxide exiting the exhaust aftertreatment system, wherein in response to the amount of nitrogen oxide exiting the exhaust aftertreatment system being less than a threshold. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the fuel mode economy circuit is further structured to control the amount of reductant added based on operation data regarding exhaust gas flowing through the exhaust aftertreatment system, wherein the operation data includes an indication of an amount of nitrogen oxide exiting the exhaust aftertreatment system, and wherein the reductant is urea. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the fuel mode economy circuit is structured to determine a nitrogen oxide conversion efficiency of the SCR component based on the stored urea amount and the indication of nitrogen oxide exiting the exhaust aftertreatment system. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the fuel mode economy circuit is further structured to control the amount of reductant added based on operation data regarding exhaust gas flowing through the exhaust aftertreatment system, wherein the operation data includes an indication of an amount of nitrogen oxide exiting the exhaust aftertreatment system, wherein in response to the amount of nitrogen oxide exiting the exhaust aftertreatment system exceeding a threshold, the fuel mode economy circuit is further structured to activate an existing engine idle process. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the reductant includes a first reductant and a second reductant, wherein the first reductant is urea and the second reductant is ammonia. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the stored reductant determination circuit is structured to determine an amount of stored ammonia, and wherein the fuel mode economy circuit is structured to control an amount of urea added to the exhaust aftertreatment system during the standard engine idle mode of operation based on the amount of stored ammonia. ### Claim 8 (depends on 1) The apparatus of claim 1, further including a timer circuit structured to activate and maintain activation of the fuel mode economy circuit for a predefined amount of time during the fuel efficient engine idle mode based on operation data regarding exhaust gas flowing through the exhaust aftertreatment system. ### Claim 9 (depends on 8) The apparatus of claim 8, further comprising a time comparison circuit structured to compare a time count stored in the timer circuit to the fuel efficient idle time threshold. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the fuel economy mode circuit is structured to dose more reductant than a minimum calculated reductant dose in order to increase the ammonia storage within the SCR system. ### Claim 11 A system comprising: an exhaust aftertreatment system including a reductant source and a selective catalytic reduction (SCR) component; and a controller in communication with the exhaust aftertreatment system, the controller structured to: determine an amount of stored reductant in the SCR component of the exhaust aftertreatment system; and control an amount of reductant added to the exhaust aftertreatment system during a standard engine idle mode of operation based on the amount of stored reductant, wherein the fuel mode economy circuit is structured to enter a fuel efficient engine idle mode in which the fuel mode economy circuit is inhibited from adding reductant during the fuel efficient engine idle mode in response to determining that a temperate of the SCR component is above a temperature threshold and in response to determining that an amount of time that the engine is in at least one of the standard engine idle mode and the fuel efficient engine idle mode is less than a fuel efficient idle time threshold. ### Claim 12 (depends on 11) The system of claim 11, wherein the controller is further structured to control the amount of reductant added based on operation data regarding exhaust gas flowing through the exhaust aftertreatment system, wherein the operation data includes an indication of an amount of nitrogen oxide exiting the exhaust aftertreatment system, wherein in response to the amount of nitrogen oxide exiting the exhaust aftertreatment system exceeding a threshold, the controller is further structured to increase the amount of reductant added to the exhaust aftertreatment system. ### Claim 13 (depends on 11) The system of claim 11, wherein the controller is further structured to control the amount of reductant added based on operation data regarding exhaust gas flowing through the exhaust aftertreatment system, wherein the operation data includes an indication of an amount of nitrogen oxide exiting the exhaust aftertreatment system, and wherein the reductant is urea. ### Claim 14 (depends on 11) The system of claim 11, wherein the controller is structured to control the amount of reductant added to the exhaust aftertreatment system based on operation data regarding exhaust gas flowing through the exhaust aftertreatment system and the stored reductant amount for a predefined amount of time. ### Claim 15 (depends on 11) The system of claim 11, wherein the controller is structured to dose more reductant than a minimum calculated reductant dose in order to increase the ammonia storage within the SCR system. ### Claim 16 A method comprising: detecting a level of nitrogen oxide present in a flow of exhaust gas downstream of a catalyst during an engine idle mode of operation; comparing the detected level of nitrogen oxide to a threshold; providing, during a standard engine idle mode, reductant to the catalyst in response to determining that the nitrogen oxide level is above the threshold; inhibiting, during a fuel efficient engine idle mode, reductant from being added during the fuel efficient engine idle mode in response to determining that a temperate of a selective catalytic reduction (SCR) component is above a temperature threshold and in response to determining that an amount of time that the engine has been in at least one of the standard engine idle mode and the fuel efficient engine idle mode is less than a fuel efficient idle time threshold. ### Claim 17 (depends on 16) The method of claim 16, further comprising determining if an ammonia level present in the catalyst is above an ammonia storage threshold. ### Claim 18 (depends on 16) The method of claim 16, wherein providing the reductant to the catalyst includes providing substantially more than a minimum calculated reductant dose. ### Claim 19 (depends on 16) The method of claim 16, further comprising timing a duration that the flow of reductant to the catalyst is inhibited, and providing reductant to the catalyst after the duration reaches a timing threshold. ### Claim 20 (depends on 16) The method of claim 16, further comprising operating an exhaust gas recirculation system when the nitrogen oxide level is above the threshold, and inhibiting operation of the exhaust gas recirculation system when the nitrogen oxide level is below the threshold.