# US 12,110,827 B1 · Fuel systems for aircraft engines > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,110,827 B1 - Document ID: US12110827B1 - Status: Granted - Kind: B1 - Application number: 18/311,660 - Filed: 2023-05-03 - Granted: 2024-10-08 - Earliest claimed: 2023-05-03 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Jeffrey D. Rambo; Scott G. Edens; Michael Joseph Murray - Web page: https://patentgrep.com/patent/US12110827B1 ## CPC - F02C 7/236: Fuel delivery systems comprising two or more pumps - F02C 7/32: Arrangement, mounting, or driving, of auxiliaries - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2270/07: to improve fuel economy - 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) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A turbo engine for an aircraft includes a gas turbine engine having a combustion section and a fuel system to provide pressurized fuel to the combustion section. The fuel system includes a fuel tank and a boost pump and a main pump driven by an accessory gearbox that is powered by a shaft of the turbo engine. The boost pump and the main pump are arranged in series. The fuel system also includes an auxiliary pump and a controller to operate the fuel system in (1) a first mode in which the boost pump and the main pump produce pressurized fuel for the turbo engine and the auxiliary pump is deactivated, and (2) a second mode in which the auxiliary pump is activated and produces the pressurized fuel for the turbo engine while bypassing the boost pump and the main pump. ## Claims ### Claim 1 A turbo engine for an aircraft, the turbo engine comprising: a gas turbine engine having a combustion section; and a fuel system to provide pressurized fuel to the combustion section, the fuel system including: a fuel tank; a boost pump and a main pump driven by an accessory gearbox that is powered by a shaft of the turbo engine, the boost pump and the main pump arranged in series; first and second temperature sensors to measure a temperature difference fuel across the boost pump and the main pump; an auxiliary pump; and a controller configured to: compare the temperature difference to a threshold; and operate the fuel system in (1) a first mode in which the boost pump and the main pump produce pressurized fuel for the turbo engine and the auxiliary pump is deactivated when the temperature difference is below the threshold, and (2) a second mode in which the auxiliary pump is activated and produces the pressurized fuel for the turbo engine while bypassing the boost pump and the main pump when the temperature difference exceeds the threshold. ### Claim 2 (depends on 1) The turbo engine of claim 1, wherein the auxiliary pump is driven by an electric motor. ### Claim 3 (depends on 2) The turbo engine of claim 2, wherein the electric motor is powered by an auxiliary power unit (APU) or an integrated power pack (IPP) of the aircraft. ### Claim 4 (depends on 1) The turbo engine of claim 1, wherein the auxiliary pump is powered by a gearbox with a clutch. ### Claim 5 (depends on 1) The turbo engine of claim 1, wherein the auxiliary pump is arranged in parallel with the boost pump and the main pump. ### Claim 6 (depends on 1) The turbo engine of claim 1, wherein the fuel system includes an eductor fluidly coupled to the boost pump and the main pump, wherein at least a portion of the pressurized fuel produced by the auxiliary pump in the second mode is routed through the eductor to cause the eductor to evacuate the boost pump and the main pump. ### Claim 7 (depends on 6) The turbo engine of claim 6, wherein the eductor is part of a recirculation manifold. ### Claim 8 (depends on 1) The turbo engine of claim 1, wherein the fuel system includes: a flow valve between the boost pump and the main pump; and an idler valve downstream of the main pump. ### Claim 9 (depends on 1) The turbo engine of claim 1, wherein at least a portion of the pressurized fuel produced by the auxiliary pump in the second mode is routed to one or more actuators to provide hydraulic pressure to operate the one or more actuators. ### Claim 10 A turbo engine for an aircraft, the turbo engine comprising: a gas turbine engine having a combustion section; and a fuel system to provide pressurized fuel to the combustion section, the fuel system including: a fuel tank; a boost pump and a main pump driven by an accessory gearbox that is powered by a shaft of the turbo engine, the boost pump and the main pump arranged in series; a flow valve between the boost pump and the main pump; and an idler valve downstream of the main pump; an auxiliary pump; and a controller configured to operate the fuel system in (1) a first mode in which the boost pump and the main pump produce pressurized fuel for the turbo engine and the auxiliary pump is deactivated, and (2) a second mode in which the auxiliary pump is activated and produces the pressurized fuel for the turbo engine while bypassing the boost pump and the main pump, wherein, during the second mode, the controller is configured to (1) partially close the flow valve and (2) control the idler valve to direct fuel back to an inlet of the main pump. ### Claim 11 (depends on 10) The turbo engine of claim 10, further including first and second temperature sensors to measure a temperature change of fuel across the boost pump and the main pump. ### Claim 12 (depends on 11) The turbo engine of claim 11, wherein the controller is configured to: compare the temperature change to a threshold; operate the fuel system in the first mode when the temperature change is below the threshold; and operate the fuel system in the second mode when the temperature change exceeds the threshold. ### Claim 13 (depends on 10) The turbo engine of claim 10, wherein the controller is configured to operate the fuel system in the second mode when the boost pump and the main pump are operating at a lower efficiency, and the controller is configured to operate the fuel system in the first mode when the boost pump and the main pump are operating at a higher efficiency. ### Claim 14 (depends on 10) The turbo engine of claim 10, further including a sensor to measure a speed of the gas turbine engine, wherein the controller is configured to compare the speed to a speed threshold. ### Claim 15 (depends on 14) The turbo engine of claim 14, wherein the controller is configured to operate the fuel system in the first mode when the speed is above the speed threshold, and the controller is configured to operate the fuel system in the second mode when the speed is below the speed threshold. ### Claim 16 A turbo engine for an aircraft, the turbo engine comprising: a gas turbine engine having a combustion section; and a fuel system to provide pressurized fuel to the combustion section, the fuel system including: a fuel tank; a boost pump and a main pump driven by an accessory gearbox that is powered by a shaft of the turbo engine, the boost pump and the main pump arranged in series; an auxiliary pump; a controller configured to operate the fuel system in (1) a first mode in which the boost pump and the main pump produce pressurized fuel for the turbo engine and the auxiliary pump is deactivated, and (2) a second mode in which the auxiliary pump is activated and produces the pressurized fuel for the turbo engine while bypassing the boost pump and the main pump; a first clutch between the boost pump and the accessory gearbox; and a second clutch between the main pump and the accessory gearbox, wherein, during the second mode, the controller is configured to cause the first and second clutches to disengage the boost pump and the main pump from the accessory gearbox. ### Claim 17 (depends on 16) The turbo engine of claim 16, further including first and second temperature sensors to measure a temperature change of fuel across the boost pump and the main pump. ### Claim 18 (depends on 17) The turbo engine of claim 17, wherein the controller is configured to: compare the temperature change to a threshold; operate the fuel system in the first mode when the temperature change is below the threshold; and operate the fuel system in the second mode when the temperature change exceeds the threshold. ### Claim 19 A non-transitory machine readable storage medium comprising instructions that, when executed, cause programmable circuitry to: compare a temperature difference to a threshold, the temperature difference measured across a boost pump and a main pump of a fuel system of a turbo engine of an aircraft, the boost pump and the main pump arranged in series, the fuel system including an auxiliary pump arranged in parallel with the boost pump and the main pump; operate the fuel system in a first mode when the temperature difference is below the threshold, wherein, in the first mode, fuel is directed through the boost pump and the main pump while the auxiliary pump is deactivated; determine the temperature difference exceeds the threshold; and in response to determining the temperature difference exceeds the threshold, operate the fuel system in a second mode by activating the auxiliary pump. ### Claim 20 (depends on 19) The non-transitory machine readable storage medium of claim 19, wherein the fuel system includes an electric motor to power the auxiliary pump, and the instructions, when executed, cause the programmable circuitry to activate the auxiliary pump during the second mode by supplying power to the electric motor from an auxiliary power unit (APU) or an integrated power pack (IPP) of the aircraft.