82, 84. It is noted that the number of blades, vanes, and turbine stages shown in FIG. 1 was selected for illustrative purposes only, and that other numbers are possible.

The HP turbine blades 82 for a stage of the turbine can be mounted to the high speed shaft 48. The LP turbine blades 84 for a stage of the turbine can be mounted to the low speed shaft 56 that is rotatably fixed to the electric machine 52. The vanes 86, 88 for a stage of the compressor can be mounted to the core housing 46 in a circumferential arrangement.

Complementary to the rotor portion, the stationary portions of the turbine engine 10, such as the static vanes 74, 76, 86, 88 among the compressor section 22 and turbine section 32 are also referred to individually or collectively as an outer rotor/stator. As illustrated, the outer rotor/stator can refer to the combination of non-rotating elements throughout the turbine engine 10. Alternatively, the outer rotor/stator that circumscribes at least a portion of the inner rotor/stator, can be designed to rotate. The inner or outer rotor/stator can include at least one component that can be, by way of non-limiting example, a shroud, vane, nozzle, nozzle body, combustor, hanger, or blade, where the at least one component is a plurality of circumferentially arranged component segments having confronting pairs of circumferential ends.

In operation, in a first mode or starting mode, the electric machine 52 functions primarily as a starter. Energy is supplied to the electric machine 52. Energy can be supplied to the electric machine 52, for example, from a battery bank, a mechanical starter, or electrical generating device. It is contemplated that the energy supplied to the electric machine 52 is from the one or more accessories 62. The energy supplied to the electric machine 52 rotates one or more components of the electric machine 52 resulting in a rotational of the output 53. The first clutch assembly 50 selectively couples the output 53 of the electric machine 52 to the high speed shaft 48, which rotates the high speed shaft 48. The rotation of the high speed shaft 48 rotates the blades 72, 82 of the HP compressor 26 and HP turbine 34.

As the electric machine 52 provides a rotational output at the output 53 to the high speed shaft 48, the low speed shaft 56 that is permanently coupled to the input/output 49 of the electric machine 52 is also supplied a rotation output. The rotation of the low speed shaft 56 results in the rotation of the blades 84 of the LP turbine 36.

As the rotational velocity of the high speed shaft 48 increases, the supplemental shaft 58 is selectively coupled to the supplemental coupling 61 of the electric machine 52 or the low speed shaft 56 via the second clutch assembly 60. The second clutch assembly 60 can selectively engage based on, for example, axial thermal expansion of one or more components of the electric machine 52, the low speed shaft 56, or other rotating component adjacent to the second clutch assembly 60. By way of non-limiting example, the second clutch assembly 60 additionally or alternatively can be activated or engage based on the load carried by one or more bearings, one or more speed or thermal sensors, counter-rotation, input provided by an active automatic control, a pilot or user, or reaching a predetermined torque value. The second clutch assembly 60 can engage before or after the electric machine 52 switches from the first mode to a second mode.

Once coupled via the second clutch assembly 60, the supplemental shaft 58 can receive a rotational output from the supplemental coupling 61 of the electric machine 52 via the second gearbox 57 or the low speed shaft 56. Alternatively, the supplemental shaft 58 can provide a rotational input at the supplemental coupling 61 to the electric machine 52 for generation of electrical power. Electric power from the electric machine 52 can be provided to the one or more accessories 62.

In a second mode or generating mode, the electric machine 52 functions primarily as a generator, providing electrical energy to the one or more accessories 62. The transition from the first mode to the second mode occurs when the first clutch assembly 50 disengages the output 53 of the electric machine 52 from the high speed shaft 48. The first clutch assembly 50 is adapted to disengage the electric machine 52 from the high speed shaft 48 when a predetermined torque or speed of the high speed shaft 48 is reached. The predetermined torque or speed can depend on the idle speed of the turbine engine 10. As used herein, “idle speed” is the speed at which the engine core 44 has to spin in order for the turbine engine 10 to idle or self-sustain. It is contemplated that the predetermined torque or speed can be greater than or equal to the idle speed of the turbine engine 10. However, it is contemplated that the predetermined torque or speed can be less than the idle speed of the turbine engine 10.

Once the engine is self-sustaining, the airflow exiting the fan section 18 is split such that a portion of the airflow is channeled into the LP compressor 24, which then supplies pressurized airflow 90 to the HP compressor 26, which further pressurizes the air.

The pressurized airflow 90 from the HP compressor 26 is mixed with fuel in the combustor 30 and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine 34, which drives the HP compressor 26. The combustion gases are discharged into the LP turbine 36, which extracts additional work to drive the electric machine 52, and the exhaust gas is ultimately discharged from the turbine engine 10 via the nozzle section 37. The driving of the LP turbine 36 can also drive the supplemental shaft 58 to rotate the fan assembly 20 and the LP compressor 24 via the electric machine 52 or the second clutch assembly 60.

The electric machine 52 can generate electricity in the second mode as a result of the rotation of the LP turbine 36 due to the exhaust of gases from the combustor 30. The rotation of the LP turbine 36 results in the rotation of the low speed shaft 56. The low speed shaft 56 can provide a rotatable input to the input/output 49 of the electric machine 52 for generating electrical energy. Alternatively, the low speed shaft 56 rotates a portion of the second gearbox 57, which provides an input to the input/output 49 of the electric machine 52. Electric power from the electric machine 52 is used to power the one or more accessories 62.

A portion of the pressurized airflow 90 can be drawn from the compressor section 22 as bleed air 92. The bleed air 92 can be drawn from the pressurized airflow 90 and provided to engine components requiring cooling. The temperature of pressurized airflow 90 entering the combustor 30 is significantly increased. As such, cooling provided by the bleed air 92 is necessary for operating of such engine components in the heightened temperature environments.

A remaining portion of the airflow 94 bypasses the LP compressor 24 and the engine core 44 and exits the turbine engine 10 through a stationary vane row, and more particularly an outlet guide vane assembly 96, comprising a plurality of airfoil guide vanes 98, at the fan exhaust side 100. More specifically, a circumferential row of radially extending airfoil guide vanes 98 are utilized adjacent the fan section 18 to exert some directional control of the airflow 94.

Some of the air supplied by the fan assembly 20 can bypass the engine core 44 and be used for cooling of portions, especially hot portions, of the turbine engine 10, and/or used to cool or power other aspects of the aircraft. In the context of a turbine engine, the hot portions of the engine are normally downstream of the combustor 30, especially the turbine section 32, with the HP turbine 34 being the hottest portion, as it is directly downstream of the combustion section 28. Other sources of cooling fluid can be, but are not limited to, fluid discharged from the LP compressor 24 or the HP compressor 26.

FIG. 2 is another example of a schematic view of a portion of a gas turbine engine 110 for an aircraft. The portion of the turbine engine 110 is similar to portions of the turbine engine 10, therefore, like parts will be identified with like numerals increased by 100, with it being understood that the description of the like parts of the turbine engine 10 applies to the turbine engine 110 unless otherwise noted.

The turbine engine 110 has a centerline or turbine engine axis of rotation. The turbine engine 110 includes, a compressor section 122 including a compressor 126, a combustion section 128 including a combustor 130, a turbine section 132 including a HP turbine 134, and a Free Power Turbine or LP turbine 136, and a nozzle section 137 that are axially aligned. A turbine core 138 can be defined by the compressor section 122, the combustion section 128, the turbine section 132, and the nozzle section 137. The compressor 126, the combustor 130, and the HP turbine 134 can form an engine core 144, which generates combustion gases. The turbine core 138 which includes the engine core 144 can be surrounded by core housing 146.

The HP spool, HP shaft, or high speed shaft 148 is disposed coaxially about the turbine engine axis of rotation 112 of the turbine engine 110 and drivingly connects the HP turbine 134 to the compressor 126. The high speed shaft 148 can be considered part of the turbine engine 110.

The LP turbine spool, LP turbine shaft, or low speed shaft 156 is disposed coaxially about a turbine engine axis of rotation 112 of the turbine engine 110. The low speed shaft 156 permanently connects the LP turbine 136 to an electrical power system or electric machine assembly 151. While the low speed shaft 156 permanently provides a rotational input/output to the electric machine assembly 151 it can be considered part of the turbine engine 110.

In the illustrated example, the electric machine assembly 151 includes an electric machine 152 having an input/output 149 permanently coupled to the low speed shaft 156 and an output 153 selectively coupled to the high speed shaft 148 via a first clutch assembly 150. Optionally, the electric machine assembly 151 can further include a first gearbox 165 and a second gearbox 167. The first gearbox 165 can couple the output 153 of the electric machine 152 to the first clutch assembly 150, where the first clutch assembly 150 selectively engages the high speed shaft 148. One or more portions of the second gearbox 167 can be part of the permanent connection between the input/output 149 of the electric machine 152 and the low speed shaft 156.

The electric machine 52 is shown, by way of example, as extending axially or generally parallel to the turbine core 138 of the turbine engine 110, wherein the term, “generally parallel” means+/−20 degrees of being at an angle of zero or parallel. The input/output 149 and the output 153 of the electric machine 152 can couple to the first gearbox 165 and the second gearbox 167, respectively. The connection between the electric machine 152 and the first gearbox 165 or second gearbox 167 can be via at least one shaft 171. The first gearbox 165 can be located adjacent the compressor section 122, while the second gearbox 167 can be located adjacent the nozzle section 137. The size to the electric machine 152 can vary and the at least one shaft 171 can be any number of shafts that couple the electric machine 152 to the first gearbox 165 and the second gearbox 167.

Further, the electric machine 152 is illustrated as adjacent the engine core 144 and radially outside of the core housing 146. It is contemplated the electric machine 152 can be located within the core housing 146 or at a location that is forward or aft of the turbine core 138 or the engine core 144.

The low speed shaft 156 permanently couples the LP turbine 136 to the input/output 149 of the electric machine 152. The connection between the low speed shaft 156 and the electric machine 152 is rotatably permanent. That is, when a portion of the electric machine 152 is rotating, the low speed shaft 156 rotates, and when the low speed shaft 156 rotates, at least a portion of the electric machine 152 rotates. The low speed shaft 156 does not disengage from the electric machine 152; the connection is permanent. Therefore, the electric machine 152 can drive the low speed shaft 156 by providing a rotatable output to the low speed shaft 156 via the input/output 149. Alternatively, or additionally, the electric machine 152 can receive an input, for example rotational kinetic energy, from the low speed shaft 156 for the generation of electrical energy via the input/output 149. Optionally, the permanent connection between the low speed shaft 156 and the electric machine 152 can be made via a bevel gearbox or the second gearbox 167. While illustrated as being similar to the first gearbox 165, it is contemplated that the second gearbox 167 can include a different number of gears, a different gearing system, or otherwise rotatably couple the input/output 149 of the electric machine 152 to the low speed shaft 156 using any known methods.

The first clutch assembly 150 selectively couples the high speed shaft 148 to the output 153 of the electric machine 152. That is, the electric machine 152 selectively operably couples to the high speed shaft 148 via the first clutch assembly 150 to selectively provide an output to the high speed shaft 148.

Optionally, the first gearbox 165 selectively operably couples the high speed shaft 148 to the output 153 of the electric machine 152 and can include or be adjacent to the first clutch assembly 150. The first gearbox 165 can include, by way of non-limiting example, three gears 169a, 169b, 169c. While illustrated as bevel gears, any known type of gearing or number of gears can be used in the first gearbox 165 to rotatably couple the electric machine 152 to the first clutch assembly 150 or the high speed shaft 148. Alternatively, the first clutch assembly 150 can be in direct rotational communication with the output 153 of the electric machine 152 to selectively provide an output to the high speed shaft 148.

As illustrated, by way of example, a second clutch assembly 160 can selectively couple a supplemental shaft 158 to the second gearbox 167. The coupling of the supplemental shaft 158 to the second gearbox 167 can be an example of a second outlet of the electric machine assembly 151. When engaged, the second clutch assembly 160 can receive a rotational input from the second gearbox 167, which is translated to the supplemental shaft 158. Alternatively, the supplemental shaft 158, via the second clutch assembly 160, can directly selectively couple to the low speed shaft 156 or the electric machine 152.

The supplemental shaft 158 can be coupled to a load 173. The load 173 can be, for example, the drive train of a helicopter, or other gearing that provides rotation to one or more propellers. Additionally, or alternatively, it is contemplated the load 173 can be a high bypass engine fan or a shaft, such as a booster shaft.

The second clutch assembly 160 selectively couples the load 173 to the electric machine 152 or the low speed shaft 156. That is, the low speed shaft 156 via the second gearbox 167 and the second clutch assembly 160 can provide an output to the load 173. Alternatively, the input/output 149 or other supplemental connection of the electric machine 152 via the second gearbox 167 and the second clutch assembly 160 can provide an output to the load 173. That is, the low speed shaft 156 or electric machine 152 selectively operably couple to the supplemental shaft 158 via the second clutch assembly 160 to selectively provide an output to the supplemental shaft 158.

In operation, in a first mode, the electric machine 152 functions primarily as a starter. Energy can be supplied to the electric machine 152, for example, from a battery bank, a mechanical starter, or electrical generating device. The energy supplied to the electric machine 152 rotates one or more components of the electric machine 152 resulting in a rotational of the output 153.

The first clutch assembly 150 selectively couples the output 153 of the electric machine 152 to the high speed shaft 148, which rotates the high speed shaft 148. The high speed shaft 148 rotates portions of the compressor 126 and HP turbine 134. As the electric machine 152 provides a rotational output to the high speed shaft 148 via the output 153, the low speed shaft 156 that is coupled to the input/output 149 of the electric machine 152 also rotates. The rotation of the low speed shaft 156 results in the rotation of portions of the LP turbine 136.

In a second mode, the electric machine 152 functions primarily as a generator, providing electrical energy to the one or more accessories 162. The transition or change from the first mode to the second mode occurs with the disengagement of the high speed shaft 148 from the output 153 of the electric machine 152 via the first clutch assembly 150. The first clutch assembly 150 disengages the electric machine 152 from the high speed shaft 148 at predetermined torque or speed of the high speed shaft 148. The predetermined torque or speed can depend on the idle speed of the turbine engine 110. It is contemplated that the predetermined torque or speed can be greater than or equal to the idle speed of the turbine engine 110. However, it is contemplated that the predetermined torque or speed can be less than the idle speed of the turbine engine 110.

The second clutch assembly 160 can engage before or after the electric machine 152 switches from the first mode to a second mode. As the rotational velocity of the high speed shaft 148 increases, the supplemental shaft 158 is selectively coupled to the electric machine 152, the second gearbox 167, or the low speed shaft 156 via the second clutch assembly 160. The second clutch assembly 160 can selectively engage based on, for example, axial thermal expansion of one or more components of the electric machine 152, the low speed shaft 156, the second gearbox 167, or another component adjacent to the second clutch assembly 160. By way of non-limiting example, the second clutch assembly 160 additionally or alternatively can be activated or engage based on the load carried by one or more bearings, one or more speed or thermal sensors, counter-rotation, input provided by an active automated control, a pilot or user, or reaching a predetermined torque value.

Once coupled via the second clutch assembly 160, the supplemental shaft 158 can receive a rotational output from the electric machine 152, the low speed shaft 156, or the second gearbox 167. The rotational output provided to the supplemental shaft 158 can be transferred to an outside load 173. That is, the supplemental shaft 158 can provide a driving force to the load 173. The load 173, by way of example, can be a drive train, a gearbox, a propeller, a high bypass engine fan, or a shaft. Additionally, or alternatively, it is contemplated that additional gearing or clutch assemblies can be located within, coupled to, or adjacent the load 173 to selectively couple the load 173 to the supplemental shaft 158.

During at least a portion of the first mode and during the second mode when the turbine engine is self-sustaining, air flows into an inlet 175 which is channeled into the compressor section 122. Pressurized airflow 190 from the compressor 126 is mixed with fuel in the combustor 130 and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine 134, which drives the compressor 126. The combustion gases are discharged into the LP turbine 136, which extracts additional work to drive the electric machine 152, and the exhaust gas is ultimately discharged from the turbine engine 110 via an outlet 177 in the nozzle section 137.

The electric machine 152 can generate electricity in the second mode as a result of the rotation of the LP turbine 136 due to the exhaust of gases from the combustor 130. The rotation of the LP turbine 136 results in the rotation of the low speed shaft 156. The low speed shaft 156 can provide a rotational input to the second gearbox 167, where the second gearbox 167 can provide a rotational input at the input/output 149 of the electric machine 152.

While not illustrated, it is contemplated that a portion of the pressurized airflow 190 can be drawn from the compressor section 122 as bleed air to provide to engine components with cool air.

FIG. 3 is yet another schematic view of a portion of a gas turbine engine 210 for an aircraft. The portion of the turbine engine 210 is similar to portions of the turbine engine 10 and the turbine engine 110 therefore, like parts will be identified with like numerals further increased by 100, with it being understood that the description of the like parts of the turbine engine 10 and the turbine engine 110 applies to the turbine engine 210 unless otherwise noted.

The turbine engine 210 has a centerline or turbine engine axis of rotation 212 extending forward 214 to aft 216. The turbine engine 210 includes, in downstream serial flow relationship, a compressor section 222 including a compressor 226, a combustion section 228 including a combustor 230, a turbine section 232 including a HP turbine 234, and a LP turbine 236, and a nozzle section 237. A turbine core 238 can be defined by the compressor section 222, the combustion section 228, the turbine section 232, and the nozzle section 237.

The compressor 226, the combustor 230, and the HP turbine 234 form an engine core 244, which generates combustion gases. The turbine core 238, which includes the engine core 244, can be surrounded by core housing 246.

The HP spool, HP shaft, or high speed shaft 248 is disposed coaxially about the turbine engine axis of rotation 212 of the turbine engine 210 and drivingly connects the HP turbine 234 to the compressor 226. The high speed shaft 248 can be considered part of the turbine engine 210.

The LP turbine spool, LP turbine shaft, or low speed shaft 256 is disposed coaxially about the turbine engine axis of rotation 212 of the turbine engine 210 within the larger diameter annular high speed shaft 248. As illustrated, the high speed shaft 248 circumscribes at least a portion of the low speed shaft 256. That is, the low speed shaft 256 and the high speed shaft 248 are at least partially co-axial.

The low speed shaft 256 permanently connects the LP turbine 236 to an electrical power system or electric machine assembly 251. While the low speed shaft 256 permanently provides a rotational input/output to the electric machine assembly 251 it can be considered part of the turbine engine 210.

In the illustrated example, the electric machine assembly 251 includes an electric machine 252 having an input/output 249 permanently coupled to the low speed shaft 256 and an output 253 selectively coupled to the high speed shaft 248 via a first clutch assembly 250. The connection between the low speed shaft 256 and the input/output 249 of the electric machine 252 is rotatably permanent. That is, when the input/output 249 of the electric machine 252 is rotating, the low speed shaft 256 rotates, and when the low speed shaft 256 rotates, the input/output of the electric machine 252 rotates. The low speed shaft 256 does not disengage from the electric machine 252; the connection is permanent. Therefore, the electric machine 252 can drive the low speed shaft 256 via the input/output 249 by providing a rotatable output to the low speed shaft 256. Alternatively, or additionally, the electric machine 252 can receive an input from the low speed shaft 256 via the input/output 249 for the generation of electrical energy. Any number of permanent coupling mechanisms can be used to couple the input/output 249 to the low speed shaft 256.

As illustrated, by way of example, the electric machine 252 is located on the cold end of the turbine engine 210, outside of the turbine core 238. Specifically, the electric machine 252 is located forward or upstream of an inlet 275 of air to the compressor section 222. The electric machine 252 can be coaxial about the turbine engine axis of rotation 212 and in line or axially aligned with the high speed shaft 248 or the low speed shaft 256. However, any configuration in which the electric machine 252 engages the concentric high speed and low speeds shafts 248, 256, wherein the connection between the input/output 249 of the electric machine 252 and low speed shaft 256 is permanent, is contemplated.

The first clutch assembly 250 selectively couples the high speed shaft 248 to the output 253 of the electric machine 252. That is, the electric machine 252 selectively operably couples to the high speed shaft 248 via the first clutch assembly 250 to selectively provide an output to the high speed shaft 248.

Optionally, the first clutch assembly 250 can be in direct rotational communication or included in output 253 of the electric machine 252 to selectively provide an output to the high speed shaft 248. Alternatively, one or more gearboxes (not shown) can be mounted between or included in the output 253 of the electric machine 252 that rotatably couple at least a portion of the first clutch assembly 250 to a portion of the electric machine 252.

As illustrated, by way of example, a second clutch assembly 260 can selectively couple a supplemental shaft 258 to a second output or supplemental coupling 263 of the electric machine 252. When engaged, the second clutch assembly 260 can receive a rotational input from the supplemental coupling 263 of the electric machine 252, which is translated to the supplemental shaft 158. Alternatively, one or more gearboxes (not shown) can be mounted between or included in the supplemental coupling 263 of the electric machine 252 that rotatably couple at least a portion of the second clutch assembly 260 to a portion of the electric machine 252.

The supplemental shaft 258 can couple to a load 273. That is, the supplemental shaft 258 can provide a driving force to the load 273. The load 273 can be, for example, a drive train for a helicopter, a propeller, or other gearing that provides rotation to one or more propellers. Additionally, or alternatively, it is contemplated the load 273 can be a high bypass engine fan or a shaft, such as a booster shaft.

The second clutch assembly 260 selectively couples the load 273 to the electric machine 252 via the supplemental coupling 263. That is, the supplemental coupling 263 of the electric machine 252 selectively operably couples to the supplemental shaft 258 via the second clutch assembly 260 to selectively provide an output to the supplemental shaft 258. Alternatively, the second clutch assembly 260 can selectively couple the load 273 to the low speed shaft 256 or the high speed shaft 248.

In operation, in a first mode, the electric machine 252 functions primarily as a starter. Energy can be supplied to the electric machine 252, for example, from a battery bank, a mechanical starter, or electrical generating device. The energy supplied to the electric machine 252 rotates one or more components of the electric machine 252 resulting in a rotation of the output 253.

The first clutch assembly 250 selectively couples the output 253 of the electric machine 252 to the high speed shaft 248, which rotates the high speed shaft 248. The high speed shaft 248 rotates portions of the compressor 226 and HP turbine 234. As the electric machine 252 provides a rotational output to the high speed shaft 248 via the output 253, the low speed shaft 256 that is coupled to the input/output 249 of the electric machine 252 also rotates. The rotation of the low speed shaft 256 results in the rotation of portions of the LP turbine 236.

In a second mode, the electric machine 252 functions primarily as a generator, providing electrical energy to the one or more accessories 262. The transition from the first mode to the second mode occurs when the first clutch assembly 250 disengages the high speed shaft 248 from the output 253 of the electric machine 252. The first clutch assembly 250 disengages the electric machine 252 from the high speed shaft 248 when a predetermined torque or speed of the high speed shaft 248 is reached. The predetermined torque or speed can depend on the idle speed of the turbine engine 210. It is contemplated that the predetermined torque or speed can be greater than or equal to the idle speed of the turbine engine 210. However, it is contemplated that the predetermined torque or speed can be less than the idle speed of the turbine engine 210.

The second clutch assembly 260 can engage before or after the electric machine 252 switches from the first mode to a second mode. As the rotational velocity of the high speed shaft 248 increases, the supplemental shaft 258 is selectively coupled to the supplemental coupling 263 of the electric machine 252 via the second clutch assembly 260. The second clutch assembly 260 can selectively engage based on, for example, axial thermal expansion of one or more components of the electric machine 252, the low speed shaft 256, or another component adjacent to the second clutch assembly 260. By way of non-limiting example, the second clutch assembly 260 additionally or alternatively can be activated or engage based on the load carried by one or more bearings, one or more speed or thermal sensors, counter-rotation, input provided by an active automated control, a pilot or user, or reaching a predetermined torque value.

Once coupled via the second clutch assembly 260, the supplemental shaft 258 can receive a rotational output from the supplemental coupling 263 of the electric machine 252 or the low speed shaft 256. The rotational output provided to the supplemental shaft 258 can be transferred to the load 273. The load 273, by way of example, can be a helicopter drive train or aircraft propeller. Additionally, or alternatively, it is contemplated that additional gearing or clutch assemblies can be located within, coupled to, or adjacent the load 273 to selectively couple the load 273 to the supplemental shaft 258.

During a portion of the start-up and once the engine is self-sustaining, air flows into an inlet 275 which is channeled into the compressor section 222. Pressurized airflow 290 from the compressor 226 is mixed with fuel in the combustor 230 and ignited, thereby generating combustion gases. Some work is extracted from these gases by the HP turbine 234, which drives the compressor 226. The combustion gases are discharged into the LP turbine 236, which extracts additional work to drive the electric machine 252, and the exhaust gas is ultimately discharged from the turbine engine 210 via an outlet 277 in the nozzle section 237.

The electric machine 252 can generate electricity in the second mode as a result of the rotation of the LP turbine 236 due to the exhaust of gases from the combustor 230. The rotation of the LP turbine 236 results in the rotation of the low speed shaft 256. The low speed shaft 256 can provide a rotational input to the input/output 249 of the electric machine 252.

While not illustrated, it is contemplated that a portion of the pressurized airflow 290 can be drawn from the compressor section 222 as bleed air to provide to engine components with cool air.

FIG. 4 is still yet another example of a schematic view of a portion of a gas turbine engine 310 for an aircraft. The portion of the turbine engine 310 is similar to portions of the turbine engines 10, 110, and 210 therefore, like parts will be identified with like numerals further increased by 100, with it being understood that the description of the like parts of the turbine engines 10, 110, and 210 applies to the turbine engine 310 unless otherwise noted.

The turbine engine 310 has a centerline or turbine engine axis of rotation 312. The turbine engine 310 includes, a compressor section 322 including a compressor 326, a combustion section 328 including a combustor 330, a turbine section 332 including a HP turbine 334, and a LP turbine 336, and a nozzle section 337 in a serial axial arrangement. A turbine core 338 can be defined by the compressor section 322, the combustion section 328, the turbine section 332, and the nozzle section 337. The compressor 326, the combustor 330, and the HP turbine 334 form an engine core 344, which generates combustion gases. The turbine core 338, which includes the engine core 344, can be surrounded by core housing 346.

The HP spool, HP shaft, or high speed shaft 348 is disposed coaxially about the turbine engine axis of rotation 312 of the turbine engine 310 and drivingly connects the HP turbine 334 to the compressor 326. The high speed shaft 348 can be considered part of the turbine engine 310.

The LP turbine spool, LP turbine shaft, or low speed shaft 356 is disposed coaxially about the turbine engine axis of rotation 312 of the turbine engine 310. The low speed shaft 356 permanently connects the LP turbine 336 to an electrical power system or electric machine assembly 351. While the low speed shaft 356 permanently provides a rotational input/output to the electric machine assembly 351 it can be considered part of the turbine engine 310.

In the illustrated example, the electric machine assembly 351 includes an electric machine 352 having an input/output 349 permanently coupled to the low speed shaft 356 and an output 353 selectively coupled to the high speed shaft 348 via a first clutch assembly 350. Optionally, the electric machine assembly 351 can further include a gearbox 381 or an extension shaft 383. The gearbox 381 can couple the first clutch assembly 350 to the high speed shaft 348. The extension shaft 383 can couple the output 353 of the electric machine 352 to the first clutch assembly 350.

As illustrated, by example, the first clutch assembly 350 selectively couples the high speed shaft 348 to the output 353 of the electric machine 352 via the gearbox 381 and the extension shaft 383. That is, the output 353 of the electric machine 352 selectively operably couples to the high speed shaft 348 via the first clutch assembly 350 to selectively provide an output to the high speed shaft 348. Optionally, the first clutch assembly 350 can be adjacent to or included in the gearbox 381 or the output 353 of the electric machine 352.

The gearbox 381 can include any known type of gearing or number of gears, shafts, or other mechanisms used to rotatably connect an extension shaft 383 extending from the output 353 of the electric machine 352 to the high speed shaft 348 when the first clutch assembly 350 is engaged. The extension shaft 383 can be any length or comprise additional rotatable or non-rotatable components.

As illustrated, by way of example, the electric machine 352 is located at the hot end of the turbine engine 310, outside of the turbine core 338. As used herein, the term “hot end” is a location that is axially downstream of the engine core 344. The electric machine 352 can be located down stream of at least a portion of the nozzle section 337. It is contemplated, however, that the electric machine 352 can be located within the core housing 346 or at a location that is forward or aft of the engine core 344 or the turbine core 338.

The connection between the low speed shaft 356 and the electric machine 352 is permanent or rotatably permanent. That is, when the input/output 349 of the electric machine 352 is rotating, the low speed shaft 356 rotates and when the low speed shaft 356 rotates, the input/output 349 of the electric machine 352 rotates. The low speed shaft 356 does not disengage from the electric machine 352; the connection is permanent. Therefore, the electric machine 352 can drive the low speed shaft 356 by providing a rotatable output at the input/output 349 to the low speed shaft 356. Alternatively, or additionally, the electric machine 352 can receive an input, for example rotational kinetic energy, at the input/output 349 from the low speed shaft 356 for the generation of electrical energy. Optionally, the permanent connection between the low speed shaft 356 and the electric machine 352 can be made via a gearbox (not shown).

As illustrated, by way of example, a second clutch assembly 360 can selectively couple a supplemental shaft 358 via the gearbox 381. When engaged, the second clutch assembly 360 can receive a rotational input from the gearbox 381, which is communicated to the supplemental shaft 358. Alternatively, the supplemental shaft 358, via the second clutch assembly 360, can selectively couple to the high speed shaft 348, the extension shaft 383, or a supplementary coupling of the electric machine 352. The coupling of the supplemental shaft 358 to the gearbox 381 or other aspect of the electric machine assembly 351 can be an example of a second output of the electric machine 352 or the electric machine assembly 351.

The supplemental shaft 358 can couple to a load 373. The load 373 can be, for example, the drive train of a helicopter, a high bypass engine fan, a shaft, such as a booster shaft, or other gearing that provides rotation to one or more propellers. Alternatively, one or more gearboxes or additional clutch assemblies (not shown) can be mounted between or included in the load 373 to rotatably couple at least a portion of the load 373 to the supplemental shaft 358.

In operation, in a first mode, the electric machine 352 functions primarily as a starter. Energy can be supplied to the electric machine 352, for example, from a battery bank, a mechanical starter, or electrical generating device. The energy supplied to the electric machine 352 rotates one or more components of the electric machine 352 resulting in a rotation of the output 353.

The first clutch assembly 350 selectively couples the output 353 of the electric machine 352 to the high speed shaft 348, which rotates the high speed shaft 348. The high speed shaft 348 rotates portions of the compressor section 322 and HP turbine 334. As the electric machine 352 provides a rotational output to the high speed shaft 348 via the output 353, the low speed shaft 356 that is coupled to the input/output 349 of the electric machine 352 also rotates. The rotation of the low speed shaft 356 results in the rotation of portions of the LP turbine 336.

In a second mode, the electric machine 352 functions primarily as a generator, providing electrical energy to the one or more accessories 362. The transition from the first mode to the second mode occurs when the first clutch assembly 350 disengages the high speed shaft 348 from the output 353 of the electric machine 352. The first clutch assembly 350 disengages the electric machine 352 from the high speed shaft 348 when a predetermined torque or speed of the high speed shaft 348 is reached. The predetermined torque or speed can depend on the idle speed of the turbine engine 310. It is contemplated that the predetermined torque or speed can be greater than or equal to the idle speed of the turbine engine 310. However, it is contemplated that the predetermined torque or speed can be less than the idle speed of the turbine engine 310.

The second clutch assembly 360 can engage after the electric machine 352 switches from the first mode to a second mode. As the rotational velocity of the high speed shaft 348 increases, the supplemental shaft 358 is selectively coupled to the gearbox 381, or the high speed shaft 348, or the electric machine 352 via the second clutch assembly 360. The second clutch assembly 360 can selectively engage based on, for example, axial thermal expansion of one or more components of the electric machine 352, the high speed shaft 348, the gearbox 381, the extension shaft 383, or another component adjacent to the second clutch assembly 360. By way of non-limiting example, the second clutch assembly 360 additionally or alternatively can be activated or engage based on the load carried by one or more bearings, one or more speed or thermal sensors, counter-rotation, input provided by an active automated control, a pilot or user, or reaching a predetermined torque value.

Once coupled via the second clutch assembly 360, the supplemental shaft 358 can receive a rotational output from the gearbox 381, the high speed shaft 348, or the electric machine 352. The rotational output provided to the supplemental shaft 358 can be transferred to the load 373. That is, the supplemental shaft 358 can provide a driving force to the load 373. The load 373, by way of example, can be a drive train, a gearbox, a high bypass engine fan, a shaft, or a propeller. Additionally, or alternatively, it is contemplated that additional gearing or clutch assemblies can be located within, coupled to, or adjacent the load 373 to selectively couple the load 373 to the supplemental shaft 158.

During at least a portion of the first mode and during the second mode when the turbine engine is self-sustaining, air flows into an inlet