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 .
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
This is a second Non Final Rejection.
Claim Rejections - 35 USC § 112
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 1-12 and 22 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 22, the recitations of the “ejector nozzle disposed within the inlet conduit“ and “the ejector nozzle…spaced from the inlet conduit” contradict each other and renders the scopes of the claims ambiguous. The recitations are interpreted to mean the ejector nozzle is spaced from a wall of the inlet conduit, while still being disposed within the conduit.
Dependent claims 2-12 are also rejected for depending on at least one rejected claim above.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim 21 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cocks 20210079848 in view of Alecu 10443503.
Regarding claim 21, Cocks teaches a fuel system (62) for a gas turbine engine (20), the fuel system comprising:
a fuel tank (66);
a first fuel pump (68) including a fuel inlet (to receive fuel from 66) and a fuel outlet (to send fuel downstream to 74, 70, 76), the first fuel pump is connected in fluid communication with the fuel tank by an inlet conduit (between 66 and 68) at the fuel inlet (Fig 1), and the first fuel pump is connected in fluid communication with an outlet conduit (between 68 and 70) at the fuel outlet (Fig 1);
a second fuel pump (70) connected in fluid communication with the first fuel pump by the outlet conduit (Fig 1);
a fuel injector assembly (required at 56 to inject the fuel into 56) connected in fluid communication with and downstream of the second fuel pump (Figs 1-2),
the fuel tank, the inlet conduit, the first fuel pump, the outlet conduit, the second fuel pump, and the fuel injector assembly forming a first fuel flow path of the fuel system from the fuel tank to the fuel injector assembly (Fig 1);
an inlet ejector (86) including an ejector nozzle (required structure for and ejector pump) disposed in the fuel tank (Fig 1),
the ejector nozzle including a nozzle fuel outlet (required for ejector pump to function) at the first fuel flow path (Fig 1); and
an ejector control valve (74) connected in fluid communication between the ejector nozzle and the outlet conduit (Fig 1),
the inlet ejector and the ejector control valve forming a second fuel flow path from the first fuel flow path at the outlet conduit to the first fuel flow path at the tank (Fig 1).
Cocks does not teach the ejector pump is disposed within the inlet conduit such that the second fuel flow path is formed from first fuel flow path at the outlet conduit to the first fuel flow path at the inlet conduit.
However, Alecu teaches the substitutional equivalence of placing an ejector pump in the fuel tank or just downstream of the fuel tank for boosting fuel flow to the first low pressure pump (col.2 ll.14-26), including alternative arrangements such as splitting a return fuel flow (26) between the fuel tank and the downstream ejector pump and/or splitting the output fuel from the ejector pump to provide a return flow (26c) to the tank (Fig 2; col.3 ll.7-15). Note the ejector pump depicted in Fig 2 uses a symbol representing conventional ejector pump.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the ejector pump arrangement relative to the fuel tank of Cocks to have the ejector pump downstream of the fuel tank, in the inlet conduit of the first fuel pump, as taught by any of the various embodiments of Alecu, because Alecu teaches the substitutional equivalence of the various arrangements for managing excess fuel flow while ensuring fuel flow from the tank to the first low pressure pump (col.2 ll.14-26, col.3 ll.7-15; Fig 2).
Claims 1-3, 7, 12 and 22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cocks 20210079848 in view of Alecu 10443503 and Wikipedia (entry for vacuum ejector, archived by Wayback Machine on 15 July 2022, https://web.archive.org/web/20220715154521/https://en.wikipedia.org/wiki/Vacuum_ejector).
Regarding Claim 1, Cocks teaches a fuel system (62) for a gas turbine engine (20), the fuel system comprising:
a fuel tank (66);
a first fuel pump (68) including a fuel inlet (to receive fuel from 66) and a fuel outlet (to send fuel downstream to 74, 70, 76), the first fuel pump is connected in fluid communication with the fuel tank by an inlet conduit (between 66 and 68) at the fuel inlet (Fig 1), and the first fuel pump is connected in fluid communication with an outlet conduit (between 68 and 70) at the fuel outlet (Fig 1);
an inlet ejector (86) including an ejector nozzle (required structure for and ejector pump) disposed in the fuel tank (Fig 1); and
an ejector control valve (74 or 76) connected in fluid communication between the ejector nozzle and the outlet conduit (Fig 1), and the ejector control valve is selectively positionable in an open position or a closed position to control a flow of a fuel from the outlet conduit through the ejector nozzle to the inlet conduit ([0042]),
the ejector nozzle including a nozzle fuel inlet and a nozzle fuel outlet (required for ejector pump to function), the nozzle fuel inlet connected in fluid communication with the ejector control valve (to receive fuel therefrom, Fig 1), the nozzle fuel outlet disposed within the tank (Fig 1), the ejector nozzle spaced from the fuel tank (interpreted under 112b to mean that a space exists between at least one wall of the fuel tank and the ejector nozzle in order for the ejector nozzle to function, by definition) to allow fuel from the fuel tank to flow in the fuel tank, around the ejector nozzle, and through the inlet conduit to the first fuel pump.
Cocks does not teach the ejector pump is disposed within the inlet conduit such that the nozzle fuel outlet is disposed in the inlet conduit, and the ejector nozzle is spaced from the inlet conduit (interpreted under 112b to mean that a space exists between at least one wall of the inlet conduit and the ejector nozzle in order for the ejector nozzle to function, as required by ejector nozzles, by definition) to allow fuel from the fuel tank to flow through the inlet conduit and around the ejector nozzle.
However, Alecu teaches the substitutional equivalence of placing an ejector pump in the fuel tank or just downstream of the fuel tank for boosting fuel flow to the first low pressure pump (col.2 ll.14-26), including alternative arrangements such as splitting a return fuel flow (26) between the fuel tank and the downstream ejector pump and/or splitting the output fuel from the ejector pump to provide a return flow (26c) to the tank (Fig 2; col.3 ll.7-15). Note the ejector pump depicted in Fig 2 uses a symbol representing conventional ejector pump.
And Wikipedia teaches the conventional ejector pump requiring a nozzle inlet (see figure below), a nozzle outlet (see figure below), the nozzle outlet disposed within a conduit (bounding the shaded fluid passageway in the figure below) of the fluid being pumped (figure below) while being spaced from the conduit (figure below) to allow the fluid being pumped to flow through the conduit and around the ejector nozzle to a downstream location (“Outlet” in the figure below).
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the ejector pump arrangement relative to the fuel tank of Cocks to have the ejector pump downstream of the fuel tank, in the inlet conduit of the first fuel pump, as taught by any of the various embodiments of Alecu, because Alecu teaches the substitutional equivalence of the various arrangements for managing excess fuel flow while ensuring fuel flow from the tank to the first low pressure pump (col.2 ll.14-26, col.3 ll.7-15; Fig 2). And it would have been obvious that the ejector pump of Cocks in view of Alecu was characterized by the claimed structures of the ejector pump, because Wikipedia teaches the structures are conventional for ejector pumps (Fig 2).
Regarding claim 2, Cocks in view of Alecu and Wikipedia teaches all the limitations of the claimed invention as discussed above. Cocks further teaches a second fuel pump (70), and the first fuel pump is connected in fluid communication with the second fuel pump by the outlet conduit (Fig 1).
Regarding claim 3, Cocks in view of Alecu and Wikipedia teaches all the limitations of the claimed invention as discussed above. Cocks further teaches a fuel injector assembly (to inject fuel into 56; [0034, 38]; including fuel line(s) between 82 and 56), the fuel injector assembly is connected in fluid communication between the second fuel pump and a combustor (56) of the gas turbine engine (Fig 1), and the fuel injector assembly is configured to direct the fuel into a combustion chamber (of 56; Fig 1) of the combustor (Fig 1; [0034, 38]).
Regarding claim 7, Cocks in view of Alecu and Wikipedia teaches all the limitations of the claimed invention as discussed above. Cocks further teaches a controller (92) connected in signal communication with the ejector control valve (Fig 2) to control the ejector control valve in the open position or the closed position based on one or more operational parameters of the gas turbine engine ([0044, 48]).
It may not be clear from Cocks (in view of Alecu and Wikipedia) whether the controller is a computer to automate the controlling (including a processor in communication with a non-transitory memory storing instructions, which instructions when executed by the processor, cause the processor to perform the controlling function).
However, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide a general purpose computer to automate the controlling by the controller of Cocks (in view of Alecu and Wikipedia) because MPEP2144.04(III) provides that broadly providing an automatic or mechanical means (i.e. generic computer) to replace a manual activity (of controlling valves with a controller) which accomplished the same result (same control achieved whether it is automated or manual) is not sufficient to distinguish over the prior art.
Regarding claim 12, Cocks in view of Alecu and Wikipedia teaches all the limitations of the claimed invention as discussed above. Cocks further teaches the ejector control valve is positionable in a plurality of intermediate positions between the open position and the closed position (proportional valve [0048]), and the controller controls the ejector control valve in the open position, the closed position, or one of the plurality of intermediate positions based on one or more operational parameters of the gas turbine engine to modulate a rate of the flow of fuel from the outlet conduit through the ejector nozzle to the inlet conduit ([0044, 48]).
Again it may not be clear from Cocks (in view of Alecu and Wikipedia) whether the controller is a computer to automate the controlling (including the processor and instructions for execution by the processor).
However, as discussed above, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide a general purpose computer to automate the controlling by the controller of Cocks (in view of Alecu and Wikipedia) because MPEP2144.04(III) provides that broadly providing an automatic or mechanical means (i.e. generic computer) to replace a manual activity (of controlling valves with a controller) which accomplished the same result (same control achieved whether it is automated or manual) is not sufficient to distinguish over the prior art.
Regarding claim 22, Cocks in view of Alecu teaches all the limitations of the claimed invention as discussed above. Cocks further teaches fuel flowing from the fuel tank through the inlet conduit to the first fuel pump (Fig 1).
Cocks in view of Alecu does not explicitly teach the ejector nozzle spaced from the inlet conduit (interpreted under 112b to mean that a space exists between at least one wall of the inlet conduit and the ejector nozzle in order for the ejector nozzle to function, by definition) to allow fuel from the fuel tank to flow around the ejector nozzle.
However, Wikipedia teaches the conventional ejector pump requiring a nozzle inlet (see figure below), a nozzle outlet (see figure below), the nozzle outlet disposed within a conduit (bounding the shaded fluid passageway in the figure below) of the fluid being pumped (figure below) while being spaced from the conduit (figure below) to allow the fluid being pumped to flow through the conduit and around the ejector nozzle to a downstream location (“Outlet” in the figure below).
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the nondescript ejector pump of Cocks in view of Alecu was characterized by the claimed structures of the ejector pump, because Wikipedia teaches the structures are conventional for ejector pumps (Fig 2).
Claim 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cocks in view of Alecu and Wikipedia, and further in view of Morioka 10358980.
Regarding claim 4, Cocks in view of Alecu and Wikipedia teaches all the limitations of the claimed invention as discussed above. Cocks further teaches the first fuel pump is a constant volume mechanical gear pumps (positive displacement pump) ([0043]).
Cocks in view of Alecu and Wikipedia does not teach the first fuel pump is a non-positive displacement pump.
However, Morioka teaches using a centrifugal pump (non-positive displacement pump) as a first low pressure pump and a gear pump as a second high pressure pump in a dual pump fuel system of an aircraft engine (Title; Fig 2).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the first low pressure positive displacement pump of Cocks in view of Alecu and Wikipedia to be a non-positive displacement pump as taught by Morioka because it has been held that combining or simple substitution of prior art elements according to known methods to yield predictable results renders the limitation obvious (see MPEP 2141 (III)). In this case, both the first low pressure positive displacement pump of Cocks and the first low pressure non-positive displacement pump of Morioka serve the same purpose of providing low level pressure increase of fuel from a fuel source to a high pressure positive displacement pump that boosts fuel pressure the high pressure level required for fuel injection in an aircraft gas turbine engine, and thus, replacing the first low pressure pump of Cocks with the first low pressure pump of Morioka would have yielded the predictable results of a sufficiently operable dual pump fuel system for a gas turbine aircraft engine.
Claim 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cocks in view of Alecu and Wikipedia, and further in view of FAA rule 14 CFR 25.975 (last amendment published 24 June 2016, retrieved from https://www.ecfr.gov/current/title-14/chapter-I/subchapter-C/part-25/subpart-E/subject-group-ECFRa93e11eb94bb0c1/section-25.975).
Regarding claim 5, Cocks in view of Alecu and Wikipedia teaches all the limitations of the claimed invention as discussed above. Cocks further teaches the gas turbine engine being an aircraft engine (Fig 1; [0035]).
Cocks in view of Alecu and Wikipedia does not teach the fuel tank includes one or more vents.
However, the FAA 14 CFR 25.975 requires fuel tanks for aircraft to include vents that are effective under normal flight conditions and fulfill specific vent requirements for safe operation.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the fuel tank of Cocks in view of Alecu and Wikipedia to include a fuel tank vent as required by the FAA in order to comply with FAA aircraft regulations.
Claims 8-11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cocks in view of Alecu and Wikipedia, and further in view of Mahoney 20030192300.
Regarding claim 8, Cocks in view of Alecu and Wikipedia teaches all the limitations of the claimed invention as discussed above (including the controller being a computer as discussed in claim 7 above). Cocks further teaches the controller controlling the ejector control valve (76) in the open position or the closed position based on whether there is an excess amount of fuel downstream of the first fuel pump to be returned to the ejector upstream of the first fuel pump ([0044-45, 47-49]).
Cocks in view of Alecu and Wikipedia does not teach a pressure sensor connected in signal communication with the controller, and the pressure sensor is connected in fluid communication with the first fuel pump downstream of the fuel outlet; wherein the instructions, when executed by the processor, further cause the processor to control the ejector control valve in the open position or the closed position based on a measured fuel pressure from the pressure sensor.
However, Mahoney teaches a pressure sensor (integrated into 128) connected in signal communication with a controller (integrated into 128; [0023]), and the pressure sensor is connected in fluid communication with a first fuel pump (108) downstream of a fuel outlet of the first fuel pump (Fig 1);
wherein instructions executed by a processor of the controller (i.e. to generate signals 132 and 134; [0022]), further cause the processor to control a control valve (122) in an open position or a closed position based on a measured fuel pressure from the pressure sensor ([0021, 23-24, 27-28] valve 122 is opened or closed depending on the measured fuel pressures, i.e. pressure drop, across the metering valve; i.e. valve 122 is opened when pressure drop is too high and closed when pressure drop is too low, e.g. ΔP = P2-P1 [Wingdings font/0xE0] when ΔP > dPt, open valve [Wingdings font/0xE0] when P2 > dPt + P1, open valve).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the non-descript fuel control (to account for excess fuel) as required by Cocks (in view of Alecu and Wikipedia) to use the metering valve, pressure sensor(s), and control arrangement of Mahoney in order to determine the excess fuel condition(s) (as required by Cocks of Cocks in view of Alecu and Wikipedia) while providing precisely metered fuel flow to the engine (Mahoney, [0021, 23-24, 27-28]). Furthermore, it has been held that combining or simple substitution of prior art elements according to known methods to yield predictable results renders the limitation obvious (see MPEP 2141 (III)). In this case, Cocks (in view of Alecu and Wikipedia) requires a means of determining when there is excess fuel to be recirculated via the ejector control valve and ejector, and Mahoney provides a specific system and method of determining an excess fuel condition (using pressure sensing across a fuel metering valve) and controlling a recirculation valve based on the excess fuel condition. Thus, the combination yielding the predictable results of accurate and precise recirculation of excess fuel based on pressure measurements across a fuel metering device.
Regarding claim 9, Cocks in view of Alecu, Wikipedia, and Mahoney teaches all the limitations of the claimed invention as discussed above. Cocks further teaches a second fuel pump (70), the first fuel pump is connected in fluid communication with the second fuel pump by the outlet conduit (Fig 1), the second fuel pump having a discharge (to downstream components including 76, 82, 56).
Cocks in view of Alecu, Wikipedia, and Mahoney as discussed so far, does not teach the pressure sensor is disposed at a discharge of the second fuel pump.
However, Mahoney further teaches the pressure sensor (128) is disposed at a discharge of a second fuel pump (110).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide the pressure sensor(s) of Cocks in view of Alecu, Wikipedia, and Mahoney at the second pump discharge as taught by Mahoney in order to provide the fuel recirculation and metering taught by Mahoney ([0021, 23-24, 27-28]). See further discussion in claim 8 above.
Regarding claim 10, Cocks in view of Alecu, Wikipedia, and Mahoney teaches all the limitations of the claimed invention as discussed above. Cocks further teaches the instructions, when executed by the processor, further cause the processor to control the ejector control valve in the open position when there is excess fuel that should be recirculated ([0044-45, 47-49]; when there is excess fuel to be recirculated, valve 76 opens).
Cocks in view of Alecu, Wikipedia, and Mahoney also teach excess fuel being determined when the measured fuel pressure is greater than or equal to a first pressure threshold.
That is, as discussed above in claim 8, the recirculation valve (122) is controlled to increase flow therethrough (relatively opened) when the pressure drop across the metering valve is greater than a first pressure threshold (e.g. for ΔP = P2-P1, open valve when ΔP > dPt [Wingdings font/0xE0] open valve when P2 > dPt + P1; thus, first pressure threshold = dPt + P1, where dPt is the desired constant pressure drop across the fuel metering valve).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the control scheme of Cocks in view of Alecu, Wikipedia, and Mahoney to use the control scheme of Mahoney in order to provide the fuel recirculation and metering taught by Mahoney ([0021, 23-24, 27-28]). See further discussion in claim 8 above.
Regarding claim 11, Cocks in view of Alecu, Wikipedia, and Mahoney teaches all the limitations of the claimed invention as discussed above. Cocks further teaches the instructions, when executed by the processor, further cause the processor to control the ejector control valve in a shut position when there is not excess fuel for recirculation ([0044-45, 47-49]; when there is not excess fuel, valve 76 is closed).
Cocks in view of Alecu, Wikipedia, and Mahoney also teaches using fuel pressure to determine that there is not excess fuel for recirculation, and closing the valve (to minimum area position) when fuel pressure is less than a second pressure threshold, which is less than the first pressure threshold.
That is, as discussed above in claim 8, the recirculation valve (122) is controlled to reduce flow therethrough (relatively closed) when the pressure drop across the metering valve is less than the desired pressure drop (e.g. for ΔP = P2-P1, reduce valve area when ΔP < dPt [Wingdings font/0xE0] reduce valve area when P2 < dPt + P1, where dPt + P1 is the first pressure threshold, and where dPt is the desired constant pressure drop across the fuel metering valve). The valve is closed (to minimum flow position) when ΔP is much smaller than dPt (ΔP << dPt) such that the second pressure threshold at which the valve is closed is smaller than the first pressure threshold (P2 << dPt + P1).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the control scheme of Cocks in view of Alecu, Wikipedia, and Mahoney to use the control scheme of Mahoney in order to provide the fuel recirculation and metering taught by Mahoney ([0021, 23-24, 27-28]). See further discussion in claim 8 above.
Claims 23-25 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cocks in view of Alecu and Mahoney.
Regarding claim 23, Cocks teaches a fuel system (62) for a gas turbine engine (20), the fuel system comprising:
a fuel tank (66);
a first fuel pump (68) including a fuel inlet (to receive fuel from 66) and a fuel outlet (to send fuel downstream to 74, 70, 76), the first fuel pump is connected in fluid communication with the fuel tank by an inlet conduit (between 66 and 68) at the fuel inlet (Fig 1), and the first fuel pump is connected in fluid communication with an outlet conduit (between 68 and 70) at the fuel outlet (Fig 1);
a second fuel pump (70) connected in fluid communication with the first fuel pump by the outlet conduit (Fig 1);
a fuel injector assembly (required at 56 to inject the fuel into 56) connected in fluid communication with and downstream of the second fuel pump (Figs 1-2),
an inlet ejector (86) including an ejector nozzle (required structure for and ejector pump) disposed in the fuel tank (Fig 1),
the ejector nozzle including a nozzle fuel outlet (required for ejector pump to function) at the first fuel flow path (Fig 1); and
an ejector control valve (76) connected in fluid communication between the ejector nozzle and the outlet conduit (Fig 1),
the ejector control valve selectively positionable in an open position or a closed position to control a flow of a fuel from the outlet conduit through the ejector nozzle to the inlet conduit through the nozzle fuel outlet ([0044-45, 47-49]);
a controller (92) connected in communication with and the ejector control valve (Fig 2) to control the ejector control valve in the open position or the closed position based on whether there is an excess amount of fuel downstream of the first fuel pump to be returned to the ejector upstream of the first fuel pump ([0044-45, 47-49]).
Cocks does not teach the ejector pump is disposed within the inlet conduit; a pressure sensor connected in fluid communication with and between the second fuel pump and the fuel injector assembly, the pressure sensor in communication with the controller; and the valve control being based on a measured fuel pressure from the pressure sensor. It also may not be clear from Cocks whether the controller is a computer to automate the controlling (including a processor in communication with a non-transitory memory storing instructions, which instructions when executed by the processor, cause the processor to perform the controlling function).
However, Alecu teaches the substitutional equivalence of placing an ejector pump in the fuel tank or just downstream of the fuel tank for boosting fuel flow to the first low pressure pump (col.2 ll.14-26), including alternative arrangements such as splitting a return fuel flow (26) between the fuel tank and the downstream ejector pump and/or splitting the output fuel from the ejector pump to provide a return flow (26c) to the tank (Fig 2; col.3 ll.7-15). Note the ejector pump depicted in Fig 2 uses a symbol representing conventional ejector pump.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the ejector pump arrangement relative to the fuel tank of Cocks to have the ejector pump downstream of the fuel tank, in the inlet conduit of the first fuel pump, as taught by any of the various embodiments of Alecu, because Alecu teaches the substitutional equivalence of the various arrangements for managing excess fuel flow while ensuring fuel flow from the tank to the first low pressure pump (col.2 ll.14-26, col.3 ll.7-15; Fig 2).
Cocks in view of Alecu still does not teach a pressure sensor connected in fluid communication with and between the second fuel pump and the fuel injector assembly, the pressure sensor in communication with the controller; and the valve control being based on a measured fuel pressure from the pressure sensor. Also, it still may not be clear from Cocks in view of Alecu whether the controller is a computer to automate the controlling (including a processor in communication with a non-transitory memory storing instructions, which instructions when executed by the processor, cause the processor to perform the controlling function).
However, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to provide a general purpose computer to automate the controlling by the controller of Cocks (in view of Alecu) because MPEP2144.04(III) provides that broadly providing an automatic or mechanical means (i.e. generic computer) to replace a manual activity (of controlling valves with a controller) which accomplished the same result (same control achieved whether it is automated or manual) is not sufficient to distinguish over the prior art.
Additionally, Mahoney teaches a pressure sensor (integrated into 128) connected in signal communication with a controller (integrated into 128; [0023]), and the pressure sensor is connected in fluid communication with a first fuel pump (108) downstream of a fuel outlet of the first fuel pump (Fig 1);
wherein instructions executed by a processor of the controller (i.e. to generate signals 132 and 134; [0022]), further cause the processor to control a control valve (122) in an open position or a closed position based on a measured fuel pressure from the pressure sensor ([0021, 23-24, 27-28] valve 122 is opened or closed depending on the measured fuel pressures, i.e. pressure drop, across the metering valve; i.e. valve 122 is opened when pressure drop is too high and closed when pressure drop is too low, e.g. ΔP = P2-P1 [Wingdings font/0xE0] when ΔP > dPt, open valve [Wingdings font/0xE0] when P2 > dPt + P1, open valve).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the non-descript fuel control (to account for excess fuel) as required by Cocks (in view of Alecu) to use the metering valve, pressure sensor(s), and control arrangement of Mahoney in order to determine the excess fuel condition(s) (as required by Cocks of Cocks in view of Alecu) while providing precisely metered fuel flow to the engine (Mahoney, [0021, 23-24, 27-28]). Furthermore, it has been held that combining or simple substitution of prior art elements according to known methods to yield predictable results renders the limitation obvious (see MPEP 2141 (III)). In this case, Cocks (in view of Alecu) requires a means of determining when there is excess fuel to be recirculated via the ejector control valve and ejector, and Mahoney provides a specific system and method of determining an excess fuel condition (using pressure sensing across a fuel metering valve) and controlling a recirculation valve based on the excess fuel condition. Thus, the combination yielding the predictable results of accurate and precise recirculation of excess fuel based on pressure measurements across a fuel metering device.
Regarding claim 24, Cocks in view of Alecu, and Mahoney teaches all the limitations of the claimed invention as discussed above. Cocks further teaches the instructions, when executed by the processor, further cause the processor to control the ejector control valve in the open position when there is excess fuel that should be recirculated ([0044-45, 47-49]; when there is excess fuel to be recirculated, valve 76 opens).
Cocks in view of Alecu, and Mahoney also teach excess fuel being determined when the measured fuel pressure is greater than or equal to a first pressure threshold.
That is, as discussed above in claim 23, the recirculation valve (122) is controlled to increase flow therethrough (relatively opened) when the pressure drop across the metering valve is greater than a first pressure threshold (e.g. for ΔP = P2-P1, open valve when ΔP > dPt [Wingdings font/0xE0] open valve when P2 > dPt + P1; thus, first pressure threshold = dPt + P1, where dPt is the desired constant pressure drop across the fuel metering valve).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the control scheme of Cocks in view of Alecu, and Mahoney to use the control scheme of Mahoney in order to provide the fuel recirculation and metering taught by Mahoney ([0021, 23-24, 27-28]). See further discussion in claim 23 above.
Regarding claim 25, Cocks in view of Alecu, and Mahoney teaches all the limitations of the claimed invention as discussed above. Cocks further teaches the instructions, when executed by the processor, further cause the processor to control the ejector control valve in a shut position when there is not excess fuel for recirculation ([0044-45, 47-49]; when there is not excess fuel, valve 76 is closed).
Cocks in view of Alecu, and Mahoney also teaches using fuel pressure to determine that there is not excess fuel for recirculation, and closing the valve (to minimum area position) when fuel pressure is less than a second pressure threshold, which is less than the first pressure threshold.
That is, as discussed above in claim 23, the recirculation valve (122) is controlled to reduce flow therethrough (relatively closed) when the pressure drop across the metering valve is less than the desired pressure drop (e.g. for ΔP = P2-P1, reduce valve area when ΔP < dPt [Wingdings font/0xE0] reduce valve area when P2 < dPt + P1, where dPt + P1 is the first pressure threshold, and where dPt is the desired constant pressure drop across the fuel metering valve). The valve is closed (to minimum flow position) when ΔP is much smaller than dPt (ΔP << dPt) such that the second pressure threshold at which the valve is closed is smaller than the first pressure threshold (P2 << dPt + P1).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the control scheme of Cocks in view of Alecu, and Mahoney to use the control scheme of Mahoney in order to provide the fuel recirculation and metering taught by Mahoney ([0021, 23-24, 27-28]). See further discussion in claim 23 above.
Response to Arguments
Applicant's arguments filed 11 March 2026 have been fully considered but they are not persuasive and/or they are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Applicant argues that the rejection under 103 over Cocks in view of Alecu does not provide sufficient rationale for modifying Cocks in view of Alecu.
However, the rejection specifically points to col.2 ll.14-26 of Alecu, which states the “ejector pump 24, which may be either located directly within the fuel tank(s) 22 or downstream thereof, pumps the fuel out of the fuel tank(s) 22 using a motive flow 26” and Fig 2 of Alecu depicts the ejector pump (24) in the inlet conduit between the fuel tank (22) and the first fuel pump (28). Thus, per MPEP2144.06(II), Alecu recognized the substitutional equivalence of the arrangement of Cocks and the arrangement of the claims, thus rendering the arrangement of the claims obvious over the prior art combination of Cocks in view of Alecu.
Applicant argues various differences between the additional elements in Alecu’s fuel system versus Cocks’ fuel system (including citation to Cocks’ [0040]).
However, such differences do not render the combination nonobvious so long as the prior art does not teach away from the modification (placing the ejector pump of Cocks in the inlet conduit between the fuel tank and the first fuel pump as taught by Alecu) and the modification does not render the combination inoperable. Both references use the ejector pump to take advantage of higher pressure motive flow to ensure fuel flow from the fuel tank to the first fuel pump (Alecu, col.2 ll.14-32, the “ejector pump 24…pumps the fuel out of the fuel tank(s) 22 using a motive flow 26…Once the fuel is pumped out of the fuel tank 22, it goes through a low pressure (LP) pump 28” emphasis added; Cocks, [0040], the “ejector pump 86 provides for movement of fuel within the fuel tank 66 to prevent starvation of fuel to the boost pump 68” emphasis added), neither reference teaches away from the combination, and the modification yields predictable results of the system of Cocks with the ejector pump being located in the inlet conduit between the fuel tank (66) and the first fuel pump (68) as taught by Alecu. The system of Cocks would still function normally with this modification. Note, placing the ejector pump in the inlet conduit between the fuel tank and the first fuel pump also “provides movement of fuel within the fuel tank” by suctioning fuel from the fuel tank.
Applicant argues that Callaghan does not teach the ejector nozzle spaced from the inlet conduit”. This is a new recitation that was not previously recited in the claims.
Without conceding to the validity of the argument, a new prior art reference (Wikipedia entry for Injector/Ejector) is further relied upon to teach the amended claim 1.
Applicant argues that the office action does not provide sufficient rationale to modify Cocks in view of Alecu with Mahoney to include the pressure sensing and control features recited in the claims.
However, the rejection now clarifies that the valve (for the interpretations of claims 8-11 and 23-25) is valve 76, not valve 74. Valve 76 opens when there is excess fuel and closes when there is not excess fuel. Mahoney measures excess fuel by measuring pressure. When pressure exceeds a threshold, there is excess fuel and when pressure is below a threshold, there is not excess fuel. This excess fuel determination of Mahoney is then applied to the non-descript excess fuel determination of Cocks (in view of Alecu) in order to provide precise fuel metering and recirculation as taught by Mahoney ([0021, 23-24, 27-28]). That is, Mahoney teaches details of a manner in which to control the valve 76 of Cocks based on a fuel pressure indication of excess fuel.
Correspondence
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/STEPHANIE SEBASCO CHENG/Primary Examiner, Art Unit 3741
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