Ex Parte Elwart et al

Board of Patent Appeals and Interferences

May 2, 2011

10767339 (B.P.A.I. May. 2, 2011)

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.
10/767,339 01/28/2004 Shane Elwart FGT 3C7 (81090700) 5227
36865 7590 05/02/2011
ALLEMAN HALL MCCOY RUSSELL & TUTTLE, LLP
806 S.W. BROADWAY, SUITE 600
PORTLAND, OR 97205
EXAMINER
JOHNSON, EDWARD M
ART UNIT PAPER NUMBER
1736
MAIL DATE DELIVERY MODE
05/02/2011 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 BOARD OF PATENT APPEALS
AND INTERFERENCES
________________

Ex parte SHANE ELWART,
SURNILLA GOPICHANDRA, and
JOSEPH R. THEIS
________________

Appeal 2010-006081
Application 10/767,339
Technology Center 1700
________________

Before ADRIENE LEPIANE HANLON, PETER F. KRATZ, and
LINDA M. GAUDETTE, Administrative Patent Judges.

GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL1

1 An oral hearing was conducted on April 13, 2011, before the above-
identified panel of judges.
Appeal 2010-006081
Application 10/767,339

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Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
decision2 finally rejecting claims 1-40, the only claims pending in the
Application.3 We have jurisdiction under 35 U.S.C. § 6(b).
We REVERSE.
At the time of the invention, it was known in the art that “[l]ean-
burning engines, or engines that run on an air/fuel mixture with a
stoichiometrically greater amount of air than fuel can offer improved fuel
economy relative to engines configured to run on stoichiometric air/fuel
mixtures.” (Spec.4 1:5-7.) It was also known that lean-burning engines can
be disadvantageous in that burning a lean air/fuel mixture may decrease the
reduction of nitrogen oxides (collectively referred to as “NOx”). To reduce
NOx emissions in lean-burning engines, it was known in the art to use a NOx
trap, which typically includes an alkali or alkaline metal, such as barium or
calcium to adsorb the NOx when the engine is running. (Spec. 1:16-17.) A
known drawback of NOx traps is that they are susceptible to poisoning from
sulfur in fuels, i.e., “[s]ulfur, typically in the form of sulfate (S042-) may
adsorb to the trap in the form of a material such as barium or calcium
sulfate. The sulfur compounds may block NOx from adsorbing to the trap
surfaces, and thus may increase NOx emissions.” (Spec. 1:22-2:2.) Methods
used to desulfate NOx traps “typically involve heating a NOx trap in the
presence of a reductant, such as hydrogen gas[, which] . . . may be produced
by temporarily providing a rich air/fuel mixture to [the] engine.” (Spec.

2 Final Office Action mailed Dec. 15, 2005 (“Final”).
3 Appeal Brief filed Oct. 22, 2008 (“App. Br.”).
4 Specification filed Jan. 28, 2004.
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Application 10/767,339

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6:23-7:2.) However, such methods can cause the production of hydrogen
sulfide. (Spec. 2:3-5.)
The present invention is directed to a method which utilizes a
hydrogen sulfide converter downstream of a catalytic converter “to catalyze
the transformation of hydrogen sulfide to a less-noxious and less-toxic gas-
phase sulfur compound (or compounds), thus lowering hydrogen sulfide in
the emissions stream.” (Spec. 7:5-8.) The method is based on the inventors’
“recogni[tion] that variations in air-fuel ratio that may occur at certain stages
of reactions can cause the production of hydrogen sulfide in different ways
depending on exhaust temperature.” (Spec. 2:5-7; see also, Spec. 2:18-20.)
Claim 1 is representative of the invention and is reproduced below from the
Claims Appendix to the Appeal Brief:
1. A method of removing hydrogen sulfide from an emissions stream,
comprising:
directing the emissions stream into a hydrogen sulfide converter
having a metal oxide catalyst;
adsorbing the hydrogen sulfide in the emissions stream to the metal
oxide catalyst in the hydrogen sulfide converter;
reacting the hydrogen sulfide with at least one of an oxidant and a
reductant in the hydrogen sulfide converter to chemically transform the
hydrogen sulfide; and
adjusting an air-fuel ratio of the emissions stream based on exhaust
temperature of an emission control device, where said adjustment varies a
duration of at least one of lean and rich operation to perform said adsorbing
and reacting even as exhaust temperature varies.
Appeal 2010-006081
Application 10/767,339

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Appellants request review of the following grounds of rejection (App.
Br. 11):
1. claims 1-3, 5-7, 10, 12, 16-18, 21, 24-27, 29, 31-33, and 36-40
under 35 U.S.C. 103(a) as unpatentable over Bartley (US 6,482,377 B2,
issued Nov. 19, 2002) (Ans.5 4-5); and
2. claims 4, 8, 9, 11, 13-15, 19, 20, 22, 23, 28, 30, 34, and 35
under 35 U.S.C. 103(a) as unpatentable over Bartley as applied to claims 1,
16, 21, and 31, above, and further in view of Li (US 6,419,890 B1, issued
Jul. 16, 2002) (Ans. 5-6).
The Examiner found that Bartley discloses the method claimed in
independent claims 1, 16, 21, and 31, with the exception of a step of
adjusting an air-fuel ratio based on exhaust temperature. (Final 2; see also,
Ans. 4.) The Examiner determined
[i]t would have been obvious to one of ordinary skill in the art
at the time the invention was made to adjust the air-fuel ratio to
either rich or lean in the method of Bartley because Bartley
discloses operation of the method for both lean and rich
stoichiometries (see column 5, lines 44-46 and 56-58), which
would obviously, to one of ordinary skill, suggest adjustment of
the ratio to perform the method at the disclosed rich and lean
stages.
(Final 2-3; see also, Ans. 4.)
The issue we consider is whether the Examiner failed to establish a
prima facie case of obviousness because the Examiner did not identify a
teaching or suggestion of making adjustments to air-fuel ratio based on
temperature. (App. Br. 18; see generally, id. 15-18.)

5 Examiner’s Answer mailed Sept. 25, 2009.
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The Examiner does not dispute that Bartley fails to expressly teach
adjusting A/F ratio based on exhaust temperature. (See generally, Ans. 6-
10.) However, the Examiner contends “[i]t would have been within the
knowledge of an ordinary artisan that temperature involving exhaust
emissions would vary to some extent.” (Ans. 10.) The Examiner further
maintains the claims do not require a “particular amount or direction of
change based on temperature” (Ans. 10) and that any adjustment of A/F ratio
in Bartley’s method would necessarily vary the duration of a lean or rich
operation (see Ans. 6-9 (“[S]o long as the ratio of the lean or rich operation
is changed, the duration thereof is also changed.”)).
The Specification identifies the following exemplary three-step
reaction scheme for transforming hydrogen sulfide (H2S) to a less-noxious
and less-toxic gas-phase sulfur compound, such as sulfur dioxide (SO2)
using a metal oxide catalyst such as nickel oxide:
(1) 3NiO + H2 + 2H2S → Ni3S2 + 3H2O
(2) Ni3S2 + SO2 + 5O2 → 3NiSO4
(3) NiSO4 + H2 → NiO + SO2 + H2O
(Spec. 7:14-19). The Specification also identifies an exemplary two-step
reaction scheme in which the nickel sulfide produced in reaction (1) can be
converted directly to sulfur dioxide and nickel oxide via the following
equation: 2Ni3S2 + 7O2 → 6NiO + 4SO2 (Spec. 15:18-21).
According to the Specification, reaction temperature may be set and
controlled by varying the A/F ratio of the engine lean and rich in order to
reduce or increase the heat generated by the reactions. (Spec. 9:9-12; 10:9-
10.) The Specification describes the following “example routine . . . for
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Application 10/767,339

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controlling engine air-fuel ratio to remove sulfur while reducing generation
of hydrogen sulfide” (Spec. 16:15-16):
If the system requests sulfur removal, exhaust gas temperature is
raised, “such as by retarding ignition timing, operating some cylinders lean
and others rich, alternating the A/F ratio of the engine lean and rich to
generate an exotherm on the catalysts, or via electrically heating the
catalyst.” (Spec. 16:17-23.) Once temperature of the NOx trap (Ttrap) is
greater than a desulphation temperature (Tdesulphate), an air-fuel ratio
modulation scheme is selected based on exhaust temperature, for example,
temperature Ttrap. (Spec. 17:1-4.) “[T]he exhaust air-fuel ratio is [then]
adjusted to regenerate[] stored sulfur and reduce H2S emissions based on the
determined temperature (e.g., Ttrap) and the selected modulation scheme.”
(Spec. 17:7-9.)
Where the Examiner establishes a reasonable assertion of inherency
and thereby evinces that a claimed process appears to be identical to a
process disclosed by the prior art and/or that the products claimed by the
applicant and disclosed in the prior art appear to be the same, the burden is
properly shifted to the applicant to show that they are not. See In re Spada,
911 F.2d 705, 708 (Fed. Cir. 1990); In re Best, 562 F.2d 1252, 1254-56
(CCPA 1977).
Appellants have persuasively argued the Examiner’s findings are
insufficient to establish that Bartley inherently discloses or suggests a step of
adjusting A/F ratio based on temperature in the manner required by the
appealed claims. (See App. Br. 12-19.) From a review of the Specification,
it is apparent the methods recited in the independent claims require a step of
measuring temperature, since the step of adjusting lean and rich operations is
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Application 10/767,339

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based on such measurement. The mere fact that exhaust temperature might
vary in Bartley’s method does not establish Bartley inherently performs a
temperature-based adjustment of lean and rich operations. (See App. Br.
16.) 6
In sum, Appellants have persuaded us that the Examiner failed to
establish a prima facie case of obviousness as to appealed claims 1-40.
Therefore, we do not sustain the rejections under 35 U.S.C. § 103(a).
REVERSED

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6 We add that Appellants have also persuasively argued the Examiner’s
findings are insufficient to support a determination that adjustment of A/F
ratio in Bartley’s method would necessarily result in a variation of the
duration of a lean or rich operation. (Rep. Br.6 6 (explaining, for example,
that a lean operation may be adjusted such that it is more or less lean without
varying the duration of the lean operation itself).)