       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

 THOMAS BECKMANN, ALEXANDER MASSNER,
              Appellants

                           v.

   HAREN S. GANDHI, JOHN VITO CAVATAIO,
  ROBERT HENRY HAMMERLE, YISUN CHENG,
                 Appellees

                ______________________

                      2015-1765
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in Interference No.
105,822.
                 ______________________

                Decided: April 29, 2016
                ______________________

    MICHAEL H. JACOBS, Crowell & Moring, LLP, Wash-
ington, DC, argued for appellants. Also represented by
VINCENT JOHN GALLUZZO; CHIEMI SUZUKI, New York, NY.

    EDWARD ANTHONY FIGG, Rothwell, Figg, Ernst &
Manbeck, P.C., Washington, DC, argued for appellees.
Also represented by ROBERT DANNY HUNTINGTON, BRETT
ALAN POSTAL.
2                                       BECKMANN   v. GANDHI



                  ______________________

     Before LOURIE, BRYSON, and DYK, Circuit Judges.
    Opinion for the court filed by Circuit Judge LOURIE.
Opinion dissenting in part filed by Circuit Judge BRYSON.
LOURIE, Circuit Judge.
    This patent appeal arises as one of a dying breed of
interference proceedings before the United States Patent
and Trademark Office Patent Trial and Appeal Board
(“the Board”) between Thomas Beckmann and Alexander
Massner (collectively, “Beckmann”), the named inventors
of U.S. Patent 7,584,605 (“the ’605 patent”), and Haren S.
Gandhi, John Vito Cavataio, Robert Henry Hammerle,
and Yisun Cheng (collectively, “Gandhi”), the applicants
of U.S. Patent Application 12/877,901 (“the ’901 applica-
tion”). Beckmann appeals from the Board’s decision,
which held that all of Beckmann’s claims involved in the
interference, viz., claims 1–4 of the ’605 patent, are un-
patentable over the cited prior art, and that claims 5, 7, 8,
and 10–17 of Gandhi’s ’901 application satisfy the written
description requirement.      See Beckmann v. Gandhi,
Interference No. 105,822, Paper No. 114 (P.T.A.B. July 8,
2013) (“Decision on Motions”); Beckmann v. Gandhi,
Interference No. 105,822, Paper No. 117 (P.T.A.B. Mar. 9,
2015) (“Rehearing Decision”).
    For the reasons that follow, we affirm the Board’s de-
termination that claims 3 and 4 of the ’605 patent are
unpatentable as obvious over the cited prior art, and that
the ’901 application contains an adequate written descrip-
tion of the “transitioning” limitation of claims 12–17, as
well as the “minimizing the oxygen content” limitation of
claims 7, 10, and 16. However, because the Board erred
in construing claim 1 of the ’605 patent as not requiring a
separate and distinct third “supplying” step, we vacate its
determination that claims 1 and 2 of the ’605 patent are
BECKMANN   v. GANDHI                                     3



unpatentable over the cited prior art and remand for
further proceedings under the proper claim construction.
Moreover, because the Board’s finding that the ’901
application contains an adequate written description of
the “minimizing the oxygen content . . . prior to a rich
cycle” limitation of claims 5, 8, 11, and 17 is unsupported
by substantial evidence, we vacate that finding and re-
mand for further proceedings consistent with this opinion.
                       BACKGROUND
                             I
    The technology at issue relates to methods of reducing
nitrogen oxide (“NOx”) emissions from internal combus-
tion engines. When an engine operates in a lean mode, a
reduced amount of fuel is provided to the cylinders, which
improves fuel efficiency. But operating in the lean mode
produces an exhaust gas with an excess of oxidizing
constituents (“lean exhaust gas”), which decreases the
effectiveness of the exhaust gas purification system,
leading to NOx emissions. In contrast, a “rich exhaust
gas” is one that has an excess of reducing constituents.
    According to Beckmann, a prior-art solution for reduc-
ing NOx emissions involved operating the engine alter-
nately in lean and rich modes to produce lean and rich
exhaust gases. Appellants’ Br. 10. In the engine, an NOx
catalytic converter (or “lean NOx trap”) stores NOx pro-
duced during the lean cycle, and then converts the stored
NOx to ammonia (“NH3”) during the rich cycle. A down-
stream selective catalytic reduction (“SCR”) catalytic
converter then stores the NH3 and reacts it with any NOx
released from the NOx catalytic converter to produce
nitrogen gas N2 for release into the atmosphere.
4                                       BECKMANN   v. GANDHI




J.A. 1453.
    When the engine switches from lean to rich mode,
however, the sudden change in exhaust gas composition
from lean to rich causes the direct mixing of oxidizing and
reducing constituents inside the cavities of the NOx
catalytic converter. ’605 patent col. 2 ll. 15–27. Such
mixing impedes the efficient reduction of NOx to NH3, and
also causes the release of a large amount of NOx from the
NOx catalytic converter. Id. col. 2 ll. 27–35. That problem
was known as “NOx spike.”
    Beckmann’s ’605 patent purportedly solves the NOx
spike problem by interposing a third operating mode
between the lean and rich modes. Id. col. 2 ll. 35–45. The
third operating mode takes place after the lean mode and
before the rich mode, id. col. 2 ll. 7–10, during which the
NOx catalytic converter is supplied with an exhaust gas
that has a lower content of oxidizing constituents than the
lean exhaust gas and a lower content of reducing constit-
uents than the rich exhaust gas (“intermediate exhaust
gas”), id. col. 2 ll. 10–14. In the third operating mode, the
intermediate exhaust gas replaces the lean exhaust gas
inside the cavities of the NOx catalytic converter, which
mitigates the NOx spike problem. Id. col. 2 ll. 46–61.
    The ’605 patent has four claims, among which claims
1 and 3 are independent. Claims 2 and 4 depend from
claims 1 and 3, respectively. Claim 1 reads as follows:
    1. A method for purifying the exhaust gas from an
       internal combustion engine having an exhaust-
       gas purification system including a nitrogen ox-
       ide storage catalytic converter and an SCR cat-
       alytic converter downstream of the nitrogen
BECKMANN      v. GANDHI                                   5



       oxide storage catalytic converter, comprising
       the steps of:
       supplying the nitrogen oxide storage catalytic
          converter with exhaust gas containing an
          excess of oxidizing constituents [“the lean
          step”];
       supplying the nitrogen oxide storage catalytic
          converter with exhaust gas containing an
          excess of reducing constituents [“the rich
          step”]; and
       supplying the nitrogen oxide storage catalytic
          converter, between the oxidizing constituents
          supplying step and the reducing constituents
          supplying step, with an exhaust gas which
          has a lower content of oxidizing constituents
          than in the oxidizing constituents supplying
          step and a lower content of reducing constit-
          uents than in the reducing constituents sup-
          plying step [“the intermediate step”],
       wherein the step between the oxidizing constitu-
         ents supplying step and the reducing con-
         stituents supplying step is terminated at the
         earliest when the nitrogen oxide storage cat-
         alytic converter is predominantly filled by
         exhaust gas delivered in step between the ox-
         idizing constituents supplying step and the
         reducing constituents supplying step.
Id. col. 13 ll. 15–39 (emphases added).
    Claim 3 recites the same preamble and lean and rich
steps as claim 1, but a different intermediate step and
wherein clause, which are reproduced below.
   3. . . .
       supplying the nitrogen oxide storage catalytic
          converter, between the oxidizing constitu-
6                                         BECKMANN   v. GANDHI



         ents supplying step and the reducing con-
         stituents supplying step, for a predeter-
         mined period with a constant exhaust gas
         composition which has a lower content of ox-
         idizing constituents than in the oxidizing
         constituents supplying step and a lower con-
         tent of reducing constituents than in the re-
         ducing constituents supplying step [“the
         intermediate step”],
      wherein in step of supplying the nitrogen oxide
        storage catalytic converter between the oxi-
        dizing constituents supplying step and the
        reducing constituents supplying step, an
        air/fuel ratio which set to control exhaust
        gas composition is set to be slightly greater
        than 1, such that the oxidizing constituents
        in the exhaust gas have an oxygen excess of
        1% or less.
Id. col. 14 ll. 11–36 (emphases added).
                             II
    In 2010, Gandhi filed the ’901 application, which is a
continuation in a series of applications, including U.S.
Patent Application 10/065,470 (“the ’470 application”).
The ’470 application was issued as U.S. Patent 7,332,135
(“Gandhi ’135”), which is prior art to Beckmann’s ’605
patent. Gandhi’s ’901 application and Gandhi ’135 share
the same specification in relevant part.
    In the Background section, the ’901 application de-
scribes the NOx spike problem that “occurs during the
short period in which the NOx trap transitions from lean
to rich,” and states that “FIG. 1a [shows] that during this
lean-rich transition, NOx spikes, the large peaks of unre-
acted NOx,” account for significant NOx emissions. J.A.
502. Then, in the Summary of the Invention section, the
’901 application states that the NOx spike problem was
BECKMANN   v. GANDHI                                     7



solved “with the use of an NH3-SCR catalyst placed down-
stream of the lean NOx adsorber catalyst.” 1 J.A. 503. The
’901 application explains that “[t]he advantage of the
catalyst system of this invention is the use of a combina-
tion of a lean NOx trap and an NH3-SCR catalyst.” J.A.
505. Additionally, in paragraph 41, the ’901 application
states that: “For this invention, the lean NOx trap is
optimized for ammonia generation by removing oxygen
storage capacity (OSC) and thereby enhancing the rich
cycle and thus creating a greater quantity of ammonia for
reaction with the NOx in the downstream NH3-SCR
catalyst.” Id. (emphasis added).
    When filing the ’901 application, Gandhi added claims
3–17, seeking to provoke an interference with Beckmann.
Gandhi’s claim 3 was copied from, and thus is identical to,
claim 1 of the ’605 patent. Although none of Gandhi’s
other claims, viz., claims 4–17, is completely identical to
any of Beckmann’s claims, Gandhi stated that claims
4–11 “are substantially identical to, and have been copied
from,” Beckmann’s claim 1, and that claims 12–17 “corre-
spond substantially to” Beckmann’s claim 1. J.A. 515.
     Claims 5, 8, 11, and 17 of the ’901 application each
contain a “minimizing the oxygen content . . . prior to a
rich cycle” limitation. J.A. 507–08, 510–13. Claim 5 is
illustrative and reads as follows:
   5. A method for reducing pollutants in the ex-
      haust gas of an engine having a system includ-
      ing a nitrogen oxide adsorber and a NH3-SCR
      catalyst downstream of the nitrogen oxide ad-
      sorber, comprising the steps of:



   1    Here, the ’901 application refers to the NOx cata-
lytic converter as a lean NOx adsorber catalyst, and the
SCR catalytic converter as an NH3-SCR catalyst.
8                                     BECKMANN   v. GANDHI



      supplying the nitrogen oxide adsorber with ex-
         haust gas while the engine operates under
         lean conditions, wherein the exhaust gas is
         a lean exhaust gas;
      transitioning the engine operations from lean
         to rich conditions[;]
      supplying the nitrogen oxide adsorber with ex-
         haust gas during said transitioning;
      minimizing the oxygen content of the nitrogen
        oxide adsorber prior to rich conditions to fa-
        cilitate the reduction of NOx to NH3;
      completing the transition from lean to rich con-
         ditions; and
      supplying the nitrogen oxide adsorber with ex-
         haust gas while the engine operates under
         rich conditions, wherein the exhaust gas is a
         rich exhaust gas.
J.A. 507, 510 (emphasis added). Claims 7, 10, and 16
each contain the limitation “the oxygen content of the
lean NOx trap is minimized to facilitate the reduction of
NOx to NH3,” but those claims do not include any “prior to
a rich cycle” language. J.A. 508, 511–12. Claims 8, 11,
and 17 depend from claims 7, 10, and 16, respectively.
    Claim 12 and its dependent claims 13–17 require
“transitioning” between a lean exhaust gas supplying step
and a rich exhaust gas supplying step and “completing
said transition.” Claim 12 reads as follows:
    12. A method for purifying the exhaust gas from
       an engine, comprising:
      supplying a zoned catalyst system with a lean
         exhaust gas, wherein said zoned catalyst
         system comprises a first zone of lean NOx
BECKMANN   v. GANDHI                                      9



          trap and a second zone of SCR catalyst
          downstream of the first zone;
       supplying the zoned catalyst system with a rich
          exhaust gas;
       transitioning between said lean exhaust gas
          supplying step and said rich exhaust gas
          supplying step, wherein exhaust gas is sup-
          plied to said zoned catalyst system during
          said transition; and
       completing said transition from said lean ex-
          haust gas supplying step to said rich exhaust
          gas supplying step.
J.A. 508, 512 (emphases added).
                            III
    In July 2011, the Board declared Interference No.
105,822 between Gandhi’s ’901 application and Beck-
mann’s ’605 patent. The interference involves a sole
count corresponding to claims 1–4 of the ’605 patent and
claims 3–17 of the ’901 application. The Count is identi-
cal to Beckmann’s claim 1 and Gandhi’s claim 3. When
declaring the interference, the Board accorded Gandhi the
benefit of the ’470 application, filed in October 2002, and
accorded Beckmann the benefit of an application filed in
October 2003. 2 Id. Based on those filing dates, the Board
designated Gandhi as the senior party.



   2    Because both the ’901 application and the ’605 pa-
tent have effective filing dates before the enactment of the
Leahy-Smith America Invents Act (“AIA”), Pub. L. No.
112-29, 125 Stat. 284 (2011), the pre-AIA versions of 35
U.S.C. §§ 102, 103, and 112 apply in this appeal. See Pub.
L. No. 112-29, § 3(n)(1), 125 Stat. at 293.
10                                    BECKMANN   v. GANDHI



    The parties then filed several preliminary motions,
including: (1) Beckmann’s motion alleging that Gandhi’s
claims 3–5, 7, 8, and 10–17 are unpatentable for lack of
written description support (“Beckmann Motion 1”);
(2) Beckmann’s motion alleging that Gandhi’s claims 3, 4,
6, 9, and 12 are unpatentable in view of European Patent
Publication EP 0 814 241 (“Kinugasa ’241”), U.S. Patent
6,109,024 (“Kinugasa ’024”), and U.S. Patent Publication
2003/0056499 (“Binder ’499”) (“Beckmann Motion 2”); and
(3) Gandhi’s motion alleging that Beckmann’s claims 1–4
are unpatentable in view of Gandhi ’135 and U.S. Patent
6,604,504 (“Surnilla ’504”) (“Gandhi Motion 1”). The
Board decided the parties’ motions in the following order:
(1) Beckmann Motion 1; (2) Beckmann Motion 2; and
(3) Gandhi Motion 1. Decision on Motions at 4.
     First, the Board denied Beckmann Motion 1, finding
that Gandhi’s claims 3–5, 7, 8, and 10–17 are not un-
patentable for lack of written description support. Id. at
7–24. Beckmann raised three separate written descrip-
tion challenges: (1) that Gandhi’s claims 3 and 4, copied
from Beckmann, must be construed in light of the ’605
patent as requiring a third exhaust gas supplying step
that is (a) separate and distinct from the lean and rich
exhaust gas supplying steps and (b) controlled in terms of
exhaust gas composition and duration, and that Gandhi’s
’901 application lacks an adequate written description of
such a third supplying step; (2) that Gandhi’s ’901 appli-
cation lacks an adequate written description of the “tran-
sitioning” limitation of claims 12–17; and (3) that
Gandhi’s ’901 application lacks an adequate written
description of the “minimizing the oxygen content” limita-
tion of claims 5, 7, 8, 10, 11, 16, and 17.
    With respect to Gandhi’s claims 3 and 4, the Board
recognized the differences between Beckmann’s and
Gandhi’s disclosures, and agreed with Beckmann that
Gandhi’s ’901 application does not contain a written
description of a separate and distinct third exhaust gas
BECKMANN   v. GANDHI                                     11



supplying step that is controlled in terms of exhaust gas
composition and duration. Id. at 14–15. But the Board
concluded that Gandhi’s claims 3 and 4, as construed in
light of Beckmann’s ’605 patent, see Agilent Techs., Inc. v.
Affymetrix, Inc., 567 F.3d 1366, 1375 (Fed. Cir. 2009), do
not require such a third supplying step. Decision on
Motions at 15–16.
    Instead, the Board concluded that the claims only re-
quire that, between the lean and rich exhaust gas supply-
ing steps, the NOx catalytic converter “is supplied with an
exhaust gas having less oxidizing constituents than lean
operations and less reducing constituents than rich condi-
tions, and that this supplying step terminates at the
earliest when the lean NOx trap is predominantly full of
exhaust gas supplied during this step.” Id. at 16. The
Board also noted that the differences between Beck-
mann’s claim 1 (which is identical to Gandhi’s claim 3)
and Beckmann’s claim 3 (which requires “a constant
exhaust gas composition” and “a predetermined period”
for the third supplying step) further support its construc-
tion of Gandhi’s claim 3. Id. at 16–19.
     The Board then found that the ’901 application pro-
vides an adequate written description of Gandhi’s claims
3 and 4 because it describes “the short period in which the
NOx trap transitions from lean to rich,” and because the
claims only require “the transition between lean and rich
supplying steps in which an exhaust gas having less
oxidizing constituents than lean operations and less
reducing constituents than rich conditions is supplied,
and that this supplying step (transition step) terminates
at the earliest when the lean NOx trap is predominantly
full of the exhaust gas supplied.” Id. at 19–20.
    With respect to Gandhi’s claims 12–17, the Board rea-
soned that claim 12 does not require “a separate and
distinct transition step between the supply of lean and
rich exhaust gases,” and that the claim “merely requires
12                                      BECKMANN   v. GANDHI



transitioning between lean and rich conditions and com-
pleting the transition to rich conditions, as described by
Gandhi’s disclosure.” Id. at 21. The Board again relied
on the ’901 application’s description of “the short period in
which the NOx trap transitions from lean to rich” and its
Figure 1a to find that the ’901 application adequately
describes “transitioning” between lean and rich conditions
and “completing” that transition. Id. at 21–22.
    With respect to Gandhi’s claims 5, 7, 8, 10, 11, 16, and
17, the Board noted that those claims require “the mini-
mization [of] the oxygen content in the NOx catalytic
converter prior to the rich cycle.” Id. at 23 (emphasis in
original). The Board found that the ’901 application,
especially its paragraph 41, which describes “removing
oxygen storage capacity” of the lean NOx trap, adequately
describes the “minimizing” limitation. Id.
     Next, the Board granted Beckmann Motion 2 in part,
holding that Gandhi’s claims 3, 4, 6, and 9, as construed
in light of Gandhi’s ’901 application, see Agilent, 567 F.3d
at 1375, are anticipated by, or would have been obvious
over, Kinugasa ’241 and Kinugasa ’024. Decision on
Motions at 24–35. The Board denied the motion as to
Gandhi’s claim 12, however, finding that the cited refer-
ence, Binder ’499, is not prior art to Gandhi’s claim 12.
Id. at 35–41.
    Pursuant to 37 C.F.R. § 41.207(c), the Board then con-
sidered whether Beckmann rebutted the presumption of
cross-applicability of the prior art to its own claims, viz.,
claims 1–4 of the ’605 patent. The Board concluded that
Beckmann failed to do so as to claims 1 and 2. Id. at
42–44. Specifically, the Board noted that Beckmann
sought to overcome the presumption by making the same
claim construction argument, namely, that Beckmann’s
claims, as construed in light of the ’605 patent, require a
separate and distinct third exhaust gas supplying step
that is controlled in terms of exhaust gas composition and
BECKMANN   v. GANDHI                                    13



duration. Recognizing that Beckmann’s claims 3 and 4
indeed require a constant exhaust gas composition and a
predetermined period for the third exhaust gas supplying
step, the Board concluded that Beckmann successfully
overcame the presumption as to those claims. But be-
cause the Board, when deciding Beckmann Motion 1,
rejected Beckmann’s proposed construction of Gandhi
claim 3 and Beckmann claim 1, the Board concluded here
that Beckmann failed to rebut the § 41.207(c) presump-
tion as to its claims 1 and 2. The Board therefore held
that claims 1 and 2 of the ’605 patent are unpatentable
over Kinugasa ’241, Kinugasa ’024, and Binder ’499.
    Last, the Board granted Gandhi Motion 1 as to Beck-
mann’s claims 3 and 4, concluding that those claims
would have been obvious over Gandhi ’135 and Surnilla
’504. Id. at 45–52. The Board acknowledged that claims
3 and 4 require a constant exhaust gas composition, a
predetermined period, and a specific air/fuel ratio for the
third exhaust gas supplying step. Id. at 48. As discussed
below, the Board implicitly found that those claims re-
quire a separate and distinct third step. But it found that
those features were taught or suggested by Surnilla ’504.
Id. at 48–50. In particular, the Board found that Surnilla
’504 taught a stepwise transition from lean to rich condi-
tions, which resulted in constant intermediate exhaust
gas compositions over a predetermined period and re-
duced NOx emissions. Id. at 49–50. The Board reasoned
that one of ordinary skill would have been motivated to
implement the stepwise transition taught by Surnilla ’504
in the system disclosed by Gandhi ’135 to further reduce
NOx emissions. The Board therefore concluded that
claims 3 and 4 of the ’605 patent would have been obvious
over Gandhi ’135 and Surnilla ’504.
    Gandhi also argued that Beckmann’s claims 1 and 2
are unpatentable over Gandhi ’135 and Surnilla ’504. But
the Board did not reach that issue because it found
14                                      BECKMANN   v. GANDHI



Beckmann’s claims 1 and 2 unpatentable over Kinugasa
’241, Kinugasa ’024, and Binder ’499. Id. at 44.
    Because the Board found all of Beckmann’s involved
claims to be unpatentable, it terminated the interference
and entered judgment. Beckmann v. Gandhi, Interfer-
ence No. 105,822, 2013 WL 3788515 (P.T.A.B. July 8,
2013). Beckmann timely requested rehearing, which the
Board denied. Rehearing Decision at 13. Beckmann then
appealed to this court. We have jurisdiction under 28
U.S.C. § 1295(a)(4)(A).
                        DISCUSSION
    We review the Board’s legal determinations de novo,
In re Elsner, 381 F.3d 1125, 1127 (Fed. Cir. 2004), and its
factual findings for substantial evidence, In re Gartside,
203 F.3d 1305, 1316 (Fed. Cir. 2000). A finding is sup-
ported by substantial evidence if a reasonable mind might
accept the evidence to support the finding. Consol. Edi-
son Co. v. NLRB, 305 U.S. 197, 229 (1938).
     On appeal, Beckmann argues that the Board erred in
construing claims 1–4 of the ’605 patent and in determin-
ing that those claims are unpatentable over the cited
prior art. Beckmann also argues that the Board erred in
construing claims 12–17 of Gandhi’s ’901 application and
in finding that the ’901 application provides adequate
written description support for the “transitioning” limita-
tion of those claims. Finally, Beckmann argues that the
Board erred in finding that the ’901 application contains
an adequate written description of the “minimizing the
oxygen content” limitation of claims 5, 7, 8, 10, 11, 16, and
17. 3 We address each of those arguments in turn.



     3  Beckmann did not appeal the Board’s finding that
the ’901 application provides adequate written description
BECKMANN   v. GANDHI                                     15



                             I
    We first consider whether the Board erred in constru-
ing claims 1 and 2 of the ’605 patent. We review the
Board’s ultimate claim construction de novo and its un-
derlying factual determinations involving extrinsic evi-
dence for substantial evidence. Microsoft Corp. v. Proxy-
Proxyconn, Inc., 789 F.3d 1292, 1297 (Fed. Cir. 2015).
Here, because the intrinsic record fully determines the
proper construction, we review the Board’s construction
de novo. See id.
    “Interference counts are given the broadest reasona-
ble interpretation possible.” Davis v. Loesch, 998 F.2d
963, 968 (Fed. Cir. 1993); see also Yorkey v. Diab, 605 F.3d
1297, 1300–01 (Fed. Cir. 2010) (stating that claims are
given their broadest reasonable interpretation in an
interference proceeding). “In determining the true mean-
ing of the language of the count, the grammatical struc-
ture and syntax thereof may be instructive.” Credle v.
Bond, 25 F.3d 1566, 1571 (Fed. Cir. 1994).
    When deciding Beckmann Motion 1, the Board con-
strued Gandhi’s claim 3, which is identical to Beckmann’s
claim 1, in light of the ’605 patent specification, see Ag-
ilent, 567 F.3d at 1375, and rejected Beckmann’s argu-
ment that the claim requires a separate and distinct third


support for Gandhi’s claims 3 and 4. See Appellants’ Br.
2–3. That finding is therefore not at issue here. More-
over, this appeal is premised on the Board’s determina-
tion that claims 1–4 of the ’605 patent and claims 3–17 of
the ’901 application correspond to the Count. We need
not decide what impact the revised construction of claim 1
of the ’605 patent (which is also the interference count)
would have on these issues. That is a matter for the
Board in the first instance.
16                                    BECKMANN   v. GANDHI



exhaust gas supplying step that is controlled in terms of
exhaust gas composition and duration. Decision on Mo-
tions at 15–16. Based on that construction, when deciding
Beckmann Motion 2, the Board found Beckmann’s claim 1
and dependent claim 2 to be unpatentable over the cited
prior art. Id. at 42–44.
     Beckmann argues that the Board erred in construing
its claim 1 as not requiring a separate and distinct third
exhaust gas supplying step. According to Beckmann, the
structure and wording of the claim demonstrate that each
of the three “supplying” steps is distinct from the other
two. Beckmann contends that the Board’s construction
improperly reads the third supplying step out of the claim
and is inconsistent with the ’605 patent’s specification,
which describes three distinct operating modes (viz., lean,
intermediate, and rich), solves the NOx spike problem by
supplying an intermediate exhaust gas between the lean
and rich modes, and distinguishes the claimed method
from prior-art methods that involved only lean and rich
modes and direct transitions between those two modes.
     Beckmann additionally argues that the Board erred in
construing claim 1 as not requiring the third exhaust gas
supplying step to be controlled in terms of both exhaust
gas composition and duration. According to Beckmann,
the claim specifies the exhaust gas composition, viz., an
intermediate exhaust gas with a lower level of oxidizing
constituents than the lean exhaust gas and a lower level
of reducing constituents than the rich exhaust gas, as well
as the duration of the third supplying step, viz., that the
third step be “terminated” when the NOx catalytic con-
verter is “predominantly filled” with the intermediate
exhaust gas. Beckmann contends that those limitations
imply control over the exhaust gas composition and
duration. Finally, Beckmann argues that the Board
misapplied the principles of claim differentiation when
analyzing the differences between Beckmann claim 1 and
Beckmann claim 3.
BECKMANN   v. GANDHI                                     17



     Gandhi responds that the Board’s construction is con-
sistent with the plain meaning of the claim language, as
well as the specification of the ’605 patent. According to
Gandhi, the Board properly declined to import limitations
from the specification into the claim. Gandhi contends
that Beckmann chose to draft its claim broadly, and that
nothing in the grammar, structure, or wording of the
claim requires that there be three separate and distinct
exhaust gas supplying steps or that the exhaust gas
composition be controlled over time during the third step.
Gandhi also responds that the Board’s construction does
not read the third step out of the claim because the con-
struction clearly requires that the third supplying step
occur between the first and second supplying steps.
Finally, Gandhi responds that the Board did not misapply
claim differentiation by recognizing that Beckmann claim
1 is broader than Beckmann claim 3.
    We agree with Beckmann that its claim 1 requires a
third exhaust gas supplying step that is separate and
distinct from the lean and rich exhaust gas supplying
steps, but we conclude that the claim does not require
that the third supplying step be controlled in terms of
exhaust gas composition and duration.
    Beginning with the language of the claim, claim 1 is
directed to a method “comprising the steps of . . . .” ’605
patent col. 13 l. 19 (emphasis added). The claim then lists
three parallel “supplying” clauses, separated by line
indentation, id. col. 13 ll. 20–32, and followed by a
“wherein” clause that refers back to the three “supplying”
clauses as steps, id. col. 13 ll. 33–39 (“wherein the step
between the oxidizing constituents supplying step and the
reducing constituents supplying step . . . delivered in step
between the oxidizing constituents supplying step and the
reducing constituents supplying step” (emphases added)).
The structure of the claim thus indicates that the claimed
method comprises three different supplying steps.
18                                     BECKMANN   v. GANDHI



     Moreover, both the third “supplying” clause and the
“wherein” clause require the third supplying step to be
between the first step (the oxidizing constituents supply-
ing step or the lean step) and the second step (the reduc-
ing constituents supplying step or the rich step). Id.
col. 13 ll. 26–39. Accordingly, the claim imposes a se-
quential requirement that the third step occur between
the first and second steps.
     The claim language also requires that the supplying
steps be separate and distinct from each other. In each
step, a different exhaust gas is supplied to the NOx cata-
lytic converter: a lean exhaust gas is supplied in the first
step; a rich exhaust gas is supplied in the second step;
and an intermediate exhaust gas is supplied in the third
step. Each step is therefore distinctly characterized by a
different exhaust gas composition that is being supplied
to the NOx catalytic converter. Moreover, the “wherein”
clause requires that the intermediate exhaust gas supply-
ing step, occurring between the lean and rich steps, be
“terminated at the earliest when” the NOx catalytic con-
verter is “predominantly filled by exhaust gas delivered”
in the step between the lean and rich steps. Thus, the
“wherein” clause imposes a further limitation that the
intermediate supplying step does not end, and the next
supplying step does not begin, until the NOx catalytic
converter is “predominantly filled” with the intermediate
exhaust gas. Id. col. 13 ll. 33–39.
     Notably, the claim uses different terms, “supply[ ]”
and “fill[ ],” and those terms carry different meanings
when read in the context of the surrounding claim lan-
guage. For example, during the third supplying step, an
intermediate exhaust gas is “suppl[ied]” to the NOx cata-
lytic converter, meaning that the intermediate exhaust
gas is introduced through an inlet into the NOx catalytic
converter. Inside the cavities of the NOx catalytic con-
verter, that exhaust gas is then mixed with the existing
exhaust gas, and shortly after the intermediate exhaust
BECKMANN   v. GANDHI                                        19



gas “predominantly fill[s]” the NOx catalytic converter,
the third supplying step terminates. This interpretation
of “supply[ ]” and “fill[ ]” is consistent with the plain
meaning of the claim and the specification of the ’605
patent. See, e.g., ’605 patent col. 2 ll. 15–61, col. 4
l. 48–col. 5 l. 16, col. 7 l. 63–col. 8 l. 6, col. 8 ll. 47–59.
    In rejecting Beckmann’s proposed claim construction,
the Board reasoned that “when operations are transi-
tioned from lean to rich, there will be mixing between the
leading edge of the rich exhaust gas and the lean exhaust
gas preceding it such that intermediate exhaust gas will
have a composition varying between lean and rich.”
Rehearing Decision at 4. But the Board failed to properly
consider the “wherein” clause, which requires that the
intermediate exhaust gas supplying step not end, and the
rich exhaust gas supplying step not begin, until the NOx
catalytic converter is “predominantly filled” with the
intermediate exhaust gas.
    It is true that when an engine transitions directly
from lean to rich, a natural consequence of that transition
is the mixing of lean and rich exhaust gases at the inter-
face to form a small amount of intermediate exhaust gas,
which is then supplied transitorily into the NOx catalytic
converter. But there is no evidence that such a small
amount of intermediate exhaust gas would inevitably
“predominantly fill[ ]” the NOx catalytic converter before
the rich exhaust gas is beginning to be supplied into the
converter. In those circumstances, the cavities of the NOx
catalytic converter may still be predominantly filled with
the lean, rather than the intermediate, exhaust gas. As
the ’605 patent specification explains, a direct transition
from lean to rich modes leads to the direct mixing of lean
and rich exhaust gases inside the cavities of the NOx
catalytic converter, which causes the undesirable NOx
spike problem. ’605 patent col. 2 ll. 21–27 (“Since the
nitrogen oxide storage catalytic converter used is either a
honeycomb body with passages passing through it or a
20                                         BECKMANN    v. GANDHI



bulk bed of shaped bodies, in the event of a sudden
change in the exhaust-gas composition from oxidizing to
reducing, the exhaust gases of different compositions
become mixed with one another in the cavities formed by
these catalyst converter structures.”).
    We therefore conclude that the Board failed to proper-
ly consider the structure and wording of the claim and
erred in construing claim 1 in an unreasonably broad
manner as not requiring a separate and distinct third
exhaust gas supplying step.
    We agree with the Board, however, that claim 1 of the
’605 patent does not require control over exhaust gas
composition and duration of the third supplying step.
Although the specification of the ’605 patent describes
various means for controlling the exhaust gas composition
and duration of the exhaust gas supplying steps, see, e.g.,
’605 patent col. 2 l. 62–col. 3 l. 3, col. 10 l. 59–col. 11 l. 50,
those descriptions are not part of claim 1. Indeed, the
language of claim 1 does not specify any means by which
to control the exhaust gas composition and duration
beyond the requirement that the NOx catalytic converter
be “suppl[ied]” with a certain type of exhaust gas in each
of the supplying steps.
    For the foregoing reasons, we conclude that Beck-
mann’s claims 1 and 2 require a third exhaust gas supply-
ing step that is separate and distinct from the other two
exhaust gas supplying steps, but that the claims do not
require control over exhaust gas composition and duration
of the third supplying step. Accordingly, we reverse the
Board’s construction of claims 1 and 2 of the ’605 patent.
                               II
    We next consider whether the Board erred in constru-
ing claims 3 and 4 of the ’605 patent. On appeal, Beck-
mann alleges that the Board erred in construing claim 3
and its dependent claim 4 as not requiring a separate and
BECKMANN   v. GANDHI                                    21



distinct third exhaust gas supplying step. Appellants’ Br.
20–28 (same argument as that raised for claims 1 and 2).
Beckmann does not allege, however, that the Board erred
by failing to construe claims 3 and 4 as requiring a third
exhaust gas supplying step controlled in terms of both
exhaust gas composition and duration. See id. at 28–30.
    The Board did not formally construe claim 3 of the
’605 patent, but the record shows that it recognized that
claim 3, unlike claim 1, requires a third exhaust gas
supplying step that has a constant exhaust gas composi-
tion, a specific air/fuel ratio, and a predetermined dura-
tion. Decision on Motions at 17, 19, 45, 48. Indeed,
relying on those limitations of claim 3 not present in
claim 1, the Board concluded that Beckmann overcame
the presumption under 37 C.F.R. § 41.207(c) for claims 3
and 4, but not for claims 1 and 2. Id. at 43–44.
    By correctly recognizing that claim 3 requires a third
exhaust gas supplying step with a constant exhaust gas
composition, a specific air/fuel ratio, and a predetermined
duration, the Board implicitly construed claim 3 as re-
quiring a third intermediate exhaust gas supplying step
that is separate and distinct from the lean and rich steps.
Beckmann’s argument to the contrary is without merit.
    We therefore conclude that the Board did not err in
construing claims 3 and 4 of the ’605 patent.
                            III
    We next consider whether the Board erred in conclud-
ing that claims 3 and 4 of the ’605 patent would have been
obvious over Gandhi ’135 and Surnilla ’504. Obviousness
is a question of law based on underlying factual findings.
In re Baxter, 678 F.3d 1357, 1361 (Fed. Cir. 2012). Those
factual inquiries include what a reference teaches, In re
Beattie, 974 F.2d 1309, 1311 (Fed. Cir. 1992), and the
existence of a reason to combine references, In re Hyon,
679 F.3d 1363, 1365–66 (Fed. Cir. 2012).
22                                      BECKMANN    v. GANDHI



    The Board found that Gandhi ’135 discloses the lean
and rich exhaust gas supplying steps, but does not dis-
close a third exhaust gas supplying step with a constant
exhaust gas composition, a predetermined duration, and a
specific air/fuel ratio as required by claim 3. Decision on
Motions at 48. The Board nevertheless found that Surnil-
la ’504 discloses or suggests those features. Id. The
Board also found that one of ordinary skill in the art
would have been motivated to combine those references to
achieve the claimed invention. Id. at 51.
    On appeal, Beckmann argues that Surnilla ’504 does
not disclose the exact composition of exhaust gas supplied
to the lean NOx trap. According to Beckmann, Surnilla
’504 only discloses the composition of exhaust gas sup-
plied to an “emission control device” 32 upstream to the
NOx trap 34. Beckmann argues that emission control
device 32 is an unknown device, and that the Board erred
in finding that component 32 is necessarily a three-way
catalyst. Gandhi responds that substantial evidence
supports the Board’s finding on what the prior art teaches
and the Board’s finding that there would have been a
reason to combine Gandhi ’135 and Surnilla ’504.
     We conclude that substantial evidence supports the
Board’s finding that Surnilla ’504 teaches or suggests a
third exhaust gas supplying step with a constant exhaust
gas composition, a predetermined period, and a specific
air/fuel ratio as required by claim 3. In particular, the
Board correctly found that Surnilla ’504 discloses control-
ling engine operations to achieve constant compositions of
intermediate exhaust gas when transitioning between
lean and rich conditions. Surnilla ’504 col. 6 ll. 8–37; id.
fig.3 & fig.4. Surnilla ’504 achieves this by sequentially
stepping down the air/fuel ratio provided to each of four
cylinders from a lean ratio to a rich ratio. Id. col. 4
l. 64–col. 5 l. 6; id. fig.2. As the Board correctly found, in
the Surnilla ’504 process, when three of the four cylinders
are stepped down, the combined air/fuel ratio is slightly
BECKMANN   v. GANDHI                                      23



greater than 1, and at that point, the exhaust gas neces-
sarily has an excess oxygen content of 1% or less. Fur-
ther, the Board properly found that Surnilla ’504 discloses
that each of the down-steps involves a specific, predeter-
mined wait period. Those factual findings are all sup-
ported by substantial evidence.
     We are also unpersuaded by Beckmann’s argument
that the Board made a reversible error by finding that
Surnilla ’504 discloses that component 32 is a three-way
catalyst. As the Board noted, Surnilla ’504 explains that
three-way catalysts are also referred to as emission
control devices, id. col. 1 ll. 31–32, and then refers to
component 32 as an emission control device, id. col. 4
l. 52. Substantial evidence therefore supports the Board’s
finding that emission control device 32 is a three-way
catalyst.
    It is true that Surnilla ’504 also refers to component
34 as an emission control device, id., and later refers to 34
as an NOx trap, id. col. 6 ll. 11–12, suggesting that an
emission control device could be an NOx trap. But for
obviousness, we consider not only what a reference neces-
sarily discloses, but also what that reference would have
suggested to one of ordinary skill in the art. Here, in view
of the teachings of Surnilla ’504 as a whole, we conclude
that the Board did not err in finding that Surnilla ’504
teaches or suggests the limitations of claim 3 not other-
wise disclosed by Gandhi ’135.
    Accordingly, for the foregoing reasons, the Board did
not err in concluding that claims 3 and 4 would have been
obvious over Gandhi ’135 and Surnilla ’504.
                             IV
    We next consider whether the Board erred in finding
claims 1 and 2 of the ’605 patent to be unpatentable over
Kinugasa ’241, Kinugasa ’024, and Binder ’499. When
granting Beckmann Motion 2 in part, the Board deter-
24                                      BECKMANN   v. GANDHI



mined that Beckmann’s claims 1 and 2 are also unpatent-
able because Beckmann failed to rebut the presumption of
cross-applicability of prior art to those claims under 37
C.F.R. § 41.207(c). But that determination is premised on
an erroneous construction that claim 1 and dependent
claim 2 do not require a separate and distinct third ex-
haust gas supplying step. Because we reverse the Board’s
construction of claim 1, we vacate its determination that
claims 1 and 2 are unpatentable over Kinugasa ’241,
Kinugasa ’024, and Binder ’499, and remand for further
proceedings under the proper claim construction.
    The Board did not decide whether claims 1 and 2 of
the ’605 patent would have been obvious over Gandhi ’135
and Surnilla ’504, an issue raised by Gandhi. On remand,
the Board will have an opportunity to address that issue.
                             V
    We next consider whether the Board erred in constru-
ing claims 12–17 of the ’901 application and in finding
that the ’901 application has an adequate written descrip-
tion of the “transitioning” limitation of those claims.
    Sufficiency of written description is a question of fact,
which we review for substantial evidence. Ariad Pharm.,
Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir.
2010) (en banc). Claims must be sufficiently supported by
the written description of a patent, such that the disclo-
sure “reasonably conveys to those skilled in the art that
the inventor had possession of the claimed subject matter
as of the filing date.” Id. “[W]hen a party challenges
written description support for an interference count or
the copied claim in an interference, the originating disclo-
sure provides the meaning of the pertinent claim lan-
guage.” Agilent, 567 F.3d at 1375. “When a party
challenges a claim’s validity under § 102 or § 103, howev-
er, this court and the Board must interpret the claim in
light of the specification in which it appears.” Id.
BECKMANN   v. GANDHI                                     25



    Beckmann argues that, when deciding the written de-
scription motion, the Board made a legal error by constru-
ing Gandhi’s claims 12–17 in light of the specification and
prosecution history of Gandhi’s ’901 application, contrary
to Agilent. Beckmann contends that the proper construc-
tion requires the “transitioning” step to be separate and
distinct. Under that construction, Beckmann argues, the
’901 application lacks an adequate written description of
the “transitioning” limitation because the application does
not contain any express or inherent disclosure of a sepa-
rate third exhaust gas supplying step controlled in terms
of both exhaust gas composition and duration.
    Gandhi responds that the Board’s construction is con-
sistent with Beckmann’s ’605 patent specification. Gan-
dhi argues that the Board referred to extrinsic evidence
only to support its understanding as to the plain meaning
of the claim terms and to find written description support
in the ’901 application. Gandhi also responds that the
Board properly declined to import limitations from the
specification into the claims, and properly construed the
claims as not requiring a separate and distinct transition
step. Finally, Gandhi responds that substantial evidence
supports the Board’s finding that Figure 1a and its relat-
ed description in the ’901 application provide an adequate
written description of the “transitioning” limitation as the
Board properly construed it.
    We agree with Gandhi and the Board that claim 12
does not require a separate and distinct transitioning step
between the lean and rich exhaust gas supplying steps,
and that the plain language of the claim merely requires
“transitioning” between lean and rich supplying steps and
“completing” the transition from lean to rich. Here again,
because the intrinsic record fully determines the proper
construction, we review the Board’s construction de novo.
See Microsoft, 789 F.3d at 1297.
26                                      BECKMANN   v. GANDHI



     Unlike claim 3 of the ’901 application, which is identi-
cal to Beckmann’s claim 1, claim 12 of the ’901 application
only refers to “supplying” the lean and rich exhaust gases
as “supplying step[s],” but does not refer to “transitioning”
between the lean and rich supplying steps or “completing”
the transition as a step. J.A. 508 (“transitioning between
said lean exhaust gas supplying step and said rich ex-
haust gas supplying step, wherein exhaust gas is supplied
to said zoned catalyst system during said transition; and
completing said transition from said lean exhaust gas
supplying step to said rich exhaust gas supplying step”
(emphases added)). Moreover, claim 12 does not impose
any limitation on the composition of exhaust gas being
supplied during the transition to distinguish it from the
lean and rich supplying steps; rather, the claim only
requires that “exhaust gas [be] supplied . . . during said
transition.” Id. Accordingly, unlike Beckmann’s claim 1
and Gandhi’s claim 3, Gandhi’s claim 12 does not require
a separate and distinct transitioning step. Nor does it
require a separate and distinct third exhaust gas supply-
ing step that is controlled in terms of exhaust gas compo-
sition and duration.
     The specification of the ’605 patent does not compel a
different conclusion. On appeal, the parties do not dis-
pute that claim 12, purportedly copied from Beckmann,
should be construed in light of the specification of the ’605
patent. See Agilent, 567 F.3d at 1375. The ’605 patent
repeatedly refers to the third intermediate exhaust gas
supplying step as a “third method step.” ’605 patent col. 4
l. 48–col. 5 l. 67. The written description of the ’605
patent uses the term “transition” only once, and that
isolated usage does not define the term differently from
its plain meaning. Id. col. 5 l. 2 (“during the transition to
the second method step”). Accordingly, in light of the
plain claim language and the ’605 patent specification, we
conclude that claim 12 of the ’901 application does not
require a separate and distinct transitioning step.
BECKMANN   v. GANDHI                                    27



    We also agree with Gandhi that substantial evidence
supports the Board’s finding that the ’901 application
provides adequate written description support for the
“transitioning” limitation of claims 12–17. Figure 1a of
the ’901 application illustrates the NOx output when the
engine transitions from lean to rich operations. J.A. 495.
The ’901 application further describes “the short period in
which the NOx trap transitions from lean to rich” and
refers to Figure 1a as showing the NOx spikes during the
“lean-rich transition.” J.A. 502. Indeed, on appeal,
Beckmann only challenges the Board’s written description
finding under its proposed narrower construction.
    We therefore affirm the Board’s finding that the ’901
application contains an adequate written description of
the “transitioning” limitation of claims 12–17.
                            VI
    Finally, we consider whether the Board erred in find-
ing that the ’901 application contains an adequate written
description of the “minimizing the oxygen content” limita-
tion of claims 5, 7, 8, 10, 11, 16, and 17.
    Beckmann argues that the Board erred by relying on
paragraph 41 of the ’901 application, which describes
“removing oxygen storage capacity” of a lean NOx trap, to
find support for the “minimizing” limitation. According to
Beckmann, the Board conflated the physical characteris-
tics of a lean NOx trap, which is described by paragraph
41, with a method step that takes place “prior to rich
conditions,” which is what the claims require. Beckmann
argues that, reading paragraph 41 and the following
paragraphs in their entireties, one of ordinary skill would
understand that the description of “removing oxygen
storage capacity” refers to how a lean NOx trap could be
constructed, not how it could be used during engine
operation. Gandhi responds that substantial evidence
supports the Board’s finding that the ’901 application
provides adequate written description support for the
28                                     BECKMANN   v. GANDHI



“minimizing” limitation, and that the Board did not err in
not crediting Beckmann’s expert testimony on that issue,
which did not specifically address paragraph 41.
    We conclude that substantial evidence supports the
Board’s written description finding regarding the “mini-
mizing the oxygen content” limitation of claims 7, 10, and
16, but not as to claims 5, 8, 11, and 17. The claims at
issue are all directed to “a method . . . comprising” a list
of actions, including “minimizing the oxygen content” of
the NOx trap. But those claims differ in that claims 5, 8,
11, and 17 contain a “minimizing the oxygen content . . .
prior to a rich cycle” limitation, whereas claims 7, 10, and
16 recite that “the oxygen content of the lean NOx trap is
minimized” without requiring that the minimization occur
“prior to” a rich cycle. Notably, claims 8, 11, and 17
respectively depend from claims 7, 10, and 16, suggesting
that the “prior to” language imposes a temporal require-
ment that “minimizing” take place “prior to” rich condi-
tions as part of the claimed method.
    The Board did not consider and analyze whether the
’901 application provides an adequate written description
of the “prior to” limitation. We therefore vacate its writ-
ten description decision as to claims 5, 8, 11, and 17.
     We do agree with the Board, however, that paragraph
41 of the ’901 application provides an adequate written
description of the “minimizing the oxygen content” limita-
tion of claims 7, 10, and 16 because those claims do not
require that “minimizing” occur before a rich cycle. Even
if the disclosures in paragraph 41 of the ’901 application
are limited to designing and constructing an NOx trap to
minimize its oxygen storage capacity, that description is
sufficient to support the “minimizing” limitation of claims
7, 10, and 16. We therefore affirm the Board’s decision
that the ’901 application contains an adequate written
description of the “minimizing the oxygen content” limita-
tion of claims 7, 10, and 16.
BECKMANN   v. GANDHI                                    29



                       CONCLUSION
    We have considered the parties’ remaining argu-
ments, but find them unpersuasive. For the foregoing
reasons, we reverse the Board’s construction of claims 1
and 2 of the ’605 patent, but we affirm the Board’s deci-
sion that claims 3 and 4 of the ’605 patent would have
been obvious over the cited references and that the ’901
application contains an adequate written description of
the “transitioning” limitation of claims 12–17 and the
“minimizing the oxygen content” limitation of claims 7,
10, and 16. Additionally, we vacate the Board’s determi-
nation that claims 1 and 2 of the ’605 patent are un-
patentable over the cited references and its finding that
the ’901 application contains an adequate written descrip-
tion of the “minimizing the oxygen content . . . prior to a
rich cycle” limitation of claims 5, 8, 11, and 17, and re-
mand for further proceedings consistent with this opinion.
    AFFIRMED IN PART, REVERSED IN PART,
      VACATED IN PART, AND REMANDED
                          COSTS
   No costs.
        NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                 ______________________

 THOMAS BECKMANN, ALEXANDER MASSNER,
              Appellants

                            v.

   HAREN S. GANDHI, JOHN VITO CAVATAIO,
  ROBERT HENRY HAMMERLE, YISUN CHENG,
                 Appellees

                 ______________________

                       2015-1765
                 ______________________

BRYSON, Circuit Judge, dissenting in part.
    I concur in all parts of the majority opinion except for
Part I of the Discussion section, which holds that the
Board erred in construing claims 1 and 2 of the ’605
patent. I would sustain the Board’s construction of those
claims and the invalidity ruling based on its construction
of those claims.
     Claims 1 and 2 of the ’605 patent (copied in Gandhi’s
claims 3 and 4) recite three steps: (1) supplying the cata-
lytic converter with exhaust gas containing an excess of
oxidizing constituents; (2) supplying the catalytic convert-
er with exhaust gas with exhaust gas containing an
excess of reducing constituents; and (3) during the period
between those two steps, supplying the catalytic converter
2                                      BECKMANN   v. GANDHI



with exhaust gas that has a lower content of oxidizing
constituents than in the oxidizing step and a lower con-
tent of reducing constituents than in the reducing step.
The intermediate step ends at the earliest when the
catalytic converter is filled by exhaust gas delivered
during that step. In other words the three steps of the
claims consist of two distinct endpoint states and a transi-
tion phase between those endpoints.
    The Board found that the claims did not require that
the exhaust gas supplying steps be separate and distinct
from each other or that the intermediate step be con-
trolled in terms of composition and duration. The majori-
ty agrees with the Board that the intermediate step is not
controlled in any way, but it concludes that Board erred in
finding that the steps were not required to be separate
and distinct. I believe that the issues are interrelated and
would hold that the Board was correct on both points.
     The logic of the Board’s position can be explained by
using a simple analogy: consider a first step consisting of
supplying an acidic solution; a second step consisting of
supplying a basic solution; and a third step consisting of
supplying a neutral solution during the transition time
between the first and second steps. In that example, the
neutral solution would simply be a natural and inevitable
consequence of the mixture created by transitioning
between the acidic and basic states. The same principle
applies here. As the Board explained, the claim language
is broad enough to read on a system that transitions
smoothly from a predominantly oxidizing mixture to a
predominantly reducing mixture. The Board explained
that the third step requirement is satisfied as long as the
quantity of oxidizing constituents is lower than in the
first step and the quantity of reducing constituents is
lower than in the second step. That means that the
intermediate step will naturally occur during the transi-
tion between the oxidizing and reducing states. The
BECKMANN   v. GANDHI                                       3



Board is therefore correct that the transition step neces-
sarily occurs between the other two steps.
     Beckmann argues that the claims “require the supply
of three separate and distinct gases, where the composi-
tion of the third exhaust gas and the amount of time the
third exhaust gas is supplied are both controlled.” That
is, Beckmann argues that the transition phase constitutes
a separate and distinct step because transition phase
requires that a specific composition of gas be present for a
specific amount of time. As the majority acknowledges,
however, claims 1 and 2 of the ’605 patent contain no
requirement that the amount of time that the third ex-
haust gas is supplied be controlled. Thus, the claims
place no constraints on the transition; they only require
the transition to occur. And while it is true that the
claimed exhaust gases in the three steps differ in compo-
sition, that is simply the necessary product of transition-
ing from an oxidizing to a reducing mixture.
     The majority characterizes the three claimed steps as
separate and distinct in part because the structure of the
claims identifies them as “three different supplying
steps,” and states that the third step occurs between the
first and second steps, such that the claim “imposes a
sequential requirement that the third step occur between
the first and second steps.” But the fact that the claims
identify three steps does not mean that the steps neces-
sarily constitute separate and distinct states. As dis-
cussed above, the intermediate step lacks the controlled
composition or duration that would allow it to be an
identifiable state. Without a substantive way of charac-
terizing the intermediate state, the three states are
“separate and distinct” only by virtue of the claim charac-
terizing them as such. Although the gas in the three
states differs—lean, rich, and in between—the characteri-
zation of the gas as having three distinct states is entirely
arbitrary. The gas could as easily be divided into five
stages—lean, mostly lean, intermediate, mostly rich, and
4                                       BECKMANN    v. GANDHI



rich. The claims would still not capture anything other
than transitioning between two distinct levels.
    The majority notes that the claims use the terms
“supply” and “fill” with reference to the gases of each step,
which the majority concludes is consistent with the steps
being separate and distinct. The use of those terms,
however, is entirely consistent with the construction of
the claims adopted by the Board and does not add an
additional limitation. As the gas supply transitions from
lean to rich, the mixture of the gas that is supplied to—
and fills—the catalytic converter will necessarily begin
lean, transition to intermediate, and then end up as rich.
Nothing defines those states as separate and distinct
except Beckmann’s characterization of them as such.
     Finally, the fact that claim 1 of the ’605 patent recites
that the intermediate step “is terminated at the earliest”
when the catalytic converter “is predominantly filled by
exhaust gas delivered in [the] step between the oxidizing
constituents supplying step and the reducing constituents
supplying step” contributes nothing to defining the inter-
mediate step as “separate and distinct,” because the gas
that is delivered in the step between the oxidizing and
reducing steps simply consists of gas that is less oxidizing
than the gas of the first step and less reducing than the
gas of the second step. All that is required of the second
stage gas, therefore, is that the converter be predominant-
ly filled with gas that is in transition from the lean to the
rich state. For the reasons given by the Board, that does
not define a “separate and distinct step,” as opposed to a
transient transition phase.
   With regard to the issue of the construction of claims
1 and 2 of the ’605 patent (and thus the corresponding
Gandhi claims 3 and 4), I therefore respectfully dissent.
