# US 9,038,399 B2 · Systems and methods for driving an oil cooling fan of a gas turbine engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,399 B2 - Document ID: US9038399B2 - Status: Granted - Kind: B2 - Application number: 13/602,395 - Filed: 2012-09-04 - Published: 2014-03-06 - Granted: 2015-05-26 - Earliest claimed: 2012-09-04 - Assignees: Pratt & Whitney Canada Corp. - Applicants: Ian A. MacFarlane - Inventors: Ian A. MacFarlane - Web page: https://patentgrep.com/patent/US9038399B2 ## CPC - F02C 7/14: of fluids in the plant {, e.g. lubricant or fuel (F02C7/185 takes precedence)} - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Systems and methods for driving an oil cooling fan (36) of a gas turbine engine (10) during different modes of operation of the gas turbine engine (10) are described. A system may include a coupling device (40) configured to: transmit motive power from a power turbine shaft (22) of the gas turbine engine (10) to the oil cooling fan (36) during a first mode of operation where the power turbine shaft (22) is turning, and to decouple the oil cooling fan (36) from the power turbine shaft (22) during a second mode of operation where the power turbine shaft (22) is prevented from turning. An alternate source (42) of motive power may be configured to drive the oil cooling fan (36) during the second mode of operation. ## Claims ### Claim 1 A system for driving an oil cooling fan of a gas turbine engine, the system comprising: a coupling device configured to: transmit motive power from a power turbine shaft driven by a low pressure turbine of the gas turbine engine to the oil cooling fan during a first mode of operation where the power turbine shaft is turning, and to decouple the oil cooling fan from the power turbine shaft during a second mode of operation where the power turbine shaft is prevented from turning; and an alternate source of motive power configured to drive the oil cooling fan during the second mode of operation, the alternate source of motive power including a high pressure turbine of the gas turbine engine. ### Claim 2 (depends on 1) The system as defined in claim 1, wherein engine is an aircraft-mounted engine. ### Claim 3 (depends on 1) The system as defined in claim 1, wherein the alternate source of motive power includes an electric motor. ### Claim 4 (depends on 3) The system as defined in claim 3, wherein the electric motor is driven by a source of electricity powered by the high pressure turbine of the gas turbine engine. ### Claim 5 (depends on 1) The system as defined in claim 1, wherein an output of the alternate source of motive power is configured to be modulated based on a cooling load on an oil cooler of the gas turbine engine. ### Claim 6 (depends on 1) The system as defined in claim 1, wherein the alternate source of motive power is configured to vary the speed of the oil cooling fan based on a cooling load on an oil cooler of the gas turbine engine. ### Claim 7 A gas turbine engine comprising: a low pressure turbine coupled to a power turbine shaft; an oil cooler including an oil cooling fan; a coupling device configured to: transmit motive power from the power turbine shaft of the gas turbine engine to the oil cooling fan during a first mode of operation where the power turbine shaft is turning, and to decouple the oil cooling fan from the power turbine shaft during a second mode of operation where the power turbine shaft is prevented from turning; and an alternate source of motive power configured to drive the oil cooling fan during the second mode of operation, the alternate source of motive power including a high pressure turbine of the gas turbine engine. ### Claim 8 (depends on 7) The gas turbine engine as defined in claim 7, wherein engine is an aircraft-mounted engine. ### Claim 9 (depends on 7) The gas turbine engine as defined in claim 7, wherein the alternate source of motive power includes an electric motor. ### Claim 10 (depends on 9) The gas turbine engine as defined in claim 9, wherein the electric motor is driven by a source of electricity powered by the high pressure turbine of the gas turbine engine. ### Claim 11 (depends on 9) The gas turbine engine as defined in claim 9, wherein the electric motor is configured to vary the speed of the oil cooling fan based on a cooling load on the oil cooler. ### Claim 12 (depends on 7) The gas turbine engine as defined in claim 7, wherein an output of the alternate source of motive power is configured to be modulated based on a cooling load on the oil cooler. ### Claim 13 A method for driving an oil cooling fan of an oil cooler of a gas turbine engine, the method comprising: driving the oil cooling fan using motive power extracted from a power turbine shaft driven by a low pressure turbine of the gas turbine engine during a first mode of operation where the power turbine shaft is turning; and driving the oil cooling fan using motive power from an alternate source during a second mode of operation where the power turbine shaft is prevented from turning, the alternate source of motive power including a high pressure turbine of the gas turbine engine. ### Claim 14 (depends on 13) The method as defined in claim 13, wherein the alternate source comprises an electric motor. ### Claim 15 (depends on 14) The method as defined in claim 14, comprising driving the electric motor using power extracted from the high pressure turbine of the gas turbine engine. ### Claim 16 (depends on 13) The method as defined in claim 13, comprising modulating an output of the alternate source based on a cooling load on the oil cooler. ### Claim 17 (depends on 13) The method as defined in claim 13, wherein the second mode of operation comprises a hotel mode where the power turbine shaft is locked.