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 application has been filed as a continuation of application 18/308435 now patent 12234778.
Election/Restrictions
Applicant’s election without traverse of Invention I claims 1-10 and Species D drawn to Fig. 5B and Species F drawn to Fig. 7 in the reply filed on 02/27/2026 is acknowledged.
Claims 11-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention and species, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 02/27/2026.
Claims 1-10 are currently being examined.
Claim Objections
Claim 10 is objected to because of the following informalities: “the second section” should read as – a [[the]] second section --. Appropriate correction is required.
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.
Claim(s) 1-6 and 8-10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Brady 20210010429 in view of Joshi et al. 20180347475.
Regarding independent claim 1, Brady teaches, with reference to Figs. 1 and 2, a method comprising:
determining a first flow rate of fuel (fuel metering valve FMV 106 allows fuel to flow to combustor 30 in gas turbine engine 10 at a flow rate of fuel determined by a throttle setting communicated to FMV 106 using controller 140 which includes a flight management computer per [0041] -[0042], [0047]) in a first section (section of 112 from inlet of 106 to 30) of a fuel pipe (fuel pipe assembly including 112 and 114); the first flow rate satisfying a first flow rate threshold (first flow rate of fuel satisfying desired fuel flow rate, i.e., first flow rate threshold, for a throttle setting is when FMV 106 is not malfunctioning and is properly positioned to obtain the desired fuel line pressure differential; upstream and downstream pressure sensors 130 and 132 provide output signals indicative of the pressure drop across FMV 106 which provides a fuel line differential per [0036] and [0050]).
Brady is silent regarding:
in response to the first flow rate satisfying the first flow rate threshold:
determining whether the first flow rate satisfies a second flow rate threshold;
in response to the first flow rate not satisfying the second flow rate threshold, adjusting the first flow rate;
in response to the first flow rate satisfying the second flow rate threshold:
determining whether the first flow rate satisfies a third flow rate threshold;
in response to the first flow rate satisfying the third flow rate threshold, maintaining the first flow rate; and
in response to the first flow rate not satisfying the third flow rate threshold, adjusting the first flow rate.
Joshi teaches, with reference to Figs. 1-3, 5 and 6 a fuel pipe for a gas turbine engine 10 with a controller 610,620 including a flight control system per [0018] and [0034], which produces a fuel flow schedule which when implemented produces an acceleration schedule for gas turbine engine 10 per [0020]. Joshi teaches:
determining whether a first flow rate (flow rate in fuel flow schedule 300 in Fig. 3) satisfies a second flow rate threshold (after steps 202 and 204 of determining if an acceleration command has been given in method 200 for reducing an acoustic signature of engine 10 in Fig. 2, fuel flow schedule 300 in Fig. 3 determines whether first flow rate is at level 302, i.e., whether first flow rate satisfies a second flow rate threshold 302);
in response to the first flow rate not satisfying the second flow rate threshold, adjusting the first flow rate (in response to first flow rate being less than level 302, i.e., not satisfying second flow rate threshold 302, first flow rate is increased, i.e., adjusted, as shown in Primary Acceleration period in Fig. 3);
in response to the first flow rate satisfying the second flow rate threshold (in Fig. 3, with first flow rate at second flow rate threshold 302, i.e., first flow rate satisfies second flow rate threshold 302):
determining whether the first flow rate satisfies a third flow rate threshold (fuel flow schedule 300 determines whether first flow rate is at level 312 in Fig. 3, i.e., satisfies a third flow rate threshold 312);
in response to the first flow rate satisfying the third flow rate threshold, maintaining the first flow rate (in Fuel Reduction period in Fig. 3, first flow rate is maintained at 312 for a portion of time); and
in response to the first flow rate not satisfying the third flow rate threshold, adjusting the first flow rate (fuel flow schedule 300 adjusts first flow rate by decreasing first flow rate from 302 to 312 during Fuel Reduction period).
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the method of Brady to include in response to the first flow rate satisfying the first flow rate threshold: determining whether the first flow rate satisfies a second flow rate threshold; in response to the first flow rate not satisfying the second flow rate threshold, adjusting the first flow rate; in response to the first flow rate satisfying the second flow rate threshold: determining whether the first flow rate satisfies a third flow rate threshold; in response to the first flow rate satisfying the third flow rate threshold, maintaining the first flow rate; and in response to the first flow rate not satisfying the third flow rate threshold, adjusting the first flow rate as taught by Joshi to reduce the acoustic signature of the gas turbine engine (Joshi [0005]).
Regarding claim 2, Brady in view of Joshi teaches all that is claimed above and Brady further teaches in response to the first flow rate not satisfying the first flow rate threshold (in response to FMV 106 malfunctioning and first flow rate not satisfying first flow rate threshold of desired fuel flow rate based on throttle setting), further including:
determining a second flow rate of the fuel (per [0050] control of the bypass pressure differential allows the thrust control malfunction accommodation TCMA to modulate the fuel flow using the BV 108 and BPV 110 in a situation in which the FMV 106 is stuck open or otherwise malfunctioning; fuel supply system 100 can then provide, in a controlled manned, the required fuel for the engine 10 to obtain the fuel it needs to maintain proper function even in the event that the FMV 106 has malfunctioned; this can be accomplished using the BPV 110 to control of the bypass pressure differential measured across the BV 108; per [0049] BPV 110 can be used to maintain the predetermined bypass pressure differential across the BV 108 with the predetermined bypass pressure differential determined by the throttle setting, the fuel line pressure differential, or an absolute value; first and second pressure sensors 136, 138 on the upstream and downstream sides of BV 108 can provide a control signal that is communicated to the controllable servo 134 of BPV 110 and BPV maintains the predetermined bypass pressure differential by allowing fuel to flow through the BPV 110 and return to the inlet 120 of the fuel pump 104), in a second section (214) of the fuel pipe,
but Brady is silent on determining whether the second flow rate satisfies the second flow rate threshold; and
in response to the second flow rate not satisfying the second flow rate threshold, adjusting the second flow rate.
However, since the second flow rate allows the fuel supply system to provide in a controlled manner the required fuel for engine 10 to obtain fuel for proper function provided when the FMV 106 is malfunctioning, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the method of Brady in view of Joshi to include determining whether the second flow rate satisfies the second flow rate threshold; and in response to the second flow rate not satisfying the second flow rate threshold, adjusting the second flow rate as part of the fuel flow schedule as taught by Joshi to reduce the acoustic signature of the gas turbine engine.
Regarding claim 3, Brady in view of Joshi teaches all that is claimed above but is silent as discussed so far regarding
in response to the second flow rate satisfying the second flow rate threshold, determining whether the second flow rate satisfies the third flow rate threshold;
in response to the second flow rate satisfying the third flow rate threshold, maintaining the second flow rate; and
in response to the second flow rate not satisfying the third flow rate threshold, adjusting the second flow rate.
However, since the second flow rate allows the fuel supply system to provide in a controlled manner the required fuel for engine 10 to obtain fuel for proper function provided when the FMV 106 is malfunctioning, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify the method of Brady in view of Joshi to include in response to the second flow rate satisfying the second flow rate threshold, determining whether the second flow rate satisfies the third flow rate threshold; in response to the second flow rate satisfying the third flow rate threshold, maintaining the second flow rate; and in response to the second flow rate not satisfying the third flow rate threshold, adjusting the second flow rate as part of the fuel flow schedule as taught by Joshi to reduce the acoustic signature of the gas turbine engine.
Regarding claim 4, Brady in view of Joshi teaches all that is claimed above and teaches the first flow rate and the second flow rate are determined differently (first flow rate is determined across FMV 106 and while second flow rate is determined across BV 108 and uses pressure sensors 136 and 138).
Regarding claim 5, Brady in view of Joshi teaches all that is claimed above and Brady teaches the first flow rate is determined using a first pressure in the second section (a first pressure sensed by either of 136 or 138 in section 114 since first flow rate to the combustor 30 flows across FMV 106 but BV 108 can control the flow of fuel from the fuel line 112 through section 114, which in turn effects the pressure difference across the FMV 106 per [0033] and control of the bypass pressure differential across BV 108 allows the TCMA to modulate the fuel flow using the BV 108 and BPV 110 in a situation in which the FMV 106 is stuck open or otherwise malfunctioning) and a second pressure in the first section (a second pressure sensed by 132 on downstream side of FMV 106).
Regarding claim 6, Brady in view of Joshi teaches all that is claimed above and Brady teaches the second flow rate is determined using the first pressure (pressure sensed by 136) and a third pressure (pressure sensed by 138) in the second section (114).
Regarding claim 8, Brady in view of Joshi teaches all that is claimed above and teaches an engine operatively coupled to the fuel pipe (engine 10 in Fig. 1 of Brady) and Joshi further teaches at least one of the second flow rate threshold or the third flow rate threshold are based on a target power output of an engine operatively coupled to the fuel pipe (per [0021] an acceleration command for the engine 10 can be a digital signal sent by a flight control system and/or a cockpit control, for example a throttle lever and per [0023] the received acceleration command indicates that the requested acceleration is from a ground idle state to a ground taxi state such that the second flow rate threshold 302 is based on a target power output of the engine to attain ground taxi state).
Regarding claim 9, Brady in view of Joshi teaches all that is claimed above and Joshi further teaches in Fig. 3 adjusting the first flow rate in response to the first flow rate not satisfying the third flow rate threshold includes increasing the first flow rate (in Fig. 3 as part of fuel flow schedule 300, when first flow rate is no longer maintained at third flow rate threshold 312, i.e., no longer satisfies 312, first flow rate is increased from end of Fuel Reduction period to Secondary Acceleration), and wherein adjusting the first flow rate in response to the first flow rate not satisfying the second flow rate threshold includes decreasing the first flow rate (in Fig. 3 as part of fuel flow schedule 300, at end of Primary Acceleration period when first flow rate is no longer at second flow rate threshold 302, i.e., no longer satisfies 302, first flow rate is decreased during end of Primary Acceleration period and beginning of Fuel Reduction period).
Regarding claim 10, Brady in view of Joshi teaches all that is claimed above and Brady further teaches the first section of the fuel pipe corresponds to an inner flow metering section (first section of 112 from inlet of 106 to 30 is an inner flow metering section with respect to proximity to combustor 30 in Fig. 2 being inner), and wherein the second section of the fuel pipe corresponds to an outer flow metering section (second section 214 is an outer flow metering section with respect to 214 being further outwardly away from combustor 30 in Fig. 2).
Claim(s) 7 is/are rejected under 35 U.S.C. 103 as being unpatentable over Brady 20210010429 in view of Joshi et al. 20180347475 as applied to claim 1 above, and further in view of Szepek et al. 20110130941.
Regarding claim 7, Brady in view of Joshi teaches all that is claimed above but is silent regarding the first flow rate threshold corresponds to a fuel flow rate at which fuel flow through the first section of the fuel pipe becomes choked.
Szepek teaches per [0003] conventional turbine systems typically operate in a "choked" state because downstream pressure changes due to changes in turbine cycle conditions, or changes in combustor pressure for example, can cause corresponding fuel rate spikes or oscillations. This method of operation is desirable for disturbance rejection so that transients in the upstream (fuel source) pressure and downstream (combustor) pressure cannot interrupt the steady flow of fuel to the turbine. Conventional gas turbine fuel control systems require a relatively high pressure gas fuel source so that the flow control valves may operate in the choked state per [0004].
It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to include in the invention of Brady in view of Joshi the first flow rate threshold corresponds to a fuel flow rate at which fuel flow through the first section of the fuel pipe becomes choked as taught by Szepek so that the flow control valve may operate in the choked state so that transients in the upstream (fuel source) pressure and downstream (combustor) pressure cannot interrupt the steady flow of fuel to the gas turbine engine.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALYSON JOAN HARRINGTON whose telephone number is (571)272-2359. The examiner can normally be reached M-F 9 am - 5 pm EST.
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/A.J.H./Examiner, Art Unit 3741
/LORNE E MEADE/Primary Examiner, Art Unit 3741
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