FINAL ACTION
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 .
This is the second office action on the merits. This office action is in response to the amendment filed on 02/20/2026. Applicant has amended claims 1-16 and 18 and cancelled claim 17. Claims 1-16 and 18 are pending and examined.
Priority
Applicant’s claim for the benefit of a prior-filed application under 35 U.S.C. 119(e) or under 35 U.S.C. 120, 121, 365(c), or 386(c) is acknowledged. Applicant has not complied with one or more conditions for receiving the benefit of an earlier filing date under 35 U.S.C. 120 as follows:
The later-filed application must be an application for a patent for an invention which is also disclosed in the prior application (the parent or original nonprovisional application or provisional application). The disclosure of the invention in the parent application and in the later-filed application must be sufficient to comply with the requirements of 35 U.S.C. 112(a) or the first paragraph of pre-AIA 35 U.S.C. 112, except for the best mode requirement. See Transco Products, Inc. v. Performance Contracting, Inc., 38 F.3d 551, 32 USPQ2d 1077 (Fed. Cir. 1994).
The disclosure of the prior-filed application, Application No. 18/892,741, fails to provide adequate support or enablement in the manner provided by 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph for one or more claims of this application. Application 18/892,741 has no disclosure of “EIidle is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for given operating conditions; EImaxTO is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the given operating conditions” (claim 1, lines 17-20 and claim 18, lines 18-21). Accordingly, claims 1-16 and 18 are not entitled to the benefit of the prior application filing date.
Drawings
The drawings were received on February 20, 2026. These drawings are acceptable.
Terminal Disclaimer
The terminal disclaimer filed on February 20, 2026 disclaiming the terminal portion of any patent granted on this application which would extend beyond the expiration date of Application Number 18/892,741 has been reviewed and is accepted. The terminal disclaimer has been recorded.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-16 and 18 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Regarding claims 1 and 18, the limitation “a lean burn combustor” is not supported in Applicant’s disclosure. The term “lean burn combustor” is not found in the specification. The specification merely provides “The combustor 16 is configured to utilise staged lean-burn combustion” (page 85, lines 39-40). However, this does not imply that combustor 16 is a “lean burn combustor”. The term “lean burn combustor” implies a device that differs structurally from that of an ordinary combustor. Therefore, the limitation constitutes new matter.
Claims 2-16 depend from claim 1 and are rejected for the same reason.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-16 and 18 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claims 1 and 18, the limitation “a lean burn combustor” is indefinite because it is not understood how a lean burn combustor differs structurally from that of an ordinary combustor. The disclosure does not show or describe structural details of a “lean burn combustor”. Rather, the specification merely provides a combustor that is “configured to utilise staged lean-burn combustion” (page 85, lines 39-40).
For examination purposes, the limitation will be interpreted as any combustor that is capable of achieving lean-burn combustion.
Claims 2-16 depend from claim 1 and are rejected for the same reason.
Claim Rejections - 35 USC § 103
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 (i.e., changing from AIA to pre-AIA ) 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.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1-14, 16, and 18 are rejected under 35 U.S.C. 103 as being unpatentable over Summerfield (US 2003/0014979 A1), in view of Durdina ("Reduction of Nonvolatile Particulate Matter Emissions of a Commercial Turbofan Engine at the Ground Level from the Use of a Sustainable Aviation Fuel Blend"), and as evidenced by Graves (US 5,987,889).
Regarding claim 1, Summerfield teaches (Figs. 1-3) a gas turbine engine (2 – Fig. 1) for an aircraft (Fig. 1 shows a turbofan engine, which is used on aircraft), comprising:
a lean burn combustor (10 – Fig. 2; see *Note below for evidence that combustor 10 is capable of lean-burn combustion), comprising a combustion chamber (Fig. 2: where “10” is pointing to) and a plurality of fuel spray nozzles (18 and 20 – Fig. 3) configured to inject fuel into the combustion chamber (10) to achieve lean combustion (as discussed in *Note below), wherein
the plurality of fuel spray nozzles (18 and 20) comprises a first subset of fuel spray nozzles (20) and a second subset of fuel spray nozzles (18), the lean burn combustor (10) is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles (20) 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 (18) – (¶ [0022], ll. 7-10: “In this mode of operation the total mass of fuel delivered per injector 20 via manifold 24 will be greater than that delivered per injector 18 via manifold 22”), a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles (20) to the number of fuel spray nozzles in the second subset of fuel spray nozzles (18) is in the range of 1:2 to 1:5 (Fig. 3 shows a quantity of 2 fuel nozzles 20 and a quantity of 10 fuel nozzles 18. Therefore, the ratio of fuel nozzles in the first subset to the second subset is 2:10, which is equivalent to 1:5).
*Note: Fig. 2 of Summerfield shows a combustor having air intake apertures 15 along liners 17 and 19 of the combustor, which would allow more air into the combustion chamber to burn leaner. Graves teaches in Fig. 1 a combustor having a similar pattern of air intake apertures (28 and 30) along the liner of the combustor. Graves’ invention addresses the problem of preventing lean blowout (col. 2, ll. 17-18), thereby showing that the Graves’ combustor is capable of lean-burn combustion. Since Summerfield’s combustor is structurally similar to that of Graves’, Summerfield’s combustor is also capable of lean-burn combustion. Alternatively, lean-burn combustion can be achieved in any combustor by (1) increasing the amount of air that is used to burn the fuel, and/or (2) decreasing the amount of fuel injected into the combustion chamber, such that there is excess air remaining after the combustion process.
However, Summerfield as evidenced by Graves, does not teach a thrust non-volatile particulate matter (nvPM) emissions index ratio is:
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EIidle is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for given operating conditions;
EImaxTO is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the given operating conditions;
FmaxTO is the thrust of the gas turbine engine at around 100% available thrust in kN for the given operating conditions; and
Fidle is the thrust of the gas turbine engine at around 7% available thrust in kN for the given operating conditions;
the thrust nvPM emissions index ratio is greater than 0.001 and less than or equal to 1.77; and
the gas turbine engine is configured to provide fuel comprising a sustainable aviation fuel (SAF) to the plurality of fuel spray nozzles.
Durdina teaches emissions testing of a gas turbine engine using a sustainable aviation fuel blend (page 14576, Abstract, ll. 4-8). Figure 2(a) shows nvPM mass emission index vs sea level static thrust (reproduced on next page). Note that the emission indices have been system loss corrected (per caption of Figure 2).
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Based on the above chart:
at a thrust of 7%, EIidle = 1.1, and
at a thrust of 100%, EImaxTO = 188.
Note that FmaxTO = 100% and Fidle = 7%, based on the definitions provided in claim 1 (the units of thrust do not matter because they will “cancel out” in the expression below).
Plugging the numbers above into the expression
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yields a thrust nvPM emissions index ratio of 12.0.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Summerfield as evidenced by Graves, by having a thrust nvPM emissions index ratio be greater than 0.001; and providing a fuel comprising sustainable aviation fuel (SAF) to the plurality of fuel spray nozzles, in order to provide an engine that can operate with sustainable aviation fuel (SAF), which reduces the carbon footprint of the fuel and reduces volatile and nonvolatile particulate matter emissions, which will ultimately reduce aviation’s adverse effects on the environment, as taught by Durdina (page 14576, paragraph titled “INTRODUCTION”).
However, Summerfield, in view of Durdina and as evidenced by Graves, does not teach the thrust nvPM emissions index ratio is less than or equal to 1.77.
Note that the expression for the thrust nvPM emissions index ratio reduces to:
0.07
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because FmaxTO = 100% and Fidle = 7%, and
1
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1
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=
1
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100
%
1
/
7
%
=
0.07
.
Furthermore, Durdina’s Figure 2(a) teaches that EIidle and EImaxTO may vary (as evidenced by the spread of values shown by the box and whisker plots), and EIidle and EImaxTO are result-effective variables, i.e., a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B).
In this case, the recognized result is that the emissions indices EIidle and EImaxTO will vary based on the fuel composition (Figure 2(a) shows that a fuel having no SAF content, such as Jet A-1, will have a higher emissions index than a fuel blended with SAF, such as HEFA-SPK blend).
Therefore, since the general conditions of the claim, i.e. that the emissions indices will vary based on the % of SAF in the fuel, and thus, the ratio of emissions indices (i.e., EImaxTO / EIidle) will also vary based on the % of SAF in the fuel, were disclosed in the prior art by Durdina, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to vary the emissions indices, and thus the ratio of emissions indices, by varying the SAF content in the fuel to provide a thrust nvPM emissions index ratio that is less than or equal to 1.77, as taught by Durdina, in order to provide a target emissions index (in this case, to lower the emissions index to reduce the carbon footprint of the aircraft). 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).
Intended use:
The limitation “the thrust nvPM emissions index ratio is greater than 0.001 and less than or equal to 1.77” is a statement of intended use because the parameters used to calculate the thrust nvPM emissions index ratio (in this case, emissions indices and thrust values) are purely functional and do not add any structure to the apparatus. It has been held that “While features of an apparatus may be recited either structurally or functionally, claims directed to an apparatus must be distinguished from the prior art in terms of structure rather than function”, In re Schreiber, 128 F.3d 1473, 1477-78, 44 USPQ2d 1429, 1431-32 (Fed. Cir. 1997); see also In re Swinehart, 439 F.2d 210, 212-13, 169 USPQ 226, 228-29 (CCPA 1971); In re Danly, 263 F.2d 844, 847, 120 USPQ 528, 531 (CCPA 1959); “[A]pparatus claims cover what a device is, not what a device does” Hewlett-Packard Co. v. Bausch & Lomb Inc., 909 F.2d 1464, 1469, 15 USPQ2d 1525, 1528 (Fed. Cir. 1990), MPEP 2114 (I). “Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established, In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977), MPEP 2112.01.
Regarding claim 2, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is greater than 0.00115 (calculated to be 12.0, which is greater than 0.00115).
Regarding claim 3, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is greater than 0.0644 (calculated to be 12.0, which is greater than 0.0644).
Regarding claim 4, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is greater than or equal to 0.003 (calculated to be 12.0, which is greater than 0.003).
Regarding claim 5, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is greater than or equal to 0.00776 (calculated to be 12.0, which is greater than 0.00776).
Regarding claim 6, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is greater than or equal to 0.434 (calculated to be 12.0, which is greater than 0.00776).
Regarding claim 7, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is less than or equal to 1.62 (intended use – see rejection of claim 1).
As stated in the rejection of claim 1, the emissions indices will vary based on the % of SAF in the fuel, and thus, the ratio of emissions indices (i.e., EImaxTO / EIidle) will also vary based on the % of SAF in the fuel, as disclosed in the prior art by Durdina. It is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to vary the emissions indices, and thus the ratio of emissions indices, by varying the SAF content in the fuel to provide a thrust nvPM emissions index ratio that is less than or equal to 1.62, as taught by Durdina, in order to provide a target emissions index (in this case, to lower the emissions index to reduce the carbon footprint of the aircraft).
Regarding claim 8, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is less than or equal to 0.0553 (intended use – see rejection of claim 1).
As stated in the rejection of claim 1, the emissions indices will vary based on the % of SAF in the fuel, and thus, the ratio of emissions indices (i.e., EImaxTO / EIidle) will also vary based on the % of SAF in the fuel, as disclosed in the prior art by Durdina. It is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to vary the emissions indices, and thus the ratio of emissions indices, by varying the SAF content in the fuel to provide a thrust nvPM emissions index ratio that is less than or equal to 0.0553, as taught by Durdina, in order to provide a target emissions index (in this case, to lower the emissions index to reduce the carbon footprint of the aircraft).
Regarding claim 9, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) the thrust nvPM emissions index ratio is in the range of 0.00776 to 1.77 (intended use – see rejection of claim 1).
As stated in the rejection of claim 1, the emissions indices will vary based on the % of SAF in the fuel, and thus, the ratio of emissions indices (i.e., EImaxTO / EIidle) will also vary based on the % of SAF in the fuel, as disclosed in the prior art by Durdina. It is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to vary the emissions indices, and thus the ratio of emissions indices, by varying the SAF content in the fuel to provide a thrust nvPM emissions index ratio that is in the range of 0.00776 to 1.77, as taught by Durdina, in order to provide a target emissions index (in this case, to lower the emissions index to reduce the carbon footprint of the aircraft).
Regarding claim 10, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and the combination further teaches (Durdina, Figure 2(a)) wherein:
a) FmaxTO is in the range 85.4 kN to 172 kN (page 14577, paragraph titled “Engine Emission Tests” teaches Foo = 117 kN); and/or
b) Fidle is in the range 5.98 kN to 12.1 kN (7% of 117 kN is 8.19 kN).
Regarding claim 11, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and Summerfield further teaches (Fig. 4) the ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles (20) to the number of fuel spray nozzles in the second subset of fuel spray nozzles (18) is in the range of 1:3 to 1:4 (Fig. 4 shows a quantity of 2 fuel nozzles 20 and a quantity of 8 fuel nozzles 18. Therefore, the ratio of fuel nozzles in the first subset to the second subset is 2:8, which is equivalent to 1:4).
Regarding claim 12, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and Summerfield further teaches (Fig. 3) the first subset of fuel spray nozzles (20) includes between 1 and 10 fuel spray nozzles (Fig. 3 shows a quantity of 2 fuel nozzles 20).
Regarding claim 13, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and Summerfield further teaches (Fig. 3) the second subset of fuel spray nozzles (18) includes between 10 and 25 fuel spray nozzles (Fig. 3 shows a quantity of 10 fuel nozzles 18).
Regarding claim 14, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, and Summerfield further teaches (Fig. 2) the lean burn combustor (10) comprises one or more ignitors (26).
Regarding claim 16, Summerfield, in view of Durdina as discussed so far and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 1, except for the fuel provided to the lean burn combustor comprises a %SAF in the range of 50% to 100%.
Durdina further teaches the fuel provided to the combustor comprises a %SAF in the range of 50% to 100% (page 14580, 1st paragraph: “A 50% HEFA blend”).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Summerfield, in view of Durdina as discussed so far and as evidenced by Graves, by providing a fuel to the combustor comprising a %SAF in the range of 50% to 100%, in order to reduce the geometric mean diameter of the emissions particles, thereby reducing total emissions, as taught by Durdina (page 14580, 1st paragraph).
Regarding claim 18, Summerfield teaches (Figs. 1-3) a method of operating a gas turbine engine (2 – Fig. 1), the gas turbine engine (2) comprising:
a lean burn combustor (10 – Fig. 2; see *Note below for evidence that combustor 10 is capable of lean-burn combustion), comprising a combustion chamber (Fig. 2: where “10” is pointing to) and a plurality of fuel spray nozzles (18 and 20 – Fig. 3) configured to inject fuel into the combustion chamber (10) to achieve lean combustion (as discussed in *Note below), wherein
the plurality of fuel spray nozzles (18 and 20) comprises a first subset of fuel spray nozzles (20) and a second subset of fuel spray nozzles (18), the combustor (10) is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles (20) 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 (18) – (¶ [0022], ll. 7-10: “In this mode of operation the total mass of fuel delivered per injector 20 via manifold 24 will be greater than that delivered per injector 18 via manifold 22”), a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles (20) to the number of fuel spray nozzles in the second subset of fuel spray nozzles (18) is in the range of 1:2 to 1:5 (Fig. 3 shows a quantity of 2 fuel nozzles 20 and a quantity of 10 fuel nozzles 18. Therefore, the ratio of fuel nozzles in the first subset to the second subset is 2:10, which is equivalent to 1:5).
*Note: Fig. 2 of Summerfield shows a combustor having air intake apertures 15 along liners 17 and 19 of the combustor, which would allow more air into the combustion chamber to burn leaner. Graves teaches in Fig. 1 a combustor having a similar pattern of air intake apertures (28 and 30) along the liner of the combustor. Graves’ invention addresses the problem of preventing lean blowout (col. 2, ll. 17-18), thereby showing that the Graves’ combustor is capable of lean-burn combustion. Since Summerfield’s combustor is structurally similar to that of Graves’, Summerfield’s combustor is also capable of lean-burn combustion. Alternatively, lean-burn combustion can be achieved in any combustor by (1) increasing the amount of air that is used to burn the fuel, and/or (2) decreasing the amount of fuel injected into the combustion chamber, such that there is excess air remaining after the combustion process.
However, Summerfield as evidenced by Graves, does not teach a thrust non-volatile particulate matter (nvPM) emissions index ratio is:
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EIidle is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for given operating conditions;
EImaxTO is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the given operating conditions;
FmaxTO is the thrust of the gas turbine engine at around 100% available thrust in kN for the given operating conditions; and
Fidle is the thrust of the gas turbine engine at around 7% available thrust in kN for the given operating conditions;
the thrust nvPM emissions index ratio is greater than 0.001 and less than or equal to 1.77; and
the method comprises providing fuel comprising a sustainable aviation fuel to the plurality of fuel spray nozzles.
Durdina teaches emissions testing of a gas turbine engine using a sustainable aviation fuel blend (page 14576, Abstract, ll. 4-8). Figure 2(a) shows nvPM mass emission index vs sea level static thrust (reproduced below). Note that the emission indices have been system loss corrected (per caption of Figure 2).
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Based on the above chart:
at a thrust of 7%, EIidle = 1.1, and
at a thrust of 100%, EImaxTO = 188.
Note that FmaxTO = 100% and Fidle = 7%, based on the definitions provided in claim 18 (the units of thrust do not matter because they will “cancel out” in the expression below).
Plugging the numbers above into the expression
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yields a thrust nvPM emissions index ratio of 12.0.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Summerfield as evidenced by Graves, by having a thrust nvPM emissions index ratio be greater than 0.001; and providing a fuel comprising sustainable aviation fuel to the plurality of fuel spray nozzles, in order to provide an engine that can operate with sustainable aviation fuel (SAF), which reduces the carbon footprint of the fuel and reduces volatile and nonvolatile particulate matter emissions, which will ultimately reduce aviation’s adverse effects on the environment, as taught by Durdina (page 14576, paragraph titled “INTRODUCTION”).
However, Summerfield, in view of Durdina and as evidenced by Graves, does not teach the thrust nvPM emissions index ratio is less than or equal to 1.77.
Note that the expression for the thrust nvPM emissions index ratio reduces to:
0.07
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because FmaxTO = 100% and Fidle = 7%, and
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=
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=
0.07
.
Furthermore, Durdina’s Figure 2(a) teaches that EIidle and EImaxTO may vary (as evidenced by the spread of values shown by the box and whisker plots), and EIidle and EImaxTO are result-effective variables, i.e., a variable which achieves a recognized result. In re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977); MPEP 2144.05(II)(B).
In this case, the recognized result is that the emissions indices EIidle and EImaxTO will vary based on the fuel composition (Figure 2(a) shows that a fuel having no SAF content, such as Jet A-1, will have a higher emissions index than a fuel blended with SAF, such as HEFA-SPK blend).
Therefore, since the general conditions of the claim, i.e. that the emissions indices will vary based on the % of SAF in the fuel, and thus, the ratio of emissions indices (i.e., EImaxTO / EIidle) will also vary based on the % of SAF in the fuel, were disclosed in the prior art by Durdina, it is not inventive to discover the optimum workable range by routine experimentation, and it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to vary the emissions indices, and thus the ratio of emissions indices, by varying the SAF content in the fuel to provide a thrust nvPM emissions index ratio that is less than or equal to 1.77, as taught by Durdina, in order to provide a target emissions index (in this case, to lower the emissions index to reduce the carbon footprint of the aircraft). 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).
Desired result:
The recitation “a thrust non-volatile particulate matter (nvPM) emissions index ratio is defined as…the thrust nvPM emissions index ratio is greater than 0.001 and less than or equal to 1.77” is a statement of desired result flowing implicitly from a process step of “providing fuel comprising a sustainable aviation fuel to the plurality of fuel spray nozzles”. It has been held that a “whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.” Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)), MPEP 2111.04 (I).
In this case, the “whereby clause” includes all the limitations that are not positively recited method steps. Note that claim 18 comprises only one method step (“the method comprises providing fuel…”).
Furthermore, it is noted that the parameters used to calculate the thrust nvPM emissions index ratio (in this case, emissions indices and thrust values) are purely functional and do not add any structure to the apparatus.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Summerfield (US 2003/0014979 A1), in view of Durdina ("Reduction of Nonvolatile Particulate Matter Emissions of a Commercial Turbofan Engine at the Ground Level from the Use of a Sustainable Aviation Fuel Blend"), and in further view of Kopecek (US 2012/0131926 A1), and as evidenced by Graves (US 5,987,889).
Regarding claim 15, Summerfield, in view of Durdina and as evidenced by Graves, teaches the invention as claimed and as discussed above for claim 14, except for 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 one or more of the ignitors is arranged diametrically opposite another one or more of the ignitors.
Kopecek teaches (Figs. 1 and 8) a similar gas turbine engine (¶ [0029], l. 7) comprising a combustor (202), a first subset of fuel spray nozzles (28), a second subset of fuel spray nozzles (28 – note that ¶ [0044], ll. 1-2 teaches “a plurality of fuel nozzles 28”), and one or more ignitors (each ignitor comprising 12, 14, and 16), and further teaches:
each of the first subset of fuel spray nozzles (28) is located nearer a respective one or more of the ignitors (12, 14, and 16) than the second subset (for example, the fuel nozzles shown in Figs. 1-2 are located nearer the ignitors than the fuel nozzles shown in Figs. 6-7 are), and/or one or more of the ignitors (12, 15, and 16) is arranged diametrically opposite another one or more of the ignitors (shown in Fig. 8).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Summerfield, in view of Durdina and as evidenced by Graves, such that 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 one or more of the ignitors is arranged diametrically opposite another one or more of the ignitors, in order to provide optimized laser ignition and/or enhance mixing and flame stabilization, as taught by Kopecek (¶ [0007]).
Response to Arguments
Applicant’s arguments regarding the new limitations in claims 1 and 18 have been considered but are moot in view of the new ground(s) of rejection, necessitated by Applicant's amendments. To the extent possible, Applicant's arguments have been addressed in the body of the rejections at the appropriate locations.
It is noted that Examiner respectfully disagrees with Applicant’s arguments that “Summerfield does not disclose a lean burn combustor” and “The disclosure from Durdina that is relied upon in the rejection is for the CFM56 engine, which includes a rich burn combustor”, for the reasons stated in the 35 U.S.C. 112 section and the prior-art rejections section above. Applicant has not shown how a “lean burn combustor” differs structurally from an ordinary combustor. Furthermore, combustors can achieve lean-burn combustion by lowering the fuel-to-air ratio to be less than the stochiometric fuel-to-air ratio. This can be achieved by either increasing the amount of air into the combustion zone, or decreasing the amount of fuel injected into the combustion zone. The combustors of both Summerfield and Durdina are capable of achieving rich-burn combustion, as well as lean-burn combustion.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant’s disclosure: see attached form PTO-892 “Notice of References Cited”.
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.
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/HENRY NG/ /GERALD L SUNG/ Primary Examiner, Art Unit 3741 Examiner, Art Unit 3741