# US 2014/0190150 A1 · Exhaust gas purification apparatus for an 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 2014/0190150 A1 - Document ID: US20140190150A1 - Status: Published application - Kind: A1 - Application number: 14/237,239 - Filed: 2011-09-06 - Published: 2014-07-10 - Earliest claimed: 2011-09-06 - Assignees: Toyota Jidosha Kabushiki Kaisha - Inventors: Kenji Sakurai; Toru Kidokoro; Yasuyuki Irisawa; Yuji Miyoshi - Web page: https://patentgrep.com/patent/US20140190150A1 ## CPC - F01N 3/18: characterised by methods of operation; Control - F01N 3/0842: {Nitrogen oxides} - F01N 3/085: {Sulfur or sulfur oxides} - F01N 3/0885: {Regeneration of deteriorated absorbents or adsorbents, e.g. desulfurization of NOx traps} - F01N 3/2073: {Means for generating a reducing substance from the exhaust gases} - F01N 13/009: {having two or more separate purifying devices arranged in series} - F02D 41/024: {to increase temperature of the exhaust gas treating apparatus} - F02D 41/028: {Desulfurisation of NOx traps or adsorbent} - F01N 3/101: {Three-way catalysts} - F01N 2550/03: of sorbing activity of adsorbents or absorbents - F01N 2570/24: Hydrogen sulfide (H2S) - 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) - 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 cases where at the upstream side of an NOx selective reduction catalyst there is provided another catalyst, sulfur poisoning of both the catalysts is recovered in an appropriate manner. To this end, provision is made for an NH3 generation catalyst arranged in an exhaust passage of an internal combustion engine for generating NH3, the NOx selective reduction catalyst arranged in the exhaust passage at a location downstream of the NH3 generation catalyst for reducing NOx in a selective manner, an upstream side recovery unit to recover sulfur poisoning of the NH3 generation catalyst, and a downstream side recovery unit to recover sulfur poisoning of the NOx selective reduction catalyst after the sulfur poisoning of the NH3 generation catalyst has been recovered by the upstream side recovery unit. ## Claims ### Claim 1 An exhaust gas purification apparatus, comprising: an NH3 generation catalyst arranged in an exhaust passage of an internal combustion engine, wherein the generation catalyst is configured to generate NH3; an NOx selective reduction catalyst arranged in the exhaust passage at a location downstream of the NH3 generation catalyst, wherein the reduction catalyst is configured to reduce NOx in a selective manner; an upstream side recovery unit configured to recover sulfur poisoning of the NH3 generation catalyst; and a downstream side recovery unit configured to recover sulfur poisoning of the NOx selective reduction catalyst after the sulfur poisoning of the NH3 generation catalyst has been recovered by the upstream side recovery unit. ### Claim 2 (depends on 1) The exhaust gas purification apparatus of claim 1, wherein the downstream side recovery unit is adapted to suppress a temperature of the NOx selective reduction catalyst, which had gone up when the upstream side recovery unit recovered the sulfur poisoning of the NH3 generation catalyst, from falling after recovery of the sulfur poisoning of the NH3 generation catalyst. ### Claim 3 (depends on 8) The exhaust gas purification apparatus of claim 8, wherein the downstream side recovery unit is adapted to carry out the recovery of the sulfur poisoning by making an amount of oxygen flowing into the NOx selective reduction catalyst in a predetermined period of time after the sulfur poisoning of the NH3 generation catalyst was recovered by the upstream side recovery unit larger than an amount of oxygen flowing into the NOx selective reduction catalyst after the predetermined period of time. ### Claim 4 (depends on 1) The exhaust gas purification apparatus of claim 1, wherein the downstream side recovery unit is adapted to make an air fuel ratio of an exhaust gas to be higher in the predetermined period of time than after the predetermined period of time. ### Claim 5 (depends on 1) The exhaust gas purification apparatus of claim 1, wherein the downstream side recovery unit is adapted to make an amount of intake air in the internal combustion engine larger in the predetermined period of time than after the predetermined period of time. ### Claim 6 (depends on 1) The exhaust gas purification apparatus of claim 1, wherein the downstream side recovery unit is adapted to make a period of time after the sulfur poisoning of the NH3 generation catalyst has been recovered by the upstream side recovery unit until a reducing agent is first supplied to the NH3 generation catalyst to be longer than intervals between first and subsequent supplies of the reducing agent. ### Claim 7 (depends on 1) The exhaust gas purification apparatus of claim 1, wherein the NOx selective reduction catalyst comprises a base metal. ### Claim 8 An exhaust gas purification apparatus, comprising: an NH3 generation catalyst arranged in an exhaust passage of an internal combustion engine, wherein the generation catalyst is configured to generate NH3; an NOx selective reduction catalyst arranged in the exhaust passage at a location downstream of the NH3 generation catalyst, wherein the reduction catalyst is configured to reduce NOx in a selective manner; an upstream side recovery unit configured to recover sulfur poisoning of the NH3 generation catalyst by adapting the internal combustion engine to operate at a rich air fuel ratio; and a downstream side recovery unit configured to recover sulfur poisoning of the NOx selective reduction catalyst by adapting the internal combustion engine to operate at a lean air fuel ratio after the sulfur poisoning of the NH3 generation catalyst has been recovered by the upstream side recovery unit. ### Claim 9 (depends on 8) The exhaust gas purification apparatus of claim 8, wherein the downstream side recovery unit is adapted to suppress a temperature of the NOx selective reduction catalyst, which had gone up when the upstream side recovery unit recovered the sulfur poisoning of the NH3 generation catalyst, from falling after recovery of the sulfur poisoning of the NH3 generation catalyst. ### Claim 10 (depends on 3) The exhaust gas purification apparatus claim 3, wherein the downstream side recovery unit is adapted to make an air fuel ratio of an exhaust gas to be higher in the predetermined period of time than after the predetermined period of time. ### Claim 11 (depends on 3) The exhaust gas purification apparatus of claim 3, wherein the downstream side recovery unit is adapted to make an amount of intake air in the internal combustion engine larger in the predetermined period of time than after the predetermined period of time. ### Claim 12 (depends on 3) The exhaust gas purification apparatus of claim 3, wherein the downstream side recovery unit is adapted to make a period of time after the sulfur poisoning of the NH3 generation catalyst has been recovered by the upstream side recovery unit until a reducing agent is first supplied to the NH3 generation catalyst to be longer than intervals between first and subsequent supplies of the reducing agent. ### Claim 13 (depends on 8) The exhaust gas purification apparatus of claim 8, wherein the NOx selective reduction catalyst comprises a base metal.