# US 12,601,492 B2 · Gas turbine engine and method thereof for reducing non-volatile particulate matter emissions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,601,492 B2 - Document ID: US12601492B2 - Status: Granted - Kind: B2 - Application number: 19/247,856 - Filed: 2025-06-24 - Published: 2025-12-11 - Granted: 2026-04-14 - Earliest claimed: 2024-06-10 - Assignees: ROLLS-ROYCE plc - Applicants: ROLLS-ROYCE plc - Inventors: Christopher P Madden; Peter Swann - Web page: https://patentgrep.com/patent/US12601492B2 ## CPC - F23R 3/34: Feeding into different combustion zones - F02C 7/22: Fuel supply systems - F02C 7/228: Dividing fuel between various burners - F23R: GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS (fluidised bed combustion apparatus specially adapted for operation at superatmospheric pressures F23C10/16) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) ## Abstract A gas turbine engine for aircraft includes a combustor with a combustion chamber and fuel spray nozzles to inject fuel into the combustion chamber. The fuel spray nozzles include a first subset and a second subset of nozzles. Each of the first subset is supplied with fuel at a greater rate than each of the second subset. A ratio of the first subset to the second subset is 1:2 to 1:5. A MTO nvPM emissions index ratio is EI maxTO , SAF EI maxTO , FF . EImaxTO,SAF is nvPM emissions index in mg/kg of the engine when operating at around 100% available thrust if fuel provided to the fuel spray nozzles includes sustainable aviation fuel. EImaxTO,FF is nvPM emissions index in mg/kg of the engine when operating at around 100% available thrust if fuel provided to the fuel spray nozzles is fossil-based hydrocarbon fuel. The MTO nvPM emissions index ratio is less than 1. ## Claims ### Claim 1 A gas turbine engine for an aircraft, comprising: a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber, wherein the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles and a second subset of fuel spray nozzles, wherein the combustor is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles is supplied with fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles, wherein a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:2 to 1:5; and wherein: a maximum take-off (MTO) non-volatile particulate matter (nvPM) emissions index ratio is defined as: EI maxTO , SAF EI maxTO , FF where: EImaxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel (SAF); and EImaxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine (10) when operating at around 100% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; the MTO nvPM emissions index ratio of the gas turbine engine is less than 1; and the gas turbine engine is configured to provide fuel comprising a SAF to the plurality of fuel spray nozzles. ### Claim 2 (depends on 1) The gas turbine engine of claim 1, wherein the MTO nvPM emissions index ratio is less than or equal to 0.93. ### Claim 3 (depends on 1) The gas turbine engine of claim 1, wherein the MTO nvPM emissions index ratio is greater than or equal to 0.15. ### Claim 4 (depends on 1) The gas turbine engine of claim 1, wherein the MTO nvPM emissions index ratio is in the range of 0.516 to 0.776. ### Claim 5 (depends on 1) The gas turbine engine of claim 1, wherein: a climb nvPM emissions index ratio is defined as: EI climb , SAF EI climb , FF where: EIclimb,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the given operating conditions, or for different given operating conditions, if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel (SAF); and EIclimb,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the same given operating conditions at which EIclimb,SAF is calculated and if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; and the climb nvPM emissions index ratio of the gas turbine engine is less than 1. ### Claim 6 (depends on 5) The gas turbine engine of claim 5, wherein the climb nvPM emissions index ratio is less than or equal to 0.9. ### Claim 7 (depends on 1) The gas turbine engine of claim 1, wherein: an approach nvPM emissions index ratio is defined as: EI approach , SAF EI approach , FF where: EIapproach,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the given operating conditions, or for different given operating conditions, if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel (SAF); and EIapproach,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the same given operating conditions at which EIapproach,SAF is calculated and if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; and the approach nvPM emissions index ratio of the gas turbine engine is less than 1. ### Claim 8 (depends on 7) The gas turbine engine of claim 7, wherein the approach nvPM emissions index ratio is less than or equal to 0.8. ### Claim 9 (depends on 1) The gas turbine engine of claim 1, wherein: an idle nvPM emissions index ratio is defined as: EI idle , SAF EI idle , FF where: EIidle,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 7% available thrust for the given operating conditions, or for different given operating conditions, and if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel (SAF); and EIidle,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 7% available thrust for the same given operating conditions at which EIidle,SAF is calculated and if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; and the idle nvPM emissions index ratio of the gas turbine engine is less than 1. ### Claim 10 (depends on 9) The gas turbine engine of claim 9, wherein the idle nvPM emissions index ratio is less than or equal to 0.8. ### Claim 11 (depends on 9) The gas turbine engine of claim 9, wherein the idle nvPM emissions index ratio is greater than or equal to 0.02. ### Claim 12 (depends on 1) The gas turbine engine of claim 1, wherein the ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:3 to 1:4. ### Claim 13 (depends on 1) The gas turbine engine of claim 1, wherein the combustor comprises one or more ignitors. ### Claim 14 (depends on 13) The gas turbine engine of claim 13, wherein each of the first subset of fuel spray nozzles is located nearer a respective one or more of the ignitors than the second subset, and/or wherein one or more of the ignitors is arranged diametrically opposite another one or more of the ignitors. ### Claim 15 (depends on 1) The gas turbine engine of claim 1, wherein the fuel provided to the plurality of fuel spray nozzles comprises a % SAF in the range of 50% to 100%. ### Claim 16 (depends on 1) A method of operating the gas turbine engine of claim 1, the method comprising providing fuel comprising a sustainable aviation fuel to the plurality of fuel spray nozzles. ### Claim 17 A method of operating a gas turbine engine, the gas turbine engine comprising: a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber, wherein the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles and a second subset of fuel spray nozzles, wherein the combustor is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles is supplied with fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles, wherein a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:2 to 1:5; and wherein: a maximum take-off (MTO) non-volatile particulate matter (nvPM) emissions index ratio is defined as: EI maxTO , SAF EI maxTO , FF where: EImaxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine operating at 100% available thrust for given operating conditions with fuel provided to the plurality of fuel spray nozzles comprising a sustainable aviation fuel (SAF); EImaxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine operating at 100% available thrust for the given operating conditions with fuel provided to the plurality of fuel spray nozzles being a fossil-based hydrocarbon fuel; and the MTO nvPM emissions index ratio of the gas turbine engine is less than 1; and the method comprises providing fuel comprising the sustainable aviation fuel to the plurality of fuel spray nozzles. ### Claim 18 (depends on 17) The method of claim 17, wherein: a climb nvPM emissions index ratio is defined as: EI climb , SAF EI climb , FF where: EIclimb,SAF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 85% available thrust for the given operating conditions, or for different given operating conditions, with the fuel provided to the plurality of fuel spray nozzles comprising the sustainable aviation fuel (SAF); and EIclimb,FF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 85% available thrust for the same given operating conditions at which EIclimb,SAF is determined and with the fuel provided to the plurality of fuel spray nozzles being the fossil-based hydrocarbon fuel; and the climb nvPM emissions index ratio of the gas turbine engine is less than 1. ### Claim 19 (depends on 17) The method of claim 17, wherein: an approach nvPM emissions index ratio is defined as: EI approach , SAF EI approach , FF where: EIapproach,SAF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 30% available thrust for the given operating conditions, or for different given operating conditions, with the fuel provided to the plurality of fuel spray nozzles comprising the sustainable aviation fuel (SAF); and EIapproach,FF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 30% available thrust for the same given operating conditions at which EIapproach,SAF is determined and with the fuel provided to the plurality of fuel spray nozzles being the fossil-based hydrocarbon fuel; and the approach nvPM emissions index ratio of the gas turbine engine is less than 1. ### Claim 20 (depends on 17) The method of claim 17, wherein: an idle nvPM emissions index ratio is defined as: EI idle , SAF EI idle , FF where: EIidle,SAF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 7% available thrust for the given operating conditions, or for different given operating conditions, and with the fuel provided to the plurality of fuel spray nozzles comprising the sustainable aviation fuel; and EIidle,FF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 7% available thrust for the same given operating conditions at which EIidle,SAF is determined and with the fuel provided to the plurality of fuel spray nozzles being the fossil-based hydrocarbon fuel; and the idle nvPM emissions index ratio of the gas turbine engine is less than 1.