# US 9,517,434 B2 · Catalyst system for exhaust gas purification utilizing base metals, and controlling method therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,517,434 B2 - Document ID: US9517434B2 - Status: Granted - Kind: B2 - Application number: 14/378,753 - Filed: 2012-11-09 - Published: 2015-01-29 - Granted: 2016-12-13 - Earliest claimed: 2012-02-15 - Assignees: Toyota Jidosha Kabushika Kaisha - Applicants: Takeshi Nobukawa - Inventors: Takeshi Nobukawa - Web page: https://patentgrep.com/patent/US9517434B2 ## CPC - B01D 53/565: {by treating the gases with solids} - B01D 53/9418: {for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas} - B01D 53/9431: {Processes characterised by a specific device} - B01J 23/72: Copper - B01J 23/83: with rare earths or actinides - B01J 23/8926: {Copper and noble metals} - B01J 23/894: {with rare earths or actinides} - F01N 3/08: for rendering innocuous (using electric or electrostatic separators F01N3/01; chemical aspects B01D53/92) - B01D 2251/2062: Ammonia - B01D 2255/106: Gold - B01D 2255/2065: Cerium - B01D 2255/20738: Iron - B01D 2255/20746: Cobalt - B01D 2255/20761: Copper - B01D 2255/50: Zeolites - B01D 2255/65: Catalysts not containing noble metals - B01D 2255/904: Multiple catalysts - B01D 2257/404: Nitrogen oxides other than dinitrogen oxide - F01N 2510/0682: having a discontinuous, uneven or partially overlapping coating of catalytic material, e.g. higher amount of material upstream than downstream or vice versa - F01N 2560/026: for measuring or detecting NOx - 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) - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - 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) ## Abstract A catalyst system for exhaust gas purification which comprises a first-stage base metal catalyst located upstream and a second-stage base metal catalyst located downstream, wherein the first-stage base metal catalyst comprises at least one oxide support selected from the group consisting of alumina, ceria, zirconia, yttria, and titania and Cu metal and/or a Cu oxide supported thereon, and in cases where the amount of NOx in the exhaust gas has become or exceeded an NOx criterion, the state of the exhaust gas is switched from slightly rich to rich. ## Claims ### Claim 1 A catalyst system for exhaust gas purification comprising: an electronic control unit (ECU); a first-stage metal catalyst located at an upstream end; and a second-stage base metal catalyst located at a downstream end, wherein the first-stage metal catalyst has Cu metal and/or Cu oxide supported on one or more oxide supports selected from the group consisting of alumina, ceria, zirconia, yttria and titania, wherein the crystallite diameter for ceria-zirconia of the oxide supports is 4 nm-12 nm, and wherein when the volume of NOx in the exhaust gas has become equal to or exceeds an NOx criteria, the ECU switches the state of the exhaust gas from slightly enriched of 14.45≦A/F1≦−14.59 to enriched of A/F2≦14.40. ### Claim 2 (depends on 1) A catalyst system for exhaust gas purification according to claim 1, wherein the ECU controls the injection of air between the first-stage metal catalyst and second-stage base metal catalyst, and controls the exhaust gas to a condition more lean than a theoretical air/fuel ratio of A/F=14.6 at the second-stage base metal catalyst. ### Claim 3 (depends on 2) A catalyst system for exhaust gas purification according to claim 2, wherein the oxide support of the first-stage metal catalyst is fine particles of a mixture of alumina, ceria, zirconia and yttria. ### Claim 4 (depends on 3) A catalyst system for exhaust gas purification according to claim 3, wherein the first-stage metal catalyst has an alloy of Au and Cu supported in place of Cu metal and/or Cu oxide. ### Claim 5 (depends on 4) A catalyst system for exhaust gas purification according to claim 4, wherein the second-stage base metal catalyst has one or more metals and/or metal oxides selected from the group consisting of Cu, Fe, Co and Ce supported on one or more oxide supports selected from the group consisting of alumina, zirconia, titania and zeolite. ### Claim 6 (depends on 5) A catalyst system for exhaust gas purification according to claim 5, wherein the second-stage base metal catalyst has Cu and/or Fe metal and/or metal oxide supported on an oxide support containing zeolite. ### Claim 7 (depends on 3) A catalyst system for exhaust gas purification according to claim 3, wherein the second-stage base metal catalyst has one or more metals and/or metal oxides selected from the group consisting of Cu, Fe, Co and Ce supported on one or more oxide supports selected from the group consisting of alumina, zirconia, titania and zeolite. ### Claim 8 (depends on 7) A catalyst system for exhaust gas purification according to claim 7, wherein the second-stage base metal catalyst has Cu and/or Fe metal and/or metal oxide supported on an oxide support containing zeolite. ### Claim 9 (depends on 2) A catalyst system for exhaust gas purification according to claim 2, wherein the second-stage base metal catalyst has one or more metals and/or metal oxides selected from the group consisting of Cu, Fe, Co and Ce supported on one or more oxide supports selected from the group consisting of alumina, zirconia, titania and zeolite. ### Claim 10 (depends on 9) A catalyst system for exhaust gas purification according to claim 9, wherein the second-stage base metal catalyst has Cu and/or Fe metal and/or metal oxide supported on an oxide support containing zeolite. ### Claim 11 (depends on 1) A catalyst system for exhaust gas purification according to claim 1, wherein the second-stage base metal catalyst has one or more metals and/or metal oxides selected from the group consisting of Cu, Fe, Co and Ce supported on one or more oxide supports selected from the group consisting of alumina, zirconia, titania and zeolite. ### Claim 12 (depends on 11) A catalyst system for exhaust gas purification according to claim 11, wherein the second-stage base metal catalyst has Cu and/or Fe metal and/or metal oxide supported on an oxide support containing zeolite.