Ex Parte Gade et al

Patent Trial and Appeal Board

Jan 31, 2014

11764089 (P.T.A.B. Jan. 31, 2014)

UNITED STATES PATENT AND TRADEMARKOFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
11/764,089 06/15/2007 Prasad Gade P000100-FCA-CHE 4920
65798 7590 01/31/2014
MILLER IP GROUP, PLC
GENERAL MOTORS CORPORATION
42690 WOODWARD AVENUE
SUITE 200
BLOOMFIELD HILLS, MI 48304
EXAMINER
SCHECHTER, ANDREWM
ART UNIT PAPER NUMBER
2857
MAIL DATE DELIVERY MODE
01/31/2014 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte PRASAD GADE, MANISH SINHA, JON R. SIENKOWSKI, and
BALASUBRAMANIAN LAKSHMANAN
____________

Appeal 2011-002426
Application 11/764,089
Technology Center 2800
____________

Before LINDA M. GAUDETTE, JAMES C. HOUSEL, and
GEORGE C. BEST, Administrative Patent Judges.

GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2011-002426
Application 11/764,089

2
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s decision1
finally rejecting claims 1, 2, 4-10, 12-18, and 20.2 We have jurisdiction under
35 U.S.C. § 6(b).
We AFFIRM-IN-PART.
Th[e] invention relates generally to a control strategy for
controlling an anode bleed from a fuel cell stack and, more
particularly, to a control strategy for controlling an anode bleed from
split fuel cell stacks that is based on the amount of anode gas that is
bled so as to improve water management and address durability and
performance issues.
(Spec.3 [0001].) Claims 1, 7, 8, and 10 are representative of the inventive method,
and are reproduced below from the Claims Appendix to the Appeal Brief:
1. A method for determining when to bleed an anode of a
fuel cell stack, said method comprising:
determining when to start the anode bleed by a controller; and
determining when to end the anode bleed based on determining
the volume of anode gas that has already been bled during the bleed
event by the controller.
7. The method according to claim 1 wherein determining
when to begin the anode bleed includes determining the concentration
of nitrogen in the anode side of the fuel cell stack using a nitrogen
estimating model.
8. The method according to claim 1 wherein determining
when to begin the anode side bleed includes measuring the
concentration of nitrogen in the anode side of the fuel cell stack.
10. A method for controlling an anode bleed from first and
second split fuel cell stacks that operate under anode flow-shifting
through first and second bleed valves, said method comprising:
determining when to start the anode bleed;

1 Final Office Action mailed May 21, 2010.
2 Appeal Brief filed Jun. 30, 2010 (“App. Br.”).
3 Specification filed Jun. 15, 2007.
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Application 11/764,089

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determining the mole flow rate of the anode gas flowing
through the bleed valves;
integrating the mole flow rate to get the number of moles of the
gas that have passed through the bleed valves;
determining a desired amount of moles to be bled; and
ending the anode bleed when the actual number of moles of the
gas that have passed through the bleed valves equals the desired
number of moles of the gas to be bled.

The Examiner maintains the following grounds of rejection (Ans.4 5-19):
1. claims 1, 7, and 8 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Iio (US 2007/0009772 A1 published Jan. 11, 2007) in view of
Williams (US 2008/0262701 A1 published Oct. 23, 2008);
2. claims 2, 10, and 15 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Iio in view of Williams, Senner (US 2002/0102445 A1
published Aug. 1, 2002), and Fraser (US 2006/0010987 A1 published Jan. 19,
2006);
3. claims 4-6 and 12-14 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Iio in view of Williams, Senner, Fraser, and Molter
(US 5,320,718 issued Jun. 14, 1994); and
4. claims 9, 16-18, and 205 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Iio in view of Williams, Senner, Fraser, and Naruse
(US 2003/0180600 A1 published Sep. 25, 2003).

4 Examiner’s Answer mailed Aug. 20, 2010.
5 The Examiner inadvertently includes claim 19 in this ground of rejection. (Ans.
14.) Claims 3, 11, and 19 are also pending, but are only objected to as dependent
upon rejected claims. (Id. at 2.)
Appeal 2011-002426
Application 11/764,089

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The Examiner relies on Iio and Williams in rejecting all appealed claims.
The Examiner finds Iio discloses a method for determining when to bleed an anode
of a fuel cell stack, which includes steps of determining when to start the anode
bleed by a controller, and determining when to end the anode bleed. (Ans. 6.) The
Examiner finds Iio’s determination as to when to end anode bleed is based on
measurements of pressure, temperature, and other properties. (Id.; cf. Iio ¶ [0069]
(“Various closing conditions may be set as the condition for closing the purge
valve 8, for example closing after remaining open for a fixed time period, closing
on the basis of the power generation output of the fuel cell stack 1, and so on.”).)
The Examiner concedes Iio does not explicitly disclose ending anode bleed based
on volume (independent claims 1 and 17) or moles (independent claim 10) of
anode gas.6 (Ans. 6, 9, and 15-16.) The Examiner relies on Williams as evidence
that at the time of the invention, the ordinary artisan was familiar with “controlling

6 According to the invention, cumulative moles of gas that have passed though the
anode bleed valve are calculated by integrating the mole flow rate ṁ of gas through
the bleed valve, which is defined by the equation:
ṁ . ⁄
“Where MW is the molecular weight of the nitrogen, PAnOut is the pressure at the
stack anode outlet, PCaOut is the pressure at the stack cathode outlet and Tcool is the
cooling fluid temperature.” (Spec. [0026].)

The relationship between moles and volume is defined by the equation:
⁄
“Where R is the universal gas constant, VAn is the volume of the anode in the
substacks and τ is the anode residence time scaling factor of the molar bleed
volume to be bled out. The scaling factor τ can be determined by any suitable
manner, such as by ad hoc techniques that look at performance and design of
experiment techniques that provide numerical optimization as would be well
understood to those skilled in the art. (Id. at [0027].)
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valves in fuel environments based upon volume of flow.” (Id. at 6-7.) The
Examiner finds “[o]ne of ordinary skill in the art would [have been] aware that the
in and out pressure (as well as temperature and a known composition of the gas)
are related to volume flow by simple mathematical relationships and would [have
found] the[] manipulation between pressure and volume to be obvious and
requiring only routine skill in the art.” (Id. at 6.) Based on these findings, the
Examiner determines it would have been obvious to one of ordinary skill in the art
at the time of the invention to employ volumetric flow determination as a means to
control the bleed event in Iio’s method. (Id. at 7.)
Appellants challenge the Examiner’s proposed combination of Iio and
Williams on the basis that the Examiner: (1) erred in applying Williams, because
Williams is not a prior art reference within the meaning of 35 U.S.C. § 102 (App.
Br. 4-5), and (2) relied on improper hindsight reasoning because Williams relates
to measuring the volume of a liquid fuel, not anode gas (id. at 6-9 (as to claim 1);
see also, id. at 11 (as to claim 10) and id. at 16-17 (as to claim 17)).
Turning first to Appellants’ contention that Williams is not a prior art
reference, Appellants do not dispute the Examiner’s finding that the effective filing
date of Williams is April 18, 2007 (see Final 2). (See generally, App. Br. 4-5.)
Appellants rely on a Declaration under 37 C.F.R. § 1.131, executed by each of the
inventors on April 19, 2010, to establish invention of the claimed subject matter
prior to April 18, 2007.7 The Declarants identify Exhibit A to the Declaration as

7 37 C.F.R. § 41.67(c)(ix) (2010) explicitly states that the Evidence Appendix to
the Appeal brief “shall contain” “copies of any evidence submitted pursuant to
§§ 1.130, 1.131, or 1.132 of this title or of any other evidence entered by the
examiner and relied upon by appellant in the appeal, along with a statement setting
forth where in the record that evidence was entered in the record by the examiner.”
Not only have Appellants failed to include a copy of the Declaration under 37
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an “Invention Disclosure.” (Decl. ¶ 3.) Exhibit A lists the invention submission
date as “24 OCT 2006,” states the invention “was first thought of 15 MAR 2006,”
and identifies the “Actual or Proposed First Use Date” as “15 SEP 2006.” (Id. at
Ex. A, 1-2.) Appellants indicate an actual reduction to practice of the invention did
not occur prior to the filing date of the present Application on June 15, 2007. (See
id. at ¶ 6.) The Declarants identify Exhibit B to the Declaration as a letter sent to
outside counsel requesting preparation of a patent application on the Invention
Disclosure. (Id. at ¶ 5.) The letter is dated December 13, 2006. The Declarants
testified that a first draft of the patent application was received from outside
counsel on June 12, 2007 (id. at ¶ 7), i.e., approximately six months after
requesting preparation thereof. Appellants do not dispute the Examiner’s finding
that Exhibit A fails to explicitly mention the use of anode volume to control the
bleed event, but direct us to page 4 of Exhibit A wherein the invention is described
as “utilizing physics based concepts such as anode residence time during bleed
(tau).” Appellants argue paragraph [0024] of the Specification describes tau, the
anode residence time scaling factor model, as including anode volume and,
therefore, it is evident that Appellants were in possession of the claimed method as
of the date of the Invention Disclosure (Exhibit A). (See App. Br. 4-5.) Appellants
further argue Exhibit D to the Declaration evidences that the equation for mole
flow rate of gas through a bleed valve, used in calculating cumulative moles of gas
that have passed through the bleed valve (see supra note 6), was present in the first
draft of the Application. (Id. at 5.) Exhibit D is a letter from one of the inventors,
dated June 13, 2007, advising outside counsel that the first draft of the Application

C.F.R. § 1.131 with their Appeal Brief, but explicitly state “There is no evidence
pursuant to § 1.130, § 1.131 or § 1.132” (Appeal Brief 25, Evidence Appendix).
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contains an error in the equations which “specify how the mole flow rate, i.e., the
volume, of bled anode gas is calculated” (id.). (See also, Decl. ¶ 8.)
To establish invention of the subject matter of a rejected claim prior to the
effective date of the reference on which the rejection is based:
[t]he showing of facts . . . be such, in character and weight, as
to establish reduction to practice prior to the effective date of the
reference, or conception of the invention prior to the effective date of
the reference coupled with due diligence from prior to said date to a
subsequent reduction to practice or to the filing of the application.
Original exhibits of drawings or records, or photocopies thereof, must
accompany and form part of the affidavit or declaration or their
absence must be satisfactorily explained.
37 C.F.R. § 1.131(b) (2004).
We find the showing of facts in Appellants’ Declaration insufficient to
establish invention of the claimed subject matter prior to April 18, 2007. Although
Exhibit A mentions the use of “concepts such as anode residence time”
(Exhibit A, 4 (emphasis added)), we agree with the Examiner (see Ans. 20) that
Exhibit A does not describe or suggest a method which includes determining when
to end an anode bleed event based on determining the volume (or moles) of anode
gas already bled as recited in the appealed claims. There is no evidence that the
term “tau,” as used in the Invention Disclosure (i.e., Exhibit A), would have been
understood by one of ordinary skill in the art as including anode volume and
reasonably conveyed that the inventive method included a determination of when
to end the bleed event based on volume of anode gas already bled. Even assuming
the June 12, 2007 (“first draft”) application (a copy of which is not in this appeal
record) did describe or suggest the invention as claimed, the evidence of record is
not sufficient to establish conception of the invention as claimed prior to April 18,
2007. For example, there is no evidence that Exhibit A, alone, would have been
sufficient for preparation of the first draft application, and there is no evidence of
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Application 11/764,089

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the date on which sufficient description of the method step(s) relating to anode
bleed event determination were provided to counsel to enable preparation of the
first draft application. Nor is there evidence that the first draft of the Application
was prepared prior to April 18, 2007. Moreover, the appeal record is devoid of any
other documentation or testimony evidencing the inventors were in possession,
prior to April 18, 2007, of a method which included determining when to end the
anode bleed of a fuel cell stack based on volume (or moles) of anode gas already
bled.
Having determined Appellants have not shown error in the Examiner’s
finding that Williams is a prior art reference within the meaning of 35 U.S.C.
§ 102, we turn to Appellants’ argument that the Examiner’s combination of Iio and
Williams is based on improper hindsight reasoning.
Appellants argue Williams relates to measuring the volume of a liquid fuel,
which “is significantly different from Appellants’ independent claim 1, which
claims, inter alia, determining the volume of anode gas that has already been bleed
[sic] during a bleed event in a fuel cell system.” (App. Br. 9; see also, App. Br. 11
and 16-17 as to independent claims 10 and 17.) This argument fails to persuade us
that the Examiner erred in determining one of ordinary skill in the art would have
been motivated to apply the teachings of Williams, because Appellants have not
shown error in the Examiner’s finding that one of ordinary skill in the art would
have been aware that “both liquids and gasses are fluids and that measuring the
volumetric flow of one is an obvious variant of measuring the volumetric flow of
the other[;] . . . one of ordinary skill in the art would understand them to be
equivalent techniques.” (Ans. 21.) The substitution of one known element for a
known equivalent is prima facie obvious. In re Mayne, 104 F.3d 1339, 1340 (Fed.
Cir. 1997).
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Appellants argue “the Examiner’s statement that one of ordinary skill in the
art would be aware that monitoring volumetric flow is an interchangeable
methodology to monitoring a differential pressure and would thus find it obvious
to try volumetric flow is a conclusory statement that utilizes impermissible
hindsight.” (App. Br. 9.) Appellants’ argument is not persuasive because the
Examiner’s finding of interchangeability is supported by the Examiner’s findings
that both Iio and Williams are concerned with controlling concentration and,
therefore, one of ordinary skill in the art would have had a reasonable expectation
of success in using Williams’ method of controlling concentration by volume flow
in place of Iio’s method of controlling concentration by time (see Ans. 21). Cf.
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) (“When there is a design
need or market pressure to solve a problem and there are a finite number of
identified, predictable solutions, a person of ordinary skill has good reason to
pursue the known options within his or her technical grasp. If this leads to the
anticipated success, it is likely the product not of innovation but of ordinary skill
and common sense. In that instance the fact that a combination was obvious to try
might show that it was obvious under § 103.”) Appellants have not explained why
these findings are erroneous or unreasonable. (See generally, Reply Br. 1-5.)
Appellants also advance separate arguments in support of patentability of
claim 8 over the combination of Iio and Williams. (See App. Br. 9-10.)
Specifically, Appellants contend the Examiner reversibly erred in finding Iio
paragraph 0050 discloses “measuring the concentration of nitrogen in the anode
side of the fuel cell stack” (claim 8 (emphasis added)). (App. Br. 9-10.)
Appellants do not dispute the Examiner’s finding that Iio paragraph 0050 discloses
“determining the concentration of nitrogen in the anode side of the fuel cell stack
using a nitrogen estimating model” (claim 7 (emphasis added)). (App. Br. 9-10.)
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We understand Appellants’ position to be that a mathematical model is based on
relationships, not actual measurements. (See Reply Br. 3-4.) Thus, if Iio
paragraph 0050 discloses a mathematical model for determining nitrogen
concentration, Iio does not perform an actual measurement as required by appealed
claim 8. (See id.)
The respective positions of the Examiner and Appellants raise an issue as to
the scope and meaning of the claim 8 phrase “measuring the concentration of
nitrogen.” During examination, claim terms must be given their broadest
reasonable construction consistent with the Specification. In re ICON Health &
Fitness, Inc., 496 F.3d 1374, 1379 (Fed. Cir. 2007). The Specification describes
triggering an anode bleed “based on certain criteria, such as the concentration of
hydrogen in the anode being below a predetermined minimum.” (Spec. [0019].)
The Specification states that “[h]ydrogen sensors are preferred because they
eliminate impact of errors in the nitrogen concentration estimation from the
nitrogen model used to determine nitrogen concentration. The nitrogen model may
have errors over the life of the stack as membrane cross-over rates change due to
changes in MEA permeability and/or pinholes.” (Id. at [0022].)
Based on our consideration of the Specification and claims, we interpret the
claim 8 phrase “measuring the concentration of nitrogen” as requiring a
determination of nitrogen concentration via an actual direct or indirect
measurement of concentration in a fuel system. In other words, claim 8 does not
require direct measurement of nitrogen concentration, but encompasses indirect
measurements of nitrogen concentration via, e.g., direct measure of hydrogen
concentration. However, claim 8 does not encompass a method wherein
measurement of nitrogen concentration is made via calculation and does not
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involve a direct or indirect measurement of concentration, even though such
calculation is based on a measurement of membrane area and thickness.
We agree with Appellants that the Examiner has failed to identify a
disclosure or suggestion in Iio of “measuring the concentration of nitrogen” as we
interpret this claim 8 phrase. (Cf. Ans. 7 (contending the calculation in Iio [0050]
is an indirect measurement of nitrogen concentration which meets the claim 8
limitation of “measuring the concentration of nitrogen”); id. at 22 (arguing
“Applicant’s claim language does not inherently prohibit an indirect measurement
as the described ‘measurement’”).) Accordingly, we do not sustain the rejection of
claim 8.
We have fully considered the remaining arguments advanced by Appellants
in traversing above-listed grounds of rejection 2-4, including the separate
arguments made by Appellants in support of various dependent claims. The
Examiner has fully addressed these arguments, and we find them unpersuasive of
error in the Examiner’s obviousness determination for the reasons expressed in the
Answer. With respect to arguments concerning the secondary references relied on
in grounds of rejection 2-4, the Examiner has correctly observed that, in general,
Appellants’ arguments do not address the Examiners’ proposed combination. (See,
e.g., Ans. 23-25.)
In conclusion, the Examiner’s decision to reject claims 1, 2, 4-7, 9, 10, 12-
18, and 20 is affirmed. The Examiner’s decision to reject claim 8 is reversed.
No time period for taking any subsequent action in connection with this
appeal may be extended under 37 C.F.R. § 1.136(a)(1).

AFFIRMED-IN-PART
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