Ex Parte Noirot et al

Board of Patent Appeals and Interferences

Sep 22, 2009

10995374 (B.P.A.I. Sep. 22, 2009)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte REMI NOIROT, MICHEL CASTAGNE, and JEAN-BAPTISTE
DEMENTHON
____________

Appeal 2009-003312
Application 10/995,374
Technology Center 3700
____________

Decided: September 22, 2009
____________

Before WILLIAM F. PATE, III, STEFAN STAICOVICI, and
KEN B. BARRETT, Administrative Patent Judges.

STAICOVICI, Administrative Patent Judge.

DECISION ON APPEAL
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STATEMENT OF THE CASE
Remi Noirot et al. (Appellants) appeal under 35 U.S.C. § 134 from the
Examiner’s decision rejecting claims 1, 2 and 6-16. Claims 3-5 have been
canceled. The Appellants’ representative presented oral argument on
September 15, 2009. We have jurisdiction over this appeal under 35 U.S.C.
§ 6 (2002).

THE INVENTION
Appellants’ invention is directed toward a method and a device for
regeneration of a particle filter and desulfation of a nitric oxide trap
including evaluating the saturation rate of the trap and the clogging rate of
the filter, and as soon as one of the rates reaches a threshold value,
performing desulfation of the trap in association with the regeneration of the
particle filter. Spec. 4, ll. 11-19.
Claims 1 and 10 are representative of the claimed invention and read
as follows:
1. A method for desulfation of a nitric oxide trap and
regeneration of a particle filter arranged in an exhaust
line for treatment of the exhaust gas of an internal-
combustion engine, characterized in that:

- the saturation rate of the trap and the clogging rate of
the filter are evaluated,

- as soon as one of the rates reaches a threshold value, the
fuel/air ratio of the exhaust gas is increased without it
reaching a ratio of 1 for initiating the regeneration of the
particle filter, then

- desulfation of the trap is carried out by increasing the
fuel/air ratio of the exhaust gas to a value higher than 1
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and by an alternation of exhaust gas lean mixture and
rich mixture periods during desulfation of the trap.

10. A device for desulfation of a nitric oxide trap and
regeneration of a particle filter arranged in an exhaust
line of an internal-combustion engine, comprising a
control unit evaluating the saturation rate of the trap and
the clogging rate of the filter, characterized in that it
comprises control means for associating each trap
desulfation with each filter regeneration as soon as one of
the rates has reached its threshold value and for
increasing the fuel/air ratio of the exhaust gas without it
reaching a fuel/air ratio of 1 for initiating the
regeneration of the particle filter, prior to desulfation,
then increasing the fuel/air ratio of the exhaust gas to a
value higher than 1 to carry out desulfation of the trap,
and performing an alternation of exhaust gas lean
mixture and rich mixture periods during desulfation of
the trap.
THE REJECTION
The Examiner relies upon the following as evidence of
unpatentability:
Boegner US 6,637,189 B1 Oct. 28, 2003
Hoffmann US 6,938,411 B2 Sep. 6, 2005

Appellants seek review of the Examiner’s rejection of claims 1, 2, and
6-16 under 35 U.S.C. § 103(a) as unpatentable over Hoffmann and Boegner.

THE ISSUES
Appellants argue that in contrast to the claimed invention where
regeneration of the particle filter occurs “as soon as one of the saturation rate
of the trap and the clogging rate of the filter reaches a threshold value,” in
Hoffmann, regeneration of the filter is “only based on the exhaust gas back
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pressure.” App. Br. 10. In other words, according to Appellants, Hoffmann
does not disclose regeneration of the particle filter and desulfurization of the
trap occurs “when the saturation rate of the trap exceeds a threshold value.”
App. Br. 11. In response, the Examiner takes the position that because
Hoffmann discloses, “continuously monitoring [of] a NOx storage capacity
of the trap and… a back pressure of the particle filter,” Hoffmann discloses
“‘evaluating a saturation rate of the trap and a clogging rate of the filter.’”
Ans. 8. Appellants counter that Hoffmann does not disclose performing
both regeneration of the particle filter and desulfation of the storage catalyst
when “one of the two conditions reaches a limit,” that is, as soon as one of
the saturation rate of the trap and the clogging rate of the filter reaches a
threshold value. Reply Br. 1, 2.
Appellants further argue that because Boegner does not relate to the
problems of desulfation of a trap in combination with the regeneration of a
particle filter, the disclosure of Boegner does not provide “an apparent
reason for one of ordinary skill in the art to modify the teachings of
Hoffmann.” App. Br. 12.
Accordingly, the issues raised in this appeal are as follows:
1. Have Appellants demonstrated that the Examiner erred in
finding that Hoffmann discloses regeneration of the particle
filter and desulfurization of the trap as soon as one of the
saturation rate of the trap and the clogging rate of the filter
exceeds a threshold value?
2. Have Appellants demonstrated that the Examiner erred in
determining that the combined teachings of Hoffmann and
Boegner would have prompted a person of ordinary skill in the
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art to desulfurize the trap of Hoffmann by providing oscillations
of the air ratio between an oxidizing and a reducing atmosphere
as taught by Boegner?

SUMMARY OF DECISION
We AFFIRM.

FINDINGS OF FACT
The following enumerated findings of facts (FF) are supported by at
least a preponderance of the evidence. Ethicon, Inc. v. Quigg, 849 F.2d
1422, 1427 (Fed. Cir. 1988) (explaining the general evidentiary standard for
proceedings before the Office).
1. Hoffmann discloses a system for removing nitrogen oxides and
particulates from the exhaust gas emission of an engine
including a combustion engine 1, an exhaust gas pipe 2, an
oxidation catalyst 10, a particle filter 4, a sensor 7 for
measuring the exhaust gas back pressure, a nitrogen oxide
catalyst storage unit 3, a nitrogen oxide sensor 8, and a
controller 6. Hoffmann, col. 9, ll. 10-17 and 33-34 and fig. 2.
2. Hoffmann further discloses a method for removing nitrogen
oxides, sulfur oxides, and particulate matter from the lean
exhaust gas of a combustion engine. The process includes a
first cycle Z1, for denitrating the nitrogen oxide storage catalyst
3, and a second cycle Z2, for regenerating the particulate filter 4
and desulfurizing the nitrogen oxide storage catalyst 3.
Hoffmann, col. 1, ll. 7-9 and col. 4, ll. 41-54.
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3. During the Z1 cycle, nitrogen oxides and sulfur oxides are
stored on the storage catalyst 3 in the form of nitrates and
sulfides, particulates are deposited on the particulate filter 4,
and the nitrogen oxide sensor 8 is monitored. When the
nitrogen oxide storage capacity of catalyst 3 has been depleted
the exhaust gas is enriched, that is, the air ratio1 of the exhaust
gas is reduced to a value below 1, such that denitration takes
place (nitrogen oxides are desorbed and reduced to nitrogen).
Hoffmann, col. 4, ll. 41-48 and 55-61; col. 5, ll. 1-14; col. 8, ll.
39-43; and fig. 6.
4. Appellants do not contest the Examiner’s finding that the
nitrogen oxide sensor 8 of Hoffmann measures the “saturation
rate” of the nitrogen oxide catalyst storage unit 3 (trap).
5. During the Z1 cycle, sulfur oxides stored in the form of sulfates
are not released and thus continue to degrade the storage
capacity of the catalyst 3. Hoffmann, col. 5, ll. 49-52. Further,
as particulates continue to deposit on the filter 4, the exhaust
gas back pressure increases. Hoffmann, col. 5, ll. 15-20.
6. When the controller 6 of Hoffmann determines that the gas
back pressure measured by sensor 7 has reached a threshold
value, the air ratio of the exhaust gas is first reduced to a value
of 1.4 to initiate regeneration of the particulate filter 4 and then

1 We note that the “air ratio” of Hoffmann is an air/fuel ratio, which is
the inverse of Appellants’ “fuel/air” ratio “R.” See Hoffmann, col. 1, ll. 22-
23 and Spec. 10, ll. 4-16 and fig. 2.
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further reduced to values under 1 in order to desulfatize the
storage catalyst 3. Hoffmann, col. 8, ll. 50-67 and fig. 6.
7. Appellants do not contest the Examiner’s finding that the gas
back pressure sensor 7 measures a “clogging rate” of the
particulate filter 4.
8. Hoffmann also discloses that the second cycle Z2 is
considerably longer than the first cycle Z1. Hoffmann, col. 28-
29 and fig. 6.
9. Boegner discloses a process for desulphurization of a nitrogen
oxide or sulphur oxide accumulator including three consecutive
phases: I, II, and III. In the first phase I, the temperature of the
accumulator is increased to the desulphurization temperature.
In the second phase II, which is a transition phase, the
temperature is maintained at the desulphurization temperature.
Finally, in a third phase III, the air ratio oscillates between an
oxidizing and a reducing atmosphere, that is, between levels
greater than 1 (lean levels) and less than 1 (rich levels).
Boegner, col. 3, ll. 57-59; col. 4, ll. 29-34 and 59-65; and fig.
1C.

PRINCIPLES OF LAW
Obviousness
It is elementary that to support an obviousness rejection all words in a
claim must be considered in judging the patentability of that claim against
the prior art. In re Wilson, 424 F.2d 1382, 1385 (CCPA 1970).
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"Section 103 forbids issuance of a patent when 'the differences
between the subject matter sought to be patented and the prior art are such
that the subject matter as a whole would have been obvious at the time the
invention was made to a person having ordinary skill in the art to which said
subject matter pertains.'" KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 406
(2007). The question of obviousness is resolved on the basis of underlying
factual determinations including (1) the scope and content of the prior art,
(2) any differences between the claimed subject matter and the prior art, (3)
the level of skill in the art, and (4) where in evidence, so-called secondary
considerations. Graham v. John Deere Co., 383 U.S. 1, 17-18 (1966). See
also KSR, 550 U.S. at 407 ("While the sequence of these questions might be
reordered in any particular case, the [Graham] factors continue to define the
inquiry that controls.")

OPINION
Appellants argue the rejection under 35 U.S.C. § 103(a) of claims 1,
2, and 6-16 together as a group. App. Br. 8. Accordingly, we have selected
claim 1 as the representative claim to decide the appeal, with claims 2 and 6-
16, standing or falling with claim 1. See 37 C.F.R. § 41.37(c)(1)(vii) (2008).
Issue (1)
As noted above, Hoffmann discloses a method for removing nitrogen
oxides and particulate matter from the lean exhaust gas of a combustion
engine including a first cycle Z1 (denitration of the storage catalyst 3) and a
second cycle Z2 (regeneration of the particulate filter 4 and desulfation of
the storage catalyst 3). FF 2. During the first cycle Z1, the nitrogen oxide
sensor 8 is monitored such that when the nitrogen oxide storage capacity of
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catalyst 3 has been depleted denitration takes place. FF 1, 3. During the
second cycle Z2, the gas back pressure sensor 7 is monitored such that when
a threshold is reached regeneration of the particulate filter 4 and desulfation
of the storage catalyst 3 takes place. FF 1, 6. Hence, in a first instance,
Hoffman discloses that the nitrogen oxide sensor 8 is monitored during the
first cycle Z1 and the gas back pressure sensor 7 is monitored during the
second cycle Z2. However, Hoffmann also discloses that the second cycle
Z2 is considerably longer than the first cycle Z1. FF 8. Accordingly, the Z2
cycle of filter regeneration and catalyst desulfation of Hoffman includes a
plurality of denitration cycles Z1. See Hoffmann, fig. 6. As such, during the
Z2 cycle of filter regeneration and catalyst desulfation of Hoffman both the
nitrogen oxide sensor 8 and the gas back pressure sensor 7 are continuously
monitored. Hence, we agree with the Examiner that Hoffmann discloses
monitoring both the nitrogen oxide sensor 8, i.e., saturation rate of the trap,
and the gas back pressure sensor 7, i.e., clogging rate of the filter,
throughout the Z1 and Z2 cycles. Ans. 8. See also FF 4, 7. Moreover,
Hoffmann specifically discloses that when the gas back pressure (clogging
rate) measured by sensor 7 reaches a threshold value both filter regeneration
and catalyst desulfation takes place. FF 6.
Claim 1 requires that filter regeneration and trap desulfation take
place when one of the clogging rate of the filter and the saturation rate of the
trap exceeds a threshold value. As shown above, the clogging rate of the
filter is one of two rates being continuously monitored throughout the
process of Hoffmann. In addition, filter regeneration and trap desulfation in
the process of Hoffmann take place when the clogging rate reaches a
threshold value. Accordingly, Hoffmann discloses filter regeneration and
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trap desulfation when one of the saturation rate of the trap and the clogging
rate of the filter reaches a threshold value, that is, when the clogging rate
reaches a threshold value. In contrast to Appellants’ position, claim 1 does
not require filter regeneration and trap desulfation to occur “when the
saturation rate of the trap exceeds a threshold value” (App. Br. 11), but
merely when one of the clogging rate of the filter and the saturation rate of
the trap exceeds a threshold value.

Issue (2)
At the outset, we note that obviousness does not require that all of the
features of the secondary reference be bodily incorporated into the primary
reference. In re Keller, 642 F.2d 413, 425 (CCPA 1981). In this case,
Hoffmann discloses a method for regenerating a particulate filter and
desulfurizing a nitrogen oxide storage catalyst where the air ratio of the
exhaust gas is first reduced to a value of 1.4 to initiate regeneration of the
particulate filter and then further reduced to values under 1 in order to
desulfatize the storage catalyst 3. FF 2, 6. Boegner discloses a process for
desulphurization of a nitrogen oxide accumulator in which the air ratio
oscillates between an oxidizing and a reducing atmosphere, that is, between
levels greater than 1 (lean levels) and less than 1 (rich levels). FF 9. As
such, Appellants’ process is nothing more than the process of Hoffmann in
which the desulfation of the trap takes place when the air ratio oscillates
between an oxidizing and a reducing atmosphere, as taught by Boegner.
Hence, modifying the process of Hoffmann to provide oscillations of the air
ratio between an oxidizing and a reducing atmosphere would not have been
uniquely challenging to a person of ordinary skill in the art, because it is no
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more than “the simple substitution of one known element for another.” KSR
at 417. The modification appears to be the product not of innovation but of
ordinary skill and common sense. Moreover, Appellants have not alleged,
much less shown, that the modification of Hoffmann to provide oscillations
of the air ratio between an oxidizing and a reducing atmosphere, as taught by
Boegner, would have been beyond the skill of a person of ordinary skill in
the art. In conclusion, we agree with the Examiner that it would have been
obvious for a person of ordinary skill in the art to provide oscillations of the
air ratio between an oxidizing and a reducing atmosphere, as taught by
Boegner, to the process of Hoffmann in order to “effectively desulfurize a
NOx trap without causing sulfide poisoning of the NOx trap.” See Ans. 4.
Hence, the Examiner has provided an articulated reasoning with rational
underpinning to support the legal conclusion of obviousness.
In conclusion, for the foregoing reasons, the rejection of claim 1, and
claims 2 and 6-16, standing or falling with claim 1, is sustained.

CONCLUSIONS
1. Appellants have failed to demonstrate that the Examiner erred in
finding that Hoffmann discloses regeneration of the particle filter and
desulfurization of the trap as soon as one of the saturation rate of the
trap and the clogging rate of the filter exceeds a threshold value.
2. Appellants have failed to demonstrate that the Examiner erred in
determining that the combined teachings of Hoffmann and Boegner
would have prompted a person of ordinary skill in the art to
desulfurize the trap of Hoffmann by providing oscillations of the air
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ratio between an oxidizing and a reducing atmosphere as taught by
Boegner.

DECISION
The Examiner’s decision to reject claims 1, 2, and 6-16 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). See 37 C.F.R.
§ 1.136(a)(1)(iv) (2007).

AFFIRMED

LV

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