# US 11,898,500 B2 · Inlet configuration enabling rapid in-flight engine restart > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,898,500 B2 - Document ID: US11898500B2 - Status: Granted - Kind: B2 - Application number: 17/130,358 - Filed: 2020-12-22 - Published: 2022-06-23 - Granted: 2024-02-13 - Earliest claimed: 2020-12-22 - Assignees: Textron Innovations Inc. - Applicants: Bell Textron Inc. - Inventors: Thomas Dewey Parsons - Web page: https://patentgrep.com/patent/US11898500B2 ## CPC - F02C 9/20: by throttling; by adjusting vanes - F02C 7/057: Control or regulation (conjointly with fuel supply control F02C9/50, with nozzle area control F02K1/16) - F02C 7/26: Starting; Ignition - F02C 7/262: Restarting after flame-out - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2260/85: Starting - F05D 2270/02: to control rotational speed (n) - F05D 2270/09: to cope with emergencies - 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 Embodiments are directed to systems and methods for controlling an aircraft engine inlet comprises determining a required engine RPM for an engine in-flight restart based upon current aircraft parameters, detecting a command to initiate the engine in-flight restart, and managing a position of an engine inlet barrier to control a volume of air entering an engine intake, wherein the ram air causes an engine turbine to achieve the required engine RPM. The required engine RPM may be an N1 gas generator RPM. The engine inlet barrier may be a hinged door positioned within the engine inlet or a series of inlet variable guide vanes that are configured to rotate between a closed position and an opened position. The position of the engine inlet barrier may be controlled by a flight control computer or an engine control computer. ## Claims ### Claim 1 A method for controlling an aircraft engine inlet, comprising: maintaining an engine inlet barrier in a closed position while an engine is shut down during flight; determining a required engine RPM for an engine in-flight restart based upon current aircraft parameters; detecting a command to initiate the engine in-flight restart; managing a position of the engine inlet barrier to control a volume of ram air entering an engine intake; monitoring parameters of the ram air in the engine intake; and adjusting the position of the engine inlet barrier, in response to the parameters of the air in the engine intake, such that the ram air causes the engine to achieve the required engine RPM. ### Claim 2 (depends on 1) The method of claim 1, wherein the required engine RPM is gas generator speed. ### Claim 3 (depends on 1) The method of claim 1, wherein the engine inlet barrier is a hinged door positioned within the engine inlet. ### Claim 4 (depends on 1) The method of claim 1, wherein the engine inlet barrier is a series of engine inlet variable guide vanes that are configured to rotate between a closed position and an opened position. ### Claim 5 (depends on 1) The method of claim 1, wherein the position of the engine inlet barrier is controlled by a flight control computer or an engine control computer. ### Claim 6 (depends on 1) The method of claim 1, further comprising: monitoring current aircraft parameters, wherein the aircraft parameters comprise one or more of: an airspeed, an altitude, and an outside air temperature; and wherein the required engine RPM for the engine in-flight restart is updated at regular intervals or when the current aircraft parameters change by a threshold amount. ### Claim 7 (depends on 1) The method of claim 1, further comprising: detecting a command to shut down the engine while in flight; and managing the position of the engine inlet barrier to block ram air from entering the engine intake. ### Claim 8 (depends on 7) The method of claim 7, further comprising: monitoring engine parameters during a shutdown sequence; and closing the engine inlet barrier when the engine is below a minimum engine RPM. ### Claim 9 (depends on 1) The method of claim 1, further comprising monitoring a current engine RPM, and wherein adjusting the position of the engine inlet barrier further comprises adjusting the position of the engine inlet barrier, in response to the parameters of the air in the engine intake and the current engine RPM, to maximize the rate at which the engine achieves the required engine RPM. ### Claim 10 (depends on 1) The method of claim 1, wherein managing the position of the engine inlet barrier comprises: adjusting the position of the engine inlet barrier according to a predetermined schedule. ### Claim 11 (depends on 1) The method of claim 1, wherein the required engine RPM is determined from aircraft performance chart data. ### Claim 12 (depends on 1) The method of claim 1, wherein managing the position of the engine inlet barrier comprises: providing a command to one or more actuators to adjust the engine inlet barrier to conform to a calculated engine inlet area. ### Claim 13 An aircraft, comprising: an engine inlet configured to provide air to an engine during flight; an engine inlet barrier configured to manage a volume of air provided to the engine; a flight control system configured to: maintain the engine inlet barrier in a closed position while the engine is shut down during flight determine a required engine RPM for an engine in-flight restart based upon current aircraft parameters; manage a configuration of the engine inlet barrier to control the volume of air entering the engine inlet during the engine in-flight restart, the volume of air selected to cause the engine to achieve the required engine RPM; monitor parameters of the air in the engine intake during the engine in-flight restart; and adjust the configuration of the engine inlet barrier during the engine in-flight restart, in response to the parameters of the air in the engine intake during the engine in-flight restart, to achieve the volume of air selected to cause the engine to achieve the required engine RPM. ### Claim 14 (depends on 13) The aircraft of claim 13, wherein the flight control system is further configured to: determine the required engine RPM after detecting a command to initiate the engine in-flight restart. ### Claim 15 (depends on 13) The aircraft of claim 13, wherein the engine inlet barrier is a hinged door positioned within the engine inlet. ### Claim 16 (depends on 13) The aircraft of claim 13, wherein the engine inlet barrier is a series of engine inlet variable guide vanes that are configured to rotate between a closed position and an opened position. ### Claim 17 (depends on 13) The aircraft of claim 13, wherein the flight control system is further configured to: detect a command to shut down the engine while in flight; and manage the position of the engine inlet barrier to block air from entering the engine intake. ### Claim 18 A flight control computer for an aircraft, comprising: one or more processors; one or more non-transitory computer-readable storage media having stored thereon computer-executable instructions that, when executed by the one or more processors, causes the processors to: maintain an engine inlet barrier in a closed position while an engine is shut down during flight; determine a required engine RPM for an engine in-flight restart based upon current aircraft parameters; select a volume of air entering an engine intake during the engine in-flight restart to cause the engine to achieve the required engine RPM; and manage a configuration of the engine inlet barrier to control the volume of air entering the engine intake during the engine in-flight restart; monitor parameters of the air in the engine intake during the engine in-flight restart; and adjust the position of the engine inlet barrier during the engine in-flight restart, in response to the parameters of the air in the engine intake during the engine in-flight restart, to achieve the volume of air selected to cause the engine to achieve the required engine RPM. ### Claim 19 (depends on 18) The flight control computer of claim 18, wherein the computer-executable instructions further cause the processors to: monitor a current engine RPM during the engine in-flight restart; and adjust the position of the engine inlet barrier, in response to the parameters of the air in the engine intake during the engine in-flight restart and the current engine RPM during the engine in-flight restart, to maximize the rate at which the engine achieves the required engine RPM. ### Claim 20 (depends on 18) The flight control computer of claim 18, wherein the computer-executable instructions further cause the processors to: adjust the position of the engine inlet barrier according to a predetermined schedule.