# US 9,433,899 B2 · Method for removing carbon monoxide and hydrocarbons from the exhaust gas of lean-burn internal combustion engines > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,433,899 B2 - Document ID: US9433899B2 - Status: Granted - Kind: B2 - Application number: 14/390,765 - Filed: 2013-03-26 - Published: 2016-02-25 - Granted: 2016-09-06 - Earliest claimed: 2012-04-05 - Assignees: Umicore AG & Co. KG - Applicants: Umicore AG & CO. KG - Inventors: Ruediger Hoyer; Anke Schuler; Stefan Franoschek; Thomas R. Pauly; Gerald Jeske - Web page: https://patentgrep.com/patent/US9433899B2 ## CPC - B01D 53/944: {Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts (three-way-catalysts [TWC] B01D53/9445)} - B01D 53/9495: {Controlling the catalytic process} - B01D 53/96: Regeneration, reactivation or recycling of reactants - F02D 41/027: {to purge or regenerate the exhaust gas treating apparatus} - F02D 41/1446: {the characteristics being exhaust temperatures} - B01D 2255/1021: Platinum - B01D 2255/1023: Palladium - B01D 2255/1025: Rhodium - B01D 2255/2063: Lanthanum - B01D 2255/2065: Cerium - B01D 2255/2092: Aluminium - B01D 2258/012: Diesel engines and lean burn gasoline engines - Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters - 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) - 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) - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE ## Abstract The invention relates to a method for removing carbon monoxide and hydrocarbons from the exhaust gas of lean-burn internal combustion engines, said exhaust gas being passed over a catalyst which contains platinum supported on one or more refractory supporting materials, pure cerium oxide, and optionally an additional noble metal selected from the group consisting of platinum, palladium and rhodium, wherein the pure cerium oxide is in close contact with the noble metal. ## Claims ### Claim 1 A method for removing carbon monoxide and hydrocarbons from the exhaust gas of lean-burn internal combustion engines, wherein the exhaust gas is passed over a catalyst which contains (i) platinum supported on one or more refractory supporting materials, (ii) pure cerium oxide, and (iii) if the ratio of platinum to cerium oxide is ≦0.5 (calculated as Pt in g/cft:cerium oxide in g/l), an additional noble metal selected from the group consisting of platinum, palladium, rhodium and mixtures thereof, wherein the pure cerium oxide (ii) being in close contact with platinum (i) and, if included, additional noble metal (iii), wherein, after a limit temperature exposure under lean exhaust gas conditions is exceeded, the catalyst is exposed for a short time to rich exhaust gas to regenerate catalytic activity. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the quantity of platinum (i) amounts to 0.4 to 2 wt. % relative to the total weight of components (i) to (iii). ### Claim 3 (depends on 1) The method as claimed in claim 1 wherein palladium is supported on the one or more refractory supporting materials in addition to platinum. ### Claim 4 (depends on 3) The method as claimed in claim 3, wherein the quantity of palladium is selected such that, relative to component (i), a ratio by weight of Pt:Pd of 2:1 to 10:1 results. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, cerium oxide, zeolite, or mixtures of mixed oxides thereof are used as refractory supporting materials for component (i). ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the pure cerium oxide contains 90 to 100 wt. % cerium oxide relative to the total weight of the pure cerium oxide. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein the catalyst comprises the additional noble metal (iii), and the additional noble metal (iii) is used in quantities of 0 to 0.5 wt. %, relative to the total weight of components (i) to (iii). ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein the short time for which the catalyst is exposed to rich exhaust gas is a time of 1 to 10 seconds. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein the limit temperature exposure is defined as a limit temperature which, if exceeded, triggers regeneration. ### Claim 10 (depends on 9) The method as claimed in claim 9, wherein the limit temperature amounts to 400° C., if the T50 value for CO light-off is to be 150° C. ### Claim 11 (depends on 9) The method as claimed in claim 9, wherein the limit temperature amounts to 350° C., if the T50 value for CO light-off is to be 125° C. ### Claim 12 (depends on 1) The method as claimed in claim 1, wherein the limit temperature exposure is defined as a residence time of the catalyst in previously defined temperature classes which, if exceeded, triggers regeneration. ### Claim 13 (depends on 12) The method as claimed in claim 12, wherein a.) the temperature of the catalyst is measured or simulated and the residence time in a temperature class is determined or the residence time in a plurality of defined temperature classes is determined and added up, b.) on a given upper limit for the residence time being exceeded, the need for regeneration of the catalyst is identified, c.) on or after the temperature falling below a further limit temperature, the engine is changed over to rich exhaust gas for a short period, and d.) on or after completion of regeneration of the catalyst with rich exhaust gas, the residence times of all the temperature classes are reset to zero. ### Claim 14 (depends on 1) The method as claimed in claim 1, wherein the engine is switched off if it is exposed to rich exhaust gas.