# US 9,038,362 B2 · Turbofan engine with variable area fan nozzle and low spool generator for emergency power generation and method for providing emergency power > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,362 B2 - Document ID: US9038362B2 - Status: Granted - Kind: B2 - Application number: 12/373,165 - Filed: 2006-10-12 - Published: 2010-09-23 - Granted: 2015-05-26 - Earliest claimed: 2006-10-12 - Assignees: United Technologies Corporation - Applicants: Michael Winter; Charles E. Lents - Inventors: Michael Winter; Charles E. Lents - Web page: https://patentgrep.com/patent/US9038362B2 ## CPC - F02C 7/262: Restarting after flame-out - F01D 21/00: Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for - F02C 3/113: with variable power transmission between rotors - F02C 7/32: Arrangement, mounting, or driving, of auxiliaries - F05D 2270/061: in particular the electrical frequency of driven generator - F05D 2270/092: in particular blow-out and relight - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - 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) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A turbofan engine (10) employs a flow control device (41) that changes an effective exit nozzle area (40) associated with a bypass flow path (B) of the turbofan engine. A spool (14) couples a fan (20) to a generator (52). The turbofan emergency power system includes a controller (50) that communicates with the flow control device (41). Upon sensing an emergency condition, the controller manipulates the flow control device to reduce the effective nozzle exit area (40) of the bypass flow path, which chokes the flow through the bypass flow path thereby increasing the rotational speed of the fan. In this manner, the generator is driven at a higher rotational speed than if the flow through the bypass flow path was not choked, which enables a smaller generator to be utilized. ## Claims ### Claim 1 A turbofan engine emergency control system comprising: a spool supporting a turbine and arranged in a core nacelle; a fan arranged upstream from the core nacelle and coupled to the spool; a fan nacelle surrounding the fan and core nacelle and providing a bypass flow path that includes a nozzle exit area; a generator coupled to the spool for receiving drive from the fan in a windmilling condition; and a flow control device adapted to effectively changing the nozzle exit area in response to an emergency condition during the windmilling condition. ### Claim 2 (depends on 1) The turbofan engine emergency system according to claim 1, comprising a controller commanding the flow control device to effectively reduce but not fully block the nozzle exit area. ### Claim 3 (depends on 2) The turbofan engine emergency control system according to claim 2, wherein the generator includes a rotational speed in the windmilling condition, and effectively reducing the nozzle exit area increases the rotational speed. ### Claim 4 (depends on 1) The turbofan engine emergency control system according to claim 1, wherein the generator is an electric generator. ### Claim 5 (depends on 1) The turbofan engine emergency control system according to claim 1, wherein the generator is a hydraulic pump. ### Claim 6 (depends on 1) The turbofan engine emergency control system according to claim 1, wherein the flow control device is arranged downstream from the fan. ### Claim 7 (depends on 1) The turbofan engine emergency control system according to claim 1, wherein the spool includes a low pressure compressor and a low pressure turbine mounted thereon. ### Claim 8 (depends on 1) The turbofan engine emergency control system according to claim 1, comprising a gear train interconnected between the spool and the fan. ### Claim 9 A method of providing emergency power using a turbofan engine comprising the steps of: windmilling a fan in response to an emergency condition; effectively reducing a nozzle exit area in response to the emergency condition to increase a rotational speed of the fan during the windmilling step; and selectively engaging a generator during the windmilling step and driving the generator at the increased speed. ### Claim 10 (depends on 9) The method according to claim 9, comprising the step of driving a generator with the fan in the windmilling step.