# US 2018/0021767 A1 · Exhaust gas purification catalyst > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0021767 A1 - Document ID: US20180021767A1 - Status: Published application - Kind: A1 - Application number: 15/550,252 - Filed: 2016-02-16 - Published: 2018-01-25 - Earliest claimed: 2015-02-17 - Assignees: Cataler Corporation - Applicants: Cataler Corporation - Inventors: Ryota ONOE; Shingo SAKAGAMI; Yasutaka NOMURA; Yuta MORISHITA; Junji KURIYAMA; Hiroshi SEKINE - Web page: https://patentgrep.com/patent/US20180021767A1 ## CPC - B01J 35/19: {Catalysts containing parts with different compositions} - B01D 53/94: by catalytic processes - B01J 23/63: with rare earths or actinides - B01J 37/02: Impregnation, coating or precipitation ({B01J37/0009 and B01J37/0018 take precedence } ; protection by coating B01J33/00) - F01N 3/035: with catalytic reactors - F01N 3/10: by thermal or catalytic conversion of noxious components of exhaust - F01N 3/24: characterised by constructional aspects of converting apparatus (filtering in combination with catalytic reactors F01N3/035) - F01N 3/28: Construction of catalytic reactors - B01D 2255/1023: Palladium - B01D 2255/1025: Rhodium - B01D 2255/9022: Two layers - B01D 2255/9155: Wall flow filters - B01J 35/56: Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional [3D] monoliths - F01N 13/08: Other arrangements or adaptations of exhaust conduits {(pipes, joints or supports therefor in general F16L; collecting or removing exhaust gases of vehicle engines in workshops B08B15/00, on highways E01C1/005)} - F01N 2250/02: filtering and catalytic conversion - F01N 2260/06: for improving exhaust evacuation or circulation, or reducing back-pressure - F01N 2370/02: used in catalytic reactors - F01N 2510/068: characterised by the distribution of the catalytic coatings - 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 2510/0684: having more than one coating layer, e.g. multi-layered coatings - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - 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) - 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 An exhaust gas purification catalyst capable of stably maintaining and exhibiting excellent catalytic performance includes a wall-flow-type substrate, a first catalytic layer and a second catalytic layer. The first catalytic layer is provided to an internal portion of a partition wall in contact with an entrance cell. The second catalytic layer is provided to an internal portion of a partition wall in contact with an exit cell. The ratio (D2/D1) of the coating density D2 of the second catalytic layer to the coating density D1 of the first catalytic layer is 1.01 to 1.4. ## Claims ### Claim 1 A wall-flow-type exhaust gas purification catalyst to be placed in an exhaust pipe of an internal combustion system to purify exhaust gas emitted from the internal combustion system, the exhaust gas purification catalyst comprising: a substrate having a wall-flow structure with an exhaust inlet-side end and an exhaust outlet-side end, the substrate having an entrance cell that is open on the exhaust inlet-side end and an exit cell that is open on the exhaust outlet-side end, separated with a porous partition wall, a first catalytic layer provided to an internal portion of the partition wall in contact with the entrance cell, having a length L1 from the exhaust inlet-side end in the running direction of the partition wall with L1 being less than the total length Lw of the partition wall in the running direction, a second catalytic layer provided to an internal portion of the partition wall in contact with the exit cell, having a length L2 from the exhaust outlet-side end in the running direction of the partition wall with L2 being less than the total length Lw of the partition wall in the running direction; wherein in the internal portion of the partition wall in contact with the entrance cell, near the exhaust outlet-side end, the exhaust gas purification catalyst has a substrate-exposing segment free of the first and second catalytic layers, and the first catalytic layer has a coating density D1 and the second catalytic layer has a coating density D2 with a D2/D1 ratio value of 1.01 or higher, but 1.4 or lower. ### Claim 2 (depends on 1) The exhaust gas purification catalyst according to claim 1 wherein the length L1 of the first catalytic layer in the running direction satisfies 0.5Lw