Parallel hybrid power plant including turbofan engine core

Abstract

The hybrid aircraft powerplant includes a turbine engine including a first shaft configured to output power from the turbine engine, a bypass fan, and an electric machine. The hybrid aircraft powerplant further includes a first mechanism configured to selectively engage the first shaft with a second shaft connected to the electric machine to output power from the turbine engine to the electric machine. The hybrid aircraft powerplant further includes a second mechanism configured to selectively engage the first shaft with a third shaft connected to the bypass fan to output power from the turbine engine to the bypass fan.

Description

[Technical field]

[0001] The present application relates to a parallel hybrid power plant including a turbofan engine core. [Background technology]

[0002] There are various types of aircraft that are propelled using different types of propulsion mechanisms, such as propellers, turbines or jet engines, rockets, ramjets, etc. Different types of propulsion mechanisms can be powered in different ways. For example, some propulsion mechanisms, such as propellers, can be powered by internal combustion engines or electric motors. Other propulsion mechanisms, such as turbofans, can be powered by turbine engines. Summary of the Invention

[0003] In one embodiment, the hybrid aircraft powerplant includes a turbine engine including a first shaft configured to output power from the turbine engine, a bypass fan, and an electric machine. The hybrid aircraft powerplant further includes a mechanism configured to selectively engage the first shaft with a second shaft connected to the electric machine such that power is output from the turbine engine to the electric machine.

[0004] In one embodiment, the hybrid aircraft powerplant includes a turbine engine having a first shaft configured to output power from the turbine engine, a bypass fan, and an electric machine, the hybrid aircraft powerplant further including a mechanism configured to selectively engage a portion of the first shaft with a second shaft connected to the bypass fan to output power from the turbine engine to the bypass fan.

[0005] In one embodiment, a method includes controlling a turbine engine including a first shaft to output power via the first shaft. The method further includes controlling a first mechanism to engage the first shaft with a second shaft in a first mode of operation. The second shaft is connected to a generator, whereby power is output from the turbine engine to the generator via the first shaft and the second shaft. The method further includes controlling the first mechanism to engage the first shaft with the second shaft and controlling the second mechanism to engage the first shaft with a third shaft in a second mode of operation. The third shaft is connected to a bypass fan, whereby power is output from the turbine engine to each of the generator and the bypass fan. [Brief description of the drawings]

[0006] [Figure 1] 1 is a cross-sectional side view of a turbofan in accordance with an exemplary embodiment; [Figure 2A] FIG. 1 is a schematic diagram illustrating an example turbofan including mechanisms such as an electric machine and a clutch, in accordance with various exemplary embodiments. [Figure 2B] FIG. 1 is a schematic diagram illustrating an example turbofan including mechanisms such as an electric machine and a clutch, in accordance with various exemplary embodiments. [Figure 2C] FIG. 1 is a schematic diagram illustrating an example turbofan including mechanisms such as an electric machine and a clutch, in accordance with various exemplary embodiments. [Figure 2D] FIG. 1 is a schematic diagram illustrating an example turbofan including mechanisms such as an electric machine and a clutch, in accordance with various exemplary embodiments. [Diagram 3] FIG. 1 is a schematic diagram illustrating an exemplary turbofan including an electric machine between a turbine engine and a bypass fan according to an exemplary embodiment. [Figure 4] 1 is a schematic diagram illustrating an exemplary turbofan including an electric machine connected to a shaft extending from a turbine engine according to an exemplary embodiment. [Diagram 5]FIG. 1 is a block diagram illustrating an aircraft control system for use with a hybrid powerplant having a turbofan engine core in accordance with an illustrative embodiment. [Figure 6] 1 is a flow chart illustrating the use of a hybrid power plant having a turbofan engine core in accordance with an exemplary embodiment. [Figure 7] FIG. 1 is a block diagram illustrating an electric machine having multiple sectors and a system for powering an aircraft component using the electric machine in accordance with an exemplary embodiment. [Figure 8] 1 is a schematic diagram of an example computing environment, in accordance with an illustrative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] One aspect of aerial flight is the ability to move through the air at very high speeds. The forward motion can be created by one or more propellers, one or more fans, or multiple jet engines. As high speeds become a priority, propellers and fans are no longer viable options and the only remaining solution is some form of turbine engine, commonly referred to as a jet. Described herein is a hybrid power plant that can advantageously power aircraft for vertical take-off and landing (e.g., VTOL aircraft), short take-off and landing (STOL, etc.), or other aircraft where a combination of physical thrust and electrical power from an aircraft power plant is desirable, potentially even achieving faster horizontal flight than would be possible using a forward thrust mechanism such as a propeller. This provides an aircraft that advantageously opens up new opportunities for travel or transportation of goods, such as eliminating the need for prepared runways of any kind in many cases.

[0008] Various embodiments of a parallel hybrid system architecture built around a high performance turbofan engine are described herein. In various embodiments, aspects of the powerplant described herein other than the turbofan engine itself can be used with other types of engines, such as any engine with a turbine and turbine core. For example, instead of a turbofan engine, a turboshaft or turboprop engine may be used. For example, a turboprop engine may include gearing to reduce the power output of the turbine to a usable propeller speed, such as 1500-2500 revolutions per minute (RPM). This solution has the advantage that while the turbofan functions normally by taking in, compressing, and expelling air through a bypass fan driven by the turbine engine, it can transition to a very high power generator to provide high voltage and high power energy to other components, such as motors and / or components adapted for vertical lift (e.g., for a vertical take-off and landing (VTOL) aircraft) via electrical grid. The combination of a turbofan generating forward thrust for flight and a blended transition to electrical power generation powered by a turbine engine can advantageously facilitate and power various flight modes and accessories of the aircraft in ways that were not previously possible. In particular, in various embodiments described herein, the shaft of the turbine engine can both power a bypass fan (e.g., in the case of a turbofan) and also power an electric machine (e.g., a generator and / or a generator / motor combination) using the same shaft. A single shaft allows each component to be oriented in parallel. Clutches associated with each of the bypass fan and electric machine allow selective connection between the bypass fan and the shaft, and between the electric machine and the shaft, such that based on the state of the clutch, the bypass fan and the electric machine can be powered (powered) together or separately from the shaft. In various embodiments, various types of turbine engines and electric machines can be connected to a power plant using a shaft without the use of a clutch.

[0009] In the aviation industry, aircraft weight may be a major concern and / or design constraint. An advantage of the parallel hybrid turbofan (or other type of turbine engine, such as turboshaft or turboprop) design described herein is that one core heat engine can generate two very different forms of propulsion in the same aircraft. In terms of thrust-to-weight ratio for atmospheric flight, turbofans are very effective compared to other types of power plants, making them valuable, for example, in commercial aircraft and business jets. As described herein, turbofan engines can also be used to efficiently generate one or several megawatts (MW) of electrical power that can be used to enable distributed electric propulsion in other aircraft, such as vertical take-off and landing (VTOL) aircraft. Other advantages of various embodiments herein may include improved center of gravity, efficient cooling, and control of power plant components.

[0010] Thus, the powerplants described herein may be advantageously used in aircraft designed for high speed travel but that also use Distributed Electric Propulsion (DEP) or that otherwise have large power demands. DEP applications may include use in aircraft such as VTOL, boundary layer control, blowing wings for short take-off and landing (STOL), or other unique uses of DEP.

[0011] More specifically, this specification describes a hybrid powerplant based on a turbofan engine configured to provide forward thrust via a bypass fan, with the additional capability of generating high power output for applications such as aircraft propulsion or other electrical applications (e.g., accessories that use large amounts of power).

[0012] FIG. 1 is a side cross-sectional view of an exemplary turbofan 101. In the turbofan 101, air enters the compressor via inlet 105. The air is compressed first by a low pressure (LP) compressor 111 and then by a high pressure (HP) compressor 115 before being fed to a combustor 121 where jet fuel is added and burned. After combustion, the resulting hot gases are sent to a high pressure (HP) turbine 125 and then to a low pressure (LP) turbine 131 before being exhausted through a metering passage 135. In other embodiments, there may be more or fewer compressor and / or turbine sections and there may be more or less gearing than the turbofan 101 shown in FIG. 1.

[0013] HP turbine 125 is coupled to HP compressor 115 via shaft 141, which may include gearing, if desired. Although not shown in FIG. 1 , in various embodiments, as described below, shaft 141 may be connected to LP compressor 111 rather than connecting LP compressor 111 to shaft 145. Shaft 141 may include further gearing, if desired, relative to LP compressor 111. Shaft 141 may be connected to either or both of LP compressor 111 and / or HP compressor 115 and operates to maintain engine function throughout use of turbofan 101.

[0014] Power and heat present in the combustion products that is not extracted by the HP turbine 125 may be extracted by the LP turbine 131. This power is transferred via shaft 145 and can be used to drive a bypass fan 150, which may or may not be connected to the LP compressor 111 as discussed above. This bypass fan 150 draws cool air from outside into a nacelle 155, pressurizes the air, and expels the air through passages 160 to generate significant forward thrust. The design of the bypass fan 150, nacelle 155, and air passages 160 allows for very high forward flight, for example, up to 400 knots indicated airspeed (400 kias) or greater.

[0015] As described further herein, a turbofan, such as the turbofan 101 of FIG. 1, may further include an electric machine connected in parallel to the turbofan (e.g., to the shaft 145) and generating electrical power based on the rotational power output by the shaft 145 of the turbofan. Such an electric machine may be located at various locations of the turbofan, such as any or all of the locations 165, 170, and / or 175 of the turbofan 101 of FIG. 1. In another embodiment, the electric machine may be located within the shaft 145, where the shaft 145 is hollow. In other embodiments, the electric machine may be located within or outside the nacelle 155 of the turbofan 101 and / or the housing of the turbine engine. For example, the electric machine may be located forward of the nacelle and / or radially offset from the nacelle. If located forward of the nacelle, the electric machine may be located significantly forward of the nacelle such that the electric machine is not in the airflow to the turbofan or does not significantly affect the airflow to the turbofan, thereby not adversely affecting the efficiency of the turbofan. Similarly, the electric machine may be located radially away from the central axis of the nacelle such that the electric machine is not in the airflow to the turbofan or does not significantly affect the airflow to the turbofan. In various embodiments, the electric machine may be located forward of the nacelle and radially offset from the nacelle. Configurations of electric machines connected to turbofans in a parallel configuration including one or more clutches are further described below with respect to Figures 2A-2D, 3, and 4. In various embodiments, any mechanism for selectively engaging rotating components other than a clutch may be used. For example, clutchless gearing or other transmissions may be used in place of a clutch as a mechanism for selectively engaging the various components described herein.

[0016] By adding such an electric machine (e.g., a generator) to the turbofan, the power plant can operate as a hybrid power plant, providing both forward thrust and electrical power. Such an embodiment has the advantage of enabling DEP at very high power levels. Specifically, an electric machine such as an electric motor / generator could be added somewhere along shaft 145 or driven by the shaft via a bevel or other gear arrangement, whereby shaft 145 and / or other components transfer power from the LP turbine to the bypass fan, and clutches could also be added at specific locations to enable multiple useful operating modes as described herein.

[0017] Although the term electric machine (or emachine) is used herein, such term may refer to a generator, a motor, or a generator / motor combination, e.g., an electric motor can also operate as a generator. Similarly, a generator can also operate as a motor by modifying the control and commutation strategies. In various embodiments described herein, the use of such a motor / generator may be to extract power generated by the LP turbine and transmitted by a shaft, such as shaft 145, and operate as a generator to generate very high electrical power for other uses of the aircraft, rather than drawing power from an on-board energy storage system to add shaft power to supplement or replace the power of the core heat engine (although, as described herein, in some operating modes, electrical power may be applied to the shaft of the turbofan by an electric machine operating as a motor). This electrical power may be high voltage, e.g., about 400 volts (V) or higher, or any voltage between 400V and 2.4 kilovolts (kV). For example, nominal voltages of such systems may include 800V or 1200V. However, in various embodiments described herein, use of the electric machine may also include outputting power from the electric machine to the shaft 145 using power from a power source such as a battery.

[0018] Such high voltage and / or high current power can be used for propulsion, lift, and / or control of an aircraft that features one or more electric motors that drive fans, propellers, or other devices. Such high voltage and / or high current can also be used for other functions of a given aircraft that require high power. The total electrical power of a turbofan, including the electric machines described herein, can be used for one or a combination of accessories or other aspects of an aircraft that may use, for example, one megawatt (1 MW) or more of power.

[0019] In various embodiments, the motor / generator may be located anywhere along the length of the turbofan engine or outside the turbofan engine housing and / or nacelle housing. In one embodiment, the motor / generator may be located a short distance forward of the bypass fan (e.g., housed within the shroud (spinner) of the turbofan, such as location 165 of turbofan 101 in FIG. 1), or may be located further forward from the bypass fan. As another example, FIGS. 2A-2D show a motor / generator that may be located forward of the bypass fan.

[0020] In FIG. 2A , the parallel hybrid power plant 200 includes a turbofan 210, a core heat engine 215, and a LP turbine 235. These components may be similar to those of the turbofan 101 shown in FIG. 1 . The power plant 200 also includes a shaft 220 configured to provide power to the bypass fan 210 and / or the electric machine 205. The electric machine 205 is selectively powered by engaging a mechanism such as a clutch 230, and the bypass fan 210 is selectively powered by engaging a mechanism such as a clutch 225. The clutches 230 and 225 may be engaged separately or simultaneously. The system may further include one or more gearboxes to convert the power output from the LP turbine 235 as needed for the bypass fan 210 and / or the electric machine 205. For example, the gearbox or gearboxes may be located anywhere along shaft 220, near one or both of clutches 225 and / or 230, near or at bypass fan 210, and / or near electric machine 205. In various embodiments, the components of the electric machine may also be configured to rotate without producing (outputting) or using electricity. As such, in various embodiments, a clutch may be omitted or not used between the electric machine and the shaft (e.g., in various embodiments, clutch 230 of FIGS. 2A-2D, clutch 330 of FIG. 3, and / or clutch 430 of FIG. 4 may not be present). This is because the electric machine is independent of the rotation of the shaft and either modifies the field current in the electric machine to allow electrical power to pass unaffected (e.g., the shaft rotates without the electric machine producing or using electricity) or takes power from the shaft to generate electricity (e.g., power from a rotating shaft is used to generate electricity). In various embodiments, other clutches (eg, clutches 225, 325, 425 associated with turbine engine components) may also be omitted or not used.

[0021] In various embodiments, different configurations of shafts and / or clutches (or mechanisms other than clutches that can selectively engage the various components described herein) may also be used. For example, in FIG. 2A , it is contemplated that shaft 220 extends from LP turbine 235, through bypass fan 210, and to electric machine 205. In such a configuration, for example, when it is desired for LP turbine 235 to power bypass fan 210, clutch 225 can engage shaft 220 with the internal shaft of bypass fan 210. In this manner, when it is not desired to rotate bypass fan 210, shaft 220 can continue to rotate within bypass fan 210 without rotating bypass fan 210, since clutch 225 has disengaged shaft 220 from the shaft of bypass fan 210. LP turbine 235 can then be used to power electric machine 205 (while clutch 230 engages shaft 220 with the shaft of electric machine 205).

[0022] In various embodiments, the shaft 220 shown in FIG. 2A (or any of the other shafts described herein) may be split at different clutch locations. For example, a first shaft may connect the LP turbine 235 and the clutch 225, a second shaft may connect the clutch 225 and the clutch 230, and a third shaft may connect the clutch 230 and the electric machine 205. In such an embodiment, both clutches 225 and 230 may be engaged to provide the electric machine 205 with the rotational power output by the LP turbine 235. In this manner, the shaft 220 may actually be three different shafts that may be connected together to operate as one shaft by the clutches 225 and 230. In such an example, the first shaft connecting the LP turbine 235 and the clutch 225 may be permanently connected to the first side of the LP turbine 235 and the clutch 225. The second shaft connecting the clutch 225 and the clutch 230 may be permanently connected to the second side of the clutch 225, the first side of the clutch 230, and the bypass fan 210. A third shaft connecting the clutch 230 and the electric machine 205 may be permanently connected to the second side of the clutch 230 and the electric machine 205. Even if not all embodiments are described in detail below, it will be understood that in any of the embodiments described herein (e.g., any of FIGS. 2A-2D, 3, 4, etc.), the shafts described herein may be split shafts connectable through various clutches described herein, or may be solid shafts passing through clutches configured to engage a single shaft to rotate a component (e.g., bypass fan, electric machine, LP turbine) as described herein. In various embodiments, different types of clutches and split or non-split shaft configurations may be used in the same embodiment.

[0023] 2B shows a housing 245 of the powerplant 240. The powerplant 240 may have similar components as the powerplant 200, but the housing 245 may contain all components including the electric machine 205 and its associated clutch 230. The housing 245 may be, for example, a nacelle of a hybrid turbofan or a shroud for only the engine / turbine of a hybrid turbofan.

[0024] 2C shows a housing 255 of powerplant 250. Powerplant 250 may have similar components as powerplants 200 and 240, but housing 255 may contain all components except electric machine 205, clutch 230, and a portion of shaft 220. As such, electric machine 205, clutch 230, and a portion of shaft 220 may be located outside of the housing in which the remainder of hybrid powerplant 250 is located. Housing 255 may be, for example, a nacelle of a hybrid turbofan, or a shroud for only the engine / turbine of a hybrid turbofan.

[0025] 2D shows a housing 265 of power plant 260. Power plant 260 may have similar components as power plants 200, 240, and 250, but housing 265 may contain all components except electric machine 205 and a portion of shaft 220. As such, electric machine 205 and a portion of shaft 220 may be located outside of the housing in which the remainder of hybrid power plant 260 is located. Housing 265 may be, for example, a nacelle of a hybrid turbofan or a shroud for only the engine / turbine of a hybrid turbofan.

[0026] FIG. 3 illustrates an example of a hybrid powerplant 300 in which an electric machine 305 is disposed between a bypass fan 310 and a turbine engine (e.g., core heat engine 315 and low pressure turbine 335). Thus, the electric machine 305 may be at location 170 and may be within a housing, shaft, and / or other portion of a turbofan. Although the housing of the hybrid powerplant 300 is not shown in FIG. 3, the electric machine 305 may be within a housing (e.g., a nacelle or shroud) of the powerplant 300. A clutch 330 may be used to selectively connect the electric machine 305 to the shaft 320 to provide power to the electric machine 305, and a clutch 325 may be used to selectively connect the shaft 320 to the bypass fan 310 to provide power to the bypass fan 310.

[0027] 4 further illustrates an example of a hybrid powerplant 400 in which an electric machine 405 is physically located near the rear of a turbofan, behind a low pressure turbine section 435 where power output is generated via shaft 420. For example, the electric machine 405 may be located inside or outside a housing or nacelle of the turbofan. A clutch 430 may be used to selectively connect the electric machine 405 to the shaft 420 to provide power to the electric machine 405, and a clutch 425 may be used to selectively connect the shaft 420 to the bypass fan 410 to provide power to the bypass fan 410. Although the housing of the hybrid powerplant 400 is not shown in FIG. 4, the clutch 430 and / or the electric machine 405 may be located within a housing (e.g., a nacelle or engine shroud) or outside such a housing.

[0028] 5 illustrates a block diagram depicting a control system 500 for use in a hybrid powerplant system according to an exemplary embodiment. Aircraft control system 500 may be used, for example, to implement one or more of the various operating modes of the hybrid powerplant described below. Engine 520 of system 500 may be the same as or similar to any turbofan combustion engine portion described herein. Bypass fan 545 may be the same as or similar to any bypass fan described herein. Generator / motor 525 may be the same as or similar to any electric machine described herein. Clutches 530 and 535 may be the same as or similar to any clutch described herein.

[0029] The aircraft control system 500 may further include one or more processors or controllers 505 (hereafter referred to as controllers 505), memory 510, power I / O 540, accessories 545, one or more sensors 515, one or more propulsion mechanisms 550, and a power source such as a battery 555. The connections in FIG. 5 show control signal related connections between the components of the aircraft control system 500. Other connections not shown in FIG. 5 may exist between various aspects of the aircraft and / or the aircraft control system 500 to provide power such as high voltage (HV) or low voltage (LV) power for the aircraft. The power I / O 540 may be a physical connection between the generator / motor 525 and one or more buses or wiring of the aircraft so that power can be distributed throughout the aircraft. The power I / O 540 may be or include sensors such as voltage or current sensors configured to measure aspects of the power flowing into or out of the generator / motor 525. Thus, the controller 505 may be configured to monitor and / or control the power flowing into or out of the generator / motor 525 .

[0030] The memory 510 may be a computer readable medium configured to store instructions. Such instructions may be computer executable code executed by the controller 505 to implement various methods and systems described herein, including various modes of using the hybrid power plant described herein, and combinations or particular sequences of those modes. The computer code may be written such that various methods of implementing various modes of the hybrid power plant described herein are automatically implemented based on various inputs, for example, indicative of a particular flight phase (landing, takeoff, cruise, etc.). In various embodiments, the computer code may be written to implement various modes herein based on inputs from a user or pilot of the aircraft or aerospace vehicle, or may be implemented based on a combination of user inputs and automatic implementation based on non-human inputs (e.g., inputs from sensors on or off the aircraft, based on a planned flight plan, etc.). The controller 505 is powered by a power source on the aircraft or aerospace vehicle, such as a generator / motor 525, one or more batteries 555, power I / O 540, a power bus of the aircraft powered by any power source, and / or any other available power source.

[0031] The controller 505 may also be in communication with each of the components of Figure 5. In this manner, the components of the hybrid power plants described herein may be controlled, including implementing the various modes described herein.

[0032] Sensors 525 may include various sensors for monitoring various components of the hybrid power plant. Such sensors may include, for example, temperature sensors to determine the current state of clutches 530 and / or 535, the current state of the gearbox, tachometers, fluid pressure sensors, voltage sensors, current sensors, status sensors, or other types of sensors. For example, voltage and / or current sensors may be used to inform the function and settings of the motor / generator, the selected state of the clutch, or adjustments of other components of the system. Status sensors may also indicate a particular mode in which the hybrid power plant is being used, and the system may receive input (e.g., from the pilot, from an automatic flight controller) to change the system to another state or mode for a particular phase of the upcoming flight. Other sensors may include a pitot tube to measure the airspeed of the aircraft, an altimeter to measure the altitude of the aircraft, and / or a global positioning system (GPS) or similar geographic location sensor to determine the position relative to the ground and / or known / mapped structures.

[0033] In various embodiments, controller 505 may also communicate with one or more batteries or battery management systems to monitor their charge levels, control when to charge or discharge the batteries, control when to use the batteries to power generators / motors 525, and control when to use the batteries to directly power other aspects of the aircraft.

[0034] In some embodiments, the controller 505 communicates with devices on board the aircraft that are hardwired to the controller 505, and / or with wireless transceivers that may be on board the aircraft or aerospace vehicle to allow the controller 505 to communicate with other computing devices that are not hardwired to the system 500. In this manner, instructions or inputs for implementing the various modes of the flexible architecture described herein may also be received wirelessly from computing devices of remote devices. In other embodiments, the system 500 may communicate only with components on board the aircraft.

[0035] Various specific modes that may be implemented using the various embodiments of the hybrid power plants described herein are further described below.

[0036] In a first mode, maximum or near maximum power output from the turbine engine is directed to the electric machine to generate the electrical power output. Thus, in such a mode, little or no forward thrust may be possible if desired. Such a mode may be beneficial, for example, during vertical takeoff and / or landing operations of a VTOL aircraft.

[0037] In a second mode, the power (electrical power) generated by the LP turbine and output by the output shaft of the hybrid power plant may be transferred entirely or primarily to the bypass fan to generate only or primarily forward thrust. Maximum thrust may be desirable, for example, during aircraft cruise (e.g., between takeoff and landing). Thus, in this mode, the aircraft minimizes other power cuts from the shaft (e.g., by electric machines) to allow the aircraft to achieve maximum or near maximum speed.

[0038] In a third mode, a combination of forward thrust and power generation may be desirable. For example, such a mode may be used during the transition from forward flight to vertical takeoff and / or landing operations (which may be electrically powered). This mode may also be used when a pilot (e.g., human or autonomous) wishes to sacrifice top speed capability (and thus reduced forward thrust) in order to generate high power for other uses of the aircraft, such as high-power accessories. This mode of operation may also be used / desired when it is desirable to minimize airflow through the turbofan core heat engine, even when forward thrust is not desired. In other words, the rotation of the bypass fan allows air to pass through the turbine engine as needed, without consuming excessive power (motive force), and still allows significant power to be generated by the electric machine.

[0039] A fourth mode may be used when some forward thrust is required from the bypass fan of the turbofan without starting or operating the core heat engine. This may be accomplished by using an on-board energy storage (e.g., battery, etc.) to drive the motor / generator as an electric motor. Such operation may be for short bursts of power to the bypass fan or to increase safety and survivability in case the core heat engine fails. To perform such operation, the output shaft of the electric machine needs to be directly or indirectly coupled to the shaft of the bypass fan so that the bypass fan can actually be driven by the output of the electric machine. This may be accomplished by the use of one or more clutches as described herein, or by other methods. In one example, an additional clutch may be used that is configured to disengage the core heat engine from the electric machine and / or the bypass fan during such an operating mode, such that the shaft of the core heat engine does not rotate while the electric machine is driving the bypass fan. In other words, in various embodiments, an additional clutch other than the clutches shown in any of Figures 2A-2D, 3, and / or 4 may be used to disengage the LP turbine shaft from the shaft of the bypass fan. In an exemplary embodiment where a split shaft is used, such as in FIG. 2A , the electric machine may provide power to the bypass fan without rotating the LP turbine without adding another clutch. In the example of FIG. 2A , the shaft is split at each clutch, and clutch 225 may be disengaged while clutch 230 is engaged, allowing electric machine 205 to output power to rotate bypass fan 210, but the shaft portion between clutch 225 and LP turbine 235 does not rotate because clutch 225 is disengaged. In this manner, the bypass fan can rotate without rotating the LP turbine section, either through an additional clutch on the LP turbine or through the use of a shaft split with a clutch.In various embodiments, the LP turbine section is allowed to rotate even when the core heat engine is not in use, thereby allowing the electric machine to provide power (motive force) to the bypass fan while spinning the LP turbine section.

[0040] To facilitate these parallel hybrid power plant operating modes, the system may include at least one clutch, as described herein. For example, a clutch may be used to operatively connect / disconnect the LP turbine shaft to the motor / generator. This clutch may be referred to herein as an electro-machine clutch. The electro-machine clutch may be mounted on the rotor or stator of the electric machine depending on whether the electric machine is an in-runner or out-runner style. A second clutch may be used to operatively connect / disconnect the LP turbine shaft to a bypass fan. This clutch may be referred to herein as a bypass fan clutch.

[0041] The first mode above can be implemented by closing the electric machine clutch and opening the bypass fan clutch, thereby transferring all of the power from the LP turbine shaft to the electric machine. The second mode above can be implemented by opening the electric machine clutch and closing the bypass fan clutch, thereby transferring all of the LP turbine shaft power to the bypass fan.

[0042] The third mode above may be implemented by fully or partially closing both the electro-mechanical clutch and the bypass fan clutch. When both clutches are fully closed, the motor / generator and bypass fan rotate at the same revolutions per minute (RPM), and the power split may be controlled, for example, by controlling the motor / generator inverter and field current. Control of the clutch pressure may serve to split the power when one or the other clutch is partially closed using an appropriate controller and clutch pressure actuator. Thus, one or both of the clutches may be controlled to control the amount of power transferred from the shaft to either the electric machine or the bypass fan. When the clutches are used in this manner, they may generate heat, and the system may be configured to cool one or both of the clutches as needed to keep one or both of the clutches at a desired temperature. Additional implementations of the third mode of operation may include thrust from the bypass fan being vectored downward and combined with lift generated by the electric fan to form a stable VTOL platform. This vector control may be accomplished via a reconfigurable nozzle or other deflector at the aft end of the turbofan and / or by rotating the turbofan.

[0043] In the fourth mode of operation described above, the relative positions of the electric machine and the clutch may affect their operating conditions to implement the fourth mode. To the extent that the electric machine and the bypass fan are connected via a shaft, the electric machine may power the bypass fan. In addition, the hybrid power plant may be further configured such that the LP turbine shaft is disconnected (e.g., via a clutch) from the core heat engine so that no engine components rotate while the electric machine is powering the bypass fan. In a similar mode, the electric machine is used to power the bypass fan, but the engine may also be used to power the bypass fan, thereby applying a maximum power to the bypass fan that is even higher than the maximum power the engine can output. In either case, the presence of an energy storage system (such as a battery) may be used to power the electric machine and thus the bypass fan of the hybrid power plant.

[0044] 6 is a flow chart illustrating a method 600 of using a hybrid power plant having a turbofan engine core as described herein. For example, at 602, one or more clutches of the hybrid power plant may be controlled to direct electrical power (motive force) primarily or entirely to an electric machine to maximize power output from the electric machine. This may be useful, for example, to provide high power to an electric motor that facilitates vertical takeoff of a VTOL aircraft. This may be implemented using the first mode described above.

[0045] At 604, the clutch can be controlled to direct power to a combination of bypass fan and electric machine. This is useful, for example, when it is desirable to direct significant power (power) to accessories or other components of the aircraft while the aircraft transitions from vertical flight to cruise / horizontal flight for takeoff and / or while the aircraft is cruising. This can be accomplished using the third mode described above.

[0046] At 606, the clutch can be controlled to direct power primarily or entirely to the bypass fan to maximize forward thrust, for example, during cruise or level flight of the aircraft, which can be implemented using the second mode of operation described above.

[0047] At 608, similar to 604, the clutch may be controlled to direct power to a bypass fan and electric machine combination. This may be useful, for example, when it is desirable to direct significant power to an aircraft accessory or other component during the transition from cruise / horizontal flight to vertical flight for landing the aircraft and / or while the aircraft is cruising. This may be implemented using the third mode of operation described above.

[0048] At 610, similar to 602, the hybrid power plant clutches can be controlled to direct power primarily or entirely to the electric machine to maximize the power output from the electric machine. This can be useful, for example, to provide high power to an electric motor to facilitate vertical landing of a VTOL aircraft. This can be implemented using the first mode described above.

[0049] As such, method 600 allows a VTOL aircraft to perform all phases of desired flight, including vertical takeoff (602), transition from vertical to horizontal flight (604), horizontal / cruise flight (606), transition from horizontal to vertical flight (608), and vertical landing (610).

[0050] Other advantages of the systems and methods described herein may also be utilized in aircraft using hybrid power plants. For example, the available electrical power generated by a single electric machine in the embodiments described herein may range from 4 MW to 10 MW per hybrid power plant.

[0051] In some embodiments where high system voltages (e.g., 800 volts DC (VDC), 1000 VDC, 1200 VDC) are required for the aircraft, there may be current available from the electric machine in the range of about 3200 amperes (A), 4000 A, or 4800 A. Traditional copper wire, like any other conductor, is limited in its ability to carry current based on inherent internal heat generation and dissipation, strength, weight (density), and other practical limitations / constraints such as manufacturing tolerances and transportation restrictions. Given the inherent limitations of copper wire, electric machines for this high power application may be designed with multiple sectors, with each sector generating only a portion of the total power and the wires carrying current from the sector carrying only a portion of the total current. Electric machines designed in this way may have multiple sectors, such as 2 to 24 sectors (2 sectors, 4 sectors, 6 sectors, 8 sectors, 12 sectors, 16 sectors, 20 sectors, or 24 sectors). An electric machine designed in this manner may be directly connected to multiple inverters, each inverter controlling one or more sectors, but not all sectors of the electric machine.

[0052] A high voltage DC bus layout for use in distributed electric propulsion (DEP) may be single, i.e., all electrical power generated or stored on the aircraft is fed to a single DC bus (e.g., a bus with two wires, positive and negative (or positive and ground)) and all motors or power consumers are electrically connected to the same single bus. In the case of high power generated by the turbofan hybrid power plant described herein, the power may be carried on multiple parallel DC buses. These multiple DC buses may be of the same system voltage, e.g., 1000 VDC. They (DC buses) may be connected to multiple inverters that control sectors (but not all sectors) of the main electric machines and may supply power in different directions to power consumers such as electric motors for lift or control. An example may be a single hybrid generator with 12 sectors supplying 12 inverters. These twelve inverters output to twelve high voltage DC buses; for example, four buses may feed lift motors on the left wing tip, four buses may feed lift motors on the right wing tip, and four buses may feed lift motors on the tail of the aircraft. In other words, different buses may be used to transfer power to different parts of the aircraft. Other connections between the buses may be selectively controlled to allow power to flow from one bus to another, or from one group of buses to another, as needed.

[0053] The high levels of power that may be generated using the hybrid power plants described herein may also be used more efficiently by using wires that have more desirable conductive properties than copper wires. For example, aluminum wires may be used instead of copper wires. Given its conductivity and density, aluminum wires may reduce the wire weight for a given conductor at high power levels by approximately 50%. In another example, wires made entirely or partially from certain superconducting materials may be used. In various embodiments, cooling equipment may also be used to keep the superconducting or other material at a desired temperature to reduce power losses. In various configurations, such aluminum or superconducting wiring (including possible associated cooling systems) may reduce the overall weight of the system compared to a copper wire system designed for the same or similar power output. The superconducting wiring may be, for example, bismuth-strontium-calcium-copper-oxide (BSCCO) or any other type of suitable superconducting material.

[0054] As described herein, the electric machine may generate or use alternating current (AC) and may be connected to an inverter, which may convert the AC power output by the electric machine to DC power for the aircraft bus (the inverter may also convert DC power from the bus to AC power for input to the electric machine to power the LP turbine shaft as described with respect to the fourth mode above). At the other end of the DC bus opposite the electric machine, the DC power is fed to another inverter, which converts the DC power back to AC power to drive the electric motor (e.g., to generate lift or control for the aircraft). To reduce the weight of the aircraft, AC power may be fed directly from the electric machine to the electric motor. In various embodiments where the electric machines are in multiple sectors, each sector having an associated bus (e.g., wiring), such functionality may be further enhanced by directly feeding the electric motor with AC power generated only by a particular sector of the electric machine, without the use of an inverter and / or DC bus. In such an embodiment, some sectors of the electric machine still have inverters to convert AC power to DC power for the DC bus, while other sectors can be configured to directly power electric motors or other equipment requiring AC power.

[0055] Figure 7 shows a block diagram 700 illustrating an electric machine having multiple segments for use as a system for powering aircraft components using a segmented electric machine. In particular, Figure 7 shows how the segmented electric machine may generate power that is output directly to a device such as a motor, to one or more DC buses, etc.

[0056] In Figure 7, an electric machine 702 is shown that includes at least six sectors 705, 710, 715, 720, 725, 730. As described herein, an electric machine can have any number of sectors, as desired. Figure 7 shows one possible configuration of sectors and how they are connected to other devices and / or buses in the system. Various other embodiments may use a different number of electric machines, sector buses, other devices, etc.

[0057] In the example of Figure 7, sectors 705 and 710 are directly connected to motor 790 via wiring 785. Wiring 785 shown in Figure 7 may represent one or more pairs of wiring extending from each sector 705 and 710 to motor 790. Wiring 785 may be or include an AC bus. Additionally, motor 790 may be one or more motors or other devices / accessories that use alternating current (AC) power output by sectors 705 and 710. In this manner, some AC power from electric machine 702 may be output directly to a particular device.

[0058] Sectors 715 and 720 are connected to inverters 735 and 740, respectively, such that AC power output by sectors 715 and 720 may be converted to DC power by inverters 735 and 740 and output to DC bus 775. DC bus 775 may be used to power various components of the aircraft, such as motor 760. Motor 760 is connected to DC bus 775 via inverter 755, such that inverter 755 may convert DC power from DC bus 775 to AC power for motor 760.

[0059] Sectors 725 and 730 are connected to inverters 745 and 750, respectively, such that AC power output by sectors 725 and 730 may be converted to DC power by inverters 745 and 750 and output to DC bus 780. DC bus 780 may be used to power various components of the aircraft, such as high-power accessories 770. High-power accessories 770 are connected to DC bus 780 via inverter 765, such that inverter 765 may convert DC power from DC bus 780 to AC power for high-power accessories 770. In various embodiments, if one or more of high-power accessories 770 uses DC power, such accessories may be connected to the DC bus without the use of an inverter.

[0060] In various embodiments, the aircraft may also have a power source, such as one or more batteries. These batteries may be connected to one or more of DC buses 775 and 780, thereby providing DC power to buses 775 and 780 and / or receiving DC power from buses 775 and 780. In this manner, the batteries may be charged by or deliver power to aircraft equipment. For example, such batteries may ultimately be charged using electrical energy generated by sectors of electric machine 702. Such batteries may be used to provide power to electric machine 702, as described herein, for example to drive an LP turbine shaft via electric machine 702, as described herein.

[0061] 8 is a schematic diagram of an example computing environment including a general-purpose computing system environment 100, such as a desktop computer, laptop, smartphone, tablet, or other device that includes the capability to execute instructions stored in a non-transitory computer-readable medium. The various computing devices disclosed herein (e.g., processor / controller 505, memory 510, a combination of the two, or other computing devices in communication that may be part of other components of the aircraft or controllers of the aircraft) may be similar to computing system 100 or may include some components of computing system 100. Additionally, while described and illustrated in the context of a single computing system 100, those skilled in the art will also appreciate that various tasks described below may be performed in a distributed environment having multiple computing systems 100 linked via a local or wide area network, where executable instructions may be associated with and / or executed by one or more of the multiple computing systems 100.

[0062] In its most basic configuration, the computing system environment 100 typically includes at least one processing unit 102 and at least one memory 104, which may be linked via a bus 106. Depending on the exact configuration and type of computing system environment, the memory 104 may be volatile (such as RAM 110), non-volatile (such as ROM 108, flash memory, etc.), or a combination of the two. The computing system environment 100 may have additional features and / or functionality. For example, the computing system environment 100 may also include additional storage (erasable and / or non-erasable) including, but not limited to, magnetic or optical disks, tape drives, flash drives, etc. Such additional memory devices may be made accessible to the computing system environment 100, for example, via a hard disk drive interface 112, a magnetic disk drive interface 114, and / or an optical disk drive interface 116. As will be appreciated, these devices, each linked to the system bus 306, enable reading and writing to the hard disk 118, reading and writing to the removable magnetic disk 120, and / or reading and writing to the removable optical disk 122, such as a CD / DVD, ROM, or other optical medium. The drive interfaces and their associated computer readable media enable non-volatile storage of computer readable instructions, data structures, program modules, and other data for the computing system environment 100. Those skilled in the art will further appreciate that other types of computer readable media capable of storing data may be used for this same purpose. Examples of such media devices include, but are not limited to, magnetic cassettes, flash memory cards, digital video disks, Bernoulli cartridges, random access memory, nano drives, memory sticks, other read / write memory and / or read-only memory, and / or other methods or technologies for storing information, such as computer readable instructions, data structures, program modules, or other data.Any such computer storage media may be part of the computing system environment 100.

[0063] A number of program modules may be stored in one or more memory / media devices. For example, a basic input / output system (BIOS) 124, containing the basic routines that help to transfer information between elements within the computing system environment 100, such as during start-up, may be stored in ROM 108. Similarly, the RAM 110, the hard drive 118, and / or the peripheral memory devices may be used to store computer-executable instructions including an operating system 126, one or more application programs 128 (which may include functionality disclosed herein, for example), other program modules 130, and / or program data 122. Additionally, computer-executable instructions may be downloaded to the computing environment 100 as needed, for example via a network connection.

[0064] An end user may enter commands and information into the computing system environment 100 through input devices such as a keyboard 134 and / or a pointing device 136. Although not shown, other input devices may include a microphone, joystick, game pad, scanner, etc. These and other input devices are typically connected to the processing unit 102 through a peripherals interface 138, which is in turn coupled to the bus 106. The input devices may be connected directly or indirectly to the processor 102 through an interface, such as, for example, a parallel port, game port, Firewire, Universal Serial Bus (USB), etc. To display information from the computing system environment 100, a monitor 140 or other type of display device may also be connected to the bus 106 through an interface, such as a video adapter 132. In addition to the monitor 140, the computing system environment 100 may also include other peripheral output devices (not shown), such as speakers and printers.

[0065] The computing system environment 100 may also utilize logical connections to one or more computing system environments. Communications between the computing system environment 100 and a remote computing system environment may be exchanged through an additional processing device, such as a network router 152 responsible for network routing. Communications with the network router 152 may be performed through a network interface component 154. Thus, it will be understood that within such a network environment, such as the Internet, the World Wide Web, a LAN, or other similar types of wired or wireless networks, program modules depicted relative to the computing system environment 100, or portions thereof, may be stored in a memory storage device of the computing system environment 100.

[0066] The computing system environment 100 may also include location determination hardware 186 for determining the location of the computing system environment 100. In some cases, the location determination hardware 156 may include only a GPS antenna, an RFID chip or reader, a WiFi antenna, or other computing hardware that can be used to capture or transmit signals that can be used to determine the location of the computing system environment 100.

[0067] Although specific embodiments have been described in this disclosure, it will be understood that the claims are not intended to be limited to these embodiments, unless expressly set forth in the claims. On the contrary, the disclosure is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the disclosure. Furthermore, in the detailed description of the disclosure, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be apparent to those skilled in the art that systems and methods consistent with the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure various aspects of the present disclosure.

[0068] Some of the detailed descriptions of this disclosure are presented in terms of procedures, logic blocks, processes, and other symbolic representations of operations on data bits within a computer or digital system memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, logic block, process, or the like, is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. These steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these physical manipulations take the form of electrical or magnetic data capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system or similar electronic computing device. For convenience, and with reference to common usage, such data will be referred to as bits, values, elements, symbols, characters, terms, numbers, or the like in reference to the various embodiments presently disclosed.

[0069] However, it should be noted that these terms should be interpreted as referring to physical operations and quantities, and are merely convenient labels that should be further interpreted in light of the terms commonly used in the art. Unless otherwise indicated, as will be apparent from the discussion herein, throughout the discussion of the present embodiments, discussions using terms such as "determine" or "output" or "transmit" or "record" or "locate" or "store" or "display" or "receive" or "recognize" or "use" or "generate" or "provide" or "access" or "confirm" or "notify" or "deliver" are understood to refer to the operations and processes of a computer system or similar electronic computing device that manipulates and transforms data. Data is represented as physical quantities (electronic quantities) in the registers and memory of the computer system, and is transformed to other data that are also represented as physical quantities in the memory or registers of the computer system, or other such information storage, transmission, or display devices, as described herein or understood by those skilled in the art.

[0070] In an exemplary embodiment, any of the operations described herein may be implemented, at least in part, as computer readable instructions stored on a computer readable medium or in a memory that, when executed by a processor, causes a computing device to perform an operation.

[0071] The foregoing description of the exemplary embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to be limited to the precise form disclosed, and modifications and variations may be possible in light of the above teachings or from practice of the disclosed embodiments. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims

1. 1. A hybrid aircraft powerplant, comprising: a turbine engine including a first shaft configured to output power from the turbine engine; Bypass fan, Electrical machinery and a mechanism configured to selectively engage the first shaft with a second shaft connected to the electric machine such that the power is output from the turbine engine to the electric machine. Hybrid aircraft powerplant.

2. 2. The hybrid aircraft powerplant of claim 1, wherein the mechanism is a clutch, and while the clutch is disengaged, the power from the turbine engine is not output to the electric machine.

3. 2. The hybrid aircraft powerplant of claim 1, wherein the mechanism is a clutch, and while the clutch is engaged, the power from the turbine engine is output to the electric machine.

4. 2. The hybrid aircraft powerplant of claim 1, wherein the mechanism is a first clutch, and the hybrid aircraft powerplant further includes a second clutch configured to selectively engage the first shaft with a third shaft connected to the bypass fan to output power from the turbine engine to the bypass fan.

5. 5. The hybrid aircraft powerplant of claim 4, wherein the first clutch and the second clutch are controllable such that the first clutch is engaged to transmit the power from the turbine engine to the electric machine while the second clutch is disengaged to not transmit the power from the turbine engine to the bypass fan machine.

6. 5. The hybrid aircraft powerplant of claim 4, wherein the first clutch and the second clutch are controllable such that the second clutch is engaged to transmit the power from the turbine engine to the bypass fan, while the first clutch is disengaged to not transmit the power from the turbine engine to the electric machine.

7. 5. The hybrid aircraft powerplant of claim 4, wherein the first clutch and the second clutch are controllable such that both the first clutch and the second clutch are engaged simultaneously to transmit the power from the turbine engine to both the electric machine and the bypass fan simultaneously.

8. 2. The hybrid aircraft powerplant of claim 1, further comprising a gearbox attached to the first shaft or the second shaft, the gearbox configured to convert power output from the turbine engine.

9. The hybrid aircraft powerplant of claim 1 , wherein the electric machine is a generator.

10. The hybrid aircraft powerplant of claim 1 , wherein the electric machine is a generator / motor combination.

11. 1. A hybrid aircraft powerplant, comprising: a turbine engine including a first shaft configured to output power from the turbine engine; Bypass fan, Electrical machinery and a mechanism configured to selectively engage a portion of the first shaft with a second shaft connected to the bypass fan to output the power from the turbine engine to the bypass fan. Hybrid aircraft powerplant.

12. 12. The hybrid aircraft powerplant of claim 11, wherein the mechanism is a clutch, and while the clutch is disengaged, the power from the turbine engine is not output to the bypass fan.

13. 12. The hybrid aircraft powerplant of claim 11, wherein the mechanism is a clutch, and while the clutch is engaged, the power from the turbine engine is output to the bypass fan.

14. 12. The hybrid aircraft powerplant of claim 11, wherein the mechanism is a first clutch, and the hybrid aircraft powerplant further includes a second clutch configured to selectively engage the first shaft with a third shaft connected to the electric machine to output the power from the turbine engine to the electric machine.

15. 12. The hybrid aircraft powerplant of claim 11, further comprising a gearbox attached to the first shaft or the second shaft, the gearbox configured to convert the power output from the turbine engine.

16. 1. A method, comprising: controlling a turbine engine including a first shaft to output power via the first shaft; controlling a first mechanism to engage the first shaft with a second shaft in a first mode of operation, the second shaft being connected to an electric generator whereby the power is output from the turbine engine through the first shaft and the second shaft to the electric generator; in a second mode of operation, controlling the first mechanism to engage the first shaft with the second shaft and controlling the second mechanism to engage the first shaft with a third shaft, the third shaft being connected to a bypass fan, whereby the power is output from the turbine engine to each of the generator and the bypass fan. method.

17. 17. The method of claim 16, wherein the first mode of operation is used during vertical takeoff or landing operations of an aircraft.

18. 17. The method of claim 16, wherein during the first mode of operation, the second mechanism is not engaged to connect the first shaft to the third shaft.

19. 17. The method of claim 16, wherein during the second mode of operation, the bypass fan is configured to generate forward thrust for an aircraft, while electrical power generated by the generator is configured to power electrical components of the aircraft.

20. 17. The method of claim 16, further comprising: in a third mode of operation, controlling the second mechanism to engage the first shaft with the third shaft without engaging the first mechanism to engage the first shaft with the second shaft, whereby the power is output from the turbine engine to the bypass fan but not to the generator.

21. 1. A hybrid aircraft powerplant, comprising: a turbine engine including a shaft configured to output power from the turbine engine; Bypass fan, an electric machine; the shaft is configured to deliver the output power to the bypass fan and to an electric machine; the electric machine is divided into a plurality of sectors whereby the electric machine is configured to generate electrical power in response to receiving the power output from the turbine engine; the power is output from the electric machine via a plurality of outputs, each of the plurality of outputs being associated with one of the plurality of sectors of the electric machine; Hybrid aircraft powerplant.

22. 22. The hybrid aircraft powerplant of claim 21, further comprising a plurality of inverters, each of the plurality of outputs configured to output alternating current (AC) power to one of the plurality of inverters, each of the plurality of inverters further configured to convert the AC power to direct current (DC) power.

23. 23. The hybrid aircraft powerplant of claim 22, wherein the plurality of inverters are configured to output the DC power to one or more DC buses.

24. 24. The hybrid aircraft powerplant of claim 23, wherein the one or more DC buses include aluminum wiring.

25. 24. The hybrid aircraft powerplant of claim 23, wherein the one or more DC buses include wiring constructed from superconducting material.

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