Office Action 1: Non-Final Rejection (2025-04-30)
Rejection types: 103 - Obviousness

CLAIMS:
WE CLAIM:
1\. A method of determining one or more fuel characteristics of an aviation fuel suitable for powering a gas turbine engine of an aircraft, the method comprising: determining a mass of a fuel being loaded, or which has been loaded, onto the aircraft; determining a corresponding volume of the fuel; and determining one or more fuel characteristics of the fuel based on the determined mass and volume.
2\. The method of claim 1, wherein determining the one or more fuel characteristics comprises calculating a fuel density based on the determined fuel mass and fuel volume.
3\. The method of claim 1, wherein:
4\. The method of claim 1, wherein:
5\. The method of claim 1, wherein the one or more fuel characteristics determined include any one or more of: (i) a hydrocarbon distribution of the fuel; (ii) a percentage of sustainable aviation fuel in the fuel; and/or (iii) an aromatic hydrocarbon content of the fuel.
6\. The method of claim 1, wherein the one or more fuel characteristics include an indication that the fuel is a fossil fuel e.g. kerosene.
7\. The method of claim 1, wherein the one or more fuel characteristics are further determined based on a signal indicative of the temperature of the fuel.
8\. A fuel characteristic determination system for determining one or more fuel characteristic of an aviation fuel suitable for powering a gas turbine engine of an aircraft, the system comprising: a fuel characteristic determination module arranged to: receive a fuel mass signal indicative of a mass of the fuel being loaded, or which has been loaded onto the aircraft; receive a fuel volume signal indicative of a volume of fuel being loaded, or which has been loaded, onto the aircraft; and determine one or more fuel characteristics of the fuel based on the fuel volume and fuel mass signals.
9\. The fuel characteristic determination system of claim 8, wherein the fuel characteristic determination module is configured to calculate a density of the fuel based on the fuel mass signal and fuel volume signal.
10\. The fuel characteristic determination system of claim 8, further comprising: a mass sensor arranged to measure a mass of the fuel, wherein the fuel mass signal is received from the mass sensor; and/or a volume sensor arranged to measure a volume of fuel, wherein the fuel volume signal is received from the volume sensor.
11\. The fuel characteristic determination system of claim 10, wherein: the mass sensor is a mass flow rate meter; and/or the volume sensor is a volume flow rate meter.
12\. The fuel characteristic determination system of claim 11, wherein the mass flow meter is arranged to measure mass flow rate at a point within a fuel supply line used to convey fuel to one or more fuel tanks on board the aircraft.
13\. The fuel characteristic determination system of claim 11, wherein the volume flow rate meter is arranged to measure a volume flow rate at a point within a fuel supply line used to supply fuel to one or more fuel tanks on board the aircraft.
14\. The fuel characteristic determination system of claim 8, wherein a) the fuel mass signal is based on a measured mass and/or change in the mass of any one or more of: the aircraft; one or more fuel tanks on board the aircraft; a fuel tanker vehicle from which the fuel is supplied; or a storage vessel from which the fuel is supplied to the aircraft; and/or b) the fuel volume signal is based on a measured volume and/or change in the volume of fuel: stored in one or more fuel tanks on board the aircraft; and/or stored in a fuel storage vessel from which the fuel is supplied to the aircraft.
15\. The fuel characteristic determination system of claim 8, wherein the one or more fuel characteristics determined include any one or more of: (i) a hydrocarbon distribution of the fuel; (ii) a percentage of sustainable aviation fuel in the fuel; and/or (iii) an aromatic hydrocarbon content of the fuel.
16\. The fuel characteristic determination system of claim 8, wherein the one or more fuel characteristics include an indication that the fuel is a fossil fuel e.g. kerosene.
17\. The fuel characteristic determination system of claim 8, wherein the fuel characteristic determination module is further arranged to determine the one or more fuel characteristics based on a signal indicative of the temperature of the fuel.
18\. A method of operating an aircraft having a gas turbine engine, the method comprising: determining one or more fuel characteristics using the method of claim 1; and operating the aircraft according to the one or more fuel characteristics.
19\. The method according to claim 18, wherein operating the aircraft according to the one or more fuel characteristics comprises: a) modifying a control parameter of the aircraft, preferably a control parameter of the gas turbine engine, in response to the one or more fuel characteristics; and/or b) providing a fuel having different fuel characteristics during refuelling of the aircraft.
20\. An aircraft comprising the fuel characteristic determination system of claim 8, further comprising a control system arranged to control operation of the aircraft according to the one or more fuel characteristics determined by the fuel characteristic determination system.

OFFICE 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 .
DETAILED ACTION
Drawings
Claim Objections
The following claim(s) is/are objected to because of the following informalities:
Appropriate correction is required.
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA  35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art.  The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph:
(A)	the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B)	the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C)	the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier.  Such claim limitation(s) is/are:
“a fuel characteristic determination module arranged to receive a fuel mass signal … a fuel volume signal … determine one or more fuel characteristics” in claim 8, interpreted to be a generic computer component, a processor, or a controller, or equivalents thereof, as described according to the specification on page 62 lines 29-35: as seen in Figure 16, the determination module 105 in communication with mass and volume sensors 103, 104 to communicate to EEC 42.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, applicant may:  (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1, 3-4, 7-8, 10-14, and 17-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Momenthy (US 4809174 A) Selstad (US 20170292457 A1).
Regarding claim 1
Momenthy discloses a method of determining one or more fuel characteristics (energy content of the fuel, Col 3 lines 25-32, interpreted to be one of the fuel characteristics) of an aviation fuel (jet fuel for flight, Col 1 lines 6-7) suitable for powering a gas turbine engine of an aircraft (aircraft and engine, Col 4 lines 32-34), the method comprising:
determining a flow of a fuel being loaded (engine fuel flow meter 31, Fig 1, Col 3 lines 45-46), or which has been loaded, onto the aircraft (fuel flow meter 31 determines the flow of fuel from refueling tank 12 to aircraft fuel tank 18, Fig 1);
determining a corresponding volume of the fuel (fuel quantity meter 20 measure the volume of fuel loaded in the aircraft fuel tank, Fig 1, Col 6 lines 6-7); and
determining one or more fuel characteristics of the fuel (energy content of the fuel) based on the determined flow of fuel and volume (data from fuel flow meter 31, volume from fuel quantity meter 20, fuel density from densitometer 24, and other parameters received by energy management computer 22 to calculate a value for energy content of the fuel, Col 3 lines 23-31, where the energy content of the fuel is interpreted to be a fuel characteristic).
Momenthy is silent on to determine a mass of the fuel.
However, Selstad teaches an aircraft fuel system (100 Fig 2) for a gas turbine engine (Fig 1) having a mass flow meter (152, Para 0040).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to modify the fuel flow meter 31 in the engine in Momenthy, to be a mass flow meter in a gas turbine engine, as suggested and taught by Selstad, in order to provide a mass flow meter signal to the controller to measure the exact amount of weight/mass of fuel flowing through (Para 0041 middle).
The combination of Momenthy in view of Selstad would result in the fuel flow meter 31 in Momenthy being a mass flow meter, thus the mass flow meter would provide a mass of the fuel to the energy management computer 22 to calculate the energy content of the fuel.
Regarding claim 3
Momenthy in view of Selstad discloses the method of claim 1.
Momenthy in view of Selstad further discloses wherein:
a) determining the mass of the fuel comprises measuring a mass flow rate (Selstad teaches a mass flow meter 152, Fig 2, Para 0040) at a point within a fuel supply line (Momenthy teaches a refueling line 16, Fig 1, Col 2 lines 63) used to convey fuel to a fuel tank (18) on board the aircraft (the combination of Momenthy in view of Selstad teaches to measure a mass flow rate with mass flow meter 152 in Selstad along the fuel line used to convey fuel to a fuel tank 18 in Momenthy).
Regarding claim 4
Momenthy in view of Selstad discloses the method of claim 1.
Momenthy in view of Selstad further discloses wherein:
b) determining the volume of the fuel comprises measuring the volume and/or a change in the volume of fuel (means for measuring the quantity of fuel is a fuel quantity meter 20 located on the aircraft to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, Fig 1): stored in a fuel tank on board the aircraft (18).
Regarding claim 7
Momenthy in view of Selstad discloses the method of claim 1.
Momenthy further discloses wherein the one or more fuel characteristics (one of the fuel characteristics being a fuel density determined by densitometer 24, Fig 1, Col 3 lines 13-15) are further determined based on a signal indicative of the temperature of the fuel (densitometer 24 has temperature compensation, Col 3 lines 59-61, indicates that there is a signal indicative of the temperature of the fuel).
Regarding claim 8
Momenthy discloses a fuel characteristic determination system (Fig 1) for determining one or more fuel characteristics (energy content of the fuel, Col 3 lines 25-32) of an aviation fuel (jet fuel for flight, Col 1 lines 6-7) suitable for powering a gas turbine engine of an aircraft (aircraft and engine, Col 4 lines 32-34), the system comprising:
a fuel characteristic determination module (energy management computer 22, Fig 1) arranged to:
receive a flow of a fuel signal indicative of a flow of fuel being loaded (engine fuel flow meter 31, Fig 1, Col 3 lines 45-46), or which has been loaded, onto the aircraft (fuel flow meter 31 determines the flow of fuel from refueling tank 12 to aircraft fuel tank 18, Fig 1);
receive a fuel volume signal indicative of a volume of the fuel being loaded, or which has been loaded, onto the aircraft (fuel quantity meter 20 measure the volume of fuel loaded in the aircraft fuel tank, Fig 1, Col 6 lines 6-7); and
determine one or more fuel characteristics of the fuel (energy content of the fuel) based on the fuel volume and fuel flow signals (data from fuel flow meter 31, volume from fuel quantity meter 20, fuel density from densitometer 24, and other parameters received by energy management computer 22 to calculate a value for energy content of the fuel, Col 3 lines 23-31, where the energy content of the fuel is interpreted to be a fuel characteristic).
Momenthy is silent on to receive a fuel mass signal indicative of a mass of the fuel.
However, Selstad teaches an aircraft fuel system (100 Fig 2) for a gas turbine engine (Fig 1) having a controller (130, Para 0041 top) to receive a fuel mass signal indicative of a mass of the fuel (signal from a mass flow meter 152, Para 0040).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to modify the fuel flow meter 31 in the engine in Momenthy, to be a mass flow meter in a gas turbine engine, as suggested and taught by Selstad, in order to provide a mass flow meter signal to the controller to more accurately monitor how much fuel is flowing through (Para 0041 middle).
The combination of Momenthy in view of Selstad would result in the fuel flow meter 31 in Momenthy being a mass flow meter, to determine the fuel characteristics based on a mass of the fuel, by providing the mass of the fuel to the energy management computer 22 to calculate the energy content of the fuel.
Regarding claim 10
Momenthy in view of Selstad discloses the fuel characteristic determination system of claim 8.
Momenthy in view of Selstad further discloses a volume sensor (means for measuring the quantity of fuel is a fuel quantity meter 20 located on the aircraft to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, Fig 1) arranged to measure a volume of fuel, wherein the fuel volume signal is received from the volume sensor (fuel volume signal is received from the volume sensor 20).
Regarding claim 11
Momenthy in view of Selstad discloses the fuel characteristic determination system of claim 10.
Momenthy in view of Selstad further discloses wherein:
the mass sensor is a mass flow rate meter (Selstad teaches the mass flow rate meter 152, Para 0040); and/or
the volume sensor is a volume flow rate meter (Momenthy discloses the fuel quantity meter 20 to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, interpreted to be a volume flow rate meter).
Regarding claim 12
Momenthy in view of Selstad discloses the fuel characteristic determination system of claim 11.
Momenthy in view of Selstad further discloses wherein the mass flow meter (Selstad teaches a mass flow meter 152, Fig 2, Para 0040) is arranged to measure mass flow rate at a point within a fuel supply line (Momenthy teaches a refueling line 16, Fig 1, Col 2 lines 63) used to convey fuel to a fuel tank (18) on board the aircraft (the combination of Momenthy in view of Selstad teaches to measure a mass flow rate with mass flow meter 152 in Selstad along the fuel line used to convey fuel to a fuel tank 18 in Momenthy).
Regarding claim 13
Momenthy in view of Selstad discloses the fuel characteristic determination system of claim 11.
Momenthy in view of Selstad further discloses wherein the volume flow rate meter (fuel quantity meter 20, Fig 1) is arranged to measure a volume flow rate at a point within a fuel supply line (a refueling line 16, Fig 1, Col 2 lines 63) used to supply fuel to a fuel tank (18) on board the aircraft (26).
Regarding claim 14
Momenthy in view of Selstad discloses the fuel characteristic determination system of claim 8.
Momenthy in view of Selstad further discloses wherein
b) the fuel volume signal is based on a measured volume and/or change in the volume of fuel (means for measuring the quantity of fuel is a fuel quantity meter 20 located on the aircraft to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, Fig 1): stored in a fuel tank on board the aircraft (18).
Regarding claim 17
Momenthy in view of Selstad discloses the fuel characteristic determination system of claim 8.
Momenthy in view of Selstad further discloses wherein the fuel characteristic determination module is further arranged to determine the one or more fuel characteristics (one of the fuel characteristics being a fuel density determined by densitometer 24, Fig 1, Col 3 lines 13-15) based on a signal indicative of the temperature of the fuel (densitometer 24 has temperature compensation, Col 3 lines 59-61, indicates that there is a signal indicative of the temperature of the fuel).
Regarding claim 18
Momenthy in view of Selstad discloses the method of claim 1.
Momenthy in view of Selstad further discloses a method of operating an aircraft (Momenthy discloses a method of refueling an aircraft fuel tank 18, Fig 1) having a gas turbine engine (Selstad teaches a gas turbine engine, Fig 1), the method comprising:
determining one or more fuel characteristics using the method of claim 1; and
operating the aircraft according to the one or more fuel characteristics (Momenthy in view of Selstad discloses to operate the fuel system of an aircraft).
Regarding claim 19
Momenthy in view of Selstad discloses the method of claim 18.
Momenthy in view of Selstad further discloses wherein operating the aircraft according to the one or more fuel characteristics comprises:
b) providing a fuel having different fuel characteristics during refuelling of the aircraft (Momenthy discloses to refuel the aircraft using a fuel with different fuel characteristics such as a density of the fuel measured by densitometer 24, volume of the fuel by fuel quantity meter 20, and flow meter 31, to determine a total required energy content of the fuel for a selected flight, Col 2, lines 1-10).
Regarding claim 20
Momenthy in view of Selstad discloses an aircraft comprising the fuel characteristic determination system of claim 8 (Momenthy discloses aircraft 26, Fig 1).
Momenthy in view of Selstad further discloses a control system (Momenthy disclsoes the energy management computer 22, Fig 1; and, Selstad teaches controller 130, Para 0041 top) arranged to control operation of the aircraft according to the one or more fuel characteristics determined by the fuel characteristic determination system (Momenthy discloses the computer 22 to determine the fuel characteristics while Selstad teaches controller 130 being a FADEC to control the flow of fuel,
thus, the combination of Momenthy in view of Selstad teaches a control system that control operation of the aircraft according to the fuel characteristics determined by the fuel characteristic determination system).
Claim(s) 2 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Momenthy in view of Selstad, as applied to claims 1 and 8 above, and further in view of Joudareff (US 20220268217 A1).
Regarding claims 2 and 9
Momenthy in view of Selstad discloses the method of claim 1 and the fuel characteristic determination system of claim 8.
Momenthy in view of Selstad further discloses the determined fuel mass (Selstad teaches a mass flow meter 152, Fig 2, Para 0040) and fuel volume (Momenthy teaches fuel quantity meter 20 measure the volume of fuel loaded in the aircraft fuel tank, Fig 1, Col 6 lines 6-7).
Momenthy in view of Selstad is silent on determining the one or more fuel characteristics comprises calculating a fuel density based on the determined fuel mass and fuel volume.
However, Joudareff teaches that a fuel density value is determined as equal to the ratio between the mass flow rate and the volume flow rate (Para 0032).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to determine another fuel characteristics in the fuel of Momenthy in view of Selstad, being a fuel density based on the determined fuel mass and fuel volume, as suggested and taught by Joudareff, because fuel density is an important characteristic to calculate weight which is crucial in flight.
Claim(s) 5-6 and 15-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Momenthy in view of Selstad, as applied to claims 1 and 8 above, and further in view of Dubois (US 20150191667 A1).
Regarding claims 5 and 15
Momenthy in view of Selstad discloses the method of claim 1 and the fuel characteristic determination system of claim 8.
Momenthy in view of Selstad further discloses the one or more fuel characteristics determined include (iii) an aromatic content of the fuel (energy management computer 22 determines an energy content of the jet fuel, Fig 1, Col 2 lines 25-31, the energy content of the jet fuel is interpreted to be the aromatic content of the fuel).
Momenthy in view of Selstad is silent on the jet fuel being a hydrocarbon fuel.
However, Dubois teaches that jet fuel is a mixture of large number of different hydrocarbon compounds (Para 0031).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to determine the aromatic content of the jet fuel in Momenthy in view of Selstad, to be the aromatic hydrocarbon content of the jet fuel, as suggested and taught by Dubois, because a jet fuel is a type of hydrocarbon fuel that is commonly used as aviation fuel.
Regarding claims 6 and 16
Momenthy in view of Selstad discloses the method of claim 1 and the fuel characteristic determination system of claim 8.
Momenthy in view of Selstad further discloses the one or more fuel characteristics determined is that the fuel is a jet fuel (aircraft fuel tank with jet fuel for flight, Col 1 lines 5-10).
Momenthy in view of Selstad is silent on the jet fuel is a fossil fuel, e.g. kerosene.
However, Dubois teaches that kerosene-type jet fuels are currently preferred because they offer the best combination in terms of energy content, performance, availability, ease of handling and price (Para 0003 middle).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to use kerosene-type jet fuels, as suggested and taught by Dubois, in the aircraft fuel tank in Momenthy in view of Selstad, because of kerosene’s advantage in energy content, performance, availability, ease of handling and price (Para 0003 middle).
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Ward (US 20140053645 A1) teaches a sensor to measure mass and volume
Orloff (US 8515694 B1) teaches a fuel system
Kanyilmaz (US 11579007 B2) teaches a fuel control system


NEXT OFFICE 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 .
DETAILED ACTION
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA  35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art.  The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, is invoked.
As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph:
(A)	the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function;
(B)	the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and
(C)	the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function.
Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function.
Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function.
Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier.  Such claim limitation(s) is/are:
“a fuel characteristic determination module arranged to receive a fuel mass signal … a fuel volume signal … determine one or more fuel characteristics” in claim 8, interpreted to be a generic computer component, a processor, or a controller, or equivalents thereof, as described according to the specification on page 62 lines 29-35: as seen in Figure 16, the determination module 105 in communication with mass and volume sensors 103, 104 to communicate to EEC 42.
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph, applicant may:  (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA  35 U.S.C. 112, sixth paragraph.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-2, 7-10, 14, and 17-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Momenthy (US 4809174 A) in view of Galati (US 20220120599 A1) and Drancea (US 20200216188 A1).
Regarding claim 1
Momenthy discloses a method of determining one or more fuel characteristics (energy content of the fuel, Col 3 lines 25-32, interpreted to be one of the fuel characteristics) of an aviation fuel (jet fuel for flight, Col 1 lines 6-7) suitable for powering a gas turbine engine of an aircraft (aircraft and engine, Col 4 lines 32-34), the method comprising:
determining a corresponding volume of the fuel (fuel quantity meter 20 measures the volume of fuel loaded in the aircraft fuel tank, Fig 1, Col 6 lines 6-7); and
determining one or more fuel characteristics of the fuel (fuel density from densitometer 24, Col 3 lines 23-31, where fuel density is interpreted to be a fuel characteristic).
Momenthy is silent on determining a mass of the fuel being loaded onto the aircraft,
determining one or more fuel characteristics of the fuel based on the determined mass and volume, wherein the one or more fuel characteristics are determined by either or both of
(i)	comparing a value derived from the determined fuel mass and fuel volume to values in a lookup table and
(ii)	calculating a deviation of a value derived from the determined fuel mass and fuel volume from an expected value.
However, Galati teaches to determine an amount of fuel in an aircraft fuel system (Abstract) by determining a mass of the fuel being loaded onto the aircraft (the actual fuel volume is multiplied by the measured density to determine the fuel mass, Para 0040 middle),
determining a fuel characteristic of the fuel based on the determined mass and volume (for determining fuel density, a first densitometer located in the center fuel tank and a second densitometer located in one of the wing fuel tanks, Para 0069, where the fuel density is determined by densitometers,
another determining method is that density equals to mass divided by volume, https://www.britannica.com/science/density, thus once mass and volume of the fuel are known, density can be calculated based on the determined mass and volume).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to use the fuel volume and fuel density in Momenthy to determine a mass of the fuel being loaded onto the aircraft, as suggested and taught by Galati, and
to determine a fuel characteristics being a fuel density based on the determined mass and volume, as known in the art, because mass and density of the fuel are important parameters in an aircraft fuel supply system.
Momenthy in view of Galati is silent on the fuel characteristic being a fuel density is determined by 	(i) comparing a value derived from the determined fuel mass and fuel volume to values in a lookup table.
However, Drancea teaches an aircraft fuel system (Fig 1A) having a fuel characteristic being a fuel density is determined by (i) comparing a value derived from the determined fuel mass and fuel volume (fuel density value equals to mass divided by volume, https://www.britannica.com/science/density, thus once mass and volume of the fuel are known, taught by Momenthy in view of Galati, density can be calculated based on the determined mass and volume) to values in a lookup table (fuel density can be determined via look-up tables, Para 0069 bottom).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to also determine the fuel characteristic being a fuel density in Momenthy in view of Galati by comparing a value derived from the determined fuel mass and fuel volume to values in a lookup table, as suggested and taught by Drancea, because fuel density is important in determining the fuel distribution of the aircraft which is used to determine an imbalance in the center of gravity of the aircraft (Para 0005, 0009), and
by comparing the value derived from the determined fuel mass and volume to a value in a lookup table, the system can verify if the derived value is close to or completely wrong from the value in the lookup table.
Regarding claim 2
Momenthy in view of Galati and Durance discloses the method of claim 1.
Momenthy in view of Galati and Durance further discloses wherein:
wherein determining the one or more fuel characteristics comprises calculating a fuel density based on the determined fuel mass and fuel volume (determining fuel density equals to mass divided by volume, https://www.britannica.com/science/density, thus once mass and volume of the fuel are known, density can be calculated based on the determined mass and volume).
Regarding claim 7
Momenthy in view of Galati and Durance discloses the method of claim 1.
Momenthy further discloses wherein the one or more fuel characteristics (one of the fuel characteristics being a fuel density determined by densitometer 24, Fig 1, Col 3 lines 13-15) are further determined based on a signal indicative of the temperature of the fuel (densitometer 24 has temperature compensation, Col 3 lines 59-61, indicates that there is a signal indicative of the temperature of the fuel).
Regarding claim 8
Momenthy discloses a fuel characteristic determination system (Fig 1) for determining one or more fuel characteristics (energy content of the fuel, Col 3 lines 25-32) of an aviation fuel (jet fuel for flight, Col 1 lines 6-7) suitable for powering a gas turbine engine of an aircraft (aircraft and engine, Col 4 lines 32-34), the system comprising:
a fuel characteristic determination module (energy management computer 22, Fig 1) comprising a processor (Col 3 lines 50-52) programmed to:
receive a fuel volume signal indicative of a volume of the fuel being loaded, or which has been loaded, onto the aircraft (fuel quantity meter 20 measure the volume of fuel loaded in the aircraft fuel tank, Fig 1, Col 6 lines 6-7); and
determine a fuel characteristic of the fuel (fuel density from densitometer 24, Col 3 lines 23-31).
Momenthy is silent on to receive a fuel mass signal indicative of a mass of the fuel,
to determine one or more fuel characteristics of the fuel based on the fuel volume and fuel mass signals, wherein the one or more fuel characteristics are determined by
(i)	comparing a value derived from the indicated fuel mass and fuel volume to values in a lookup table and.
However, Galati teaches to determine an amount of fuel in an aircraft fuel system (Abstract) by determining a mass of the fuel being loaded onto the aircraft (the actual fuel volume is multiplied by the measured density to determine the fuel mass, Para 0040 middle),
determine a fuel characteristic of the fuel based on the determined volume and fuel mass signals (for determining fuel density, a first densitometer located in the center fuel tank and a second densitometer located in one of the wing fuel tanks, Para 0069, where the fuel density is determined by densitometers,
another determining method is that density equals to mass divided by volume, https://www.britannica.com/science/density, thus once mass and volume of the fuel are known, density can be calculated based on the determined mass and volume).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to use the fuel volume and fuel density in Momenthy to determine and generate a fuel mass signal indicative of a mass of the fuel being loaded onto the aircraft, as suggested and taught by Galati, and
to determine a fuel characteristic being a fuel density based on the fuel volume and fuel signals, as known in the art, because mass and density of the fuel are important parameters in an aircraft fuel supply system.
Momenthy in view of Galati is silent on the fuel characteristic being a fuel density is determined by 	(i) comparing a value derived from the determined fuel mass and fuel volume to values in a lookup table.
However, Drancea teaches an aircraft fuel system (Fig 1A) having a fuel characteristic being a fuel density is determined by (i) comparing a value derived from the determined fuel mass and fuel volume (fuel density value equals to mass divided by volume, https://www.britannica.com/science/density, thus once mass and volume of the fuel are known, taught by Momenthy in view of Galati, density can be calculated based on the determined mass and volume) to values in a lookup table (fuel density can be determined via look-up tables, Para 0069 bottom).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to also determine the fuel characteristic being a fuel density in Momenthy in view of Galati by comparing a value derived from the determined fuel mass and fuel volume to values in a lookup table, as suggested and taught by Drancea, because fuel density is important in determining the fuel distribution of the aircraft which is used to determine an imbalance in the center of gravity of the aircraft (Para 0005, 0009) , and
by comparing the value derived from the determined fuel mass and volume to a value in a lookup table, the system can verify if the derived value is close to or completely wrong from the value in the lookup table.
Regarding claim 9
Momenthy in view of Galati and Durance discloses the fuel characteristic determination system of claim 8.
Momenthy in view of Galati and Durance further discloses wherein:
wherein the processor of the fuel characteristic determination is programmed to calculate a fuel density based on the fuel mass signal and the fuel volume signal (determining fuel density equals to mass divided by volume, https://www.britannica.com/science/density, thus once mass and volume of the fuel are known, density can be calculated based on the determined mass and volume).
Regarding claim 10
Momenthy in view of Galati and Durance discloses the fuel characteristic determination system of claim 8.
Momenthy further discloses a volume sensor (means for measuring the quantity of fuel is a fuel quantity meter 20 located on the aircraft to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, Fig 1) arranged to measure a volume of fuel, wherein the fuel volume signal is received from the volume sensor (fuel volume signal is received from the volume sensor 20).
Regarding claim 14
Momenthy in view of Galati and Durance discloses the fuel characteristic determination system of claim 8.
Momenthy further discloses wherein
b) the fuel volume signal is based on a measured volume and/or change in the volume of fuel (means for measuring the quantity of fuel is a fuel quantity meter 20 located on the aircraft to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, Fig 1): stored in a fuel tank on board the aircraft (18).
Regarding claim 17
Momenthy in view of Galati and Durance discloses the fuel characteristic determination system of claim 8.
Momenthy further discloses wherein the processor of the fuel characteristic determination module is further programmed to determine the one or more fuel characteristics (one of the fuel characteristics being a fuel density determined by densitometer 24, Fig 1, Col 3 lines 13-15) based on a signal indicative of the temperature of the fuel (densitometer 24 has temperature compensation, Col 3 lines 59-61, indicates that there is a signal indicative of the temperature of the fuel).
Regarding claim 18
Momenthy in view of Galati and Durance discloses the method of claim 1.
Momenthy in view of Galati and Durance further discloses a method of operating an aircraft (Momenthy discloses a method of refueling an aircraft fuel tank 18, Fig 1) having a gas turbine engine (Durance teaches a gas turbine engine 20, Fig 1A), the method comprising:
determining one or more fuel characteristics (Durance teaches the fuel characteristic being a fuel density, Para 0009) using the method of claim 1; and
operating the aircraft according to the determined one or more fuel characteristics (Durance teaches to determine the fuel distribution based on fuel density to prevent center of gravity imbalance of the aircraft, Para 0005).
Regarding claim 19
Momenthy in view of Galati and Durance discloses the method of claim 18.
Momenthy further discloses wherein operating the aircraft according to the one or more fuel characteristics comprises:
b) providing a fuel having different fuel characteristics during refuelling of the aircraft (Momenthy discloses to refuel the aircraft using a fuel with different fuel characteristics such as a density of the fuel measured by densitometer 24, volume of the fuel by fuel quantity meter 20, and flow meter 31, to determine a total required energy content of the fuel for a selected flight, Col 2, lines 1-10).
Regarding claim 20
Momenthy in view of Galati and Durance discloses an aircraft comprising the fuel characteristic determination system of claim 8 (Momenthy discloses aircraft 26, Fig 1).
Momenthy in view of Galati and Durance further discloses a control system (Momenthy discloses the energy management computer 22, Fig 1; and Durance teaches a control system or aircraft computer, Para 0071) arranged to control operation of the aircraft according to the one or more fuel characteristics determined by the fuel characteristic determination system (Momenthy discloses the computer 22 to determine the fuel characteristics while Selstad teaches controller 130 being a FADEC to control the flow of fuel,
thus, the combination of Momenthy in view of Galati and Durance teaches a control system that control operation of the aircraft according to the fuel characteristics determined by the fuel characteristic determination system).
Claim(s) 3-4, 11-13 is/are rejected under 35 U.S.C. 103 as being unpatentable over Momenthy in view of Galati and Durance, as applied to claim 1 above, and further in view of Selstad (US 20170292457 A1).
Regarding claim 3
Momenthy in view of Galati and Durance discloses the method of claim 1.
Momenthy in view of Galati and Durance is silent on wherein:
a) determining the mass of the fuel comprises measuring a mass flow rate at a point within a fuel supply line used to convey fuel to one or more fuel tanks on board the aircraft.
However, Selstad teaches an aircraft fuel system (100 Fig 2) for a gas turbine engine (Fig 1) having a mass flow meter (152, Para 0040) for:
a) determining the mass of the fuel comprises measuring a mass flow rate (a mass flow meter 152, Fig 2, Para 0040) at a point within a fuel supply line used to convey fuel to a fuel tank (fuel line from fuel tank 102 to combustor 56) on board the aircraft (Para 0029).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to add to the fuel system in Momenthy in view of Galati and Durance, a mass flow meter for determining the mass of the fuel comprises measuring a mass flow rate at a point within a fuel supply line used to convey fuel to one or more fuel tanks on board the aircraft, as suggested and taught by Selstad, in order to provide a mass flow meter signal to the controller to measure the exact rate of fuel flowing to the combustor (Para 0041 middle).
Regarding claim 4
Momenthy in view of Galati and Durance discloses the method of claim 1.
Momenthy in view of Galati and Durance is silent on wherein:
b) determining the volume of the fuel comprises measuring the volume and/or a change in the volume of fuel stored in one or more fuel tanks on board the aircraft.
However, Selstad teaches an aircraft fuel system (100 Fig 2) for a gas turbine engine (Fig 1) including a step of:
b) determining the volume of the fuel comprises measuring the volume and/or a change in the volume of fuel (means for measuring the quantity of fuel is a fuel quantity meter 20 located on the aircraft to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, Fig 1): stored in a fuel tank on board the aircraft (18).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to add to the fuel system in Momenthy in view of Galati and Durance, a step of measuring the volume and/or a change in the volume of fuel stored in one or more fuel tanks on board the aircraft, as suggested and taught by Selstad, in order to have an accurate reading of the remaining fuel volume.
Regarding claim 11
Momenthy in view of Galati and Durance discloses the fuel characteristic determination system of claim 10.
Momenthy in view of Galati and Durance is silent on wherein:
the mass sensor is a mass flow rate meter; and/or
the volume sensor is a volume flow rate meter.
However, Selstad teaches an aircraft fuel system (100 Fig 2) wherein:
the mass sensor is a mass flow rate meter (Selstad teaches the mass flow rate meter 152, Para 0040); and/or
the volume sensor is a volume flow rate meter (Momenthy discloses the fuel quantity meter 20 to sense the change in volume of fuel in tank 18, Col 3 lines 17-21, interpreted to be a volume flow rate meter).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to add to the fuel system in Momenthy in view of Galati and Durance, the mass sensor is a mass flow rate meter; and the volume sensor is a volume flow rate meter, as suggested and taught by Selstad, in order to have an accurate reading of the fuel mass flow and volume.
Regarding claim 12
Momenthy in view of Galati, Durance and Selstad discloses the fuel characteristic determination system of claim 11.
Momenthy in view of Galati, Durance and Selstad further discloses wherein the mass flow rate meter (Selstad teaches a mass flow meter 152, Fig 2, Para 0040) is arranged to measure mass flow rate at a point within a fuel supply line (fuel line from fuel tank 102 to combustor 56) on board the aircraft (Para 0029).
Regarding claim 13
Momenthy in view of Galati, Durance and Selstad discloses the fuel characteristic determination system of claim 11.
Momenthy further discloses wherein the volume flow rate meter (fuel quantity meter 20, Fig 1) is arranged to measure a volume flow rate at a point within a fuel supply line (a refueling line 16, Fig 1, Col 2 lines 63) used to supply fuel to a fuel tank (18) on board the aircraft (26).
Claim(s) 5-6 and 15-16 is/are rejected under 35 U.S.C. 103 as being unpatentable over Momenthy in view of Galati and Durance, as applied to claims 1 and 8 above, and further in view of Dubois (US 20150191667 A1).
Regarding claims 5 and 15
Momenthy in view of Galati and Durance discloses the method of claim 1 and the fuel characteristic determination system of claim 8.
Momenthy in view of Galati and Durance further discloses the one or more fuel characteristics determined include (iii) an aromatic content of the fuel (energy management computer 22 determines an energy content of the jet fuel, Fig 1, Col 2 lines 25-31, the energy content of the jet fuel is interpreted to be the aromatic content of the fuel).
Momenthy in view of Galati and Durance is silent on the jet fuel being a hydrocarbon fuel.
However, Dubois teaches that jet fuel is a mixture of large number of different hydrocarbon compounds (Para 0031).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to determine the aromatic content of the jet fuel in Momenthy in view of Galati and Durance, to be the aromatic hydrocarbon content of the jet fuel, as suggested and taught by Dubois, because a jet fuel is a type of hydrocarbon fuel that is commonly used as aviation fuel.
Regarding claims 6 and 16
Momenthy in view of Galati and Durance discloses the method of claim 1 and the fuel characteristic determination system of claim 8.
Momenthy in view of Galati and Durance further discloses the one or more fuel characteristics determined is that the fuel is a jet fuel (aircraft fuel tank with jet fuel for flight, Col 1 lines 5-10).
Momenthy in view of Galati and Durance is silent on the jet fuel is a fossil fuel.
However, Dubois teaches that fossil fuels being kerosene-type jet fuels are currently preferred because they offer the best combination in terms of energy content, performance, availability, ease of handling and price (Para 0003 middle).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date to use fossil fuel being kerosene-type jet fuels, as suggested and taught by Dubois, in the aircraft fuel tank in Momenthy in view of Galati and Durance, because of kerosene’s advantage in energy content, performance, availability, ease of handling and price (Para 0003 middle).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.

CITED REFERENCE SUMMARIES: Ref US20220268217A1: Claims:
A method for metering fuel in a fuel supply circuit of an aircraft engine, the method comprising: metering fuel in an aircraft engine fuel circuit downstream of a fuel pumping system and upstream of injectors, the metering being performed by a metering member disposed in series with a cut-off member; discharging into a recirculation branch of the fuel circuit fuel provided in excess by the pumping system, the discharging being performed by a regulating valve; determining a value of a density of the metered fuel based on measurements made by at least one flow-metric sensor on the recirculation branch; and controlling the metering member based on the density value.
the method comprising: metering fuel in an aircraft engine fuel circuit downstream of a fuel pumping system and upstream of injectors, the metering being performed by a metering member disposed in series with a cut-off member; discharging into a recirculation branch of the fuel circuit fuel provided in excess by the pumping system, the discharging being performed by a regulating valve; determining a value of a density of the metered fuel based on measurements made by at least one flow-metric sensor on the recirculation branch; and controlling the metering member based on the density value.
metering fuel in an aircraft engine fuel circuit downstream of a fuel pumping system and upstream of injectors, the metering being performed by a metering member disposed in series with a cut-off member;
discharging into a recirculation branch of the fuel circuit fuel provided in excess by the pumping system, the discharging being performed by a regulating valve;
determining a value of a density of the metered fuel based on measurements made by at least one flow-metric sensor on the recirculation branch; and
controlling the metering member based on the density value.
The fuel metering method according to claim 1 , comprising determining a mass flow rate and a volume flow rate based on signals measured by the flow-metric sensor, the density value being determined as equal to a ratio between the mass flow rate and the volume flow rate.
the density value being determined as equal to a ratio between the mass flow rate and the volume flow rate.
The fuel metering method according to claim 1 , comprising calculating a metered flow rate by subtracting a recirculated flow rate from a pumped flow rate seen by the flow-metric sensor on the recirculation branch.
The fuel metering method according to claim 1 , the method comprising: determining another value of the density of the metered fuel based on measurements of at least one downstream flow-metric sensor disposed downstream of the metering device; controlling the metering member based on the other density value and on the fuel density value determined based on the measurements of the sensor disposed on the recirculation branch.
the method comprising: determining another value of the density of the metered fuel based on measurements of at least one downstream flow-metric sensor disposed downstream of the metering device; controlling the metering member based on the other density value and on the fuel density value determined based on the measurements of the sensor disposed on the recirculation branch.
determining another value of the density of the metered fuel based on measurements of at least one downstream flow-metric sensor disposed downstream of the metering device;
controlling the metering member based on the other density value and on the fuel density value determined based on the measurements of the sensor disposed on the recirculation branch.
A fuel supply circuit for an aircraft engine, the circuit including a metering device including downstream of a fuel pumping system and upstream of injectors: a fuel inlet, a metering member and a cut-off member disposed in series, a regulating valve disposed on a fuel recirculation branch, and a computer configured for controlling the metering member and the regulating valve, wherein at least one flow-metric sensor is disposed on the recirculation branch, the computer being configured to implement a method comprising: metering fuel by the metering member; discharging into the recirculation branch fuel provided in excess by the pumping system, the discharging being performed by the regulating valve; determining a value of a density of the metered fuel based on measurements made by the flow-metric sensor; and controlling the metering member based on the density value.
the circuit including a metering device including downstream of a fuel pumping system and upstream of injectors: a fuel inlet, a metering member and a cut-off member disposed in series, a regulating valve disposed on a fuel recirculation branch, and a computer configured for controlling the metering member and the regulating valve,
a metering member and a cut-off member disposed in series,
a regulating valve disposed on a fuel recirculation branch, and
a computer configured for controlling the metering member and the regulating valve,
wherein at least one flow-metric sensor is disposed on the recirculation branch,
the computer being configured to implement a method comprising: metering fuel by the metering member; discharging into the recirculation branch fuel provided in excess by the pumping system, the discharging being performed by the regulating valve; determining a value of a density of the metered fuel based on measurements made by the flow-metric sensor; and controlling the metering member based on the density value.
metering fuel by the metering member;
discharging into the recirculation branch fuel provided in excess by the pumping system, the discharging being performed by the regulating valve;
determining a value of a density of the metered fuel based on measurements made by the flow-metric sensor; and
A supply circuit according to claim 5 , wherein at least one downstream flow-metric sensor is disposed downstream of the metering device, the computer being configured to implement the method comprising: determining another value of the density of the metered fuel based on measurements of the downstream flow-metric sensor; and controlling the metering member based on the other density value and on the fuel density value determined based on the measurements of the sensor disposed on the recirculation branch.
the computer being configured to implement the method comprising: determining another value of the density of the metered fuel based on measurements of the downstream flow-metric sensor; and controlling the metering member based on the other density value and on the fuel density value determined based on the measurements of the sensor disposed on the recirculation branch.
determining another value of the density of the metered fuel based on measurements of the downstream flow-metric sensor; and
An aircraft engine, in particular a turbomachine, including a supply circuit according to claim 5 .
An aircraft including an aircraft engine according to claim 7 .
Ref US20170292457A1: Claims:
A method comprising: determining a correction factor for a fuel flow of a fuel system of an engine; determining a nominal fuel flow based on a metering valve stroke; and applying the correction factor to the nominal fuel flow to produce an estimated fuel flow to control combustion in the engine.
determining a correction factor for a fuel flow of a fuel system of an engine;
determining a nominal fuel flow based on a metering valve stroke; and
applying the correction factor to the nominal fuel flow to produce an estimated fuel flow to control combustion in the engine.
The method of claim 1 , wherein the correction factor is determined as a difference between a calculated fuel flow and a mass flow meter reading at one or more flight regimes and divided by the calculated fuel flow.
The method of claim 1 , wherein the correction factor is a vector and the one or more flight regimes comprise ground idle, cruise, and a maximum takeoff power of the engine.
The method of claim 3 , wherein the correction factor is weighted to apply a greater weighting for the cruise flight regime than the ground idle or the maximum takeoff power flight regimes.
The method of claim 1 , wherein the correction factor is a weighted value that applies a greater weighting to a previously computed correction factor from a previous flight.
The method of claim 1 , wherein the correction factor is reset upon installation or replacement of a fuel metering valve and/or a mass flow meter of the fuel system.
The method of claim 1 , wherein the estimated fuel flow includes an adjustment for fuel density effects.
The method of claim 1 , wherein the correction factor is determined based on feedback of a past value of the estimated fuel flow.
The method of claim 1 , wherein a trend of changes in the correction factor over a plurality of flights is monitored to determine a need for a maintenance action or a repair action.
The method of claim 1 , wherein a trend of the estimated fuel flow as compared to an on-board model with a fuel flow tuner is monitored to determine validity of the correction factor.
A fuel system of an engine, the fuel system comprising: a fuel metering valve; a mass flow meter; and a controller operable to: determine a correction factor for a fuel flow of the fuel system based on one or more readings of the mass flow meter; determine a nominal fuel flow based on a metering valve stroke of the fuel metering valve; and apply the correction factor to the nominal fuel flow to produce an estimated fuel flow to control combustion in the engine.
a fuel metering valve;
a mass flow meter; and
a controller operable to: determine a correction factor for a fuel flow of the fuel system based on one or more readings of the mass flow meter; determine a nominal fuel flow based on a metering valve stroke of the fuel metering valve; and apply the correction factor to the nominal fuel flow to produce an estimated fuel flow to control combustion in the engine.
determine a correction factor for a fuel flow of the fuel system based on one or more readings of the mass flow meter;
determine a nominal fuel flow based on a metering valve stroke of the fuel metering valve; and
apply the correction factor to the nominal fuel flow to produce an estimated fuel flow to control combustion in the engine.
The fuel system of claim 11 , wherein the correction factor is determined as a difference between a calculated fuel flow and a mass flow meter reading at one or more flight regimes and divided by the calculated fuel flow.
The fuel system of claim 11 , wherein the correction factor is a vector and the one or more flight regimes comprise ground idle, cruise, and a maximum takeoff power of the engine.
The fuel system of claim 13 , wherein the correction factor is weighted to apply a greater weighting for the cruise flight regime than the ground idle or the maximum takeoff power flight regimes.
The fuel system of claim 11 , wherein the correction factor is a weighted value that applies a greater weighting to a previously computed correction factor from a previous flight.
The fuel system of claim 11 , wherein the correction factor is reset upon installation or replacement of the fuel metering valve and/or the mass flow meter of the fuel system.
The fuel system of claim 11 , wherein the estimated fuel flow includes an adjustment for fuel density effects.
The fuel system of claim 11 , wherein the correction factor is determined based on feedback of a past value of the estimated fuel flow.
The fuel system of claim 11 , wherein a trend of changes in the correction factor over a plurality of flights is monitored to determine a need for a maintenance action or a repair action.
The fuel system of claim 11 , wherein a trend of the estimated fuel flow as compared to an on-board model with a fuel flow tuner is monitored to determine validity of the correction factor.
Ref US20140053645A1: Claims:
A method of determining a quantity of fuel within a fuel tank having a drain valve penetrating a lower boundary of the fuel tank, the method including: interconnecting a pressure measurement probe with the drain valve to permit direct or indirect contact between a pressure sensor and fuel within the tank; measuring a pressure of the fuel with the pressure sensor; and using the measured pressure and information relating to the geometry of the fuel tank to determine the quantity of fuel within the tank.
interconnecting a pressure measurement probe with the drain valve to permit direct or indirect contact between a pressure sensor and fuel within the tank;
measuring a pressure of the fuel with the pressure sensor; and
using the measured pressure and information relating to the geometry of the fuel tank to determine the quantity of fuel within the tank.
A method according to claim 1 , wherein the step of using the measured pressure and information relating to the geometry of the fuel tank to determine the quantity of fuel within the tank includes one of: consulting a look-up table comprising a matrix of corresponding pressures and fuel quantities for said fuel tank; and using one or more conversion equations.
A method according to claim 1 , including detecting an identifier associated with said fuel tank, wherein the step of determining the quantity of fuel within the tank includes using the detected identifier and measured pressure and information relating to the geometry of the fuel tank to determine the quantity of fuel.
A method according to claim 3 , wherein the step of detecting an identifier associated with said fuel tank includes interrogating an identification device attached to said fuel tank.
A method according to claim 1 , including detecting a temperature of either fuel within said fuel tank or air external to said fuel tank, wherein the step of determining the quantity of fuel within the tank includes using the detected temperature and measured pressure to determine the quantity of fuel.
A method according to claim 1 , including detecting an attitude of said fuel tank, wherein the step of determining the quantity of fuel within the tank includes using the detected attitude and measured pressure to determine the quantity of fuel.
A method according to claim 1 , including interconnecting a drain probe with the drain valve to drain some or all of the fuel from the fuel tank.
A method according to claim 1 , wherein the fuel tank is arranged to supply fuel to one or more engines of an aircraft.
Equipment for determining a quantity of fuel within a fuel tank having a drain valve penetrating a lower boundary of the fuel tank, the equipment comprising: a device including a pressure measurement probe and a pressure sensor, the pressure measurement probe being adapted to interconnect with the drain valve to permit direct or indirect contact between the pressure sensor and fuel within the tank; and quantity calculation means for generating a value indicative of the quantity of fuel using a pressure measured by the pressure sensor and information relating to the geometry of the fuel tank.
Equipment according to claim 9 , including a fuel duct arranged to provide fluid communication between the drain valve and the pressure sensor when the pressure measurement probe is interconnected with the drain valve.
Equipment according to claim 9 , wherein the device includes a power source arranged to provide operating power to the pressure measurement probe.
Equipment according to claim 9 , wherein the device includes a computation module arranged to convert a measured pressure from the pressure sensor into the quantity of said fuel.
Equipment according to claim 12 , including an identity detection module arranged to interrogate an identification device of the fuel tank to determine an identify of the fuel tank, wherein the computation module is arranged to receive from the identity detection module identification data indicative of a detected identity of the fuel tank, and to use that identification data to convert the measured pressure into the quantity of said fuel.
Equipment according to claim 12 , including a temperature sensor arranged to detect a temperature of either fuel within the fuel tank or air external to the fuel tank, wherein the computation module is arranged to receive from the temperature sensor temperature data indicative of a detected temperature, and to use that temperature data to convert the measured pressure into the quantity of said fuel.
Equipment according to claim 12 , wherein the computation module is arranged to receive attitude data indicative of an attitude of the fuel tank, and to use that attitude data to convert the measured pressure into the quantity of said fuel.
Equipment according to any claim 12 , wherein the computation module is arranged to calculate an error band representative of an accuracy of the determined quantity of said fuel.
Equipment according to claim 9 , wherein the quantity calculation means comprises at least one of: a look-up table comprising a matrix of corresponding pressures and fuel quantities for said fuel tank; and one or more conversion equations.
A device according to claim 9 , wherein the fuel tank is arranged to supply fuel to one or more engines of an aircraft.
Apparatus for determining a quantity of fuel within a fuel tank, the apparatus including: a drain valve penetrating a lower boundary of the fuel tank, the drain valve being biased towards a closed configuration in which fuel is prevented from flowing through the drain valve; equipment according to claim 9 , wherein the pressure measurement probe is adapted to interconnect with the drain valve to urge the drain valve to a measurement configuration in which fuel is permitted to flow within the drain valve to directly or indirectly contact the pressure sensor and thereby permit measurement of a pressure of the fuel.
a drain valve penetrating a lower boundary of the fuel tank, the drain valve being biased towards a closed configuration in which fuel is prevented from flowing through the drain valve;
equipment according to claim 9 , wherein the pressure measurement probe is adapted to interconnect with the drain valve to urge the drain valve to a measurement configuration in which fuel is permitted to flow within the drain valve to directly or indirectly contact the pressure sensor and thereby permit measurement of a pressure of the fuel.
Apparatus according to claim 19 , wherein the quantity calculation means comprises one of: a look-up table comprising a matrix of corresponding pressures and fuel quantities for said fuel tank; and a computation module arranged to receive a measured pressure from the pressure sensor and to use that measured head of pressure to calculate the fuel quantity.
Apparatus according to claim 19 , wherein the drain valve has an open configuration in which it permits draining of fuel from the fuel tank through the drain valve.
Apparatus according to claim 19 , including a drain device adapted to interconnect with the drain valve to urge the drain valve to the open configuration, the drain device optionally having a sampling container arranged to collect a sample volume of fuel draining from the fuel tank via the drain valve.
Apparatus according to claim 19 , wherein the fuel tank is arranged to supply fuel to one or more engines of an aircraft.
Ref US20150191667A1: Claims:
An aviation fuel composition comprising: an energy providing component, including i) 70 to 99.9 vol. % of a hydrocarbon mixture, and ii) 0.1 to 30 vol. % of an alcohol component selected from the group consisting of one or more Guerbet alcohols, having a number or mean value of number of carbon atoms, respectively, of equal to or less than 12, and optionally one or more aviation fuel additives.
an energy providing component, including i) 70 to 99.9 vol. % of a hydrocarbon mixture, and ii) 0.1 to 30 vol. % of an alcohol component selected from the group consisting of one or more
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