Ex Parte Sinha

Patent Trial and Appeal Board

Jun 22, 2015

12622212 (P.T.A.B. Jun. 22, 2015)

UNITED STATES PATENT AND TRADEMARK OFFICE
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.
12/622,212 11/19/2009 Manish Sinha P005371-FCA-CHE 3905
65798 7590 06/22/2015
MILLER IP GROUP, PLC
GENERAL MOTORS CORPORATION
42690 WOODWARD AVENUE
SUITE 300
BLOOMFIELD HILLS, MI 48304
EXAMINER
DEVITO, ALEX T
ART UNIT PAPER NUMBER
2855
MAIL DATE DELIVERY MODE
06/22/2015 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 MANISH SINHA1
____________

Appeal 2013-006088
Application 12/622,212
Technology Center 2800
____________

Before BRADLEY R. GARRIS, CHUNG K. PAK, and LINDA M. GAUDETTE,
Administrative Patent Judges.

PAK, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on an appeal2 under 35 U.S.C. § 134(a) from the
Examiner’s decision3 finally rejecting claims 1‒19, which are all of the claims
pending in the above-identified application. We have jurisdiction under 35 U.S.C.
§ 6(b).
We affirm.
The subject matter on appeal is directed to “a method for estimating fuel cell
stack cathode inlet and cathode outlet relative humidity (RH) from stack high

1 The real party in interest is said to be GM Global Technology Operations LLC, a
Delaware Limited Liability Company. Appeal Brief filed December 3, 2012
(“App. Br.”), 3.
2 Id.
3 Final Action mailed October 4, 2012 (“Final Act.”), 1‒9 and the Examiner’s
Answer mailed February 14, 2013 (“Ans.”), 3‒6.
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frequency resistance (HFR).” Spec. 1, ¶ 1. Details of the appealed subject matter
are recited in representative claims 1‒6, 7, 9 and 10,4 which are reproduced below
from the Claims Appendix of the Appeal Brief:
1. A method for estimating a cathode inlet and cathode outlet
relative humidity (RH) of a fuel cell stack based on a high frequency
resistance (HFR) of the fuel cell stack, said method comprising:
measuring inlet and outlet pressure of a cathode air flow
passing through the fuel cell stack;
measuring inlet and outlet coolant temperature of a coolant
passing through the fuel cell stack;
determining cathode stoichiometry based on measured stack
current and measured cathode air flow;
utilizing a model to estimate the HFR of the fuel cell stack,
wherein the model uses the measured inlet and outlet pressure of the
cathode airflow, the measured inlet and outlet coolant temperature of
the coolant, and the cathode stoichiometry to estimate the HFR;
measuring the HFR of the fuel cell stack using an HFR sensor;
comparing the model estimation of the HFR of the fuel cell
stack to the measured HFR from an HFR sensor;
determining an error between the estimated model HFR and the
HFR measured by the HFR sensor;
minimizing the error between the estimated model HFR and the
HFR measured; and
estimating the cathode outlet RH by solving a water specie balance.

2. The method according to claim 1 wherein minimizing the error

4 Appellants have separately argued claims 1, 7, and 17 as a first group, claims 2,
12, and 18 as a second group, claim 3 as a third group, claims 4 and 14 as a fourth
group, claims 5 and 15 as a fifth group, claims 6 and 16 as a sixth group, claim 9 as
a seventh group, and claim 10 as an eighth group. App. Br. 7‒13. Therefore, for
purposes of this appeal, we select claims 1‒6, 9, and 10 as representative and
decide the propriety of the Examiner’s §103(a) rejection of record based on these
representative claims alone. 37 C.F.R. § 41.37(c)(1)(iv) (2012). Because claims 9
and 10 are dependent on claim 7, claim 7 is also reproduced below.
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between the estimated model HFR and the measured HFR includes
optimizing the difference between the estimated model HFR and the
measured HFR.

3. The method according to claim 1 further comprising
estimating an average stack HFR by integrating the model estimation
of the HFR from cathode inlet to cathode outlet.

4. The method according to claim 3 further comprising
determining a cathode inlet RH such that the resulting RH profile
matches the measured HFR and the model average HFR after the error
has been minimized.

5. The method according to claim 4 further comprising
determining the mole fraction of water in the cathode inlet from the
cathode inlet RH that matches the measured HFR and the model
average HFR after the error has been minimized.

6. The method according to claim 5 further comprising
determining cathode outlet RH from the mole fraction of water in the
cathode inlet by solving the water specie balance.

7. A method for estimating a cathode inlet and cathode outlet
relative humidity (RH) of a fuel cell stack based on a high frequency
resistance (HFR) of a fuel cell stack, said method comprising:
utilizing a model to estimate the HFR of the fuel cell stack;
measuring the HFR of the fuel cell stack;
comparing the model estimation of the HFR of the fuel cell
stack to the measured HFR;
determining an error between the estimated model HFR and the
HFR measured;
utilizing a regression tool to minimize the error; and
estimating the cathode outlet RH by solving a water specie balance.

9. The method according to claim 7 wherein utilizing a model to
estimate the HFR of the fuel cell stack includes measuring the
temperature of a coolant flow entering the fuel cell stack and exiting
the fuel cell stack.

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10. The method according to claim 7 wherein utilizing a model to
estimate the HFR of the fuel cell stack includes measuring the
pressure of the cathode air entering the fuel cell stack and the pressure
of the cathode air exiting the fuel cell stack.

App. Br. 15‒17 (emphasis added).
Appellant seeks review of the Examiner’s rejection of claims 1‒19 under 35
U.S.C. §103(a) as unpatentable over Goebel5 in view of Zyokou6 maintained in the
Final Action and the Answer. See id. at 7.
DISCUSSION
Upon consideration of the evidence and the arguments relied upon by the
Examiner and Appellant, we find that Appellant has not identified reversible error
in the Examiner’s determination that the collective teachings of Goebel and
Zyokou would have rendered the subject matter recited in claims 1‒19 obvious to
one of ordinary skill in the art within the meaning of 35 U.S.C. § 103(a).
Accordingly, we sustain the Examiner’s § 103(a) rejection of the above claims
substantially for the reasons set forth in the Final Action and the Answer. We add
the following primarily for emphasis and completeness.
The Examiner correctly found that Goebel teaches that “HFR [(high
frequency resistance)] is indicative of [relative] humidity inside the fuel cell” and
“plots [in] figure 5 the relationship between HFR and relative humidity [input and]
output of the fuel cell” which are indicative of the relative humidity profile within
the fuel cell. See Ans. 5; Goebel ¶¶ 60‒62, Fig. 5. The Examiner also correctly
found that Goebel discloses that a theoretical model employing fuel cell operating

5 US 2006/0263654 A1 published in the name of Goebel et al. on November 23,
2006 (“Goebel”).
6 EP 0 350 013 A1 published in the name of Zyokou et al. on October 1, 1990
(“Zyokou”).
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parameters that predicts the relative humidity profile within a fuel cell stack also
predicts the HFR of the fuel cell stack, for the HFR of the fuel cell stack is a
function of the relative humidity of the fuel cell stack. See Final Act. 2‒3, Ans. 5‒
6, and Goebel ¶¶ 33‒48,7 54, 58 and 60‒62, and Fig. 5. The operating parameters
used in the above model taught by Goebel include:
(1) [T]emperature of the cathode reactant through the cathode reactant
flow path via coolant temperature control; (2) stoichiometric quantify
of cathode reactant flowing into the fuel cell; (3) pressure drop in the
cathode reactant flowing through the cathode flow path; and/or (4)
relative humidity of the cathode reactant flowing into the fuel cells.
Goebel ¶ 54(emphasis added); see also the Examiner’s additional reference to
Goebel ¶¶ 33‒48, which also describes measuring, inter alia, the coolant inlet and
outlet temperatures, the coolant temperature rise, the cathode inlet and outlet
pressures, the local cathode pressure, the local and inlet molar flow rate of water
(for solving the water specie balance) in the cathode reactant stream, and the
cathode stoichiometry, which are recited in claims 1, 4, 5, 6, 9, and 10.
Further, the Examiner correctly found that Goebel impliedly teaches using a
model for predicting or estimating HFR for a given fuel cell stack which is related
to the model for predicting or estimating a relative humidity profile within the fuel
cell stack. See Final Act. 2‒3; Ans. 4‒6. Using such model for predicting or
estimating the HFR to obtain the actual desired HFR, which is used for
determining the estimated relative humidity profile, can be found at paragraphs
60‒62 and Figures 5 and 7 of Goebel. Specifically, Goebel discloses monitoring
the actual HFR (High Frequency Resistance), comparing the actual HFR to a
predetermined HFR standard or range (at least impliedly based on a model (using

7 Table 1 referred by the Examiner at page 5 of the Answer is located at paragraph
48 of Goebel.
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operating parameters8 or Table)) to determine any difference between the actual
HFR and the predetermined HFR standard or range, and adjusting operating
parameters (which are the basis for the model for predicting or estimating the
HFR) so that the actual HFR corresponds to the predetermined HFR standard or
range, thereby providing an estimated relative humidity profile, inclusive of
cathode inlet and outlet relative humidity (RH) of the fuel cell stack. See Goebel
¶¶ 60‒62; Figs. 5, 7.
Appellant does not dispute the Examiner’s finding that using an HFR sensor
for monitoring HFR was well known at the time of the invention as evidenced by
Zyokou. Compare Final Act. 3 with App. Br. 7‒14. Rather, Appellant contends
that neither Goebel nor Zyokou teaches or suggests minimizing or optimizing an
error (difference) between the model for estimating the HFR and the actual
(measured) HFR as required by claims 1‒6, 9 and 10. See App. Br. 7‒14. To the
extent that minimizing or optimizing an error or difference is interpreted as
including conducting a regression algorithm as exemplified at paragraph 27 of the
Specification or claims 9 and 10,9 the Examiner found, and Appellant does not
dispute, that when the measured HFR value is used in conjunction with a model
resistance value, Zyokou teaches “determining an amount of compensation
therebetween and correcting using a compensation section.” Compare Final Act. 3

8 Goebel, by virtue of teaching adjusting operating parameters appropriately to
obtain the actual desired HFR, indicates that it predicts the actual HFR based on a
model that employs operating parameters. See Goebel ¶¶ 60‒62; Fig. 5.
9 Minimizing or optimizing an error or a difference, as recited in claims 1‒3, can
also be interpreted as including the adjustment of operating parameters (factors
affecting the model for estimating either the HFR or the RH) to match the actual
HFR with the predetermined HFR standard or range at least impliedly based on a
model taught by Goebel as indicated supra. See also Appellant’s claim 5 which
indicates that by matching the HFR value predicted by the model and the actual
(measured) HFR value, an error is minimized.
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and 5 with App. Br. 7‒14. The Examiner also found, and Appellant does not
dispute, that the “regression [algorithm technique] is “a well-known in the art
family of math techniques to compensate errors.” Compare Final Act. 5 with App.
Br. 7‒14. In fact, at a relevant portion of paragraph 27 of the Specification,
Appellant acknowledges that:
The calculated HFRmdl is compared to an HFR measured by the HFR
sensor 54, HFRsensor, at box 64 to provide an error as the difference
between HFRmdl and HFRsensor. A regression algorithm, such as
optimization using a proportional integral-derivative (PID)
controller, is used to minimize the error at box 66 and provide the RH
profile, or average RH of the stack. One skilled in the art will
recognize various regression tools are available to minimize the error
discussed above. [(Emphasis added.)]

In other words, compensating or correcting error between the measured resistance
value and the resistance value resulting from the model for estimating or predicting
the resistance value via using a regression algorithm was known to those skilled in
the art at the time of the invention. Id.
Given the fact that Goebel teaches or suggests using the actual or measured
HFR and the model for estimating or predicting the HFR to determine a relative
humidity profile within the fuel cell stack, we find no reversible error in the
Examiner’s determination that one of ordinary skill in the art would have been led
to compensate (minimize or optimize) the difference or error between the actual
HFR measured by a known HFR sensor and the predicted or estimated value
resulting from the model via the admittedly known regression algorithm technique
for correcting any error or difference between them before using them to identify
the estimated relative humidity profile within the fuel cell stack (which includes
cathode inlet and outlet relative humidity) with a reasonable expectation of
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successfully improving or ensuring the prediction and obtention of the desired
(measured or actual) HFR and estimated relative humidity of the fuel cell stack.
In reaching this outcome, we have carefully considered Appellant’s
argument that Zyokou teaches compensating or correcting error or difference
between the measured resistance value and the model for estimating or predicting a
resistance value in relation to a welding device. App. Br. 10. However, in so
arguing, Appellant ignores the collective teachings of Goebel and Zyokou, coupled
with the knowledge of one of ordinary skill in the art. In re Young, 927 F.2d 588,
591 (Fed. Cir. 1991) (“The test for obviousness is what the combined teachings of
the references would have suggested to those of ordinary skill in the art.”); In re
Merck & Co., Inc., 800 F.2d 1091, 1097 (Fed. Cir. 1986) (“Non-obviousness
cannot be established by attacking references individually where the rejection is
based upon the teachings of a combination of references.”) When the collective
teachings of Goebel and Zyokou are considered with the knowledge of one of
ordinary skill in the art as we must, we find no error in the Examiner’s
determination that a person having ordinary skill in the art, interested in using the
actual or measured HFR and the model for estimating or predicting the HFR, as
taught or suggested by Goebel, would have looked to a known error compensation
method for correcting any discrepancies between the actual HFR and the predicted
HFR resulting from the model, such as the error compensation technique taught by
Zyokou or the known error correcting regression tool discussed supra, before using
the model and the actual HFR measuring means to determine a relative humidity
profile within a fuel cell stack.
Appellant also contends (App. Br. 8) that:
[T]he Examiner asserts that Go[e]bel discloses a method for
estimating cathode inlet and cathode outlet relative humidity.
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However, [a]ccording to Go[e]bel, cathode inlet relative humidity is
known, see paragraph [0043] of Go[e]bel.

However, as indicated supra, Goebel not only teaches a method for estimating
cathode inlet and cathode outlet relative humidity (RH) (which, in turn, indicate a
relative humidity profile within a fuel cell) using the actual HFR and the HFR
model as required by claim 1, but also teaches “determining a cathode inlet RH”
for the purpose of matching the RH profile with the measured HFR as required by
claim 4. See Final Act. 2‒4; Ans. 5; Goebel ¶¶ 60‒62, Figs. 5 and 7. Moreover,
as indicated above, Goebel teaches or suggests that the cathode inlet RH is one of
the optional fuel cell operating parameters which can be used in a model for
predicting or estimating the relative humidity profile and/or predicting or
estimating the HFR. See also Goebel ¶ 54 and Figs. 5 and 7.
Accordingly, based on the reasons set forth in the Final Action,
Answer, and above, we find that Appellant has not shown error in the Examiner’s
rejection of claims 1–19 under 35 U.S.C. §103(a).
ORDER
In view of the foregoing, the decision of the Examiner to reject claims 1‒19
under 35 U.S.C. §103(a) as unpatentable over Goebel in view of Zyokou is
AFFIRMED.
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)(iv).

AFFIRMED

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