DETAILED ACTION
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.
Claim(s) 1-13 and 15-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Smith 2022/0333534 in view of Bainville 2008/0083841, Schripp “Aircraft engine particulate matter emissions from sustainable fuels: Results from ground-based measurements during the NASA/DLR campaign ECLIF2/ND-MAX” and Seda 6,619,030.
In regards to Independent Claims 1 and 17 and Dependent Claims 2-13, 16 and 18-20, Smith teaches a gas turbine engine (paragraph [0001]) for an aircraft (paragraph [0100]), comprising: a bypass duct (176); and an engine core (22) with a combustor (shown in figure 3), comprising a combustion chamber (56 and 57) and a plurality of fuel spray nozzles (28 and 26) configured to inject fuel into the combustion chamber (as shown in figure 3), wherein the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles (28) and a second subset of fuel spray nozzles (26), wherein the 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 fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles (engine startup valve 66 may shut off flow 32 leading to 26, paragraph [0099]); and wherein: a MTO nvPM emissions index ratio is defined as: ElmaxTO,SAFElmaxTO,FF where: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 when a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel (SAF); and ElmaxTo,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 when a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; the MTO nvPM emissions index ratio of the gas turbine engine is less than 1 (fuel nozzles may receive additives such as SAF to the fuel, paragraph [0122], resulting in a ratio less than 1, where 1 would occur without any additives); and the gas turbine engine is configured to provide fuel comprising a SAF to the first subset of fuel spray nozzles (SAF fuel added to nozzle 28, paragraph [0122], resulting in an nvPM that is less than 1). However, Smith does not teach that all of the nozzles have SAF fuel passing through the nozzles (at the ratios claimed in claims 2, 3, 5, 6, 8, 9, 11 and 12), that the ratio of first to second subsets of fuel spray nozzles is 1:3 to 1:6, or that the bypass ratio is at least 6.66 at cruise conditions. Bainville teaches a ratio of first to second fuel nozzles of 1:3 (where fuel nozzles are defined in claim 1 and the ratio of 1:3 is defined in claim 3, and there can be up to 18 nozzles, paragraph [0029], such that there would be a maximum of 4 first nozzles and 12 second nozzles when the ratio is 1:3). Seda teaches a turbofan engine (10) with a bypass ratio greater than 6.66 (5 - 15 at Col. 2, ll. 43-44). Schripp teaches using a jet fuel SAF mixture for fuel for an aircraft engine during operation (Three concentrations of SAF used in Table 1 on line 147, with SAJF2 and SAJF3 include 30 and 17% HEFA-SPK respectively resulting in a reduction of nvPM emissions at a high fuel flow rate of 9.69 and 083 respectively, Figure 2 at l. 281). It would have been obvious to one of ordinary skill in the art prior to the filing date of the invention to use a ratio of first to second nozzles of Smith of 1:3 resulting in 4 and 12 nozzles respectively, as taught by Bainville, to operate the engine of Smith at cruise at a bypass ratio of 6.66 or more, as taught by Seda, increase and to use a percentage of SAF fuel for all the fuel injectors during operation, as taught by Schripp, in order to provide enough fuel to orifices during startup when only the first set of nozzles is used and provide enough flow rate at full power with all of the fuel nozzles (paragraph [0029] of Bainville), to increase the operating efficiency of the engine (Col. 1, ll. 51-53 of Seda), and to reduce contrail ice particle number formation and lifetimes to mitigate climate impacts (ll. 97-100 of Schripp). Figure 2 on l. 281 of Schripp further teaches an emissions ratio of about 0.62 for SAF fuel mixture SAJF2 and approximately 0.88 for SAF fuel mixture SAJF3 at approximately 85% thrust; an emissions ratio of about 0.14 for SAF fuel mixture SAJF2 and approximately 0.43 for SAF fuel mixture SAJF3 at approximately 30% thrust; and an emissions ratio of about 0.13 for SAF fuel mixture SAJF2 and approximately 0.5 for SAF fuel mixture SAJF3 at approximately 7% thrust.
Claims 2-12 and 18-20 depend from claims 1 and 17 respectively, and only further limit the claimed ranges of claims 1 and 17 with narrower ranges or under different operating conditions, and the narrower limitations and different operating conditions have been rejected in the rejection above.
Regarding Dependent Claim 15, Smith in view of Bainville, Seda and Schripp teaches the invention as claimed and discussed above. However, Smith in view of Bainville, Seda and Schripp does not teach that 50 to 100 percent SAF is used for the fuel spray nozzles. Schripp teaches that increasing the percentage of SAF fuel in the fuel mixture (e.g. from SAJF3 to SAJF2 in figure 2) will reduce the nvPM emissions rate (as shown in figure 2). Therefore, the percentage of SAF used in a fuel is recognized as a result-effective variable, i.e. a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.0(II)(B). In this case, the recognized result is that increasing the percentage of SAF in the fuel mixture will reduce nvPM emissions. Therefore, since the general conditions of the claim, i.e. that the percentage of SAF fuel used in the fuel mixture, was disclosed in the prior art by Schripp, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to one of ordinary skill in the art prior to the filing date of the invention to use between 50 and 100 percent SAF fuel for the system of Smith in view of Bainville and Schripp in order to reduce nvPM emissions. It has been held that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955); MPEP 2144.05(II)(A).
Claim(s) 14 is rejected under 35 U.S.C. 103 as being unpatentable over Smith in view of Bainville, Seda and Schripp as applied to claim 1 above, and further in view of Daniau 2010/0186370.
Regarding Dependent Claim 14, Smith in view of Bainville, Seda and Schripp teaches the invention as claimed and discussed above. However, Smith in view of Bainville, Seda and Schripp does not teach that one or more of the ignitors is arranged diametrically opposite another of the ignitors. Daniau teaches diametrically opposed igniters (10 and 11, paragraph [0054]) for a combustor (figure 1). It would have been obvious to one of ordinary skill in the art prior to the filing date of the invention to use the diametrically opposed igniters of Daniau for the combustor of Smith in view of Bainville, Seda and Schripp, in order to obtain reliable and uniform ignition of fuel (paragraph [0037]).
Response to Arguments
Applicant's arguments filed 3/18/2026 have been fully considered but they are not persuasive.
Applicant argues that the teachings of Schripp with regards to the MTO nvPM emissions index ratio do not apply to the claimed engine with a bypass ratio of 6.66 or greater at cruise conditions. Schripp is relied upon to teach using different concentrations of SAF fuel, which will reduce nvPM emissions regardless of the bypass ratio of the engine. Schripp’s teaching that using a percentage of SAF fuel will result in a corresponding reduction in nvPM emissions applies to any gas turbine engine that replaces a portion of fuel with SAF to reduce emissions.
Applicant argues that the V2500 engine family referenced in Schripp has a higher nvPM index when the bypass ratio is higher. The claims are drawn to, and Schripp is relied upon to reject the nvPM emissions index ratio, not the value of the emissions index of an engine run on a single fuel. The ratio represents the reduction in emissions when the engine is run on at least a portion of SAF instead of jet fuel versus being run solely upon jet fuel.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEVEN M SUTHERLAND whose telephone number is (571)270-1902. The examiner can normally be reached M-F 8-5.
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/STEVEN M SUTHERLAND/Primary Examiner, Art Unit 3752