DETAILED 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 third office action on the merits. This office action is in response to the request for continued examination filed on 02/03/2026. Applicant has amended claims 1, 10, 13, 16, 18, and 20; cancelled claims 5-9, 14-15, and 19; and added claims 21-23. Claims 10-12, 16-17, and 20 remain withdrawn from further consideration. Claims 1, 3, 13, 18, and 21-23 are pending and examined.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 February 3, 2026 has been entered.
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. 17/871,270, 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 17/871,270 has no disclosure of “wherein the core engine is supported within a core case that is attached to a turbine exhaust case and the core engine is mounted to a wing of an aircraft”, “wherein at least one of the bottoming compressor section and the bottoming turbine section are mounted to the core case”, and “wherein the fuel/working fluid heat exchanger is mounted to the core case” (claim 1, lines 4-6, 10-11, and 21-22, and similarly for claims 13 and 18). Accordingly, claims 1, 3, 10-13, 16-18, and 20-23 are not entitled to the benefit of the prior application filing date.
Drawings
The drawings are objected to under 37 CFR 1.83(a). The drawings must show every feature of the invention specified in the claims. Therefore, the claim 1 limitations "wherein at least one of the bottoming compressor section and the bottoming turbine section are mounted to the core case" and "wherein the fuel/working fluid heat exchanger is mounted to the core case", and similarly for claims 13, 18, and 21-23, must be shown or the feature(s) canceled from the claim(s). No new matter should be entered.
It is further noted that the second limitation above is in relation to the other limitations of claim 1, specifically: “a fuel/working fluid heat exchanger providing thermal communication between the cryogenic fuel and the working fluid to cool a flow of the working fluid from the bottoming turbine section to the bottoming compressor section”. As shown in Fig. 1 of the disclosure, fuel/working fluid heat exchanger 78 is located in the closed circuit of bottoming cycle 52, downstream of bottoming turbine 56 and upstream of bottoming compressor 54. The drawings do not provide a visual understanding of how the bottoming cycle will look when fuel/working fluid heat exchanger 78 is relocated to be mounted to core case 30 and is also required to be located downstream of bottoming turbine 56 and upstream of bottoming compressor 54.
Corrected drawing sheets in compliance with 37 CFR 1.121(d) are required in reply to the Office action to avoid abandonment of the application. Any amended replacement drawing sheet should include all of the figures appearing on the immediate prior version of the sheet, even if only one figure is being amended. The figure or figure number of an amended drawing should not be labeled as “amended.” If a drawing figure is to be canceled, the appropriate figure must be removed from the replacement sheet, and where necessary, the remaining figures must be renumbered and appropriate changes made to the brief description of the several views of the drawings for consistency. Additional replacement sheets may be necessary to show the renumbering of the remaining figures. Each drawing sheet submitted after the filing date of an application must be labeled in the top margin as either “Replacement Sheet” or “New Sheet” pursuant to 37 CFR 1.121(d). If the changes are not accepted by the examiner, the applicant will be notified and informed of any required corrective action in the next Office action. The objection to the drawings will not be held in abeyance.
Claim Objections
Claim 18 is objected to because of the following informalities:
Claim 18, line 5: “the cryogenic a fuel” is believed to be in error for --the cryogenic fuel-- (delete extra “a”)
Claim 18, line 7: “the primary energy convertion devices” is believed to be in error for --the primary energy conversion device-- (“convertion” is spelled wrong and “devices” should not be pluralized)
Appropriate correction is required.
Claim Interpretation
With respect to functional claim limitations and their interpretation, please refer to the Office Action mailed July 3, 2025.
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, 3, 13, 18, and 21-23 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 claim 1, and similarly for claims 13 and 18, the limitations “wherein at least one of the bottoming compressor section and the bottoming turbine section are mounted to the core case” and “wherein the fuel/working fluid heat exchanger is mounted to the core case” are not supported in the specification. Rather, the specification provides the following:
Paragraph [0004], lines 7-8: “at least a portion of the bottoming cycle is mounted to a second structure of the aircraft that is different from the first structure”
Paragraph [0044], lines 4-5: “In the example arrangement 106, the fuel/working fluid heat exchanger 78 is located at the core case mount 30”
Paragraph [0052], lines 2-4: “The bottoming compressor 54 and the fuel/working fluid heat exchanger 78 is located in or on the core case mount 30”.
Care must be taken when considering the term “mounted to the core case”. Paragraph [0004], ll. 7-8 recites “mounted to a second structure”. However, the specification does not state that the second structure may be a core case. Paragraph [0044], ll. 4-5 recites “located at the core case mount”. However, this does not mean “mounted to” the core case. When an object is located at the core case mount, the object can be located in the vicinity of the core case mount. It does not mean that the object is “mounted to” the core case mount. Paragraph [0052], ll. 2-4 recites “located in or on the core case mount 30”. However, this does not mean “mounted to the core case” because the core case is not the same as the core case mount. Rather, this can mean that something is mounted to a mount of the core case, which can be a support structure of the core case.
As a result, the claimed limitations recite subject matter that is different from what is provided in the specification. Additionally, the drawings do not show any bottoming cycle elements being “mounted to the core case”. Therefore, the limitations above constitute new matter.
In addition to the issue of new matter, the limitation “wherein the fuel/working fluid heat exchanger is mounted to the core case” is not described in the specification in relation to “a fuel/working fluid heat exchanger providing thermal communication between the cryogenic fuel and the working fluid to cool a flow of the working fluid from the bottoming turbine section to the bottoming compressor section”. As stated in the drawing objection above, the drawings do not show how such a system would look. The specification does not provide any details of how such a system would be constructed. The specification merely provides “In the example arrangement 106, the fuel/working fluid heat exchanger 78 is located at the core case mount 30” (¶ [0044]). There are no further details of this arrangement in relation to the bottoming cycle, the bottoming compressor, or the bottoming turbine.
Rather, Fig. 1 provides a system contrary to what is claimed. In Fig. 1, all the elements of the bottoming cycle are mounted to a structure that is different from the core case. Fig. 3 merely provides a label “CORE CASE” with the elements of the bottoming cycle to the right of said label. This does not provide sufficient support for having elements of the bottoming cycle being “mounted to the core case”.
Therefore, one of ordinary skill in the art cannot reasonably conclude that the inventor had possession of the claimed invention.
Claim 3 is also rejected because it depends on claim 1.
Claims 21-23 recite similar subject matter and are also rejected for the same reasons listed above.
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 18 and 21 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.
Claim 18 recites the limitation "the second structure" in line 19. There is insufficient antecedent basis for this limitation in the claim.
Claim 21 is also rejected because it depends on claim 18.
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, 3, and 23 are rejected under 35 U.S.C. 103 as being unpatentable over Ranjan (US 2023/0075009 A1), in view of Miller (US 2025/0179958 A1), Sibbach (2025/0084789 A1), and Prociw (US 2021/0156310 A1).
Regarding claim 1, Ranjan teaches (Figs. 1-2) an aircraft propulsion system comprising:
a core engine (32) comprising a combustor (48 – Fig. 2) where a cryogenic fuel (62) is mixed with compressed air (“Air” – Fig. 2) and ignited to generate an exhaust gas flow, and the exhaust gas flow is expanded through a turbine section (46 – Fig. 2) to generate shaft power (¶ [0033], l. 5), wherein the core engine (32) is supported within a core case (inherent in a core engine) that is attached to a turbine exhaust case (inherent due to the presence of exhaust from turbine 46 – see ¶ [0038], l. 5) and the core engine (32) is mounted to a wing (14 – Fig. 1) of an aircraft (10 – Fig. 1) – (as shown in Fig. 1);
a bottoming cycle (80 – Fig. 2) where a working fluid (supercritical CO2) is circulated within a closed circuit (as shown by the arrows starting at 70 → 92 → 88 → 72 → 92 → 84, and finally back to 70) comprising a bottoming compressor section (70 – Fig. 2) and a bottoming turbine section (72 – Fig. 2), wherein the working fluid (sCO2) is compressed in the bottoming compressor section (70) and expanded through the bottoming turbine section (72) to generate shaft power (as evidenced by generator 74);
a primary heat exchanger (88 – Fig. 1) providing communication of thermal energy from the exhaust gas flow (from 46) to the working fluid (sCO2) of the bottoming cycle (80), wherein the primary heat exchanger (88) is mounted within the turbine exhaust case (¶ [0036], ll. 4-6 teaches “Turbine 46 includes…an outlet portion 112 coupled to heat exchanger system 88”. Therefore, heat exchanger 88 is also coupled to the turbine exhaust case) and the exhaust gas flow is routed through the primary heat exchanger (88) for heating the working fluid (sCO2) of the bottoming cycle (80);
a fuel system comprising a cryogenic fuel storage tank (64) and a fuel flow path (path of 64 → 68 → 116 → 84 → 120 → 54) for routing the cryogenic fuel (62) to the core engine (32); and
a fuel/working fluid heat exchanger (84 – Fig. 2) providing thermal communication between the cryogenic fuel (62) and the working fluid (sCO2) to cool a flow of the working fluid (sCO2) from the bottoming turbine section (72) to the bottoming compressor section (70).
However, Ranjan does not teach the turbine section to generate shaft power utilized to drive a propulsive fan.
It is noted that Ranjan does not specify what type of engine ref. no. 32 is. Rather, ref. no. 32 is merely called “first turbine engine”.
Miller teaches “Example gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc.” Furthermore, Miller teaches in Fig. 1 a gas turbine engine (10) having a turbine section (30) to generate shaft power utilized to drive a propulsive fan (38).
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 Ranjan by substituting Ranjan’s turbine engine 32 with a turbofan engine as taught by Miller, in order to obtain predictable results, which in this case would be providing an interchangeable gas turbine engine (KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007), MPEP 2143 (I)(B)), therefore providing:
the turbine section (Ranjan – 46) to generate shaft power utilized to drive a propulsive fan (Miller, 38).
However, Ranjan, in view of Miller, does not teach at least one of the bottoming compressor section and the bottoming turbine section are mounted to the core case.
Sibbach teaches (Fig. 2) a similar aircraft propulsion system comprising:
a core engine (within 18) comprising a combustor (26) where a cryogenic fuel (from 82) is mixed with compressed air (from 24) and ignited to generate an exhaust gas flow (66), wherein the core engine (within 18) is supported within a core case (18);
a bottoming cycle (100) where a working fluid (water/steam) is circulated within a closed circuit comprising a bottoming compressor section (108) and a bottoming turbine section (110), wherein the working fluid is compressed in the bottoming compressor section (108) and expanded through the bottoming turbine section (110) to generate shaft power (¶ [0041], ll. 14-16); and further teaches:
at least one of the bottoming compressor section (108) and the bottoming turbine section (110) are mounted to the core case (18) – (Fig. 2 shows steam turbine 110 located next to LPT 30 and further coupled to LP shaft 36. In addition, Fig. 1 shows steam system 100, which includes steam turbine 110, being mounted to core case 18 through direct contact with the right end of core case 18. Therefore, at the very least, steam turbine 110 is mounted to core case 18).
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 Ranjan, in view of Miller, by relocating at least one of the bottoming compressor section and the bottoming turbine section to be mounted to the core case, in order to extract additional work by the bottoming cycle to contribute approximately 25% of the power to the core engine shaft, thus enabling a size of the core engine to be reduced and increasing efficiency of the core engine, as taught by Sibbach (¶ [0043], ll. 4-6 and ¶ [0047], ll. 1-4 and 10-14).
However, Ranjan, in view of Miller and Sibbach, does not teach the fuel/working fluid heat exchanger is mounted to the core case.
Prociw teaches (Fig. 1) a similar core engine (¶ [0017], l. 11) that is supported within a core case (102), and a heat exchanger (104) for heating fuel (150), and further teaches:
the heat exchanger (104) is mounted to the core case (102) – (via fitting 142, also it is obvious to provide support structures to mount heat exchanger 104 to core case 102).
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 Ranjan, in view of Miller and Sibbach, by relocating the fuel/working fluid heat exchanger to be mounted to the core case, in order to have the fuel/working fluid heat exchanger be close to fuel manifolds, thereby reducing weight, cost, and risk, as taught by Prociw (¶ [0025], ll. 10-11).
Regarding claim 3, Ranjan, in view of Miller, Sibbach, and Prociw, teaches the invention as claimed and as discussed above for claim 1, and Ranjan further teaches (Fig. 2) the closed circuit (70 → 92 → 88 → 72 → 92 → 84 → 70) communicates the flow of the working fluid (sCO2) from the bottoming cycle (80) to the primary heat exchanger (88) mounted within the turbine exhaust case (as discussed above and in ¶ [0036], ll. 4-6).
Regarding claim 23, Ranjan, in view of Miller, Sibbach, and Prociw as discussed so far, teaches the invention as claimed and as discussed above for claim 1, except for both the bottoming compressor section and the bottoming turbine section are mounted to the core case.
As discussed in the rejection of claim 1, Sibbach provided a teaching for mounting the bottoming turbine section (steam turbine 110) to the core case (18), but not for mounting the bottoming compressor section to the core case.
It is noted that Sibbach’s bottoming cycle (100) includes the bottoming compressor section (108), and Sibbach’s Fig. 1 shows the bottoming cycle (100) being mounted to the core case (18) through direct contact with the right end of the core case (18) and providing structural support to the downstream section (54) of the nacelle (50).
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 Ranjan, in view of Miller, Sibbach, and Prociw as discussed so far, by additionally relocating the bottoming compressor section to be mounted to the core case, for the same reasons as discussed in the rejection of claim 1 and to also provide structural support to the downstream section of the nacelle, as taught by Sibbach (Fig. 1).
Claims 13, 18, and 21-22 are rejected under 35 U.S.C. 103 as being unpatentable over Ranjan (US 2023/0075009 A1), in view of Sibbach (2025/0084789 A1) and Prociw (US 2021/0156310 A1).
Regarding claim 13, Ranjan teaches (Figs. 1-2) a power generating system for an aircraft (10 – Fig. 1) comprising:
a core engine (32) comprising a compressor (44 – Fig. 2), a combustor (48 – Fig. 2), and a turbine (46 – Fig. 2) where a cryogenic fuel (62) is mixed with compressed air (“Air” – Fig. 2) from the compressor (44) in the combustor (48) and ignited to generate an exhaust gas flow that is expanded through the turbine (46) to generate shaft power (¶ [0033], l. 5), wherein the core engine (32) is supported within a core case (inherent in a core engine) that is attached to a turbine exhaust case (inherent due to the presence of exhaust from turbine 46 – see ¶ [0038], l. 5) and is mounted to a wing (14 – Fig. 1) of the aircraft (10) – (as shown in Fig. 1);
a bottoming cycle (80 – Fig. 2) where a working fluid (supercritical CO2) is circulated within a closed circuit (as shown by the arrows starting at 70 → 92 → 88 → 72 → 92 → 84, and finally back to 70) comprising a bottoming compressor section (70 – Fig. 2) and a bottoming turbine section (72 – Fig. 2), wherein the working fluid (sCO2) is compressed in the bottoming compressor section (70) and expanded through the bottoming turbine section (72) to generate shaft power (as evidenced by generator 74);
a primary heat exchanger (88 – Fig. 1) providing communication of thermal energy from the exhaust gas flow (from 46) to the working fluid (sCO2) of the bottoming cycle (80), wherein the primary heat exchanger (88) is mounted within the turbine exhaust case (¶ [0036], ll. 4-6 teaches “Turbine 46 includes…an outlet portion 112 coupled to heat exchanger system 88”. Therefore, heat exchanger 88 is also coupled to the turbine exhaust case);
a fuel system comprising a cryogenic fuel storage tank (64) and a fuel flow path (path of 64 → 68 → 116 → 84 → 120 → 54) for routing the cryogenic fuel (62) to the combustor (48) of the core engine (32); and
a fuel/working fluid heat exchanger (84 – Fig. 2) providing thermal communication between the cryogenic fuel (62) and the working fluid (sCO2) to cool a flow of the working fluid (sCO2) from the bottoming turbine section (72) to the bottoming compressor section (70), the closed circuit (70 → 92 → 88 → 72 → 92 → 84 → 70) communicates the flow of the working fluid (sCO2) from the bottoming cycle (80) to the primary heat exchanger (88) mounted within the turbine exhaust case (as discussed above and in ¶ [0036], ll. 4-6).
However, Ranjan does not teach at least one of the bottoming compressor section and the bottoming turbine section are mounted to the core case.
Sibbach teaches (Fig. 2) a similar aircraft propulsion system comprising:
a core engine (within 18) comprising a compressor (22 and 24), a combustor (26), and a turbine (28 and 30) where a cryogenic fuel (from 82) is mixed with compressed air (from 24) from the compressor (22 and 24) in the combustor (26) and ignited to generate an exhaust gas flow (66), wherein the core engine (within 18) is supported within a core case (18);
a bottoming cycle (100) where a working fluid (water/steam) is circulated within a closed circuit comprising a bottoming compressor section (108) and a bottoming turbine section (110), wherein the working fluid is compressed in the bottoming compressor section (108) and expanded through the bottoming turbine section (110) to generate shaft power (¶ [0041], ll. 14-16); and further teaches:
at least one of the bottoming compressor section (108) and the bottoming turbine section (110) are mounted to the core case (18) – (Fig. 2 shows steam turbine 110 located next to LPT 30 and further coupled to LP shaft 36. In addition, Fig. 1 shows steam system 100, which includes steam turbine 110, being mounted to core case 18 through direct contact with the right end of core case 18. Therefore, at the very least, steam turbine 110 is mounted to core case 18).
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 Ranjan by relocating at least one of the bottoming compressor section and the bottoming turbine section to be mounted to the core case, in order to extract additional work by the bottoming cycle to contribute approximately 25% of the power to the core engine shaft, thus enabling a size of the core engine to be reduced and increasing efficiency of the core engine, as taught by Sibbach (¶ [0043], ll. 4-6 and ¶ [0047], ll. 1-4 and 10-14).
However, Ranjan, in view of Sibbach, does not teach the fuel/working fluid heat exchanger is mounted to the core case.
Prociw teaches (Fig. 1) a similar core engine (¶ [0017], l. 11) that is supported within a core case (102), and a heat exchanger (104) for heating fuel (150), and further teaches:
the heat exchanger (104) is mounted to the core case (102) – (via fitting 142, also it is obvious to provide support structures to mount heat exchanger 104 to core case 102).
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 Ranjan, in view of Sibbach, by relocating the fuel/working fluid heat exchanger to be mounted to the core case, in order to have the fuel/working fluid heat exchanger be close to fuel manifolds, thereby reducing weight, cost, and risk, as taught by Prociw (¶ [0025], ll. 10-11).
Regarding claim 18, Ranjan teaches (Figs. 1-2) a method of assembling an aircraft propulsion system comprising:
assembling a primary energy conversion device (32) that uses a cryogenic fuel (62) and air (“Air” – Fig. 2) to generate power and thermal energy to a first structure (wing 14 – Fig. 1) of an aircraft (10 – Fig. 1), wherein the primary energy conversion device (32) comprises a core engine (32) that uses the cryogenic a fuel (62) mixed with compressed air (from 44 – Fig. 2) and ignited to generate an exhaust gas flow that is expanded through a turbine section (46 – Fig. 2) and assembling the primary energy convertion devices comprises supporting the core engine (32) within a core case (inherent in a core engine) attached to a turbine exhaust case (inherent due to the presence of exhaust from turbine 46 – see ¶ [0038], l. 5);
mounting at least a portion of a bottoming cycle (80 – Fig. 2), wherein the bottoming cycle (80) includes a working fluid (supercritical CO2) that is circulated within a closed circuit (as shown by the arrows starting at 70 → 92 → 88 → 72 → 92 → 84, and finally back to 70) comprising a bottoming compressor section (70 – Fig. 2) and a bottoming turbine section (72 – Fig. 2), wherein the working fluid (sCO2) is compressed in the bottoming compressor section (70) and expanded through the bottoming turbine section (72) to generate shaft power (as evidenced by generator 74);
mounting a primary heat exchanger (88 – Fig. 2) within the turbine exhaust case (¶ [0036], ll. 4-6 teaches “Turbine 46 includes…an outlet portion 112 coupled to heat exchanger system 88”. Therefore, heat exchanger 88 is also coupled to the turbine exhaust case) proximate to the primary energy conversion device (32) within the first structure (14), wherein the primary heat exchanger (88) provides communication of thermal energy from the primary energy conversion device (32) to the working fluid (sCO2) of the bottoming cycle (80), wherein the closed circuit (70 → 92 → 88 → 72 → 92 → 84 → 70) extends between the first structure (14) and the second structure (18) – (inherent in order for the system of Fig. 2 to work);
assembling a fuel system comprising a cryogenic fuel storage tank (64) and a fuel flow path (path of 64 → 68 → 116 → 84 → 120 → 54) for routing the cryogenic fuel (62) to the primary energy conversion device (32); and
mounting a fuel/working fluid heat exchanger (84 – Fig. 2) to provide thermal communication between the cryogenic fuel (62) and the working fluid (sCO2) to cool a flow of the working fluid (sCO2) from the bottoming turbine section (72) to the bottoming compressor section (70).
However, Ranjan does not teach mounting at least the portion of the bottoming cycle to the core case.
Sibbach teaches (Fig. 2) a similar aircraft propulsion system comprising:
a core engine (within 18) comprising a compressor (22 and 24), a combustor (26), and a turbine (28 and 30) where a cryogenic fuel (from 82) is mixed with compressed air (from 24) from the compressor (22 and 24) in the combustor (26) and ignited to generate an exhaust gas flow (66), wherein the core engine (within 18) is supported within a core case (18);
a bottoming cycle (100) where a working fluid (water/steam) is circulated within a closed circuit comprising a bottoming compressor section (108) and a bottoming turbine section (110), wherein the working fluid is compressed in the bottoming compressor section (108) and expanded through the bottoming turbine section (110) to generate shaft power (¶ [0041], ll. 14-16); and further teaches:
mounting at least a portion of the bottoming cycle (100) to the core case (18) – (Fig. 2 shows steam turbine 110 located next to LPT 30 and further coupled to LP shaft 36. In addition, Fig. 1 shows steam system 100, which includes steam turbine 110, being mounted to core case 18 through direct contact with the right end of core case 18. Therefore, at the very least, steam turbine 110 is mounted to core case 18).
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 Ranjan by relocating at least a portion of the bottoming cycle to be mounted to the core case, in order to extract additional work by the bottoming cycle to contribute approximately 25% of the power to the core engine shaft, thus enabling a size of the core engine to be reduced and increasing efficiency of the core engine, as taught by Sibbach (¶ [0043], ll. 4-6 and ¶ [0047], ll. 1-4 and 10-14).
However, Ranjan, in view of Sibbach as discussed so far, does not teach at least the bottoming compressor section is mounted to the core case.
It is noted that Sibbach’s bottoming cycle (100) includes the bottoming compressor section (108), and Sibbach’s Fig. 1 shows the bottoming cycle (100) being mounted to the core case (18) through direct contact with the right end of the core case (18) and providing structural support to the downstream section (54) of the nacelle (50).
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 Ranjan, in view of Sibbach as discussed so far, by additionally relocating at least the bottoming compressor section to be mounted to the core case, for the same reasons as discussed above and to also provide structural support to the downstream section of the nacelle, as taught by Sibbach (Fig. 1).
However, Ranjan, in view of Sibbach, does not teach mounting the fuel/working fluid heat exchanger to the core case.
Prociw teaches (Fig. 1) a similar core engine (¶ [0017], l. 11) that is supported within a core case (102), and a heat exchanger (104) for heating fuel (150), and further teaches:
mounting the heat exchanger (104) to the core case (102) – (via fitting 142, also it is obvious to provide support structures to mount heat exchanger 104 to core case 102).
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 Ranjan, in view of Sibbach, by relocating the fuel/working fluid heat exchanger such that it is mounted to the core case, in order to have the fuel/working fluid heat exchanger be close to fuel manifolds, thereby reducing weight, cost, and risk, as taught by Prociw (¶ [0025], ll. 10-11).
Regarding claim 21, Ranjan, in view of Sibbach and Prociw, teaches the invention as claimed and as discussed above for claim 18, and the combination further teaches mounting the bottoming turbine section (Ranjan, 72) to the core case (Ranjan, 32) – (via Sibbach’s teaching as discussed in the rejection of claim 18).
Regarding claim 22, Ranjan, in view of Sibbach and Prociw as discussed so far, teaches the invention as claimed and as discussed above for claim 13, except for both the bottoming compressor section and the bottoming turbine section are mounted to the core case.
As discussed in the rejection of claim 13, Sibbach provided a teaching for mounting the bottoming turbine section (steam turbine 110) to the core case (18), but not for mounting the bottoming compressor section to the core case.
It is noted that Sibbach’s bottoming cycle (100) includes the bottoming compressor section (108), and Sibbach’s Fig. 1 shows the bottoming cycle (100) being mounted to the core case (18) through direct contact with the right end of the core case (18) and providing structural support to the downstream section (54) of the nacelle (50).
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 Ranjan, in view of Sibbach and Prociw as discussed so far, by additionally relocating the bottoming compressor section to be mounted to the core case, for the same reasons as discussed in the rejection of claim 13 and to also provide structural support to the downstream section of the nacelle, as taught by Sibbach (Fig. 1).
Response to Arguments
Applicant’s arguments regarding the new limitations in claims 1, 13, 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.
Regarding Applicant’s argument against the drawing objections and the 35 U.S.C. 112(a) rejections, Applicant argues “This feature is schematically shown in Figure 3 and described in at least paragraph 44 of the specification as filed”. Examiner respectfully disagrees because Figure 3 and paragraph 44 do not sufficiently show or provide support for “mounted to the core case”. Figure 3 merely provides a label “CORE CASE” with the elements of the bottoming cycle to the right of said label. Paragraph 44 merely recites “located at the core case mount”, which is not the same as “mounted to the core case”. See the 35 U.S.C. 112(a) section above for further details.
Conclusion
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/HENRY NG/Examiner, Art Unit 3741 /DEVON C KRAMER/Supervisory Patent Examiner, Art Unit 3741
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