INGEVITY SOUTH CAROLINA, LLC, EXHIBIT 2002
`Mahle Filter Systems North America, Inc. v. Ingevity South Carolina, LLC
`IPR2019-00960
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`ISSUE SLIP STAPLE AREA for additional cross-references
`ISSUING CLASSIFICATION
`CROSS REFERENCE(S
`SUBCLASS (ONE SUBCLASS PER BLOCK
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`CLASSIFICATION NOTES
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`Examiner/
`Classifier
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`PATENT APPLICATION SERIAL NO. /© L,LD 3b 2 |
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`U.S. DEPARTMENT OF COMMERCE
`PATENT AND TRADEMARK OFFICE
`FEE RECORD SHEET
`
`03/22/2002 EHAILEL
`OL FCsiO1
`02 FCrigs —
`
`00000014 10100a62
`740.00 OF
`180,00 GF
`
`PTO-1556
`(5/87)
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`“U.S.GovernmentPrinting Office: 2001 — 481-697/59173
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`CONFIRMATION No.3899
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`BIBDATASHEET 4
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`FILING DATE?
`03/18/2002 —
`|
`ATTORNEY
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`epoupaBTUNIT
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`CHR 2001-79
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`APPLICANTS
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`Laurence H. Hiltzik, Charleston, SC;
`JacekZ.Jagiello, Charleston, SC;
`.
`EdwardD. Tolles, Charleston, SC:‘Roger S, Wiliams,Lexington,SC;
`ee CONTINUING DATAsesnnanannnnennnnenin
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`MWestvaco Corporation
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`5255. Virginia Avenue
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`P.O: Box:t 18005.
`os Charleston , SC
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`129423-8005
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`oes —
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`mY EXPRESS MAIL NO. EK902687082US
`
`Case Docket No. CHR 2001-79
`
` “To:
`
`FORM PTO-1082
`
` -. PATENT APPLICATION TRANSMITTAL LETTER
`
`Box Patent Application
`Assistant Commissioner for Patents
`Washington, DC
`20231
`
`Transmitted herewith for filing under 35 USC 111 and 37 CFR 1.53
`is the original
`(nonprovisional) patent application of
`
`
`Inventor(s): Laurence H. Hiltzik, Jacek Z. Jagiello,
`
`Edward D. Tolles, and Roger S. Williams
`
`XXX
`
`
`Entitled: METHOD FOR REDUCING EMISSIONS FROM
`
`EVAPORATIVE EMTSSIONS CONTROL SYSTEMS
`Enclosed are:
`pages of specification.
`XXK
`18
`XXX
`5
`pages of claims.
`©
`XXX
`3
`sheets of drawings.
`.
`formal ~
`informal
`3
`page(s) Abstract...
`1
`Executed declaration or oath of the inventors.
`
`An assignment of the invention to: Westvaco Corporation,
`Westvaco Corporate Center,
`1 High Ridge Park, Stamford,
`Connecticut 06905, a corporation of the State of Delaware.
`A separate cover sheet for Assignment
`(Document) accompanying new patent
`application is also attached.
`A certified copy of a
`application,
`Associate power of attorney.
`A verified statement to establish smal]entity status under
`
`37 CFR 1.9 and 1.27.
`Information disclosure statement.
`Preliminary amendment.
`Other:
`
`:
`:
`
`|
`
`,
`
`~
`
`
`
`
`.
`CLAIMS AS FILED.
`NUMBER FILED NUMBER EXTRA.RATE
`
`
`FEE
`
`
`
`BASIC FEE
`
`$ 740.00
`
`$ 740.00
`
`18.00
`* 10
`30 - 20 =
`TOTAL CLAIMS
`84.00
`* 0
`2- 35
`INDEPENDENT CLAIMS
`
`TOTAL
`*NUMBER EXTRA MUST BE ZERO OR*LARGER
`ASSIGNMENT RECORDATION FEE
`TOTAL
`
`x
`x
`
`-180.00
`0 7
`S 920.00
`§
`§ 920.00
`
`L
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`1
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`nsssispEEREBRaAFEHEEEearRenereennlerceranenSenne SoMEASA APE ihn
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`Case Docket No. CHR 2001-79
`
`If applicant has small entity status under
`37 CFR 1.9
`and 1.27,
`then divide total fee
`by 2,
`‘and enter amount here.
`
`SMALL ENTITY TOTAL
`
`§
`
`XXX
`
`A check in the amount of '$ 920.00
`application filing fee.
`
`is enclosed to cover the
`
`A check in the amount of §.
`Assignment recordation fee.
`
`©
`
`is enclosed to cover the
`
`RAK
`
`The Commissioner is hereby authorized to charge or credit
`Deposit Account No.
`23-1160
`as described below.
`I have
`enclosed a duplicate copy of this sheet.
`
`Charge the amount of §
`XXX Credit any overpayment.
`
`no
`
`‘as Filing fee.
`
`Date March 18, 2002
`
`XXX Charge any additional filing fees required under 37 CFR
`~ 1.16 and 1.17.
`
`Charge the issue fee set in 37 CFR 1.18 at the mailing
`of the Notice of Allowance, pursuant to 37 CFR 1.311(b).
`
`
`
`Terry B. McDaniel, Regis. No. 28,444
`
`Westvaco Corporation
`5255 Virginia Avenue
`P. O. Box 118005
`Charleston, SC’ 29423-8005
`
`-
`
`Telephone:
`
`(843) 746-8490
`
`Page 9 of 141
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`EXPRESS MAIL NO. EK902687082US
`
`Case Docket No. CHR 2001-79
`
`
`
`CERTIFICATE UNDER37 C.F.R. 1.10(a)
`Therebycertify that this correspondenceis being deposited with the United States Postal
`
`' Service as Express Mail in an envelope addressed to the Assistant Commissioner for Patents,
`
`
`
`Washington, D. C. 20231, on March 18, 2002 .
`
`
`
`Attorney,for'the Applicants
`Registration No. 28,444
`
`Page 10 of 141
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`eS
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`Ca. Docket No. CHR 2001-79
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`ft
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`Abstract}
`
`
`
`Disclosed is a method for sharply reducing diurnal breathing loss emissions from
`automotive evaporative emissions control systems by providing multiple layers, or stages, of
`
`adsorbents. On the fuel source-side of an emissions control system canister, high working
`capacity carbonsare preferred ina first canister (adsorb) region. In subsequent canister
`
`region(s) on the vent-side, the preferred adsorbent should exhibit a flat or flattened adsorption
`
`isotherm on a volumetric basis andrelatively lower capacity for high concentration vapors as
`compared with the fuel source-side adsorbent. Multiple approaches are described for attaining
`the preferred properties for the vent-side canister region: One approachis to usea filler and/or
`
` improved combination of high working capacity carbons on the fuel source-side and preferred
`
`voidages as a volumetric diluentfor flattening an adsorption isotherm. Another approach is to
`employ an adsorbent with the desired adsorption isotherm properties and to process it into an
`appropriate shape or form without necessarily requiring any special provision for dilution. The
`
`lower working capacity adsorbent on the vent-side provides substantially lower diurnal
`
`breathing emissions withouta significant loss in working capacity or increasein flow restriction
`
`compared with known adsorbents used in canister configurations for automotive emissions
`
`control systems.
`
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`SseeEERSPSncrtRPMSEPAREPEEEEEaRNEETROOE
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`preitygENOSESEOSNEATYSIMONEDDR pms EE MINER on
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`Cavw-docket No. CHR 2001-79
`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`Patent Application for
`
`METHOD FOR REDUCING EMISSIONS
`
`psteenEVAPORATIVEEMISSIONS CONTROL SYSTEMS
`AY
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`
`This invention relates to a methodfor reducing emissions from evaporative control
`
`systems including activated carbon particulate-filled canisters and adsorptive monolith-
`
`containing canisters,WhichThonotiths include activated carbon, and tousing said adsorbing
`canisters to remove volatile organic compounds, and other chemical agents from fluid streams.
`Moreparticularly, this invention relates to using said vapor-adsorbing materials in hydrocarbon
`
`fuel consuming engines. . ne
`
`
`2. Description of Related Art (Including Information Disclosed Under 37 CFR 1.97
`and 37 CFR 1.98)
`
`(a)
`
`Standard Working Capacity Adsorbents
`
`Evaporation of gasoline from motor vehicle fuel systems is a major potential source of
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`hydrocarbon air pollution. The automotive industry is challenged to design engine components
`
`and systems to contain, as much as possible, the almost one billion gallons of gasoline
`evaporated from fuel systems each year in the United States alone. Such emissions can be
`
`controlled by canister systems that employ activated carbon toadsorb and hold the vapor that
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`evaporates. Under certain modes of engine operation, the adsorbed hydrocarbon vaporis
`periodically removed from the carbon bydrawing airthrough the canister and burning: the
`desorbed vapor in the engine. The regenerated carbon is then ready to adsorb additional vapor.-
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`Under EPA mandate, such control systems have been employedin the U.S. for about 30 years,
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`Casedocket No. CHR 2001-79
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`and during that time governmentregulations have gradually reduced the allowable emission |
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`_
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`levels for these systems. In response, improvements in the control systems have beenlargely
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`focused on improving the capacity of the activated carbon to hold hydrocarbon vapor. For
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`example, current canister systems, containingactivated carbon of uniform capacity, are readily
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`capable of capturing and releasing 100 grams of vapor during adsorption and air purge
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`regeneration cycling. These canister systems also must have low flow restrictions in order to
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`accommodate the bulk flow of displaced air and hydrocarbon vapor from the fuel tank during
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`refueling. Improvements in activated carbons for automotive emission control systems are
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`- disclosed in U. S. Patent Nos.: 4,677,086; 5,204,310; 5,206,207; 5,250,491; 5,276,000;
`
`5,304,527; 5,324,703; 5,416,056; 5,538,932; 5,691,270; 5,736,481; 5,736,485; 5,863,858;
`
`5,914,294; 6,136,075; 6,171,373; 6,284,705.
`A typical canister employed in a state of the art auto emission coritrolsystem is shown
`in Figure 1. Canister 1 includes support screen 2,dividing wall 3, a vent port 4 to the
`
`atmosphere (for when the engine is off), a vapor source connection 5 (from the fueltank), a
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`vacuum purge connection 6-(for when the engine is running), and adsorbent material fill 7.
`~ Other basic auto emissioncontrol system canisters are disclosed in U.S.PatentNos.:
`5,456,236; 5,456,237; 5,460,136; and 5,477,836.
`|
`| Typical carbons for evaporative emission canisters are characterized by standard
`
`measurements of bed packing density (“apparent density,” g/mL), equilibrium saturation
`capacity for 100% butane vapor(“butane.activity,” g/100g-carbon), and purgeability (“butane
`ratio”), specifically, the proportion of adsorbed butane from the saturation step which can be
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`~
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`recovered from the carbon by an air purge step. The multiplicative product of these three
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`properties yields a measure ofthe carbon’s effective butane “working capacity” (“BWC”, g/dL),
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`Case-ocket No. CHR 2001-79
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`measured by ASTM D5228-92, which hasbeen establishedin the art as a good predictor of the
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`.
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`canister working capacity for gasoline vapors. Carbonsthat excel for this application have high
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`BWC,typically 9 to 15+ g/dL BWC,as aresult ofhigh saturation capacities on a volumetric-
`basis for butane (the product of density and butaneactivity), and high butane ratios (50.85). In
`termsof isothermal equilibrium adsorption capacities across all vapor concentrations, these
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`carbons characteristically have high incremental capacity as a function of increased vapor
`
`concentration (i.e., isotherm curved upward on a semi-log graph). This isotherm upward curve
`
`reflects the high working capacity performancefeature of these carbons, in that gasoline vapors
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`are adsorbed in high quantity at high concentrations butreadily released in high concentration
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`to an air purge stream.
`
`In addition, these carbons tend to be granular (somewhatirregularly
`
`shaped)or cylindrical pellet, typically of a size just about 1-3 mm in diameter. It has been
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`_
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`found that somewhatlarger sizes hinder diffusional transport of vapors into and out of the
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`carbon particle during dynamic adsorb and purge cycles. On the other. hand, somewhat smaller
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`size particles have unacceptably high flow restriction for displaced air and hydrocarbon vapors
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`during refueling.
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` (b)
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`Diurnal Breathing Loss (DBL) Requirements
`Recently, regulations have been promulgated that require a change in the approach with.
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`respect to the way in which vapors must be controlled. Allowable emission levels from
`canisters would be reduced to such low levels that the primary source of emitted vapor, the fuel
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`tank, is no longer the primary concern, as current conventional evaporative emission control
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`appears to have achieved a high efficiency of removal. Rather, the concern now is actually the
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`‘hydrocarbonleft on the carbon adsorbentitself as a residual “heel” after the regeneration
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`(purge) step. Such emissions typically occur when a vehicle has been parked andsubjectedto
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`/
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`oeERIONPTEBEEPEEReRSSBEESoriFA tonnetenaamonGeen teenies asaiar nasatitenth ene
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`Case Docket No. CHR 2001-79
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`diurnal temperature changes over a period of several days, commonly dalled “diurnal breathing
`
`_ losses.” Now, the California Low Emission Vehicle Regulation makesit desirable for these
`diurnal breathing loss (DBL) emissionsfrom the canister system to be below 10 meg (“PZEV”)
`fora numberof vehicles beginning with the 2003 model year and below 50 mg, typically below
`20 mg, “LEV-ID’) for a larger number of vehicles beginning with the 2004 modelyear.
`(“PZEV”and “LEV-I’arecriteria of the California Low Emission Vehicle Regulation.)
`
`|
`
`While standard carbons used in the commercial canisters excel in terms of working
`
`.ycapacity, these carbons are unableto meet DBL emission targets under normalcanister
`operation. Furthermore, none of the standard measures of working capacity properties correlate
`with DBL emission performance. Nonetheless, one option for meeting emission targets is to
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`significantly increase the volume of purge gas during regeneration in order to reduce the
`
`amountof residual hydrocarbon heel in the carbon bed and thereby reduce subsequent
`
` 4,894,072.)
`
`emissions. This strategy, however, has the drawback of complicating managementof the
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`fuel/air mixture to the engine during purgeregeneration and tends to adversely affect tailpipe
`
`emissions, i.é., moving or redefining the problem rather than solving it. (See U. S. Patent No.
`
`Another option is to design the carbon bed so that there is a relatively low cross-
`
`sectional area on the vent-side of the canister system (the first portion of the bed to encounter
`
`purge air), either byredesign of the existing canisterdimensionsor by the installation of a
`supplemental, auxiliary vent-side canister of appropriate dimensions. This alternative has the
`
`effect of locally reducing residual hydrocarbon heel by increasing the intensity of purge for that
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`vent-side portion of the bed, thereby improvingits ability to retain vapors that would otherwise _
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`be emitted from the canister system under diurnal breathing conditions. The drawbackis that
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`Casedocket No. CHR 2001-79
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`there is a useful limit to which a portion of the bed can-be elongated at reduced cross-sectional
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`area without otherwise incurring excessive flow restriction by the canister system. In practice,
`
`this limit does not allow employinga sufficiently narrowed and elongated geometry to meet
`emission targets. (See U. S. Patent No. 5,957,114.)
`|
`Another option for increasing the purge efficiency of a fuel vapor/air mixture fraction
`
`adsorbedin the pores of the adsorbent material is suggested by the teachings of U. S. Patent
`Nos. 6,098,601 and 6,279,548 by providing a heating capability internal of the canister, or a
`
`
`
`section thereof, either to increase pressure in the vapor storage canister to expel hot vapor
`
`through the vapor/purge conduit back into the fuel tank where it condenses at the lower ambient
`temperature therein (601) or to increase the purging efficiency of hydrocarbons from the heated
`adsorbent material and carry the purged fuel vapor to the induction system of an associated
`engine (548). However, this increases thecomplexity of control.
`system management, and
`there appears some inherent safety concernsin providing heating ihternal of a canister for.
`trapping fuel vapors.
`|
`Thus, an acceptable remedy, which does not have drawbacks as the cited alternative
`approaches, is greatly desired. It is submitted that the invention disclosed and claimed herein
`provides the desired solution.
`|
`
`SUMMARY OF THE INVENTION
`
`An invention is disclosed for sharply reducing diurnal breathing loss emissions from
`evaporative emissions canisters by the use of multiple layers, orstages, of adsorbents. On the
`fuel source-side of the canister, standard high working capacity carbons are preferred. On the
`
`vent-side, the preferred adsorbent volume exhibitsa flat or flattened adsorbent isotherm on a
`
`volumetric basis in addition to certain characteristically desirable adsorptive properties across
`
`LA
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`CaseDocket No. CHR 2001-79
`broad vapor concentrations, specifically relatively low incremental capacity at high
`|
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`‘
`
`concentration vapors compared with the fuel source-side adsorbent volume. Two approaches
`
`are described for attaining the preferred properties for the vent-side adsorbent volume. One
`
`approach is to use a fillerand/or bed voidagesas a volumetric diluentfor flattening an isotherm,
`A second approach is to employ an adsorbentwith the desired isotherm properties and to
`
`process it into an appropriate shape or form without necessarily requiring any special provision
`
`for dilution. Both such approaches providea substantially lower emissions canister system
`withouta significant loss in working capacity ot an increase in flow restriction compared with
`prior art adsorbents used for automotive emissions control.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Figure hows, in cross-section, a priorart canister system.
`
`Figure 2 shows,in cross-section, one embodimentof the invention canister comprising
`multiple adsorbents.
`|
`
`
`
`Figure 3}shows butane isotherm properties for different activated carbon adsorbents.
`DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
`The disclosed invention relates to the use of multiple beds (or layers, stages, or
`
`chambers)of adsorbent materials, which, in combination, significantly reduce DBL emissions
`
`while maintaining the high working capacity and low flow restriction properties of the canister
`system.
`(See Figure 2.) These adsorbents includeactivated cabonfrom a variety ofraw
`materials, including wood,peat, coal, coconut, synthetic or naturalpolymer, and a variety of
`processes, including chemical and/or thermal activation, as well as inorganic adsorbents,
`including molecular sieves, porous alumina, pillared clays, zeolites, and poroussilica, and
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`organic adsorbents, including porous polymers. The adsorbents maybe in granular, spherical,
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`or pelletized cylindrical shapes, or may be extrudedintospecial thin-walled cross-sectional
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`»
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`shapes, such as hollow-cylinder,star, twisted spiral, asterisk, configured ribbons, or other
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`shapes within the technical capabilities of the art. In shaping, inorganic and/or organic binders .
`may be used. The adsorbents may be formed into amonolith or honeycombpart. The ~
`adsorbents may be incorporated into acanister as one or more layers, or separate chambers, or
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`they may be inserted in the fluid stream flow as auxiliary canister beds.
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`One commonfeature for all of these approachesis to have a vent-side adsorbent with a
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`relatively flat-shaped isotherm. This isotherm shape is important for reasonsrelated to purge
`efficiency across the adsorbent bed depth. For an adsorbent with a flat adsorption isotherm, the
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`concentration of hydrocarbon vaporin equilibrium with adsorbed hydrocarbon, by definition,
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`decreases further as the adsorbed hydrocarbon isremoved compared with an adsorbent with a
`more steeply sloped isotherm. Thus, whensuchamaterial is employed as an adsorbent volume
`on the vent-side region of a canister, purgeis able to reduce the vapor concentration in the area
`of the purge inlet to a very low level. Since it is the vapor near the purge inlet that eventually
`emerges as bleed, decreasing this concentration reduces thebleed emission level. The degree of
`removal of adsorbed hydrocarbon during purgeis determined by the differerice between the
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`concentration of hydrocarbon picked up in the purge gas and the concentration in equilibrium
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`
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`with the adsorbentat any point in the bed. Thus, adsorbent in the immediate vicinity of the
`purge inlet will be most thoroughly regenerated. At points deeper in the adsorbent bed,less
`hydrocarbon will be removed because the purge gas will already contain hydrocarbon removed
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`from previous points in the bed. An adsorbent with a flatter adsorption isotherm will give up
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`less vapor into the purge stream and this purge will then be moreefficient in reducing vapor
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`concentrations deeper into the bed. Therefore, for a given quantity of purge gas, it will be
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`CaseDocket No. CHR 2001-79
`possible to reduce the vapor concentration inavolume of adsorbent with a flat adsorption
`isotherm to a lower level than the concentrationin the same volume of an adsorbent with a
`| steep adsorption isotherm. Bleed emission from such a volumewill therefore be lower when
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`the adsorbenthasa flatter adsorption isotherm.
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`A region within a canister containing particulate or in an adsorbent-containing monolith
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`with the preferred adsorption isotherm properties for achieving low bleed emission levels will,
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`however, have a relatively low adsorption working capacity compared to the activated carbons
`| commonly usedin automotive evaporative emission control. For example, the BWC of a low
`capicity adsorbent will be about 6 g/dL compared.to the 9 g/dL to 15+ g/dL range as used in
`typical automotive carbons. Therefore, in order to maintain the required hydrocarbon capacity
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`for normal emission control system operation, the low-bleed adsorbent will be used in a vent-
`side auxiliary region within thecanister or outsidethe canister in combination with an fuel
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`source-side region containing a volumeofthe high capacity carbon normally employed. When
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`two different adsorbents are used, for example, system design will involve providing sufficient
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`volume of the high capacity carbon in the main part, or fuel source-side, of an emisssion control
`canister to achieve the desired working capacity, and a sufficient volumeof the low-bleed
`adsorbent to contain vapor emitted from the main bed to such an extent that such vapor does
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`not materially affect the bleed emissions from the low-bleed adsorbent.
`In the context of the invention, “monolith”is intended to include foams, woven and
`non-woven fibers, mats, blocks and bound aggregates of particulates.
`It is notable that the emission of vapor from the main, high-capacity fuel source-side
`volume of adsorbent into the auxiliary lower capacity vent-side volumeis significantly affected .
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`by the presence of that vent-side volume. During purge, a vent-side adsorbent volume having a
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`flat adsorption isotherm will give up a relatively small hydrocarbon load into the purge gas. °
`Therefore, the concentration of vapor carried by the purge gas will be low as it emerges from
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`the low-bleed vent-side volume andenters the high-capacity, fuel source-side volume. This
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`allows good regeneration of the high-capacity adsorbentin the vicinity of the junction of the
`two adsorbent volumes, and helps protect the vent-side volume from emissions from the fuel
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`source-side region of the canister during diurnal breathing flow. Specifically, the greater
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`regeneration efficiency of the fuel source-side volume reduces diurnal emissions by retarding
`the rate of bulk phase diffusion across the flow length of the canister system. Since bulk phase
`diffusion is a major mode of vapor transport during diurnal breathing conditions, by reducing
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`the vapor concentration difference across the flow length of the canister system by enhanced
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`regeneration, the redistribution of vapors within the canister system and subsequent emissions
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` isotherm properties must be defined in terms of volumetric capacity. On this basis, the
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`into the vent-side volume and outof the vent portare reduced.
`Examples of adsorbents with isotherms having the preferred shape to provide low bleed
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`performance are compared with standardcanister-fill carbons (Westvaco Corporation’s BAX
`1100 and BAX 1500) in Figure 3. It is importantto note that, as shown in this figure, the
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`preferred low-bleed adsorbent portion will have an incremental n-butane capacity of less than
`about 35 g/liter between 5 and 50 volumepercent n-butane vapor concentration.
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`While in some instances, known adsorbents may have the preferred properties for the
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`vent-side, these adsorbents would not be expected to be useful in an evaporative canister. In
`somecases, these materials have low purgeability (butaneratio less than 0.85) and low working
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`capacity (BWCless than 9 g/dL) as measured by the standard BWCtest for qualifying canister
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`carbons. Common wisdom and experiencein the art associate low butane ratio with high
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`residual hydrocarbon heel, whichis the potential source for high emissions. Furthermore, low
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`BWCadsorbents were not considered useful for inclusion into a canister system as working
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`capacity for gasoline vapors would be assumed impaired, with no expectation that there would
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`be a utility for reducing emissions. In fact, one preferred embodimentof this invention, lower
`capacity adsorbents have BWC values preferably below 8 g/dL, which is well below the 9-15+
`g/dLBWClevel normally deemed suitable for use in evaporative emission control canister
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`systems. The preferred selection of these low BWC materials for inclusion into a canister
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`system as a vent-side layer to produce low emissions was only realized once the dynamics
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`within the adsorbent bed wererealized (7.e., the significance of low residual vapor
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`concentration within the vent-side bed volumeandtheinteractive effect that the vent-side bed
`volume has on the distribution and diffusion ofvapor across the entire canister system during
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`the diurnal breathing loss period).
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`Therefore, it has been found that the preferred vent-side adsorbentproperties,in
`addition to a relatively low BWC, includes butane ratios between 0.40 and 0.98, which in total
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`are substantially different properties compared with adsorbents previously conceived as useful
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`for these canister systems.
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`The proposedalternative approaches described above are shown tobe effectivein
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`canister bleed emission control in the following examples. One approach for preparing the
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`vent-side adsorbentis to volumetrically dilute a high working capacity adsorbent sothat its
`resulting isotherm is flattened on a volumetric basis. A second approachis to begin with an
`adsorbent that has the desired adsorption capacity and flat isotherm shape and processit into a
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`shape or form, such as a pellet or honeycomb.
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`Case Docket No. CHR 2001-79
`A particular preferred embodiment for a canister with multiple adsorbents is shown in
`Figure 2. Figure 2 showsa canister system comprising a primary canister body 1, a support
`screen 2, a dividing wall 3, a vent port 4 to the atmosphere, a vapor source connection 5, a
`vacuum purge connection 6, a fuel source-sideregion 7, vent-side canister regions 8 — 11of
`varying low-capacities, supplemental canister body 12, and connecting hose 13 permitting fluid
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`stream flow from the primary canister body 1 to the supplemental canister body 12. Additional
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`embodiments, as discussed above,are also envisioned to be within the scopeof the subject of
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`the invention.
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`The desired results for the subject matter of the invention can beattained with a single
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`vent-side uniform lowercapacity adsorbent material as the subsequent adsorbent material. The
`option of multiples of lower capacity adsorbents with the desirable adsorptive properties across
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` remaining canister fill. The honeycomb was tested as an auxiliary bed canister that was placed
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`broad vapor concentrations is demonstrated merely as one embodiment.
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`The measuresfor gasoline working capacity (GWC) and emissions in the Table were
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`derived from the Westvaco DBLtest that uses a 2.1L canister. The pellet examples were tested
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`as a 300 mL vent-side layer within the canister, with the 1800 mL of BAX 1500 pellets as the
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`in-line with the 2.1L main canister of BAX 1500 pellets. Forall examples, the canister system
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`was uniformly first preconditioned by repetitive cycling of gasoline vapor adsorption andair
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`purge (400 bed volumesair). This cycling generated the GWC value. Butane emissions were
`subsequently measured after a butane adsorption and an air purge step, specifically during a
`diurnal breathing loss period when the canister system was attached to a temperature-cycled
`fuel tank. The reported value is the2% day DBL emissions during an 11-hour period when the ©
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`fuel tank was warmed and vapor-laden air was vented to the canister system and exhausted
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`11
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`(ZL
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`from the vent-side adsorbent where the emissions were measured. The procedure employedfor
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`measuring DBL emissions has been described in SAE Technical Paper 2001-01-0733,titled
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`“Impact and Control of Canister Bleed Emissions,” by R. S. Williams and C. R. Clontz.
`Example L Microsphere Filler Pellets. These 2 mm pellets are an example of the
`| volumetric dilution method by addinga solid filler to the extrusion formulation. ‘Thepellets
`were prepared from an extrusion blend consisting of Westvaco SA-1500 powder (12.8 wt%),
`solid glass microsphere filler (79.7 wt% PQ Cotporation A3000), bentonite clay (7.2 wt%), and
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`phosphoric acid (0.3 wt%). The pellets were tumbled for four minutes, dried overnight at
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`105°C, and subsequently heat-treated in steam at 650°C for 15 minutes. An appropriate non-
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`adsorbing filler reduces adsorption capacities across all vapor concentrations, resulting in a
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`flattened adsorption isotherm (“Example 1”in Figure 3). Alternative methods for diluting the
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`vent-side region are to co-mix adsorbent granules or pellets with inert filler particles of similar
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`size, to form the extrusion paste into high voidage shapes such as hollow cylinders, asterisks,
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`stars, or twisted, bent, or spiral ribbon pieces, or to place multiple thin layers of non-adsorbing
`particles or porous mats (e.g., foam), or simply trapped alr space between layers of adsorbent.
`Example 2: Ceramic-Bound Honeycomb. The 200 cpsi (cells per square inch) carbon-
`containing honeycombis another example of the volumetric dilution method. The honeycomb
`in the Tablewas prepared according to the method described in U.S. Patent No. 5,914,294,
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`which discloses forming an adsorptive monolith comprising the steps of (a) extruding an
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`extrudable mixture through an extrusion die such that a monolith is formed having a shape
`wherein the