# US 8,769,934 B2 · Exhaust purifying system for internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,769,934 B2 - Document ID: US8769934B2 - Status: Granted - Kind: B2 - Application number: 13/498,181 - Filed: 2009-10-20 - Published: 2012-08-02 - Granted: 2014-07-08 - Earliest claimed: 2009-10-20 - Assignees: Toyota Jidosha Kabushiki Kaisha - Applicants: Kenji Sakurai - Inventors: Kenji Sakurai - Web page: https://patentgrep.com/patent/US8769934B2 ## CPC - F01N 3/0814: {combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts} - F01N 3/2066: {Selective catalytic reduction [SCR]} - F01N 9/00: Electrical control of exhaust gas treating apparatus (monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00) - F01N 13/009: {having two or more separate purifying devices arranged in series} - F01N 13/011: {having two or more purifying devices arranged in parallel} - F02D 41/027: {to purge or regenerate the exhaust gas treating apparatus} - F02D 41/1463: {of the exhaust gases downstream of exhaust gas treatment apparatus} - F01N 13/107: {More than one exhaust manifold or exhaust collector} - F01N 2560/021: for measuring or detecting ammonia NH3 - F01N 2560/025: for measuring or detecting O2, e.g. lambda sensors - F01N 2560/026: for measuring or detecting NOx - F01N 2900/102: Travelling distance - F01N 2900/1402: Exhaust gas composition - F01N 2900/1406: Exhaust gas pressure - F01N 2900/1612: SOx amount trapped in catalyst - F02D 41/025: {by changing the composition of the exhaust gas, e.g. for exothermic reaction on exhaust gas treating apparatus} - F02D 41/0285: {the exhaust gas treating apparatus being a SOx trap or adsorbent} - F02D 41/1441: {Plural sensors} - F02D 2200/0818: SOx storage amount, e.g. for SOx trap or NOx trap - 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 In an internal combustion engine including an NSR catalyst and an SCR, to provide an exhaust purifying system that can limit aggravation of emissions by allowing the SCR to recover effectively from degraded performance caused by poisoning. An exhaust purifying system for an internal combustion engine capable of a lean burn operation includes an NSR catalyst disposed in an exhaust passage of the internal combustion engine; an SCR disposed downstream of the NSR catalyst; means for detecting sulfur poisoning of the SCR; and means for increasing a bed temperature of the SCR when the poisoning detecting means detects sulfur poisoning of the SCR. The temperature increasing means includes bank control, stoichiometric control, and rich spike control, any one of which is selected for performance according to an operating condition of the internal combustion engine. ## Claims ### Claim 1 An exhaust purifying system for an internal combustion engine capable of a lean burn operation, comprising: a NOx storage-reduction catalyst (NSR catalyst) disposed in an exhaust passage of the internal combustion engine; a NOx selective catalytic reduction (SCR) disposed downstream of the NSR catalyst; means for detecting sulfur poisoning of the SCR; and means for increasing a bed temperature of the SCR when the poisoning detecting means detects sulfur poisoning of the SCR, wherein: the internal combustion engine includes a plurality of cylinder groups; the temperature increasing means includes means for performing a bank control in which a rich air-fuel ratio is set for a first cylinder group and a lean or stoichiometric air-fuel ratio is set for a second cylinder group; and the bank control is performed when the sulfur poisoning of the SCR is detected and a distance driven from performance of a preceding bank control is longer than a predetermined distance. ### Claim 2 (depends on 1) The exhaust purifying system for an internal combustion engine according to claim 1, wherein: the temperature increasing means further includes means for performing a stoichiometric control in which the internal combustion engine is operated at the stoichiometric air-fuel ratio as changed over from the lean air-fuel ratio; and the stoichiometric control is performed when the sulfur poisoning of the SCR is detected, and when the distance driven is equal to, or less than, the predetermined distance and an engine speed of the internal combustion engine is greater than a predetermined speed. ### Claim 3 (depends on 2) The exhaust purifying system for an internal combustion engine according to claim 2, wherein: the temperature increasing means further includes means for performing a rich spike control in which the air-fuel ratio of the internal combustion engine is temporarily brought to a rich air-fuel ratio; and frequency at which the rich spike control is performed is increased when the sulfur poisoning of the SCR is detected, and when the distance driven is equal to, or less than, the predetermined distance and the engine speed is equal to, or lower than, a predetermined speed. ### Claim 4 (depends on 1) The exhaust purifying system for an internal combustion engine according to claim 1, further comprising: means for stopping performance by the temperature increasing means when the bed temperature of the SCR reaches a predetermined temperature. ### Claim 5 An exhaust purifying system for an internal combustion engine capable of a lean burn operation, comprising: a NOx storage-reduction catalyst (NSR catalyst) disposed in an exhaust passage of the internal combustion engine; a NOx selective catalytic reduction (SCR) disposed downstream of the NSR catalyst; a NOx sensor for detecting sulfur poisoning of the SCR; and an electronic control unit including instructions for increasing a bed temperature of the SCR when the NOx sensor detects sulfur poisoning of the SCR, wherein: the internal combustion engine includes a plurality of cylinder groups; the electronic control unit including instructions for performing a bank control in which a rich air-fuel ratio is set for a first cylinder group and a lean or stoichiometric air-fuel ratio is set for a second cylinder group; and the bank control is performed when the sulfur poisoning of the SCR is detected and a distance driven from performance of a preceding bank control is longer than a predetermined distance.