Electronic Patent Application Fee Transmittal
`
`Application Number:
`
`14497454
`
`Filing Date:
`
`Title of Invention:
`
`Catalyzed SCR Filter and Emission Treatment System
`
`First Named Inventor/Applicant Name:
`
`Joseph A. Patchett
`
`Filer:
`
`Rebecca A. Smirk/Linda Murphy
`
`Attorney Docket Number:
`
`EH4919G CON
`
`Filed as Large Entity
`
`Utility under 35 USC 111 (a) Filing Fees
`
`Description
`
`Fee Code
`
`Quantity
`
`Amount
`
`Sub-Total in
`USO($)
`
`Basic Filing:
`
`Pages:
`
`Claims:
`
`Miscellaneous-Filing:
`
`Late Filing Fee for Oath or Declaration
`
`1051
`
`1
`
`140
`
`140
`
`Petition:
`
`Patent-Appeals-and-Interference:
`
`Post-Allowance-and-Post-Issuance:
`
`Extension-of-Time:
`
`1
`
`JM 1002
`
`

`

`Description
`
`Fee Code
`
`Quantity
`
`Amount
`
`Sub-Total in
`USO($)
`
`Miscellaneous:
`
`Total in USO($)
`
`140
`
`2
`
`

`

`Electronic Acknowledgement Receipt
`
`EFSID:
`
`Application Number:
`
`20252768
`
`14497454
`
`International Application Number:
`
`Confirmation Number:
`
`7626
`
`Title of Invention:
`
`Catalyzed SCR Filter and Emission Treatment System
`
`First Named Inventor/Applicant Name:
`
`Joseph A. Patchett
`
`Customer Number:
`
`48226
`
`Filer:
`
`Rebecca A. Smirk/Linda Murphy
`
`Filer Authorized By:
`
`Rebecca A. Smirk
`
`Attorney Docket Number:
`
`EH4919G CON
`
`Receipt Date:
`
`26-SEP-2014
`
`Filing Date:
`
`Time Stamp:
`
`11:11:17
`
`Application Type:
`
`Utility under 35 USC 111 (a)
`
`Payment information:
`
`Submitted with Payment
`
`Payment Type
`
`Payment was successfully received in RAM
`
`RAM confirmation Number
`
`yes
`
`Credit Card
`
`$140
`
`16391
`
`Deposit Account
`
`Authorized User
`
`File Listing:
`Document I
`Number
`
`Document Description
`
`File Name
`
`I
`
`File Size( Bytes)/ I Multi I Pages
`(if appl.)
`Message Digest
`Part /.zip
`
`I
`
`3
`
`

`

`1
`
`Fee Worksheet (SB06)
`
`fee-info.pdf
`
`no
`
`2
`
`29818
`
`33 e6be25 b23 5 f2 6d 6f14 7f2a5 f34 f835 684 2 (
`bb9
`
`Warnings:
`
`Information:
`
`Total Files Size (in bytes)
`
`29818
`
`This Acknowledgement Receipt evidences receipt on the noted date by the USPTO of the indicated documents,
`characterized by the applicant, and including page counts, where applicable. It serves as evidence of receipt similar to a
`Post Card, as described in MPEP 503.
`
`New A~~lications Under 35 U.S.C. 111
`If a new application is being filed and the application includes the necessary components for a filing date (see 37 CFR
`1.53(b)-(d) and MPEP 506), a Filing Receipt (37 CFR 1.54) will be issued in due course and the date shown on this
`Acknowledgement Receipt will establish the filing date of the application.
`
`National Stage of an International A~~lication under 35 U.S.C. 371
`If a timely submission to enter the national stage of an international application is compliant with the conditions of 35
`U.S.C. 371 and other applicable requirements a Form PCT/DO/E0/903 indicating acceptance of the application as a
`national stage submission under 35 U.S.C. 371 will be issued in addition to the Filing Receipt, in due course.
`
`New International A~~lication Filed with the USPTO as a Receiving Office
`If a new international application is being filed and the international application includes the necessary components for
`an international filing date (see PCT Article 11 and MPEP 181 O), a Notification of the International Application Number
`and of the International Filing Date (Form PCT/R0/1 OS) will be issued in due course, subject to prescriptions concerning
`national security, and the date shown on this Acknowledgement Receipt will establish the international filing date of
`the application.
`
`4
`
`

`

`Doc Code: TRACK1 .REQ
`Document Description: TrackOne Request
`
`PTO/SB/424 (12-11)
`
`CERTIFICATION AND REQUEST FOR PRIORITIZED EXAMINATION
`UNDER 37 CFR 1.102(e) (Page 1of1)
`
`First Named
`Inventor:
`Title of
`Invention:
`
`I
`I Nonprovisional Application Number (if
`Joseph Patchett
`known):
`CATALYZED SCR FILTER AND EMISSION TREATMENT SYSTEM
`
`APPLICANT HEREBY CERTIFIES THE FOLLOWING AND REQUESTS PRIORITIZED EXAMINATION FOR
`THE ABOVE-IDENTIFIED APPLICATION.
`
`1. The processing fee set forth in 37 CFR 1.17(i), the prioritized examination fee set forth in 37
`CFR 1.17(c), and if not already paid, the publication fee set forth in 37 CFR 1.18(d) have been
`filed with the request. The basic filing fee, search fee, examination fee, and any required
`excess claims and application size fees are filed with the request or have been already been
`paid.
`
`2. The application contains or is amended to contain no more than four independent claims and
`no more than thirty total claims, and no multiple dependent claims.
`
`3. The applicable box is checked below:
`
`I.
`
`!?1 Original Application (Track One) - Prioritized Examination under§ 1.102(e)(1)
`
`i.
`
`(a) The application is an original nonprovisional utility application filed under 35 U.S.C. 111 (a).
`This certification and request is being filed with the utility application via EFS-Web.
`---OR---
`(b) The application is an original nonprovisional plant application filed under 35 U.S.C. 111 (a).
`This certification and request is being filed with the plant application in paper.
`
`ii. An executed oath or declaration under 37 CFR 1.63 is filed with the application.
`
`II.
`
`[] Request for Continued Examination - Prioritized Examination under§ 1.102(e)(2)
`
`i. A request for continued examination has been filed with, or prior to, this form.
`ii.
`If the application is a utility application, this certification and request is being filed via EFS-Web.
`iii. The application is an original nonprovisional utility application filed under 35 U.S.C. 111 (a), or is
`a national stage entry under 35 U.S.C. 371.
`iv. This certification and request is being filed prior to the mailing of a first Office action responsive
`to the request for continued examination.
`v. No prior request for continued examination has been granted prioritized examination status
`under 37 CFR 1.102(e)(2).
`
`sianature /Rebecca A. Smirk, Reg. #61295/
`~p~~~Typed) Rebecca. A. Smirk
`
`oate September 26, 2014
`61 295
`
`Practitioner
`Registration Number
`
`Note: Signatures of all the inventors or assignees of record of the entire interest or their representative(s) are required in accordance with
`37CFR 1.33 and 11.18. Please see 37 CFR 1.4(d) for the form of the signature. If necessary, submit multiple forms for more than one
`sianature, see below*.
`
`tJ *Total of 1
`
`forms are submitted.
`
`5
`
`

`

`Privacy Act Statement
`
`The Privacy Act of 1974 (P.L. 93-579) requires that you be given certain information in connection with your
`submission of the attached form related to a patent application or patent. Accordingly, pursuant to the requirements of
`the Act, please be advised that: (1) the general authority for the collection of this information is 35 U.S.C. 2(b)(2); (2)
`furnishing of the information solicited is voluntary; and (3) the principal purpose for which the information is used by the
`U.S. Patent and Trademark Office is to process and/or examine your submission related to a patent application or
`patent. If you do not furnish the requested information, the U.S. Patent and Trademark Office may not be able to
`process and/or examine your submission, which may result in termination of proceedings or abandonment of the
`application or expiration of the patent.
`
`The information provided by you in this form will be subject to the following routine uses:
`
`1. The information on this form will be treated confidentially to the extent allowed under the Freedom of
`Information Act (5 U.S.C. 552) and the Privacy Act (5 U.S.C 552a). Records from this system of records may
`be disclosed to the Department of Justice to determine whether disclosure of these records is required by the
`Freedom of Information Act.
`2. A record from this system of records may be disclosed, as a routine use, in the course of presenting evidence
`to a court, magistrate, or administrative tribunal, including disclosures to opposing counsel in the course of
`settlement negotiations.
`3. A record in this system of records may be disclosed, as a routine use, to a Member of Congress submitting a
`request involving an individual, to whom the record pertains, when the individual has requested assistance from
`the Member with respect to the subject matter of the record.
`4. A record in this system of records may be disclosed, as a routine use, to a contractor of the Agency having
`need for the information in order to perform a contract. Recipients of information shall be required to comply
`with the requirements of the Privacy Act of 1974, as amended, pursuant to 5 U.S.C. 552a(m).
`5. A record related to an International Application filed under the Patent Cooperation Treaty in this system of
`records may be disclosed, as a routine use, to the International Bureau of the World Intellectual Property
`Organization, pursuant to the Patent Cooperation Treaty.
`6. A record in this system of records may be disclosed, as a routine use, to another federal agency for purposes
`of National Security review (35 U.S.C. 181) and for review pursuant to the Atomic Energy Act (42 U.S.C.
`218(c)).
`7. A record from this system of records may be disclosed, as a routine use, to the Administrator, General
`Services, or his/her designee, during an inspection of records conducted by GSA as part of that agency's
`responsibility to recommend improvements in records management practices and programs, under authority of
`44 U.S.C. 2904 and 2906. Such disclosure shall be made in accordance with the GSA regulations governing
`inspection of records for this purpose, and any other relevant (i.e., GSA or Commerce) directive. Such
`disclosure shall not be used to make determinations about individuals.
`8. A record from this system of records may be disclosed, as a routine use, to the public after either publication of
`the application pursuant to 35 U .S.C. 122(b) or issuance of a patent pursuant to 35 U .S.C. 151. Further, a
`record may be disclosed, subject to the limitations of 37 CFR 1.14, as a routine use, to the public if the record
`was filed in an application which became abandoned or in which the proceedings were terminated and which
`application is referenced by either a published application, an application open to public inspection or an issued
`patent.
`9. A record from this system of records may be disclosed, as a routine use, to a Federal, State, or local law
`enforcement agency, if the USPTO becomes aware of a violation or potential violation of law or regulation.
`
`Page 2
`
`6
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`1
`
`CATALYZED SCR FILTER AND EMISSION TREATMENT SYSTEM
`
`CROSS-REFERENCE TO RELATED APPLICATIONS
`
`[0001]
`
`This application is a continuation of U.S. Application No. 13/274,635, filed October
`
`17, 2011, which is a continuation of U.S. Application No. 11/676,798, filed February 20, 2007,
`
`which is a divisional application of U.S. Application No. 10/634,659, filed August 5, 2003,
`
`now U.S. Patent No. 7 ,229 ,597, issued June 12, 2007, the contents of each of which are hereby
`
`incorporated by reference in their entireties.
`
`BACKGROUND
`
`[0002]
`
`The present invention relates to an emission treatment system having an oxidation
`
`catalyst upstream of a soot filter coated with a material effective in the Selective Catalytic
`
`Reduction (SCR) of NOx by a reductant, e.g., ammonia.
`
`In one embodiment, the system
`
`provides an effective method of simultaneously remediating the nitrogen oxides (NOx),
`
`particulate matter, and gaseous hydrocarbons present in diesel engine exhaust streams.
`
`[0003] Diesel engine exhaust is a heterogeneous mixture which contains not only gaseous
`
`emissions such as carbon monoxide ("CO"), unburned hydrocarbons ("HC") and nitrogen
`
`oxides ("NOx "), but also condensed phase materials (liquids and solids) which constitute the
`
`so-called particulates or particulate matter. Often, catalyst compositions and substrates on
`
`which the compositions are disposed are provided in diesel engine exhaust systems to convert
`
`certain or all of these exhaust components to innocuous components. For example, diesel
`
`exhaust systems can contain one or more of a diesel oxidation catalyst, a soot filter and a
`
`catalyst for the reduction of NOx.
`
`[0004] Oxidation catalysts
`
`that contain platinum group metals, base metals and
`
`combinations thereof are known to facilitate the treatment of diesel engine exhaust by
`
`promoting the conversion of both HC and CO gaseous pollutants and some proportion of the
`
`particulate matter through oxidation of these pollutants to carbon dioxide and water. Such
`
`catalysts have generally been contained in units called diesel oxidation catalysts (DOC's ),
`
`which are placed in the exhaust of diesel engines to treat the exhaust before it vents to the
`
`atmosphere.
`
`In addition to the conversions of gaseous HC, CO and particulate matter,
`
`oxidation catalysts that contain platinum group metals (which are typically dispersed on a
`
`refractory oxide support) also promote the oxidation of nitric oxide (NO) to N0 2.
`
`7
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`2
`
`[0005]
`
`The total particulate matter emissions of diesel exhaust are comprised of three main
`
`components. One component is the solid, dry, solid carbonaceous fraction or soot fraction.
`
`This dry carbonaceous matter contributes to the visible soot emissions commonly associated
`
`with diesel exhaust. A second component of the particulate matter is the soluble organic
`
`fraction ("SOF"). The soluble organic fraction is sometimes referred to as the volatile organic
`
`fraction ("VOF"), which terminology will be used herein. The VOF can exist in diesel exhaust
`
`either as a vapor or as an aerosol (fine droplets of liquid condensate) depending on the
`
`temperature of the diesel exhaust. It is generally present as condensed liquids at the standard
`
`particulate collection temperature of 52° C in diluted exhaust, as prescribed by a standard
`
`measurement test, such as the U.S. Heavy Duty Transient Federal Test Procedure. These
`
`liquids arise from two sources: (1) lubricating oil swept from the cylinder walls of the engine
`
`each time the pistons go up and down; and (2) unburned or partially burned diesel fuel.
`
`[0006]
`
`The third component of the particulate matter is the so-called sulfate fraction. The
`
`sulfate fraction is formed from small quantities of sulfur components present in the diesel fuel.
`
`Small proportions of S03 are formed during combustion of the diesel, which in turn combines
`
`rapidly with water in the exhaust to form sulfuric acid. The sulfuric acid collects as a
`
`condensed phase with the particulates as an aerosol, or is adsorbed onto the other particulate
`
`components, and thereby adds to the mass of TPM.
`
`[0007]
`
`One key aftertreatment technology in use for high particulate matter reduction is the
`
`diesel particulate filter. There are many known filter structures that are effective in removing
`
`particulate matter from diesel exhaust, such as honeycomb wall flow filters, wound or packed
`
`fiber filters, open cell foams, sintered metal filters, etc. However, ceramic wall flow filters,
`
`described below, receive the most attention. These filters are capable of removing over 90% of
`
`the particulate material from diesel exhaust. The filter is a physical structure for removing
`
`particles from exhaust, and the accumulating particles will increase the back pressure from the
`
`filter on the engine. Thus, the accumulating particles have to be continuously or periodically
`
`burned out of the filter to maintain an acceptable back pressure. Unfortunately, the carbon soot
`
`particles require temperatures in excess of 500° C to burn under oxygen rich (lean) exhaust
`
`conditions. This temperature is higher than what is typically present in diesel exhaust.
`
`[0008]
`
`Provisions are generally introduced to lower the soot burning temperature in order to
`
`provide for passive regeneration of the filter. The presence of a catalyst promotes soot
`
`combustion, thereby regenerating the filters at temperatures accessible within the diesel
`
`8
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`3
`
`engine's exhaust under realistic duty cycles.
`
`In this way a catalyzed soot filter (CSF) or
`
`catalyzed diesel particulate filter (CDPF) is effective in providing for >80% particulate matter
`
`reduction along with passive burning of the accumulating soot, and thereby promoting filter
`
`regeneration.
`
`[0009]
`
`Future emissions standards adopted throughout the world will also address NOx
`
`reductions from diesel exhaust. A proven NOx abatement technology applied to stationary
`
`sources with lean exhaust conditions is Selective Catalytic Reduction (SCR). In this process,
`
`NOx is reduced with ammonia (NH3) to nitrogen (N2) over a catalyst typically composed of
`
`base metals. The technology is capable of NOx reduction greater than 90%, and thus it
`
`represents one of the best approaches for achieving aggressive NOx reduction goals. SCR is
`
`under development for mobile applications, with urea (typically present in an aqueous
`
`solution) as the source of ammonia. SCR provides efficient conversions of NOx as long as the
`
`exhaust temperature is within the active temperature range of the catalyst.
`
`[0010] While separate substrates each containing catalysts to address discrete components
`
`of the exhaust can be provided in an exhaust system, use of fewer substrates is desirable to
`
`reduce the overall size of the system, to ease the assembly of the system, and to reduce the
`
`overall cost of the system. One approach to achieve this goal is to coat the soot filter with a
`
`catalyst composition effective for the conversion of NOx to innocuous components. With this
`
`approach, the catalyzed soot filter assumes two catalyst functions: removal of the particulate
`
`component of the exhaust stream and conversion of the NOx component of the exhaust stream
`
`to N2.
`
`[0011]
`
`Coated soot filters that can achieve NOx reduction goals require a sufficient loading
`
`of SCR catalyst composition on the soot filter. The gradual loss of the catalytic effectiveness
`
`of the compositions that occurs over time through exposure to certain deleterious components
`
`of the exhaust stream augments the need for higher catalyst loadings of the SCR catalyst
`
`composition. However, preparation of coated wall flow soot filters with higher catalyst
`
`loadings can lead to unacceptably high back pressure within the exhaust system. Coating
`
`techniques that allow higher catalyst loadings on the wall flow filter, yet still allow the filter to
`
`maintain flow characteristics that achieve acceptable back pressures are therefore desirable.
`
`[0012] An additional aspect for consideration in coating the wall flow filter is the selection
`
`of the appropriate SCR catalyst composition. First, the catalyst composition must be durable
`
`so that it maintains its SCR catalytic activity even after prolonged exposure to higher
`
`9
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`4
`
`temperatures that are characteristic of filter regeneration. For example, combustion of the soot
`
`fraction of the particulate matter often leads to temperatures above 700° C. Such temperatures
`
`render many commonly used SCR catalyst compositions such as mixed oxides of vanadium
`
`and titanium less catalytically effective. Second, the SCR catalyst compositions preferably
`
`have a wide enough operating temperature range so that they can accommodate the variable
`
`temperature ranges over which the vehicle operates. Temperatures below 300° C are typically
`
`encountered, for example, at conditions of low load, or at startup. The SCR catalyst
`
`compositions are preferably capable of catalyzing the reduction of the NOx component of the
`
`exhaust to achieve NOx reduction goals, even at lower exhaust temperatures.
`
`[0013]
`
`The prior art contains descriptions of the use of SCR catalyst compositions, soot
`
`filters and combinations thereof for the abatement of both the NOx and particulate components
`
`of diesel exhaust. These references are described below.
`
`[0014]
`
`Japanese Kokai 3-130522, for example, discloses the treatment of diesel exhaust
`
`gases characterized by use of an ammonia injector and porous ceramic filter having a
`
`denitration catalyst within the pores. The filter is installed in the wake of the diesel engine
`
`exhaust. The ceramic porous filter comprises an upstream fine pore path layer, and a
`
`downstream side course ceramic particle layer on which the denitration catalyst was supported.
`
`The fine layer can support a platinum or palladium or other hydrocarbon combustion catalyst.
`
`The diesel exhaust gas containing unburned carbon flows through the porous ceramic filter and
`
`the carbon particles are filtered onto the surf ace. The gas containing nitric oxides and the
`
`ammonia passes through the denitration catalyst containing side of the filter and the nitric
`
`oxides are reduced to nitrogen and water. The oxidation catalyst on the upstream side causes
`
`the particulate component to burn off catalytically.
`
`[0015] United States Patent No. 4,912,776 discloses an oxidation catalyst, an SCR catalyst
`
`downstream and adjacent to the SCR catalyst, and a reductant source introduced to the exhaust
`
`stream between the oxidation catalyst and the SCR catalyst. Providing a higher feed
`
`containing a high proportion of N0 2 to NO to the SCR reactor is said to allow the use of lower
`
`temperatures and higher space velocities than is possible with a feed of NO.
`
`[0016] WO 99/39809 discloses a system for treating combustion exhaust gas containing
`
`NOx and particulates that has an oxidation catalyst effective to convert at least a portion of the
`
`NO in the NOx to N02, a particulate trap, a source of reductant fluid and an SCR catalyst. The
`
`particulate trap is downstream of the oxidation catalyst; the reductant fluid source is
`
`10
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`5
`
`downstream of the particulate trap; and the SCR catalyst is downstream of the reductant fluid
`
`source. Reductant fluids disclosed include ammonia, urea, ammonium carbamate and
`
`hydrocarbons (e.g., diesel fuel).
`
`[0017] A catalytic wall flow filter for an exhaust system of a combustion engine is
`
`described in WO 01/12320. The wall flow filter has channels that are in honeycomb
`
`arrangement, where some of the channels are blocked at the upstream end and some of the
`
`channels that are unblocked at the upstream end are blocked at the downstream end. An
`
`oxidation catalyst is disposed on a gas impermeable zone at an upstream end of channels that
`
`are blocked at the downstream end. The filter has a gas permeable filter zone that is
`
`downstream of the oxidation catalyst that is for trapping soot. The oxidation catalyst is
`
`described to be capable (when in an exhaust system) of generating N02 from NO to combust
`
`the trapped soot continuously at temperatures below 400° C. The oxidation catalyst preferably
`
`includes a platinum group metal. Exhaust streams containing NO are initially passed over the
`
`oxidation catalyst to convert NO to N02 prior to filtering to remove soot. The exhaust gas then
`
`containing N0 2 is used to combust the soot trapped on the filter.
`
`[0018]
`
`In some embodiments of the wall flow filter described in WO 01/12320 the
`
`downstream channels of the soot filter contain a catalyst for a NOx absorber and an SCR
`
`catalyst downstream of the NOx absorber. The SCR catalyst can be a copper-based material,
`
`platinum, a mixed oxide of vanadium and titania or a zeolite, or mixtures of two or more
`
`thereof.
`
`SUMMARY OF THE INVENTION
`
`[0019]
`
`In one aspect, the invention relates to an emission treatment system for treatment of
`
`an exhaust stream that contains NOx and particulate matter. The emission treatment system
`
`includes an oxidation catalyst, an injector that periodically meters ammonia or an ammonia
`
`precursor into the exhaust stream; and a wall flow monolith. The injector is in fluid
`
`communication with the oxidation catalyst, and is positioned downstream of the oxidation
`
`catalyst. The wall flow monolith contains an SCR catalyst composition, is in fluid
`
`communication with the injector, and is positioned downstream of the injector.
`
`[0020]
`
`The wall flow monolith has a plurality of longitudinally extending passages formed
`
`by longitudinally extending walls bounding and defining said passages. The passages include
`
`inlet passages that have an open inlet end and a closed outlet end, and outlet passages that have
`
`11
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`6
`
`a closed inlet end and an open outlet end. The wall flow monolith contains an SCR catalyst
`composition that permeates the walls at a concentration of at least 1.3 g/in3 (and preferably
`from 1.6 to 2.4 g/in3
`
`). The wall flow monolith has a wall porosity of at least 50% with an
`
`average pore size of at least 5 microns. Preferably, the SCR catalyst composition permeates
`
`the walls of the wall flow monolith so that the walls have a wall porosity of from 50 to 75%
`
`with an average pore size of from 5 to 30 microns.
`
`[0021]
`
`In a preferred embodiment of the emission treatment system, the SCR catalyst
`
`composition contains a zeolite and base metal component selected from one or more of a
`
`copper and iron component. Preferably, the base metal component is a copper component.
`
`Preferred zeolites of the SCR catalyst composition have a silica to alumina ratio of at least
`
`about 10. For instance, a beta zeolite can be used in the SCR catalyst composition.
`
`[0022] Among other things, the oxidation catalyst of the system is useful for combusting
`
`substantial portions of the particulate matter, and in particular, the VOF, entrained in the
`
`exhaust. In addition, a substantial portion of the NO in the NOx component is oxidized to N02
`
`over the oxidation catalyst. In preferred embodiments, the oxidation catalyst is disposed on a
`
`honeycomb flow through monolith substrate or an open cell foam substrate. Preferably, the
`
`oxidation catalyst includes a platinum group metal component, and in particular, a platinum
`
`component.
`
`In some embodiments, the oxidation catalyst can also contain a zeolite
`
`component.
`
`[0023]
`
`In another preferred embodiment of the emission treatment system, the system also
`
`has a diesel engine which is located upstream of, and in fluid communication with the
`
`oxidation catalyst.
`
`[0024] Another aspect of the invention relates to a method for treating emissions produced
`
`in an exhaust stream that contains NOx and particulate matter. The method includes:
`
`(a)
`
`passing the exhaust stream through an oxidation catalyst wherein a substantial
`
`portion of NO is oxidized to N0 2 to provide an N02-enriched exhaust stream;
`
`(b)
`
`metering at periodic intervals, ammonia or an ammonia precursor into the N02-
`
`enriched exhaust stream; and,
`
`( c)
`
`subsequently passing the exhaust stream through a wall flow monolith wherein
`
`particulate matter is filtered and a substantial portion of NOx is reduced to N2.
`[0025] Here again, the wall flow monolith has a plurality of longitudinally extending
`
`passages formed by longitudinally extending walls bounding and defining said passages. The
`
`12
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`7
`
`passages include inlet passages that have an open inlet end and a closed outlet end, and outlet
`
`passages that have a closed inlet end and an open outlet end. The wall flow monolith contains
`an SCR catalyst composition that permeates the walls at a concentration of at least 1.3 g/in3
`(and preferably from 1.6 to 2.4 g/in3
`
`). The wall flow monolith has a wall porosity of at least
`
`50% with an average pore size of at least 5 microns. Preferably, the SCR catalyst composition
`
`permeates the walls of the wall flow monolith so that the walls have a wall porosity of from 50
`
`to 75% with an average pore size of from 5 to 30 microns.
`
`[0026]
`
`In another aspect, the invention relates to a method for disposing an SCR catalyst
`
`composition on a wall flow monolith. The method includes:
`
`(a) immersing the wall flow monolith in an aqueous slurry comprising the SCR catalyst
`
`composition from a first direction to deposit the SCR catalyst composition on the inlet
`
`passages;
`
`(b) removing excess slurry from the inlet passages by forcing a compressed gas stream
`
`through the outlet passages and applying a vacuum to the inlet passages;
`
`( c) immersing the wall flow monolith in the aqueous slurry from a second direction,
`
`opposite the first direction, to deposit the SCR catalyst composition on the outlet passages;
`
`(d) removing excess slurry from the outlet passages by forcing a compressed gas stream
`
`through the inlet passages and applying a vacuum to the outlet passages; and
`
`( e) drying and calcining the coated wall flow monolith.
`
`[0027]
`
`The wall flow monolith used in the method preferably has a porosity of at least 50%
`
`(e.g., from 50 to 75%) having a mean pore size of at least 5 microns (e.g., from 5 to 30
`
`microns).
`
`[0028]
`Preferably, the SCR catalyst composition permeates the walls at a concentration of
`at least 1.3 g/in3 (and preferably from 1.6 to 2.4 g/in\
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0029]
`
`Figures lA and lB are schematic depictions of two embodiments of the emission
`
`treatment system of the invention;
`
`[0030]
`
`[0031]
`
`[0032]
`
`Figure 2 shows a perspective view of a wall flow filter substrate;
`
`Figure 3 shows a cutaway view of a section of a wall flow filter substrate;
`
`Figure 4 shows an embodiment of the emission treatment system of the invention
`
`that includes a urea reservoir and injector;
`
`13
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`8
`
`[0033]
`
`Figure 5 is a plot of the DTA signal in microvolts as a function of temperature for
`
`two SCR catalyst compositions mixed with a model particulate mass (carbon black and lube
`
`oil);
`
`[0034]
`
`Figure 6 shows the pressure drop as a function of the air flow for several coated wall
`
`flow filter substrates and an uncoated wall flow filter substrate; and
`
`[0035]
`
`Figure 7 is a schematic depiction of a laboratory bench system used to evaluate NOx
`
`and particulate reduction for an exemplary emission treatment system of the invention.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`[0036]
`
`The invention relates to an emission treatment system that effectively provides
`
`simultaneous treatment of the particulate matter, the NOx and other gaseous components of
`
`diesel engine exhaust. The emission treatment system uses an integrated soot filter and SCR
`
`catalyst to significantly minimize the weight and volume required for the emissions system.
`
`Moreover, due to the choice of catalytic compositions implemented in the system, effective
`
`pollutant abatement is provided for exhaust streams of varying temperatures. This feature is
`
`advantageous for operating diesel vehicles under varying loads and vehicle speeds which
`
`significantly impact exhaust temperatures emitted from the engines of such vehicles.
`
`[0037]
`
`Integration of NOx reduction and particulate removal functions into a single catalyst
`
`article is accomplished using a wall flow substrate coated with an SCR catalyst composition.
`
`Applicants have found a method for applying an SCR catalyst composition to a wall flow
`
`substrate to form a substrate that can be used in an application where high filtration efficiency
`
`is required. For instance, a substrate formed with this method is suitable for effectively
`
`removing particulate matter (e.g., greater than 80%) in the emission treatment system of the
`
`invention. The coating method disclosed herein allows wall flow substrates to be loaded with
`
`practical levels of SCR catalyst without causing excessive back pressure across the coated
`
`article when implemented in emission treatment systems.
`
`[0038] Achieving practical levels of SCR catalyst composition on the wall flow substrate is
`
`important for providing sufficient catalytic activity to achieve mandated NOx reduction levels,
`
`and for lowering the combustion temperature of the soot fraction trapped on the filter.
`
`Achieving adequate levels of SCR washcoat compositions on the soot filter is also important to
`
`secure adequate durability for the catalyst. Over extended use of the emission treatment
`
`system, catalysts are invariably exposed to various levels of catalyst poisons that may be
`
`14
`
`

`

`DOCKET NO. 4919G/ENG0048-06CT
`
`9
`
`derived through break down of lubricating oils, or may arise from impurities in the diesel fuel.
`
`Examples of such catalyst poisons include phosphorus, zinc, alkali and alkaline earth elements.
`
`Higher levels of catalyst compositions are therefore typically deposited on catalyst substrates
`
`to overcome the inevitable loss of catalytic activity.
`
`[0039] One emb