DETAILED ACTION
This Office Action is responsive to the reply filed on January 07, 2026. Claims 1-11, 13-20 are pending. Claim 3 is withdrawn. Claim 12 is canceled.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on January 07, 2026 has been entered.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
Prior Art Relied Upon
This action references the following issued US Patents and/or Patent Application Publications:
US PATENT or PUBLICATION NUMBER
HEREINAFTER
US-11591973-B1
“SWANN”
US-20140165580-A1
“SIMMONS”
US-20120131926-A1
“KOPECEK”
This action references the following non-patent documents:
AUTHOR OR EDITOR
TITLE (DATE),
PUBLISHER,
EDITION
CHAPTERS / PAGES
COPY
HEREINAFTER
DURDINA ET AL
Reduction of Nonvolatile Particulate Matter Emissions of a Commercial Turbofan Engine at the Ground Level from the Use of a Sustainable Aviation Fuel Blend (2021),
Environ. Sci. Technol.
55
14576−14585
PROVIDED PREVIOUSLY
“DURDINA”
Anderson et al.
Alternative Aviation Fuel Experiment (AAFEX) [2011],
NASA,
NASA/TM-2011-217059
ALL
PROVIDED PREVIOUSLY
“ANDERSON”
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-2, 4-10 and 13-20 are rejected under 35 U.S.C. 103 as being unpatentable over SWANN in view of SIMMONS and DURDINA.
Re Claims 1-2 and 13-14, SWANN teaches a gas turbine engine 10 for an aircraft 1 and method of operating the gas turbine engine, the gas turbine engine comprising: a controller 42; a fan 23; a bypass duct 12; a splitter valve 306 (Figure 5; 43:25 to 44:70; 54:61-56:40) ; and an engine core 11 with a lean burn combustor 16, comprising a combustion chamber and a plurality of fuel spray nozzles 313, 314 configured to inject fuel into the combustion chamber (Fig. 5; 43:4 to 44:43), wherein a bypass ratio defined as a ratio of mass flow rate through the bypass duct to mass flow rate through the engine core is from 7.18 to 11.3 (28:62 to 29:15), the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles [one of 313 and 314] and a second subset of fuel spray nozzles [the other of 313 and 314] (43:25 to 44:70), the controller is configured to control the splitter valve so that the lean burn combustor is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles is supplied with the fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles (43:58 to 44:44); the gas turbine engine is configured to provide fuel comprising a sustainable aviation fuel [SAF] to the plurality of fuel nozzles for control of nvpm emissions (40:61 to 41:39; 46:10 to 47:45; 54:61-56:40), the controller is configured to control the flow of the fuel spray nozzles to achieve 100% available thrust and to separately achieve 85% available thrust (32:12 to 33:30; 56:21 to 57:43), the lean burn combustor is configured to combustor the fuel (43:4 to 44:43) and the method comprising provide fuel comprising sustainable aviation fuel to the plurality of fuel spray nozzles (40:61 to 41:39; 47:5-45; 54:61-56:40), controlling the splitter valve to operate the lean burner combustor in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles is supplied with the fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles (43:58 to 44:44; 54:61-56:40), controlling the flow of the fuel to the plurality of fuel spray nozzles to achieve 100% available thrust and to separately achieve 85% available thrust (32:12 to 33:30; 56:21 to 57:43) and combusting the fuel with the lean burn combustor (Fig. 5; 43:4 to 44:43). SWANN notes different numbers of fuel spray nozzles may be used with respect to the different subsets (43:33-36; 44:19-27), but fails to teach a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is 1:3 to 1:6.
SIMMONS teaches a gas turbine engine 10 comprising: a combustor 14 wherein a ratio of the number of fuel spray nozzles in a first subset of fuel spray nozzles 52 to the number of fuel spray nozzles (from less than 3 up to 18, ¶0014-0015) in a second subset of fuel spray nozzles (total nozzles excepting those in the first subset made up of nozzles 52; total number of nozzles ranging from 10 to 100, ¶0013; thus the number in the second subset is equal to total nozzles minus the number in the first subset)(¶¶0014-0016) is 1:3 to 1:6 (from less than 3 up to 18, ¶0014-0015) to the number of fuel spray nozzles in the second subset of fuel spray nozzles (total number of nozzles ranging from 10 to 100, ¶0013) is in the range of 1:3 to 1:6 (e.g., total nozzles may be 100 and first subset may be 18 nozzles, such that second subset would be 82 nozzles; i.e., ratio of 1:4.56. Notably various other disclosed numbers of nozzles in the first and second subset also fall within the claimed range for the ratio). The number of fuel nozzles in each subset of subsets of nozzles was recognized as a result effective variable optimized to achieve fuel staging that maintains stable combustion within operability limits throughout operating regime (e.g., above flameout threshold) and/or load responsiveness, as well as total number of nozzles which is varied to achieve desired flow for given engine size. See SWANN 43:33-36 and 44:19-27 and SIMMONS ¶¶0013-0015. Therefore, it would have been obvious to one of ordinary skill in the art at the time of invention to provide a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is 1:3 to 1:6, since it has been held that where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges [of a result effective variable] by routine experimentation. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), MPEP § 2144.05 II (B), and In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955), MPEP § 2144.05 II (A). Further, it has been held that [when] all the claimed elements were known in the prior art (in the instant case, fuel injectors supplying fuel to a combustor) and one skilled in the art could have combined the elements as claimed by known methods (providing subsets of fuel nozzles according to known ratios) with no change in their respective functions (supplying fuel for combustion), and the combination would have yielded nothing more than predictable results to one of ordinary skill in the art (a predictable fuel flow to the combustor of a gas turbine), it would have been an obvious extension of prior art teachings, KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007); citing Sakraida v. AG Pro, Inc., 425 U.S. 273, 282, 189 USPQ 449, 453 (1976) See MPEP § 2143 (I) A.
However, SWANN in view of SIMMONS as fails to describe but necessarily includes a lean cruise nvPM emissions index ratio is defined as:
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EIcruise(lean),SAF is defined as:
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EImaxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel;
EIclimb,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel;
EImaxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; and
EIclimb,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel;
However, SWANN in view of SIMMONS fails to teach the combustor is configured to combust the fuel so that the lean cruise nvPM emissions index ratio of the gas turbine engine is between 0.05 and 1 or 0.9, wherein the sustainable aviation fuel is a kerosene-type fuel with a hydrogen mass fraction of 13.7% to 16.9% and/or the sustainable aviation fuel comprises a calorific value between 101% and 105% that of kerosene.
DURDINA teaches a gas turbine engine having a combustor configured to combustor fuel so that a lean cruise nvPM emissions index ratio (Figure 2) between a fossil-based hydrocarbon fuel (JET A-1) and a sustainable aviation fuel (32% HEFA-SPK blend) that is defined as:
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EIcruise(lean),FF is defined as:
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EImaxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel;
EIclimb,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel;
EImaxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; and
EIclimb,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel
wherein the combustor is configured to combust the fuel so that the lean cruise nvPM emissions index ratio of the gas turbine engine is between 0.05 and 1 or 0.9 (Figure 2, annotated below) when the fuel comprises the sustainable aviation fuel (HEFA-SPK blend), wherein the sustainable aviation fuel is a kerosene-type fuel with a hydrogen mass fraction of 13.7% to 16.9% (14.05% mass fraction of hydrogen; Table 1 on page 14577) and/or the sustainable aviation fuel comprises a calorific value between 101% and 105% that of kerosene.
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Notably, it is clear that the measured lean cruise nvPM emissions index ratio shown in Figure 2 between fossil-based hydrocarbon fuel Jet A-1 and the sustainable aviation fuel HEFA-SPK blend is less than 1 and less than 0.9. Values for the emissions indices making up the index ratio can be extrapolated from Figure 2, for thrust near 85% and 100% (power %). See Figure 2 annotations above. Figure 2 shows EImaxTO,SAF, EIclimb,SAF EImaxTO,FF EIclimb,FF of about 188, 163, 228, 198 mg/kg respectively. The same corresponds to EIcruise(lean),SAF EIcruise(lean),FF of 175.5 and 213 mg/kg respectively and thus a lean cruise nvPM emissions index ratio of 0.823944. Therefore, DURDINA suggests in Figure 2 wherein the combustor is configured to combust the fuel so that the lean cruise nvPM emissions index ratio of the gas turbine engine is between 0.05 and 0.9 (Figure 2, annotated above) when the combustor can use the sustainable aviation fuel (HEFA-SPK blend), wherein the sustainable aviation fuel is a kerosene-type fuel with a hydrogen mass fraction of 13.7% to 16.9% (14.05% mass fraction of hydrogen; Table 1 on page 14577). Even without extrapolating values for the emission indexes, done for Applicant’s convenience, one of ordinary skill would have appreciated DURDINA teaches a lean cruise nvPM emissions index ratio less than 1 and less than 0.9 in Figure 2.
It would have been obvious to one having ordinary skill in the art prior to the effective filing date of the claimed invention to provide the method and engine wherein the combustor is configured to combust the fuel so that the lean cruise nvPM emissions index ratio of the gas turbine engine is between 0.05 and 0.9, wherein the sustainable aviation fuel is a kerosene-type fuel with a hydrogen mass fraction of 13.7% to 16.9% as taught by DURDINA, in order to provide an engine that can operate with sustainable aviation fuel SAF and thereby reduce PM emissions and/or reduce environmental impact and/or comply with regulations (DURDINA page 14576). Additionally, SWANN teaches control of nvPM emissions (SWANN 46:10 to 49:62)
Re Claims 4-9, 15-20, SWANN in view of SIMMONS and DURDINA teaches the gas turbine engine of claim 1 and method of Claim 14 as discussed above. However, the rejections so far have not yet discussed the emission index ratios claimed in Claims 4-9 and 15-20. DURDINA, referring to the measured values shown for mg/kg emissions indexes for hydrocarbon fuel (Jet A-1) and sustainable aviation fuels HEFA-SPK blend at corresponding available thrust percentages shown by % power in Figure 2 of DURDINA, DURDINA would suggest idle-MTO nvPM emissions index ratio of the gas turbine engine is less than 1, lean cruise/MTO nvPM emissions index ratio of the gas turbine engine is less than 1, idle/lean cruise nvPM emissions index ratio of the gas turbine engine is less than 1, rich cruise nvPM emissions index ratio of the gas turbine engine is less than 1, and rich cruise/MTO nvPM emissions index ratio of the gas turbine engine is less than 1 to one of ordinary skill, on the basis of the values readily extracted from Figure 2.
An attempt has been made to show annotations to illustrate such extractions from Figure 2 combined with an image of the performed calculations for each of the ratios that rely on those values hereafter.
[continued on next page]
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It would have been obvious to one having ordinary skill in the art prior to the effective filing date of the claimed invention to provide the method and engine wherein the index ratios of claims 4-9 and 15-20 are less than 1, in order to provide an engine that can operate with sustainable aviation fuel SAF and thereby reduce PM emissions and/or reduce environmental impact and/or comply with regulations (DURDINA page 14576). The extracted values from Figure 2 suggest values for each of the ratios within the claimed ranges for each of Claims 4-9, 15-20 as noted above. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). To the extent that the extrapolation may result in a minute amount of imprecision, it is noted that it has been held that a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985). In the instant case, the values of Figure 2 are such that they would suggest to one of ordinary skill values for each of the ratios within the claimed ranges for each one of Claims 4-9, 15-20 as noted above.
Re Claim 10, SWANN in view of SIMMONS and DURDINA the gas turbine engine of claim 1, wherein the ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:4 to 1:5 (see Claim 1 above and SIMMONS).
NOTE: The limitation “and/or wherein the first subset of fuel spray nozzles includes between 1 and 10 fuel spray nozzles; and wherein the second subset of fuel spray nozzles includes between 10 and 25 fuel spray nozzles.” is considered optional due to the ‘or’. However, SIMMONS further teaches wherein the first subset of fuel spray nozzles includes between 1 and 10 fuel spray nozzles (Fig. 2; from less than 3 up to 18, ¶0014-0015, claims 10-11); and wherein the second subset of fuel spray nozzles includes between 10 and 25 fuel spray nozzles (Fig. 2, ¶¶0013-0015, claims 10-11). It would have been obvious to one having ordinary skill in the art prior to the effective filing date of the claimed invention to provide wherein the first subset of fuel spray nozzles includes between 1 and 10 fuel spray nozzles; and wherein the second subset of fuel spray nozzles includes between 10 and 25 fuel spray nozzles for the reasons discussed above in Claim 1 and since at the time of the invention, there was a recognized problem, design need or market pressure to solve a problem in the art (SIMMONS ¶¶0013-0015, number of fuel nozzles) with a finite number of identified, predictable potential solutions (SIMMONS ¶¶0013-0015 and claims), and one of ordinary skill in the art could have pursued the known potential solutions with a reasonable expectation of success (¶¶0018). Thus, (wherein the first subset of fuel spray nozzles includes between 1 and 10 fuel spray nozzles, or preferably between 3 and 5 fuel spray nozzles the second subset of fuel spray nozzles includes between 10 and 25 fuel spray nozzles, or preferably between 14 and 22 fuel spray nozzles, or further preferably between 16 and 20 fuel spray nozzles) would have been "obvious to try" for one of ordinary skill in the art and therefore would have been obvious extension of prior art teachings, KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007). See MPEP § 2143 (I) E.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over SWANN in view of SIMMONS and DURDINA as applied above, further in view of KOPECEK.
Re Claim 11, SWANN in view of SIMMONS and DURDINA teaches the gas turbine engine of claim 1, but is silent to wherein the combustor comprises one or more ignitors, wherein each of the first subset of fuel spray nozzles is located nearer a respective one or more of the ignitors than the second subset, and/or wherein oner or more of the ignitors is arranged diametrically opposite another one or more of the ignitors.
KOPECECK teaches wherein a combustor comprises one or more ignitors, wherein each of the first subset of fuel spray nozzles is located nearer a respective one or more of the ignitors than the second subset, and/or wherein oner or more of the ignitors is arranged diametrically opposite another one or more of the ignitors (Fig. 8). It would have been obvious to one having ordinary skill in the art prior to the effective filing date of the claimed invention to provide the engine such that the combustor comprises one or more ignitors, wherein each of the first subset of fuel spray nozzles is located nearer a respective one or more of the ignitors than the second subset, and/or wherein oner or more of the ignitors is arranged diametrically opposite another one or more of the ignitors to provide optimized laser ignition and/or enhance mixing and flame stabilization (KOPECECK ¶¶0007).
Response to Arguments
Applicant's arguments filed 01/07/2026 have been fully considered.
Applicant’s amendment overcame the prior rejections under 35 U.S.C. 112.
Applicant’s arguments to the prior art rejections are not persuasive. SWANN teaches a lean combustor and bypass ratio within the claimed range. Moreover, Applicant’s argument concerning bypass ratio and “rich burn combustor” of CFM56 amount to mere allegations that are not factually supported in the record. It has been held that arguments of counsel cannot take the place of factually supported objective evidence. See, e.g., In re Huang, 100 F.3d 135, 139-40, 40 USPQ2d 1685, 1689 (Fed. Cir. 1996); In re De Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. Cir. 1984). See MPEP § 2145. Further, it is noted that a “rich burn quick quench lean burn” combustor qualifies as a “lean burn combustor” under the terms plain meaning to those of ordinary skill. Applicant has not shown the CFM56 series includes no lean combustors. Nevertheless, the same is taught by SWANN. Furthermore, SAFs would be expected to reduce NVPM emissions with respect to fossil fuel. See DURDINA 14576 and ANDERSON (discussed below). In the instant case, there is a reasonable expectation of success in achieving to ratios taught by DURDINA, particularly since SWANN teaches control of nvPM emissions via fuel (SWANN 46:10 to 48:50) and the same are desirable providing an emissions benefit. See DURDINA 14576 and ANDERSON (discussed below)
Pertinent Art
The following prior art previously made of record and not relied upon is considered pertinent to applicant's disclosure.
ANDERSON is a NASA technical report relevant to sustainable aviation fuels. Appendix H and Appendix I (pages 179-235) are particularly relevant to nvPM emissions and index ratios thereof, as they are directed to engine testing and corresponding nvPM emissions. Of particular relevance is the discussion of emission benefit between sustainable aviation fuels and conventional fuel, a relevant portion of which is reproduced below.
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Correspondence
Any inquiry concerning this communication or earlier communications from the examiner should be directed to JASON H DUGER whose telephone number is (313) 446-6536. The examiner can normally be reached 8:30a to 4:30p EST Monday & Tuesday and 8:00a to 2:00p Wednesday, and is OFF Thursday and Friday.
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JASON H DUGER
PRIMARY EXAMINER, ART UNIT 3741
PHONE (313) 446 6536
FAX (571) 270 9083
DATE
March 07, 2026
/JASON H DUGER/Primary Examiner, Art Unit 3741