US20180058286A1 - METHOD AND APPARATUS TO MINIMIZE DEACTIVATION OF A LOW TEMPERATURE NOx ADSORBER IN AN EXHAUST AFTERTREATMENT SYSTEM - Google Patents

METHOD AND APPARATUS TO MINIMIZE DEACTIVATION OF A LOW TEMPERATURE NOx ADSORBER IN AN EXHAUST AFTERTREATMENT SYSTEM Download PDF

Info

Publication number
US20180058286A1
US20180058286A1 US15/253,136 US201615253136A US2018058286A1 US 20180058286 A1 US20180058286 A1 US 20180058286A1 US 201615253136 A US201615253136 A US 201615253136A US 2018058286 A1 US2018058286 A1 US 2018058286A1
Authority
US
United States
Prior art keywords
zeolite
aftertreatment system
exhaust aftertreatment
catalyst
disposed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US15/253,136
Other languages
English (en)
Inventor
Gongshin Qi
Shouxian Ren
Wei Li
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GM Global Technology Operations LLC
Original Assignee
GM Global Technology Operations LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by GM Global Technology Operations LLC filed Critical GM Global Technology Operations LLC
Priority to US15/253,136 priority Critical patent/US20180058286A1/en
Assigned to GM Global Technology Operations LLC reassignment GM Global Technology Operations LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: REN, SHOUXIAN, LI, WEI, QI, GONGSHIN
Priority to DE102017214572.2A priority patent/DE102017214572A1/de
Priority to CN201710730445.9A priority patent/CN107781003A/zh
Publication of US20180058286A1 publication Critical patent/US20180058286A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B67/00—Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for
    • F02B67/10—Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for of charging or scavenging apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0821—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with particulate filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/103—Oxidation catalysts for HC and CO only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
    • F01N3/108—Auxiliary reduction catalysts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
    • F01N3/2807—Metal other than sintered metal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/12—Combinations of different methods of purification absorption or adsorption, and catalytic conversion

Definitions

  • Emission control systems are employed to oxidize, reduce, filter and/or store and release various exhaust gas constituents prior to release into the atmosphere, and may achieve high efficiencies once reaching warmed up operating temperatures. However, such systems may be less efficient when operating at temperatures that are less than warmed up operating temperatures, such as may occur following a cold start.
  • Effective control of exhaust emissions at low temperatures is critical for emission compliance due to the generation of exhaust gas constituents during cold-start engine operation.
  • Fuel-saving technologies such as lean burn engine operation, turbocharging, and other advanced combustion techniques may result in lower overall exhaust temperatures, further complicating low temperature emissions control.
  • An exhaust aftertreatment system for purifying an exhaust gas feedstream from an internal combustion engine that is disposed to operate at a lean air/fuel ratio includes an oxidation catalyst disposed upstream of a low-temperature NOx adsorber.
  • the oxidation catalyst includes a zeolite catalyst including a base metal, a noble metal, and a zeolite disposed on a substrate, and the low-temperature NOx adsorber includes a zeolite catalyst and a supported platinum group metal catalyst.
  • FIG. 1 schematically illustrates relevant portions of an embodiment of an exhaust aftertreatment system for an internal combustion engine that includes a diesel oxidation catalyst (DOC) disposed upstream of a low-temperature NOx adsorber (LTNA), in accordance with the disclosure;
  • DOC diesel oxidation catalyst
  • LTNA low-temperature NOx adsorber
  • FIG. 2 schematically illustrates relevant portions of another embodiment of an exhaust aftertreatment system for an internal combustion engine including a forced air induction device, wherein the exhaust aftertreatment system includes a diesel oxidation catalyst (DOC) disposed upstream of a low-temperature NOx adsorber (LTNA), in accordance with the disclosure;
  • DOC diesel oxidation catalyst
  • LTNA low-temperature NOx adsorber
  • FIG. 3-1 graphically shows data results associated with flow of a representative exhaust gas feedstream across an embodiment of the LTNA that is disposed as a stand-alone device in a close-coupled arrangement downstream of an exhaust manifold of an engine, in accordance with the disclosure;
  • FIG. 3-2 graphically shows data results associated with flow of a representative exhaust gas feedstream across an embodiment of the DOC and the LTNA that are disposed in a close-coupled arrangement downstream of the exhaust manifold of the engine that is described with reference to FIG. 1 , in accordance with the disclosure;
  • FIG. 4 graphically shows data results associated with NOx storage capacity for an embodiment of the LTNA after exposure to a lean aging protocol, and after exposure to a lean/rich cycle aging protocol of comparable time, temperature and flow conditions, in accordance with the disclosure.
  • upstream and related terms refer to elements that are towards an origination of a flow stream relative to an indicated location
  • downstream and related terms refer to elements that are away from an origination of a flow stream relative to an indicated location.
  • FIG. 1 illustrates an exhaust aftertreatment system 20 that is disposed to purify an exhaust gas feedstream 15 that is output from an internal combustion engine (engine) 10 during its operation.
  • the internal combustion engine 20 may be disposed in a vehicle to provide propulsion power.
  • the vehicle may include, but not be limited to a mobile platform in the form of a commercial vehicle, industrial vehicle, agricultural vehicle, passenger vehicle, aircraft, watercraft, train, all-terrain vehicle, personal movement apparatus, robot and the like to accomplish the purposes of this disclosure.
  • the engine 10 may be any suitable internal combustion engine, and is preferably configured as a multi-cylinder compression-ignition engine that primarily operates at an air/fuel ratio that is lean of stoichiometry in one embodiment.
  • the engine 10 may include a cylinder block having a plurality of cylinders and pistons therein (not separately shown), which, along with a cylinder head (also not separately shown), may define combustion chambers for internal combustion of a mixture of fuel and induction gases.
  • the engine 10 may also include any suitable quantities of intake valves and exhaust valves disposed in the cylinder head for controlling flow of intake air and exhaust gases.
  • the engine 10 preferably includes an exhaust manifold 12 that entrains exhaust gases that are output as a result of the combustion process and channels them into the exhaust aftertreatment system 20 for purification and expulsion into the atmosphere.
  • the exhaust aftertreatment system 20 preferably includes one or more additional aftertreatment devices that are disposed to oxidize, reduce, store, filter or otherwise treat the exhaust gas feedstream 15 of the engine 10 .
  • an exhaust system may include hydrocarbon trapping components that employ zeolite materials. In such systems, the zeolite material adsorbs and stores hydrocarbons during the start-up period and releases the stored hydrocarbons when the exhaust temperature is high enough to desorb hydrocarbons. The desorbed hydrocarbons are preferably oxidized in downstream catalytic components.
  • an exhaust system may include NOx storage and release catalysts such as selective catalytic reduction (SCR) devices or NOx adsorbers to reduce NOx to nitrogen. Such catalysts adsorb NOx during warm-up and thermally desorb NOx at higher exhaust temperatures.
  • SCR selective catalytic reduction
  • the exhaust aftertreatment system 20 preferably includes a diesel oxidation catalyst (DOC) 30 that is disposed upstream of a low-temperature NOx adsorber (LTNA) 40 .
  • DOC diesel oxidation catalyst
  • LTNA low-temperature NOx adsorber
  • another exhaust purification device 50 such as an SCR device or a SCR device that is disposed on a substrate that includes a particulate filter (SCRF)
  • SCRF particulate filter
  • the exhaust purification device 50 is an SCR or an SCRF
  • a reductant injector system 42 is disposed upstream thereto.
  • Design, implementation and operational control of reductant injector systems 42 and purification devices 50 such as SCRs and SCRFs are application-specific and known to one of ordinary skill in the art, and thus not described herein.
  • the DOC 30 and the LTNA 40 are disposed in a close-coupled arrangement relative to the engine 10 and exhaust manifold 12 .
  • the term “close-coupled” refers to a position of a device of the exhaust aftertreatment system 20 that is in as close proximity to the exhaust manifold 12 as is practicable in order to minimize loss of thermal energy from the exhaust gas feedstream prior to the exhaust gas reaching the device, e.g., DOC 30 .
  • the close-coupled arrangement includes having the DOC 30 at a location that is less than about 1 meter downstream from the exhaust manifold 12 or turbocharger, and is preferably about 0.05 to about 0.5 meters.
  • a close-coupled exhaust component is preferably located underhood in an engine compartment, although such an arrangement may not be practicable in some embodiments.
  • exhaust aftertreatment devices that are arranged in a close-coupled position may be exposed to higher exhaust gas temperatures as compared to devices that are further downstream.
  • FIG. 2 schematically shows a second embodiment of the exhaust aftertreatment system 120 that may be advantageously fluidly coupled to the exhaust manifold 12 of the internal combustion engine 10 .
  • a forced air induction device 134 e.g., a turbocharger or a supercharger is employed.
  • the exhaust aftertreatment system 120 preferably includes a DOC 130 that is close-coupled to the exhaust manifold 12 , and is disposed upstream of the forced air induction device 134 .
  • a hydrocarbon injector 132 is preferably disposed to inject unburned hydrocarbons downstream of the forced air induction device 134 and upstream of an embodiment of the LTNA 140 .
  • another exhaust purification device 150 such as an SCR device or a SCR device that is disposed on a substrate that includes a particulate filter (SCRF), is disposed downstream of the LTNA 140 .
  • SCRF particulate filter
  • a reductant injector system 142 and a mixing device 144 may be interposed between the LTNA 140 and the SCRF 150 .
  • the DOC 30 , 130 is configured to promote oxidation of several exhaust gas components in the exhaust gas feedstream in the presence of oxygen, which may be abundant in a lean exhaust environment.
  • the exhaust components that may be oxidized include carbon monoxide (CO), gas phase hydrocarbons (HC), and a soluble organic fraction (SOF) of particulates.
  • the DOC 30 , 130 includes, for example, catalytic material that is supported on a surface of a substrate via washcoating and other processes that may include impregnation, adsorption, ion-exchange, etc.
  • the substrate may be in the form of a structure having a multiplicity of flow channels arranged in parallel to an axial axis between an inlet and an outlet, wherein the flow channels are capable of retaining a washcoat that contains catalytic materials.
  • the cross-sectional shape of the channels may be any suitable shape, including e.g., square, sinusoidal, triangular, rectangular, hexagonal, trapezoidal, circular, or oval.
  • the substrate is fabricated from extruded ceramic materials such as cordierite.
  • the substrate is fabricated from metal foil.
  • the substrate is formed from ceramic materials, it preferably has a honeycomb structure, and can be arranged as a flow-through device, or alternatively, as a wall-flow filter device that is able to remove particulate matter from the exhaust gas feedstream.
  • the ceramic substrate may be fabricated from any suitable refractory material, e.g., alumina, silica, titania, ceria, zirconia, magnesia, zeolites, silicon nitride, silicon carbide, zirconium silicates, magnesium silicates, aluminosilicates, metallo aluminosilicates (such as cordierite and spudomene), or a mixture or mixed oxide of any two or more thereof. Cordierite, a magnesium aluminosilicate, and silicon carbide are preferred.
  • the metallic substrates may be fabricated from any suitable metal, and in particular heat-resistant metals and metal alloys such as titanium and stainless steel as well as ferritic alloys containing iron, nickel, chromium, and/or aluminum in addition to other trace metals.
  • the substrate When the substrate is arranged as a wall-flow filter device, adjacent flow channels are blocked on alternate axial ends. This allows the exhaust gas feedstream to enter a channel from an inlet, flow through the channel walls, and exit the filter from a different channel leading to the outlet. Particulates in the exhaust gas stream may be thus trapped in the particulate filter and subsequently oxidized.
  • the catalytic material is preferably a zeolite catalyst that includes a base metal, a noble metal, and a zeolite.
  • the catalytic material further includes an oxygen storage capacity material disposed on the substrate.
  • the oxygen storage capacity material is ceria.
  • the catalytic material may include, by way of non-limiting examples, an inorganic oxide selected from the group consisting of alumina, silica, titania, and zirconia.
  • the noble metal may be selected from the group consisting of Pt, Pd, Rh, Ag, Au and Ir.
  • the LTNA 40 , 140 may be composed as a zeolite catalyst and a supported platinum group metal catalyst that are disposed on a substrate.
  • the zeolite catalyst preferably includes a base metal, a noble metal, and a zeolite.
  • the base metal is preferably iron, copper, manganese, chromium, cobalt, nickel, tin, or mixtures thereof; more preferably, iron, copper, manganese, cobalt, or mixtures thereof. Iron is particularly preferred.
  • the noble metal is preferably palladium, platinum, rhodium, silver, or mixtures thereof.
  • the zeolite may be any natural or a synthetic zeolite, including molecular sieves, and is preferably composed of aluminum, silicon, and/or phosphorus.
  • the zeolite may have a three-dimensional arrangement of SiO4, AlO4, and/or PO4 that are joined by the sharing of oxygen atoms.
  • the zeolite frameworks may be anionic, which are counterbalanced by charge compensating cations, including alkali and alkaline earth elements (e.g., Na, K, Mg, Ca, Sr, and Ba) and also protons.
  • Other metals e.g., Fe, Ti, and Ga
  • iron may be substituted for aluminum in the framework of beta zeolite to produce an iron-beta zeolite (Fe-p zeolite).
  • the zeolite is a beta zeolite, a faujasite (such as an X-zeolite or a Y-zeolite, including NaY and USY), an L-zeolite, a ZSM zeolite (e.g., ZSM-5, ZSM-48), an SSZ-zeolite (e.g., SSZ-13, SSZ-41, SSZ-33), a mordenite, a chabazite, an offretite, an erionite, a clinoptilolite, a silicalite, an aluminum phosphate zeolite (including metalloaluminophosphates such as SAPO-34), a mesoporous zeolite (e.g., MCM-41, MCM-49, SBA-15), a metal-incorporated zeolite, or mixtures thereof; more preferably, the zeolites are beta zeolite, ZSM-5 zeolite, ZSM
  • the zeolite catalyst may be prepared employing any suitable process.
  • the base metal and noble metal may be added to the zeolite to form the zeolite catalyst employing any suitable process.
  • a noble metal compound such as palladium nitrate
  • a base metal compound such as iron nitrate
  • the noble metal compound and a base metal compound may be added to the zeolite simultaneously in one step, or sequentially in multiple steps.
  • the supported platinum group metal catalyst includes one or more platinum group metals (“PGM”) and one or more inorganic oxide carriers.
  • PGM platinum group metals
  • the PGM may be platinum, palladium, rhodium, iridium, or combinations thereof, and most preferably platinum and/or palladium.
  • the inorganic oxide carriers most commonly include oxides of Groups 2, 3, 4, 5, 13 and 14 elements.
  • Useful inorganic oxide carriers preferably have surface areas in the range 10 to 700 m.sup.2/g, pore volumes in the range 0.1 to 4 mL/g, and pore diameters from about 10 to 1000 Angstroms.
  • the inorganic oxide carrier is preferably alumina, silica, titania, zirconia, ceria, niobia, tantalum oxides, molybdenum oxides, tungsten oxides, or mixed oxides or composite oxides of any two or more thereof, e.g. silica-alumina, ceria-zirconia or alumina-ceria-zirconia. Alumina and ceria are particularly preferred.
  • the supported platinum group metal catalyst may be prepared employing any suitable process.
  • the one or more platinum group metals are loaded onto the one or more inorganic oxides employing any suitable process to form the supported PGM catalyst.
  • a platinum compound such as platinum nitrate
  • Other metals may also be added to the supported PGM catalyst.
  • the LTNA 40 , 140 further includes a flow-through substrate or a filter substrate.
  • the zeolite catalyst and the supported platinum group metal catalyst are coated onto the substrate, and preferably deposited on the substrate using a washcoat procedure to produce the LTNA 40 , 140 .
  • the zeolite catalyst and the supported platinum group catalyst may be added to the substrate employing any suitable process.
  • a representative process for preparing the LTNA 40 using a washcoat procedure is set forth below. It will be understood that the process below can be varied according to different embodiments.
  • the zeolite catalyst and the supported PGM catalyst may be added onto the substrate in any suitable order.
  • the zeolite catalyst may be washcoated on the substrate prior to the supported PGM catalyst, or, alternatively the supported PGM catalyst may be washcoated on the substrate prior to the zeolite catalyst.
  • the pre-formed zeolite catalyst may be added to the substrate by a washcoating step.
  • the zeolite catalyst may be formed on the substrate by first washcoating unmodified zeolite, a noble metal/zeolite or a base metal/zeolite onto the substrate to produce a zeolite-coated substrate.
  • Noble metal and/or base metal may then be added to the zeolite-coated substrate, which may be accomplished by an impregnation procedure, or the like.
  • the substrate is composed of the zeolite catalyst, and the supported platinum group metal catalyst is coated onto the zeolite catalyst substrate.
  • the zeolite may be extruded to form the substrate, and is preferably extruded to form a honeycomb substrate.
  • Extruded zeolite substrates and honeycomb bodies, and processes for making them, are known in the art. If a zeolite substrate is formed, the zeolite substrate is then subjected to an impregnation procedure if necessary to load noble metal and/or base metal to the zeolite substrate, followed by a washcoating step to washcoat the supported PGM catalyst.
  • the SCR 50 , 150 is formulated as a part of a substrate that includes a particulate filter.
  • the SCR 50 , 150 is an SCR catalyst washcoat provided on a ceramic substrate, which may include a particulate filter.
  • the reductant delivery system 42 , 142 that is positioned upstream of the SCR 50 , 150 respectively may include any suitable type of reductant injector or delivery device known in the art, including a urea or ammonia injector, and further including an air-assisted, liquid phase, or gas phase injector.
  • the SCR 50 , 150 is preferably used to convert oxides of nitrogen (NOx) into diatomic nitrogen (N 2 ) and water (H 2 O).
  • Selective catalytic reduction (SCR) systems are devices that reduce NOx to N 2 by reaction with nitrogen compounds (such as ammonia or urea) or hydrocarbons (lean NOx reduction).
  • An SCR catalyst may include a vanadia-titania catalyst, a vanadia-tungsta-titania catalyst, or a metal/zeolite catalyst such as iron/beta zeolite, copper/beta zeolite, copper/SSZ-13, copper/SAPO-34, Fe/ZSM-5, or copper/ZSM-5.
  • Particulate filters are devices that remove particulates from the exhaust gas feedstream 15 .
  • Particulate filters include catalyzed particulate filters and bare (non-catalyzed) particulate filters.
  • Catalyzed particulate filters include metal and metal oxide components (such as Pt, Pd, Fe, Mn, Cu, and ceria) to oxidize hydrocarbons and carbon monoxide in addition to oxidizing particulate matter that is trapped by the particulate filter.
  • metal and metal oxide components such as Pt, Pd, Fe, Mn, Cu, and ceria
  • FIG. 3-1 graphically shows data results associated with flow of a representative exhaust gas feedstream 205 across an embodiment of the LTNA 40 that is disposed as a stand-alone device in a close-coupled arrangement downstream of the exhaust manifold 12 of the engine 10 .
  • the data results include concentrations of H 2 , CO and HC 210 and a NOx storage level 212 in relation to an axial length of a sample of an embodiment of the LTNA 40 .
  • the LTNA 40 has been subjected to an aging protocol that includes repetitively executed lean/rich air/fuel ratio excursions.
  • the concentrations of H 2 , CO and HC 210 reduce over the axial length of the LTNA 40 to its outlet 215 , and indicates that the LTNA 40 provides an acceptable level of emissions reduction for those exhaust gas constituents after aging.
  • NOx storage level 212 there is a reduction in NOx storage level 212 , indicating a deterioration in the NOx storage level 212 after aging, which may affect emissions since the NOx emissions that pass through the LTNA 40 , e.g., during cold engine operation, may not be reduceable in a downstream SCR device.
  • FIG. 3-2 graphically shows data results associated with flow of a representative exhaust gas feedstream 205 across an embodiment of the DOC 30 and the LTNA 40 that are disposed in a close-coupled arrangement downstream of the exhaust manifold 12 of the engine 10 , all of which are described with reference to FIG. 1 .
  • the data results include reductions in concentrations of H 2 , CO and HC 220 and a NOx storage level 222 in relation to the axial length of a sample.
  • the DOC 30 and the LTNA 40 have been subjected to the lean/rich aging protocol that includes repetitively executed lean/rich air/fuel ratio excursions.
  • the concentrations of H 2 , CO and HC 210 reduce over the axial length of the DOC 30 and the LTNA 40 to the outlet 225 , indicating that the DOC 30 and the LTNA 40 provide an acceptable level of emissions reduction for those exhaust gas constituents after aging.
  • the NOx storage level 212 in the LTNA 40 remains level, indicating there is minimal deterioration in the NOx storage level 212 .
  • exhaust emissions may be unaffected since the NOx emissions may be stored during cold engine operation and may be subsequently available for reduction in a downstream SCR device after warmup has occurred.
  • the arrangement of the DOC 30 upstream of the LTNA 40 and in a close-coupled configuration as described herein reduces likelihood of exposing the LTNA 40 to reductive gas (CO, H2 and HC) 220 at high temperature excursions, thus minimizing deactivation of the LTNA 40 due to high temperature PGM deactivation that may occur in service. This may serve to improve exhaust purification performance of the LTNA 40 over its service life.
  • reductive gas CO, H2 and HC
  • FIG. 4 graphically shows data results associated with NOx storage capacity 310 for an embodiment of the LTNA 40 after exposure to a lean aging protocol, and after exposure to a lean/rich cycle aging protocol of comparable time, temperature and flow conditions.
  • the storage capacity 310 is indicated on the vertical axis.
  • the results include a first NOx storage capacity 320 for the LTNA 40 after exposing the LTNA 40 to a lean aging protocol.
  • the lean aging protocol includes exposing a sample of the LTNA 40 to a hydrothermal aging condition that includes a feedstream that is lean of stoichiometry at 750° C. for 2 hours with 10% H 2 O.
  • the results include a second NOx storage capacity 330 for the LTNA 40 after exposing the LTNA 40 to a lean/rich aging protocol.
  • the lean/rich aging protocol includes exposing a sample of the LTNA 40 to a hydrothermal aging condition that includes a feedstream that periodically alternates between a lean air/fuel ratio condition, e.g., an air/fuel ratio of 22:1, and a rich air/fuel ratio condition, e.g., an air/fuel ratio of 14.3:1, at 750° C. for 2 hours with 10% H 2 O.
  • a comparison of the results 320 , 330 indicate that reduction in the NOx storage capacity of the LTNA 40 under lean/rich air/fuel ratio conditions is more substantial than the reduction in NOx storage capacity of the LTNA 40 under lean air/fuel ratio conditions.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Materials Engineering (AREA)
  • Exhaust Gas After Treatment (AREA)
US15/253,136 2016-08-31 2016-08-31 METHOD AND APPARATUS TO MINIMIZE DEACTIVATION OF A LOW TEMPERATURE NOx ADSORBER IN AN EXHAUST AFTERTREATMENT SYSTEM Abandoned US20180058286A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US15/253,136 US20180058286A1 (en) 2016-08-31 2016-08-31 METHOD AND APPARATUS TO MINIMIZE DEACTIVATION OF A LOW TEMPERATURE NOx ADSORBER IN AN EXHAUST AFTERTREATMENT SYSTEM
DE102017214572.2A DE102017214572A1 (de) 2016-08-31 2017-08-21 Verfahren und vorrichtung zum minimieren der deaktivierung eines niedertemperatur-stickoxidabsorbers in einem abgasaufbereitungssystem
CN201710730445.9A CN107781003A (zh) 2016-08-31 2017-08-23 使排气后处理系统中低温氮氧化物吸附剂的失活最小化的方法和装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15/253,136 US20180058286A1 (en) 2016-08-31 2016-08-31 METHOD AND APPARATUS TO MINIMIZE DEACTIVATION OF A LOW TEMPERATURE NOx ADSORBER IN AN EXHAUST AFTERTREATMENT SYSTEM

Publications (1)

Publication Number Publication Date
US20180058286A1 true US20180058286A1 (en) 2018-03-01

Family

ID=61167159

Family Applications (1)

Application Number Title Priority Date Filing Date
US15/253,136 Abandoned US20180058286A1 (en) 2016-08-31 2016-08-31 METHOD AND APPARATUS TO MINIMIZE DEACTIVATION OF A LOW TEMPERATURE NOx ADSORBER IN AN EXHAUST AFTERTREATMENT SYSTEM

Country Status (3)

Country Link
US (1) US20180058286A1 (zh)
CN (1) CN107781003A (zh)
DE (1) DE102017214572A1 (zh)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10399037B1 (en) 2018-04-20 2019-09-03 GM Global Technology Operations LLC Nitrogen oxides storage catalyst and methods of using the same
US10953366B2 (en) 2018-04-20 2021-03-23 GM Global Technology Operations LLC Nitrogen oxides and hydrocarbon storage catalyst and methods of using the same
WO2022195072A1 (en) * 2021-03-18 2022-09-22 Basf Corporation System for the treatment of an exhaust gas of a diesel combustion engine

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018118091B4 (de) * 2018-07-26 2021-12-09 Volkswagen Aktiengesellschaft Vorrichtung und Verfahren zur Abgasnachbehandlung eines Verbrennungsmotors
DE102018118093A1 (de) * 2018-07-26 2020-01-30 Volkswagen Aktiengesellschaft Vorrichtung und Verfahren zur Abgasnachbehandlung eines Verbrennungsmotors
DE102018122875A1 (de) * 2018-09-18 2020-03-19 Volkswagen Aktiengesellschaft Vorrichtung und Verfahren zur Abgasnachbehandlung eines Verbrennungsmotors
DE102020106911A1 (de) 2020-03-13 2021-09-16 Volkswagen Aktiengesellschaft Verfahren zur Abgasnachbehandlung eines Verbrennungsmotors sowie Abgasnachbehandlungssystem

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6311484B1 (en) * 2000-02-22 2001-11-06 Engelhard Corporation System for reducing NOx transient emission
US20040244368A1 (en) * 2001-10-08 2004-12-09 Yang Koon Chul Low emission vehicle
US20050028518A1 (en) * 2003-08-07 2005-02-10 Wei Li Removing nitrogen oxides during a lean-burn engine cold start
US20050129601A1 (en) * 2003-11-04 2005-06-16 Engelhard Corporation Emissions treatment system with NSR and SCR catalysts
US20060117742A1 (en) * 2004-12-03 2006-06-08 Bellinger Steven M Exhaust gas aftertreatment device for an internal combustion engine
US20070104623A1 (en) * 2005-11-10 2007-05-10 Dettling Joseph C Diesel particulate filters having ultra-thin catalyzed oxidation coatings
US20070113545A1 (en) * 2003-11-25 2007-05-24 Puegeot Citroen Automobiles Sa System for purging sulfate from a nox trap
US20100242448A1 (en) * 2009-03-26 2010-09-30 Gm Global Technology Operations, Inc. Exhaust gas treatment system including a four-way catalyst and urea scr catalyst and method of using the same
US20110239646A1 (en) * 2010-03-30 2011-10-06 Gm Global Technology Operations, Inc. Closely coupled exhaust aftertreatment system for a turbocharged engine
US20140090374A1 (en) * 2012-10-03 2014-04-03 Caterpollar Inc. Exhaust aftertreatment system and method
US20140170044A1 (en) * 2012-12-12 2014-06-19 Basf Corporation Catalyst Compositions, Catalytic Articles, Systems And Processes Using Protected Molecular Sieves
US20150139874A1 (en) * 2012-04-06 2015-05-21 Xiaolai Zheng Lean NOx Trap Diesel Oxidation Catalyst With Hydrocarbon Storage Function
US20160177859A1 (en) * 2014-12-18 2016-06-23 GM Global Technology Operations LLC Method of operating an internal combustion engine

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB201221025D0 (en) * 2012-11-22 2013-01-09 Johnson Matthey Plc Zoned catalysed substrate monolith

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6311484B1 (en) * 2000-02-22 2001-11-06 Engelhard Corporation System for reducing NOx transient emission
US20040244368A1 (en) * 2001-10-08 2004-12-09 Yang Koon Chul Low emission vehicle
US20050028518A1 (en) * 2003-08-07 2005-02-10 Wei Li Removing nitrogen oxides during a lean-burn engine cold start
US20050129601A1 (en) * 2003-11-04 2005-06-16 Engelhard Corporation Emissions treatment system with NSR and SCR catalysts
US20070113545A1 (en) * 2003-11-25 2007-05-24 Puegeot Citroen Automobiles Sa System for purging sulfate from a nox trap
US20060117742A1 (en) * 2004-12-03 2006-06-08 Bellinger Steven M Exhaust gas aftertreatment device for an internal combustion engine
US20070104623A1 (en) * 2005-11-10 2007-05-10 Dettling Joseph C Diesel particulate filters having ultra-thin catalyzed oxidation coatings
US20100242448A1 (en) * 2009-03-26 2010-09-30 Gm Global Technology Operations, Inc. Exhaust gas treatment system including a four-way catalyst and urea scr catalyst and method of using the same
US20110239646A1 (en) * 2010-03-30 2011-10-06 Gm Global Technology Operations, Inc. Closely coupled exhaust aftertreatment system for a turbocharged engine
US20150139874A1 (en) * 2012-04-06 2015-05-21 Xiaolai Zheng Lean NOx Trap Diesel Oxidation Catalyst With Hydrocarbon Storage Function
US20140090374A1 (en) * 2012-10-03 2014-04-03 Caterpollar Inc. Exhaust aftertreatment system and method
US20140170044A1 (en) * 2012-12-12 2014-06-19 Basf Corporation Catalyst Compositions, Catalytic Articles, Systems And Processes Using Protected Molecular Sieves
US20160177859A1 (en) * 2014-12-18 2016-06-23 GM Global Technology Operations LLC Method of operating an internal combustion engine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10399037B1 (en) 2018-04-20 2019-09-03 GM Global Technology Operations LLC Nitrogen oxides storage catalyst and methods of using the same
US10953366B2 (en) 2018-04-20 2021-03-23 GM Global Technology Operations LLC Nitrogen oxides and hydrocarbon storage catalyst and methods of using the same
WO2022195072A1 (en) * 2021-03-18 2022-09-22 Basf Corporation System for the treatment of an exhaust gas of a diesel combustion engine

Also Published As

Publication number Publication date
DE102017214572A1 (de) 2018-03-01
CN107781003A (zh) 2018-03-09

Similar Documents

Publication Publication Date Title
US11401852B2 (en) In-exhaust electrical element for NOx storage catalyst and SCR systems
US20180058286A1 (en) METHOD AND APPARATUS TO MINIMIZE DEACTIVATION OF A LOW TEMPERATURE NOx ADSORBER IN AN EXHAUST AFTERTREATMENT SYSTEM
US8795617B2 (en) Catalyzed substrate and exhaust system for internal combustion engine
EP3077084B1 (en) Cold start catalyst and its use in exhaust systems
US9968916B2 (en) Three-way catalyst and its use in exhaust systems
JP6396636B2 (ja) 排気ガス制御の改善
EP2922629A1 (en) Zoned catalyst on monolithic substrate
US10119445B2 (en) Exhaust system with a modified lean NOx trap
KR20130103502A (ko) 조합된 슬립 촉매와 탄화수소 발열 촉매
WO2009129903A1 (en) Process and apparatus for purifying exhaust gases from an internal combustion engine
US11123720B2 (en) Hydrocarbon trap catalyst

Legal Events

Date Code Title Description
AS Assignment

Owner name: GM GLOBAL TECHNOLOGY OPERATIONS LLC, MICHIGAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:QI, GONGSHIN;REN, SHOUXIAN;LI, WEI;SIGNING DATES FROM 20160901 TO 20160902;REEL/FRAME:039619/0885

STPP Information on status: patent application and granting procedure in general

Free format text: FINAL REJECTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: ADVISORY ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION