`___________________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`___________________
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`DECLARATION BY JAMES M. LYONS IN SUPPORT OF PETITION FOR
`INTER PARTES REVIEW OF
`U.S. PATENT RE38,844
`
`Mail Stop PATENT BOARD
`Patent Trial and Appeal Board
`U.S. Patent & Trademark Office
`P.O. Box 1450
`Alexandria, VA 22313–1450
`
` MAHLE-1003
`U.S. Patent No. RE38,844
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`Table of Contents
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`I. Introduction ........................................................................................................... 1
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`II. Qualifications ........................................................................................................ 4
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`III. Level of ordinary skill in the art ........................................................................... 8
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`IV. Applicable legal standards ............................................................................... 9
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`V. Background of the technologies disclosed in the ’844 patent ............................ 11
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`A. Evaporative Emissions .................................................................................. 11
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`1. Diurnal breathing emissions ..................................................................... 12
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`2. Refueling emissions .................................................................................. 14
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`B. Capturing evaporative emissions with adsorbent material ............................ 14
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`C. Performance of Evaporative Emissions Control Systems ............................. 18
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`1. Adsorption Capacity and Adsorption Isotherms ...................................... 19
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`2. Butane Working Capacity ........................................................................ 21
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`VI. The ’844 patent. ............................................................................................. 22
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`A. Overview of the disclosure of the ’844 patent............................................... 22
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`B. Overview of the claims of the ’844 patent. ................................................... 27
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`VII. Claim construction. ........................................................................................ 31
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`VIII.
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`The prior art. ............................................................................................. 31
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`A. Overview of Meiller. ..................................................................................... 31
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`B. Overview of Abe. ........................................................................................... 34
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`C. Overview of Park. .......................................................................................... 37
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`IX. Summary of the ’844 patent in view of the prior art. .................................... 39
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`A. Honeycomb Scrubbers ................................................................................... 39
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`B. Incremental Adsorption Capacity .................................................................. 44
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`1. High IAC volumes .................................................................................... 44
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`2. Low IAC volumes .................................................................................... 45
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`X. Motivation to combine the prior art. ................................................................... 47
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`XI. Claims 1, 2, 6, 8, 11, 12, 14–16, 18, 20, 21, 24, 25, 27–29, 31–33, 36, 37,
`39–41, 43–45, 48, 49, and 51–53 in view of Meiller, Park, and admitted prior
`art. ....................................................................................................................... 49
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`A. Claims 1, 18, 31, and 43. ............................................................................... 49
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`1. Independent claim 1. ................................................................................ 59
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`2. Independent claim 18. .............................................................................. 60
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`3. Independent claim 31. .............................................................................. 61
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`4. Independent claim 43. .............................................................................. 69
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`B. Dependent claim 2. ........................................................................................ 69
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`C. Dependent claims 6, 20, 32, and 44. .............................................................. 69
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`D. Dependent claims 8, 21, 33, and 45. .............................................................. 70
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`E. Dependent claims 11, 24, 36, and 48. ............................................................ 72
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`F. Dependent claims 12, 25, 37, and 49. ............................................................ 72
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`G. Dependent claims 14, 27, 39, and 51. ............................................................ 73
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`H. Dependent claims 15, 28, 40, and 52. ............................................................ 73
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`I. Dependent claims 16, 29, 41, and 53. ............................................................ 74
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`XII. Claims 1, 2, 6, 8, 11, 12, 14–16, 18, 20, 21, 24, 25, 27–29, 31–33, 36, 37,
`39–41, 43–45, 48, 49, and 51–53 in view of Abe, Park, and admitted prior art.74
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`A. Claims 1, 18, 31, and 43. ............................................................................... 74
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`1. Independent claim 1. ................................................................................ 78
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`2. Independent claim 18. .............................................................................. 79
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`3. Independent claim 31. .............................................................................. 81
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`4. Independent claim 43. .............................................................................. 82
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`B. Dependent claim 2. ........................................................................................ 83
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`C. Dependent claims 6, 20, 32, and 44. .............................................................. 83
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`D. Dependent claims 8, 21, 33, and 45. .............................................................. 84
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`E. Dependent claims 11, 24, 36, and 48. ............................................................ 86
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`F. Dependent claims 12, 25, 37, and 49. ............................................................ 87
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`G. Dependent claims 14, 27, 39, and 51. ............................................................ 87
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`H. Dependent claims 15, 28, 40, and 52. ............................................................ 88
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`I. Dependent claims 16, 29, 41, and 53. ............................................................ 88
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`XIII.
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`Claims 3–5, 7, and 19 in view of Meiller, Park, AAPA, and Tennison. .. 89
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`A. Overview of Tennison. .................................................................................. 89
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`B. Claims 4 and 19. ............................................................................................ 90
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`C. Claim 3. .......................................................................................................... 93
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`D. Claim 5. .......................................................................................................... 94
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`E. Claim 7. .......................................................................................................... 95
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`XIV.
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`Objective indicia of non-obviousness. ..................................................... 95
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`XV. Conclusion ..................................................................................................... 96
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`I.
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`Introduction
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`1. My name is James M. Lyons. I have been employed since October
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`2014 as a Principal Consultant by Trinity Consultants Inc. (Trinity) and work at
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`Trinity’s Sacramento California office located in Suite 400, 3301 C Street. Trinity
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`is an environmental consulting company that specializes in air pollution control as
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`well as other areas. In October 2014, Trinity acquired my former employer Sierra
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`Research, Inc. (Sierra), which was also an environmental consulting firm
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`specializing in research and regulatory matters pertaining to air pollution control.
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`2.
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`I have been retained as an expert on behalf of MAHLE, which I
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`understand to be the Petitioner in this matter, to provide opinions regarding U.S.
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`Patent No. RE38,844 (“the ’844 patent”). In particular I have been asked to
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`provide expert opinions related to the level of skill of ordinary people working in
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`the field of vehicular evaporative emissions control, the state of the art of the
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`vehicular evaporative emissions control technology described in the ’844 patent at
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`the time of the effective filing date of the ’844 patent, and the disclosure of the
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`prior art relative to the claims of the ’844 patent.
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`3.
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`The bases for my opinions include the following: (i) my education as
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`a degreed Chemist and Chemical Engineer; (ii) my 33 years of experience in the
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`development, assessment, and testing of emissions control systems for automobiles
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`and equipment, including direct experience related to the design and operation of
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`evaporative emissions control systems; (iii) my previous experience in reviewing
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`prior art related to U.S. patents directed toward emissions control, vehicle refueling
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`vapor recovery systems, the design of vehicle engines, and evaporative emissions
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`control devices for lawn and garden equipment; (iv) my review of certain prior art
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`literature pertaining to evaporative emissions control systems for gasoline vehicles;
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`and (v) my review of certain documents pertaining to this proceeding.
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`4.
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`In the preparation of this declaration, I have studied at least:
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`• The ’844 patent (MAHLE-1001);
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`• English translation of Japanese Patent Application Publication
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`Number: H10-37812, which I refer to here as “Abe” (MAHLE-1009);
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`• U.S. Patent Number: 5,914,294, which I refer to here as “Park”
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`(MAHLE-1010);
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`• U.S. Patent 2002/0073847 A1, which I refer to here as “Sheline”
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`(MAHLE-1022);
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`• U.S. Patent 6,537,355 B2, which I refer to here as “Scardino”
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` (MAHLE-1017);
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`• U.S. Patent 6,896,852 B1 which I refer to here as “Meiller”
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` (MAHLE-1016);
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`• WO 92/01585 Publication which I refer to here as “Tennison”
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` (MAHLE-1011).
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`5.
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`In forming the opinions expressed below, I have considered the
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`documents listed above, as well as:
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`• Williams, R., Impact and Control of Canister Bleed Emissions (2001)
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`(MAHLE-1012).
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`• U.S. Patent 5,691,270 to Miller (MAHLE-1025);
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`• Society of Automotive Engineers, Technical Paper Series, Paper No.
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`902119, 1990 (MAHLE-1026);
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`• Society of Automotive Engineers, Technical Paper Series, Paper No.
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`901110, 1990 (MAHLE-1027);
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`• Society of Automotive Engineers, Technical Paper Series, Paper No.
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`2000-01-0895, 2000 (MAHLE-1028);
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`• ASTM D5228 (MAHLE-1024).
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`6. My experience and qualifications are set forth in my curriculum vitae,
`which I understand is being submitted as Exhibit 1004. My curriculum vitae also
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`includes a list of all publications I authored in the previous ten years and a list of
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`cases in which I testified as an expert at trial or by deposition. The cases in which I
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`have testified as an expert at trial or by deposition within the preceding four years
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`are Ingevity Corp. et al. v. BASF Corp., 1:18-cv-01391 (DED), Pirnik et al. v. Fiat
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`Chrysler Automobiles N.V., et al, No. 1:15-cv-07199-JMF, Orange County Water
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`District v. Unocal Corp., et al., 8:03-cv-01742-CJC (DJM), People of the state of
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`California, Ex Rel. California Air Resources Board v. BP West Coast Products
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`LLC, Superior Court of California, County of Contra Costa, Case No. C12-00567
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`and Stant USA Corporation v. Briggs & Stratton Corporation, Case No. No. 1:13-
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`cv-01908-TWP-TAB, U.S. District Court Southern District of Indiana,
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`Indianapolis Division.
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`7. My firm is being compensated at the standard hourly rate of $275
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`for my work in this case. My compensation is not contingent on the outcome of
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`this litigation.
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`II. Qualifications
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`8.
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`In 1983, I graduated cum laude from the University of California,
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`Irvine with a Bachelor of Science degree in Chemistry. In 1985, I graduated from
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`the University of California, Los Angeles with a Master of Science degree in
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`Chemical Engineering.
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`9.
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`Following my graduation from the University of California, Los
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`Angeles, I held several different positions at the California Air Resources Board
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`(“CARB”) before joining Sierra Research, a consulting firm specializing in air
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`quality and air pollution control, in 1991.
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`10. My first position at CARB was as an Associate Air Resources
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`Engineer. I was later promoted to Air Resources Engineer and then to Air Pollution
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`Research Specialist. My duties during this time included analysis of vehicle
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`emissions data for the purposes of evaluating the efficacy of emission control
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`systems of different types and designs in reducing exhaust, crankcase, and
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`evaporative emissions of regulated and toxic compounds, and determining the
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`impact of emissions from gasoline and diesel-powered vehicles on ambient levels
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`of toxic air contaminants; participation in the development of California
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`regulations regarding “gray market” vehicles; and preparation of technical papers
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`and reports related to vehicle exhaust and evaporative emissions.
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`11.
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`In 1989, I advanced to the position of Senior Air Pollution Specialist.
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`I supervised a staff of four professionals whose primary responsibilities were to
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`characterize emissions of toxic compounds from mobile sources and to develop
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`control strategies to reduce those emissions. In addition, the group was responsible
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`for determining the effects of compositional changes to gasoline and diesel fuel on
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`emissions of regulated and toxic pollutants. Other responsibilities included
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`overseeing the development of the California state plan to control toxic emissions
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`from motor vehicles and reduce emissions of chlorofluorocarbons from motor
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`vehicles. During this time, one of my primary responsibilities was the development
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`of the original version of CARB’s “real-time” evaporative emissions test
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`procedures and standards for diurnal breathing, hot-soak, and running loss
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`emissions for vehicles tested using those procedures. These regulations were
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`adopted by CARB in 1990 and applied to 1995 and later model-year vehicles.
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`12.
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`In April 1991, I joined Sierra Research as a Senior Engineer. I became
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`a Senior Partner at Sierra Research (Sierra) in 1996 and worked in that capacity
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`until Sierra Research was acquired by Trinity (Trinity) Consultants Inc. in October
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`of 2014. During my 27 years with Sierra/Trinity, I have continued to work
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`extensively on issues related to the design and performance of exhaust and
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`evaporative emissions control systems applied to vehicles, engines, and equipment.
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`I have been involved with the development, assessment, and testing of advanced
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`exhaust and evaporative emissions control systems for on- and off-road gasoline-
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`and diesel-powered vehicles, equipment and engines, as well as Stage I and Stage
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`II vehicle refueling vapor recovery systems.
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`13. During the course of my career at Sierra/Trinity, I have closely
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`followed developments affecting evaporative emission test procedures,
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`performance standards, and evaporative emission control system designs, including
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`diagnostic requirements, as they pertain to vehicles and other types of mobile
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`sources. My activities have included tracking and describing the development of
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`California regulations in Sierra/Trinity’s monthly newsletter entitled CVS News,
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`attending regulatory workshops and industry conferences, being involved in related
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`research, both authoring and reviewing technical publications, and providing
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`technical assistance to clients affected by regulatory proceedings.
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`14. With respect to specific requirements for on-road light-duty vehicles
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`that have occurred since I developed the “real-time” evaporative emission
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`regulations at CARB, by way of example, I have followed:
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`a) the development of federal “real-time” evaporative emission test procedures
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`and standards, as well as California and federal standards and test
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`procedures for on-board refueling vapor recovery (ORVR) systems;
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`b) the establishment of on-board diagnostic requirements, which include
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`monitoring of evaporative emission control systems for defects and
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`malfunctions;
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`c) the development of more stringent California and federal “real-time”
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`evaporative emissions requirements, including the “near zero” evaporative
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`emission standards associated with the California Low-Emission Vehicle
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`(LEV) II and U.S. EPA Tier 2 rulemakings, as well as the establishment of
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`regulatory requirements for fuel system materials; and
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`d) changes in evaporative emission test fuel specifications intended to address
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`issues related to evaporative emissions resulting from due permeation of
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`materials used in automotive fuel systems.
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`15.
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`In addition, I have also closely followed the establishment of CARB’s
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`“partial-zero emission vehicle” standards as part of the LEV II regulations which
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`must comply with “zero-evaporative” emission standards and the expansion of
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`those requirements under the CARB LEV III rulemaking and U.S. EPA’s
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`subsequent adoption of similar requirements as part of its Tier 3 regulations.
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`16.
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`I am a member of the American Chemical Society and the Society of
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`Automotive Engineers.
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`III. Level of ordinary skill in the art
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`17.
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`I have been asked to define the level of a “person of ordinary skill in
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`the art” or “POSITA” in the field of evaporative emissions control systems and
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`component design. In forming my opinion of the level of ordinary skill in the art, I
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`have considered the following factors, which I have been informed are relevant to
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`the determination of the level of ordinary skill in the art: 1) the type of problems
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`encountered in the art; 2) the prior art solutions to these problems; 3) the rapidity
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`with which innovations are made; 4) the sophistication of the technology; and 5)
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`the educational level of active workers in the field.
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`18.
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`In my opinion, a person of ordinary skill in the art of the field of
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`evaporative emission control systems and component design would possess at least
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`a bachelor’s degree in chemistry or chemical or mechanical engineering. They
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`would also have at least one year of experience working primarily on issues related
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`to the control of automotive evaporative emissions. They would, given both their
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`education background and experience, understand the chemistry and physics
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`associated with the phenomena of fuel vapor adsorption, desorption, and diffusion.
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`IV. Applicable legal standards
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`19.
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`I have been asked to provide my opinions regarding the disclosure of
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`the prior art and knowledge of a POSITA relative to independent claims 1, 18, 31,
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`and 43 and dependent claims 2–8, 11, 12, 14–16, 19–21, 24, 25, 27–29, 32, 33, 36,
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`37, 39–41, 44, 45, 48, 49, and 51–53 (collectively the “Challenged Claims”) of the
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`’844 patent at the time of the alleged invention.
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`20.
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`I am not an attorney. In preparing and expressing my opinions and
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`considering the subject matter of the ’844 patent, I am relying on certain legal
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`principles that counsel has explained to me.
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`21.
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`I have been informed and understand that a claimed invention is
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`unpatentable under 35 U.S.C. § 103 if the differences between the invention and
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`the prior art are such that the subject matter as a whole would have been obvious at
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`the time the invention was made to a person of ordinary skill in the art
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`(“POSITA”). I understand that the obviousness analysis takes into account factual
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`inquiries, including the level of ordinary skill in the art, the scope and content of
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`the prior art, and the differences between the prior art and the claimed subject
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`matter.
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`22.
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`I have been informed and understand that the Supreme Court has
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`recognized several rationales for combining references or modifying a reference to
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`show obviousness of claimed subject matter. Some of these rationales include the
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`following: (a) combining prior art elements according to known methods to yield
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`predictable results; (b) simple substitution of one known element for another to
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`obtain predictable results; (c) use of a known technique to improve a similar device
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`(method, or product) in the same way; (d) applying a known technique to a known
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`device (method, or product) ready for improvement to yield predictable results; (e)
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`choosing from a finite number of identified, predictable solutions, with a
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`reasonable expectation of success; and (f) some teaching, suggestion, or motivation
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`in the prior art that would have led a POSITA to modify the prior art reference or
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`to combine prior art reference teachings to arrive at the claimed invention.
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`23. Also, I have been informed and understand that obviousness does not
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`require physical combination/bodily incorporation, but rather consideration of what
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`the combined teachings would have suggested to a POSITA at the time of the
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`alleged invention.
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`24.
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`I understand that certain objective indicia can be evidence regarding
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`whether a patent is obvious. Such indicia include: commercial success of products
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`covered by the patent claims; a long-felt need for the invention; failed attempts by
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`others to make the invention; copying of the invention by others in the field;
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`unexpected results achieved by the invention as compared to the closest prior art;
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`praise of the invention by an infringer or others in the field; the taking of licenses
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`under the patent by others; expressions of surprise by experts and those skilled in
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`the art at the making of the invention; and the patentee proceeding contrary to the
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`accepted wisdom of the prior art.
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`V. Background of the technologies disclosed in the ’844 patent
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`25. The ’844 patent discloses a system for reducing emissions of gasoline
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`vapor from automobile fuel tanks. However, every single component of the ’844
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`system was known in the prior art, arranged in the same way as the ’844 patent,
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`and used for the same application as the ’844 patent.
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`A. Evaporative Emissions
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`26. Gasoline is a mixture of a number of compounds, many of which are
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`known as volatile organic compounds, or VOCs. The terms VOC and hydrocarbon
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`emissions are often used synonymously in the field of automotive emissions
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`control. VOCs are of importance because they contribute to air pollution including
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`the formation of “Smog” and its principle constituent ozone through
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`photochemical reactions in the atmosphere. With respect to evaporative emissions,
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`the VOC’s of concern evaporate at relatively low temperatures and can therefore
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`pass into the atmosphere as vapors. Automobiles can emit gasoline fuel vapors in a
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`number of different ways, but evaporation of fuel and displacement of fuel vapors
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`11
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`from automotive fuel tanks have and continue to represent a substantial source of
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`VOC emissions in the United States.
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`27. Research into the causes, regulation, and mitigation of evaporative
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`emissions dates back to the 1960s (MAHLE-1013, pp. 235-238), motivated by
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`concerns with SMOG and the subsequently adopted federal health-based standards,
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`known as National Ambient Air Quality Standards (NAAQS), which set limits on
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`ambient concentrations of certain air pollutants including ozone and fine
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`particulate matter that can impacted by emissions of VOCs. There are at least five
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`different processes that cause evaporative emissions from gasoline-powered on-
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`road vehicles. Of most relevance to the ’844 patent are the processes known as
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`“diurnal breathing emissions” and “refueling emissions.” I discusses these two
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`processes in the following sections.
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`1. Diurnal breathing emissions
` A typical fuel tank contains a mixture of fuel vapor and air that fills
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`28.
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`the volume of the tank not occupied by liquid fuel. The illustration below shows
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`the vapor (orange)/air (blue) mixture above the liquid fuel (orange).
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`12
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`29. The diurnal breathing emissions (also referred to as diurnal breathing
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`losses or DBL) result primarily from the expansion of the vapor above the fuel in
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`the fuel tank in response to the increase in the ambient air temperature that occurs
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`during the course of a day. When the vapor expands, it escapes out the vent, which
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`allows the pressure in the fuel tank to remain constant as the tank is filled or as the
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`engine consumes fuel during operation. The escape of the vapor from the vent is
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`illustrated below.
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`30. As the ambient temperature gradually rises, the temperature of the
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`fuel tank and the vapor present in the fuel tank also begins to gradually rise. Given
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`the constant volume of the fuel tank, this rise in temperature causes vapor
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`expansion and the pressure in the vapor space over the fuel tank to increase. On a
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`vehicle without an evaporative emission control system, a vented fuel cap would
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`generally be used to allow this increase in pressure to be relieved by venting (e.g.,
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`emitting) hydrocarbon-containing fuel vapors to the atmosphere.
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`Refueling emissions
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`2.
` When a partially filled fuel tank is filled with gasoline, the incoming
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`31.
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`liquid displaces the hydrocarbon containing vapor present in the tank. The rate of
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`tank filling is usually quite rapid. On vehicles not designed to control refueling
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`emissions through the incorporation of an ORVR system, hydrocarbon vapors can
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`be vented (e.g., emitted to the atmosphere) through the fill pipe or, to the extent
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`that appropriate regulations have been promulgated in a given area, captured by a
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`service station based refueling vapor recovery system.
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`B. Capturing evaporative emissions with adsorbent material
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`32.
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`In California in 1970 and in the rest of the U.S. in 1971, new vehicle
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`evaporative emission standards took effect which led to the development of
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`evaporative emission control systems. (See, e.g., MAHLE-1001, 1:39–40.) Since their
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`initial deployment, the design of these systems has generally relied on the use of c
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`anisters containing adsorbent materials (principally, if not exclusively, activated ca
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`rbons) that remove fuel vapors while allowing the air to vent to the atmosphere. (
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`MAHLE-1012, p. 2.)
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`33. The adsorbed hydrocarbons are intended to be stored in the canister
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`until purged by using vacuum produced by the operating engine to draw fresh air
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`14
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`through the adsorbent which is typically present in the form of granules or pellets
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`and then to draw the hydrocarbon containing vapor to the intake manifold where it
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`is burned by the engine. Before and by 2000, canisters often were designed with
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`three ports: 1) a vapor inlet port which was coupled to the gas tank; 2) a vent port
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`which vented air to the atmosphere and, during purge, drew air in from the
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`atmosphere; and 3) a purge port to which desorbed vapors would travel on their w
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`ay to be burned up in the engine. (MAHLE-1001, Figure 1; MAHLE-1016, Figure
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`10.) A schematic of vapor/air pathways associated with the adsorption/desorption
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`process is illustrated in the figure below for a three-port canister. (MAHLE-1020,
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`Figure 6.)
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`15
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`34. The ’844 patent admits that this three-port design is prior art. (See
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`MAHLE-1001, Figure 1, 1:58–64, 3:67.) It was also disclosed in, for example,
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`Figures 4, 9, and 10 of Meiller.
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`35. Evaporative emission control systems capture fuel vapors using the
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`process of adsorption. From a chemical perspective, this involves the deposition of
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`hydrocarbon molecules present in gasoline vapors onto the surface of the activated
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`carbon. The hydrocarbon molecules are bound to the activated carbon by physical
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`rather than chemical attractions or bonds through what are known as “Van Der
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`Waal” forces.
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`36. To increase the amount of material that can be deposited onto the
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`surface of the adsorbent, the adsorbent material is often designed to have a large
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`surface area by creating microscopic pores throughout the material. The process of
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`creating these pores in a carbon material is known as “activating” the carbon.
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`Generally, a higher surface area adsorbent will have a higher capacity to adsorb an
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`adsorbate. The adsorption of adsorbate onto an activated carbon is illustrated in th
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`e figure below. (MAHLE-1013, p. 247.)
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`37. Adsorption is a type of diffusion process that is driven by a gradient in
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`the concentration between the vapor and the surface of the activated carbon. Given
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`enough time, an equilibrium will be established between the hydrocarbon
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`concentrations in the gasoline vapor and on the surface of the activated carbon.
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`38. Once adsorbed, the hydrocarbon molecules can move about the
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`surface of the activated carbon or leave the surface – a process which is referred to
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`as “desorption.” As with adsorption, desorption rates depend on a number of
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`factors including the hydrocarbon concentration in the vapor. At equilibrium, the
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`rates of adsorption and desorption are equal. Given the need to both adsorb and
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`desorb hydrocarbons, in automotive applications, desorption is facilitated by
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`passing fresh air through the activated carbon beds used in evaporative emission
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`control system devices—the “purge” that I referred to previously.
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`39. Although not required by any regulation, activated carbon has
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`historically been the primary adsorbent used in vehicle evaporative emission
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`canisters in the U.S. and elsewhere in the world since their introduction in the
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`1970s. However, other adsorbent materials have long been known to exist,
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`including resins, silica gels, porous silica, molecular sieves, and zeolites.
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`40. Although, before and by 2000, most automotive canisters relied on
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`granular or pelleted forms of activated carbon, monoliths, honeycombs, and other
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`structural forms impregnated with activated carbon or other adsorbents were also
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`well known before 2001. (See, e.g., MAHLE-1025, U.S. Patent 5,691,270 to Miller;
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`MAHLE-1010, U.S. Patent 5,914,294 to Park; MAHLE-1018, Gadkaree, K.P., Carbon
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`honeycomb structures for adsorption applications, 36 Carbon 1998, 981–989.)
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`C. Performance of Evaporative Emissions Control Systems
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`41. As I discuss in detail in Section VI, the ’844 patent discloses and
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`claims a performance metric called “incremental adsorption capacity” that was not
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`a common term in 2001 or even today. In this section, I discuss well-known
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`performance metrics as understood by a POSITA in 2001.
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`42. Different activated carbons exhibit different properties and
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`characteristics, in part because activated carbon can be prepared from a variety of
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`carbon sources using various preparation methods. In considering evaporative
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`emission control systems, vehicle manufacturers are concerned with several issues
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`including:
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`• the need for the system to allow compliance with regulatory
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`performance standards set by environmental agencies such as CARB
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`and EPA;
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`• the cost of the system and individual components;
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`• the size of the system “package” given the space limitations on a
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`given vehicle;
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`• the need for the emission control performance of the system to be
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`durable (e.g., not deteriorate excessively with use); and
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`• the need for the system to be physically durable so that it survives in
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`the automotive environment.
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`43.
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`In the following sections I discuss different well-known ways to
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`measure the performance of an adsorbent to be used for evaporative emissions
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`control.
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`Adsorption Capacity and Adsorption Isotherms
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`1.
`44. An adsorbent’s adsorption capacity for a specific gas (e.g., n-butane)
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`can be defined as the amount (mass) of the gas that a unit (volume or mass) of the
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`19
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`adsorbent can adsorb. It is often expressed in grams per liter, grams per gram, or
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`grams per deciliter.
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`45. A material’s adsorption capacity is related to its surface area, which
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`itself is related to the number and size of pores in the material. The adsorption
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`capacity generally varies with temperature and vapor concentration. For a fixed
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`temperature (isothermal conditions), the adsorption capacity is often presented
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`g