Flexible architecture of aerospace hybrid systems and their optimized components.

Abstract

The hybrid powertrain system includes an engine, an electric machine having a power shaft therein, and a clutch configured to releasably engage an output of the engine with the power shaft of the electric machine. The electric machine further includes an electric output. The power shaft is mechanically attached to the propulsion device and configured to provide mechanical power to the propulsion device. A controller is configured to control the engine, the electric machine, and the clutch to achieve one or more power output modes.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED PATENT APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 280,543, filed November 17, 2021, U.S. Provisional Patent Application No. 63 / 163,165, filed March 19, 2021, and U.S. Provisional Patent Application No. 63 / 151,760, filed February 21, 2021, the entire contents of each of which are incorporated herein by reference in their entirety.

[0002] This application relates to a flexible architecture of aerospace hybrid systems and their optimized components. [Background technology]

[0003] There are many different types of aircraft that are propelled using different types of propulsion mechanisms, such as propellers, turbine or jet engines, rockets, or ramjets. The different types of propulsion mechanisms may be powered in different ways. For example, some propulsion mechanisms, such as propellers, may be powered by an internal combustion engine or an electric motor. As such, the combination of the propulsion mechanisms and the methods of powering them are often specially designed for a particular aircraft, so that the propulsion mechanisms and the methods of powering them meet the specifications necessary to properly and safely propel the aircraft. Summary of the Invention

[0004] In one embodiment, the hybrid powertrain system includes an engine, an electric machine having a power shaft therein, and a clutch configured to releasably engage an output of the engine and the power shaft of the electric machine. The electric machine further includes an electric output. The power shaft is mechanically attached to a propulsion device and configured to provide mechanical power to the propulsion device. A controller is configured to control the engine, the electric machine, and the clutch to achieve one or more power output modes.

[0005] In one embodiment, the hybrid powertrain system includes an engine, a power shaft, and an electric machine having the power shaft therein. The electric machine further includes an electrical input / output. The hybrid powertrain system further includes a clutch configured to releasably engage an output of the engine to the power shaft. The electric machine is configured to receive electrical power from an electrical energy storage device via the electrical input / output and drive the power shaft. The electric machine is configured to output electrical power via the electrical input / output upon rotation of the power shaft by the engine. The power shaft is configured to be mechanically attached to the propulsion device and to provide mechanical power to the propulsion device.

[0006] In one embodiment, the hybrid powertrain system includes an engine and an electric machine having a power shaft therein. The electric machine further includes an electrical input / output. The power shaft is mechanically attached to the propulsion device and configured to provide mechanical power to the propulsion device. The power shaft is configured to be rotated by an output of the engine. The engine and the electric machine are configured to operate in a first mode in which the electric machine outputs a first electrical power via the electrical input / output based on the rotation of the power shaft, the power shaft being rotated by the engine. The engine and the electric machine are configured to operate in a second mode in which both the engine and the electric machine drive the power shaft, the electric machine drives the power shaft based on a second electrical power received via the electrical input / output.

[0007] In one embodiment, a method includes controlling an engine and an electric machine having a power shaft therein to operate in a first mode. The first mode includes driving the power shaft by the engine, the power shaft being configured to rotate by an output of the engine. The first mode further includes outputting a first electrical power from the electric machine based on rotation of the power shaft by the engine via an electrical input / output of the electric machine. The method further includes controlling the engine and the electric machine to operate in a second mode including simultaneously driving the power shaft by the engine and the electric machine, the electric machine driving the power shaft based on a second electrical power received via the electrical input / output. [Brief description of the drawings]

[0008] [Figure 1A] FIG. 1 illustrates an example of a flexible architecture for an aerospace hybrid system in accordance with an illustrative embodiment. [Figure 1B] 1 illustrates an additional example of a flexible architecture for an aerospace hybrid system in accordance with an illustrative embodiment; [Figure 2A] FIG. 1 is a block diagram illustrating a first aircraft control system for use with the flexible architecture of an aerospace hybrid system in accordance with an illustrative embodiment. [Figure 2B] FIG. 1 is a block diagram illustrating a second aircraft control system for use with the flexible architecture of the aerospace hybrid system in accordance with an illustrative embodiment. [Diagram 3] FIG. 1 illustrates a first example of an aircraft that can use the flexible architecture of an aerospace hybrid system in accordance with an illustrative embodiment. [Figure 4] FIG. 1 illustrates a second example of an aircraft that can use the flexible architecture of an aerospace hybrid system in accordance with an illustrative embodiment. [Diagram 5] FIG. 10 illustrates a third example of an aircraft that may use the flexible architecture of an aerospace hybrid system in accordance with an illustrative embodiment. [Figure 6] 1 is a flowchart illustrating a first exemplary method for using a flexible architecture of an aerospace hybrid system during different flight phases of an aircraft equipped with a main propulsion propeller, in accordance with an exemplary embodiment. [Figure 7] 1 is a flowchart illustrating a second exemplary method for using a flexible architecture of an aerospace hybrid system during different flight phases of an aircraft equipped with a main propulsion propeller, in accordance with an exemplary embodiment. [Figure 8] FIG. 1 illustrates an example of a flexible architecture for an aerospace hybrid system having a flywheel in accordance with an illustrative embodiment. [Figure 9] FIG. 1 illustrates a perspective view of an example flexible architecture for an aerospace hybrid system in accordance with an illustrative embodiment; [Figure 10] FIG. 10 is a top view of the example flexible architecture of FIG. 9 in accordance with an exemplary embodiment. [Figure 11] FIG. 10 is a side view of the example flexible architecture of FIG. 9 in accordance with an exemplary embodiment. [Figure 12] FIG. 1 illustrates a perspective view of another example of a flexible architecture for an aerospace hybrid system in accordance with an illustrative embodiment; [Figure 13] 1 is a diagram illustrating example downstream and upstream components for propelling an aircraft in accordance with an illustrative embodiment; [Figure 14] FIG. 1 illustrates an example of a flexible architecture for an aerospace hybrid system having a flywheel and a spring coupler in accordance with an illustrative embodiment. [Figure 15] FIG. 1 illustrates an example of a computing environment, in accordance with an illustrative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Aircraft typically have custom-designed propulsion mechanisms and methods for powering those propulsion mechanisms. In this way, the propulsion mechanisms and the power provided to those propulsion mechanisms can be optimized to provide the amount of propulsion required for a particular type and size of aircraft while minimizing the weight of components within the aircraft. In other words, the propulsion mechanisms and the power of those propulsion mechanisms are often optimized for a particular type and size of aircraft, so that components of one aircraft cannot easily be used with different types of aircraft drive architectures, such as direct drive aircraft, parallel drive aircraft, and serial drive aircraft.

[0010] Various embodiments of flexible architectures and optimized components thereof for aerospace hybrid systems are described herein. A hybrid system may be or include a system in which fuel is combusted in a piston, rotary, turbine, or other engine and the output of the piston engine is operatively connected to a generator to output electrical power. The embodiments described herein may include a flexible system capable of powering many different types of aircraft and propulsion mechanisms. Such a system may advantageously reduce the complexity of designing different types of aircraft, reduce the manufacturing costs of such systems as less customization allows for economies of scale in mass production of the systems, and ultimately reduce the complexity of aircraft using the systems described herein.

[0011] The flexible architecture described herein may further be used to power propulsion mechanisms in different ways within the same aircraft or different aircraft. For example, a flexible architecture for powering propulsion mechanisms may be capable of operating in multiple different modes to power different types of propulsion mechanisms. A first aircraft may utilize one, some, or all of the multiple different modes in which the flexible architecture can operate. A second aircraft may utilize one, some, or all of the multiple different modes, and the mode utilized by the second aircraft may be different from the mode utilized by the first aircraft.

[0012] Thus, different aircraft may utilize different modes of powering the propulsion mechanisms provided by the flexible architecture described herein. Although the use of the flexible architecture may be customized in this manner, the physical hardware of the flexible architecture may be adapted for use by different aircraft with minimal or no changes to the physical components of the flexible architecture described herein. Instead, the use of different modes in different aircraft may be achieved primarily based on how the components of the flexible architecture are controlled using a processor or controller. Thus, computer readable instructions may be stored in a memory operatively coupled to a processor or controller, such that when the instructions are executed by the processor or controller, a computing device including the processor or controller may control the various components of the flexible architecture described herein to utilize any possible modes of use desired for a particular implementation, aircraft, flight phase, etc.

[0013] Power generation and propulsion systems for aircraft may also utilize various cooling systems to ensure that various components of the aircraft are kept at safe temperatures for operation, as well as to ensure that the components remain within temperature ranges that they can operate more efficiently. Further, described herein are advantageous cooling systems that utilize various aspects of the hybrid architecture described herein to efficiently cool components of a flexible architecture for powering the propulsion mechanisms of an aircraft.

[0014] An aircraft having hardware for providing different modes of power to the propulsion mechanisms may have various components for which it is desirable to provide cooling. Thus, a single cooling system that efficiently moves air to the various components that enable the different power modes may reduce the weight of the aircraft as well as the power consumption of the cooling system. Figures 1-8 and the following accompanying description relate specifically to an example flexible architecture for powering the propulsion system of an aircraft. Figures 9-12 and the following accompanying description relate to various embodiments of a cooling system for the example flexible architecture.

[0015] 1A illustrates an example of a flexible architecture 101 for an aerospace hybrid system in accordance with an illustrative embodiment. As discussed herein, the flexible architecture 101 can be efficiently used in a wide range of applications with a single hybrid generator system that can be adapted in multiple ways (e.g., used in different modes) depending on the requirements of the aircraft and the flight phase.

[0016] The flexible architecture 101 of FIG. 1A is a hybrid generator including an engine 105, a clutch 115, a generator / motor 121, and a power shaft 111. As described further below, the flexible architecture 101 can be used to achieve a variety of different modes as needed depending on the installation requirements of a particular aircraft or a particular flight phase. The engine 105 can be a combustion engine, such as an internal combustion engine. More specifically, the engine 105 can be one of a piston internal combustion engine, a rotary engine, or a turbine engine. Such engines can use standard gasoline, jet fuel (e.g., Jet A, Jet A-1, Jet B fuel), diesel fuel, biofuel alternatives, and the like. In various embodiments, small engines (such as Rotax gasoline engines) of the drone implementations and other types of engines can also be used.

[0017] As mentioned above, the engine 105 may be a piston combustion engine. A piston combustion engine may advantageously rotate an output rotor or shaft at revolutions per minute (RPM) that is more desirable for direct output to power a generator and / or a propulsion mechanism (e.g., a propeller) than other engines. For example, a piston combustion engine may have an output on the order of several thousand RPM. For example, the output of a piston combustion engine may be in the range of 2200-2500 RPM, which may be a desirable RPM for a propeller. In particular, the propeller may be designed to have a size that results in a desired tip speed of the propeller based on the RPM output of the piston combustion engine (e.g., 2200-2500 RPM). Other types of engines, such as turbine engines, may output rotational power on the order of tens of thousands of RPM, much higher than a piston combustion engine. Alternative embodiments may drive a motor / generator at the higher RPM of the turbine engine to benefit efficiency, power output, or other important factors. In some embodiments, a gearbox can be added between the high RPM engine output and other components of FIG. 1A to reduce the output RPM of the engine 105. However, adding a gearbox may also increase the weight of the system, which may be undesirable in some embodiments. Piston combustion engines may have an additional advantage in terms of noise compared to turbine engines. Turbine engines are typically louder than piston combustion engines, and the human-perceived noise from turbine engines is typically more annoying to the listener than the noise generated by piston combustion engines. In urban or densely populated environments where reduced noise is desired, quieter engines may be more valuable.

[0018] The engine 105 can output rotational power to the clutch 115, which can be controlled to engage or disengage the power shaft 111. In other words, the power shaft 111 can be engaged with the rotational output of the engine 105 by the clutch 115, whereby rotational power can be transferred between the output of the engine 105 and the power shaft 111. When the clutch 115 is disengaged from the output of the engine 105 and the power shaft 111, the power shaft 111 can rotate independently of the output of the engine 105. The clutch 115 can be physically located between the engine 105 and the generator / motor 121, and can even contact the opposite side of the engine 105 and the generator / motor 121 to reduce the overall footprint of the flexible architecture. In FIG. 1A, the clutch 115 is further described herein and shown in other figures. However, in various embodiments, any mechanism capable of releasably decoupling the engine 105 and the power shaft 111 can be used in addition to or in place of the clutch. For example, the decoupling can be based on absolute revolutions per minute (RPM) or relative RPM between the output of the engine 105 and the power shaft 111, such as in an overrunning clutch.

[0019] The generator / motor 121 may also be engaged with the power shaft 111 or disengaged from the power shaft 111. In other words, the generator / motor 121 may be controlled to be switched off so that the rotation of the power shaft 111 does not cause the generator / motor 121 to generate power. Similarly, the generator / motor 121 may be controlled to be switched on so that the rotation of the power shaft causes the generator / motor 121 to generate power. The generator / motor 121 is referred to as a generator / motor because it can function as both a generator and a motor. In various embodiments, the generator / motor 121 may be referred to as an electric machine, which may be a generator, an electric motor, or both.

[0020] The flexible architecture further includes a power input / output (I / O) 125 connected to the generator / motor 121. As described further herein, the generator / motor 121 may generate power based on the rotation of the power shaft 111 that is output via the power I / O 125, or may receive power via the power I / O 125 that may be used to drive the power shaft 111. The wiring of the power I / O 125 may include multiple wires. In various embodiments, the wiring for inputting power to the generator / motor 121 may be the same as the wiring used to output power from the generator / motor 121. In various other embodiments, a first wiring may be used for inputting power and a different second wiring may be used for outputting power (using different wiring for input and output). In various embodiments, the generator / motor 121 may also have wiring that is used to control the generator / motor 121 and is connected to relay sensor or other data regarding the operation of the generator / motor 121 to a controller or the like.

[0021] The generator / motor 121 can also function as a driver for the power shaft 111. Upon receiving power via the power I / O 125 from a battery or some other form of electrical energy storage elsewhere in the system, the generator / motor 121 can provide a rotational force to drive the power shaft 111. This can occur as long as the generator / motor 121 is controlled to be switched on so that it is engaged with the power shaft 111. If the generator / motor 121 is controlled to be switched off so that it is not engaged with the power shaft 111, the power shaft 111 may no longer be rotated by the generator / motor 121.

[0022] The power output from the power I / O 125 may be used to drive electric motors for electric propulsion (e.g., propellers). The power output from the power I / O 125 may also be used to power and / or charge other devices on the aircraft or aerospace vehicle. For example, the power output from the power I / O 125 may be used to charge one or more batteries. The power output from the power I / O 125 may also be used to power other devices or accessories on the aircraft or aerospace vehicle. Because the power I / O 125 also has an input, the power shaft 111 may be driven by any power received via the power I / O 125, such as power from one or more batteries. The power generated by the generator / motor 121 may be alternating current (AC) power. The AC power may be converted to direct current (DC) power by power electronics (e.g., a rectifier or inverter) and output to a DC bus. This DC bus may be connected to a battery and / or an electric propulsion. In this manner, the electric propulsion may be powered via the DC bus. In various embodiments, the motors of the electric propulsion mechanisms may use AC power, and therefore the DC power from the DC bus may be converted from DC power to AC power before being used by the electric propulsion mechanisms (e.g., an inverter).

[0023] Any rotation of the power shaft 111 itself may also be used to drive one or more propulsion mechanisms, whether driven by the engine 105 or the generator / motor 121. For example, the rotation of the power shaft 111 may be used to directly drive a propeller or may be used to power an electric motor that drives the propulsion mechanism. The rotation of the power shaft 111 may also drive a gearbox that is operatively connected to another component, such as one or more propellers, one or more rotors, or other rotating devices for various applications on the aircraft.

[0024] The accessory pad 130 may also be coupled to the engine 105 and may include a low voltage direct current (DC) generator for power separate from the generator / motor 121 and power I / O 125, which may be configured for high voltage and high power I / O. In some embodiments, the generator / motor 121 may have two different windings and the power I / O 125 may have two different outputs (e.g., high voltage and low voltage). An accessory power source may be associated with one of the outputs of the power I / O 125 in addition to or instead of the output of the accessory pad 130. The accessory pad 130 may be used to power devices or accessories on the aircraft or aerospace vehicle that do not require the high voltage or current output that may be output by the generator / motor 121 at the power I / O 125. The voltage (HV) of the aircraft may be, for example, 400 volts (V) or 800V, but could be anywhere between 50V and 1200V. The low voltage (LV) of the aircraft may be 12V, 14V, 28V, or other voltage less than 50V.

[0025] FIG IB illustrates an additional example of a flexible architecture 150 for an aerospace hybrid system in accordance with an illustrative embodiment. In particular, the flexible architecture 150 of FIG IB includes several components that may be the same or similar to those described above with respect to FIG 1A, where the flexible architecture 150 includes an engine 155, a clutch 175, a power shaft 180, and / or a generator / motor 185. The flexible architecture 150 further illustrates an output of the engine 155 in the form of a crankshaft 160, which is rigidly connected to an output flange 165. The output flange 165 is rigidly connected to one side of the clutch 175 using bolts 170.

[0026] The clutch 175 may be configured to engage the power shaft 180 to convert rotational motion from the crankshaft 160 and the output flange 165 to the power shaft 180. The clutch 175 may further be configured to disengage from the power shaft 180, thereby allowing the power shaft 180 to rotate independently relative to the crankshaft 160 and the output flange 165. Additionally, FIG. 1B illustrates how all of the rotatable components of the flexible architecture 150 may be aligned along a single axis 190. The rotatable components of FIG. 1A may be aligned along a single axis as well, as shown in FIG. 1B. Additionally, the power shaft 180 may be a splined shaft that fits into the inner diameter openings of the clutch 175 and the generator / motor 185. Other features other than splines, such as tapers, may also be used. In either case, the generator / motor 185 and / or the clutch 175 may be configured to match and connect to the splines, tapers, or other features on the power shaft 180 so that the components can properly engage with one another.

[0027] In various embodiments, the clutch 175 may be a different type of clutch or other mechanism capable of decoupling the power shaft 180 from the output of the engine 155. For example, the clutch 175 may be a plate-type clutch and may be a dry or wet clutch. Such a plate-type clutch may be engaged / disengaged or otherwise controlled mechanically, hydraulically, and / or electrically (e.g., by the controllers 205, 220, and / or 280 of FIGS. 2A and 2B). A plate-type clutch may have a variety of numbers of plates, such as three, five, or ten plates. In various embodiments, the clutch 175 or other clutches described herein may be a one-way clutch, an overrunning clutch, or a sprag clutch. A one-way clutch or a sprag clutch may be configured to disengage the engine output from the power shaft while the electric machine rotates the power shaft faster than the engine output. In other words, when the engine 155 is outputting less power to the power shaft 180 than the generator / motor 185, the clutch 175 can automatically mechanically disengage the output of the engine 155 from the power shaft 180, e.g., without any electrical control input being used to accomplish that disengagement. When the engine 155 has a higher RPM or outputs more power than the generator / motor 185, a one-way or sprag clutch is engaged so that power is added from the output of the engine 155 to the power shaft 180. Another type of clutch that can be used is a centrifugal clutch, where as the RPM increases, the weight of the plates of the clutch gradually activates one or more levers, compressing the plates of the centrifugal clutch and engaging the plates to connect, e.g., the output of the engine 155 and the power shaft 180.

[0028] Advantageously, the generator / motor 121 and / or the generator / motor 185 of FIG. 1A may be used as a starter for the engine 105 or the engine 155, respectively. In other words, the generator / motor 185 may be used to rotate the crankshaft 160 while the clutch 175 is engaged to start the engine 155. Such a system may be advantageous, for example, where the generator / motor 185 may be powered by a battery or other power source. Thus, the engine 155 may be a piston combustion engine as described herein, and may not require a separate starter component, reducing the weight and complexity of the flexible architecture described herein.

[0029] FIG. 2A illustrates a block diagram depicting an aircraft control system 200 used with a flexible architecture 201 for an aerospace hybrid system, according to an exemplary embodiment. The aircraft control system 200 may be used to realize one or more of the various modes discussed below, in which the flexible architecture described herein may be used, for example. The flexible architecture 201 may have the same, similar, or some or all of the components of the flexible architectures 101 and / or 150 of FIG. 1A and / or FIG. 1B. The aircraft control system 200 may include one or more processors or controllers 205 (hereinafter referred to as controller 205), memory 210, an aircraft main controller 220, an engine 230, a generator / motor 235, a clutch 240, a power I / O 245, an accessory pad 250, and one or more sensors 260. The connections in FIG. 2A illustrate control signal related connections between the components of the aircraft control system 200. Other connections not shown in FIG. 2A may exist between different aspects of the aircraft and / or aircraft control system 200 to provide power, such as high voltage (HV) or low voltage (LV) power for the aircraft.

[0030] The memory 210 may be a computer-readable medium configured to store instructions. Such instructions may be computer-executable code executed by the controller 205 to implement various methods and systems described herein, including various modes and combinations of modes using the flexible architecture herein. The computer code may be written such that various methods of implementing different modes of the flexible architecture herein are automatically implemented based on various inputs, for example, indicative of a particular flight phase (e.g., 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 implementations based on non-human inputs (e.g., from sensors on or off the aircraft, based on a planned flight plan, etc.). The controller 205 may be powered by a power source on the aircraft or aerospace vehicle, such as the accessory pad 130, one or more batteries, an output of the power I / O 125, a power bus of the aircraft powered by any power source, and / or any other available power source.

[0031] The controller 205 may also communicate with each of the engine 230, the generator / motor 235, the clutch 240, the power I / O 245, the accessory pads 250, and / or the sensors 260. In this manner, the components of the flexible architecture may be controlled to achieve the various modes described herein. In various embodiments, the engine 230, the generator / motor 235, the clutch 240, the power I / O 245, and the accessory pads 250 may be similar to or similarly named components shown in and described above with respect to FIG. 1A. The power I / O 245 may also include pre-charge electronics to protect the electrical components of the flexible architecture, including, for example, a direct current (DC) bus, from excessive inrush current during startup as described herein. For example, if a high voltage (HV) bus is 400V and a new component is connected to the 0V HV bus, the instantaneous inrush current may be very large and may cause damage to the HV bus and / or the component. As a result, the pre-charge electronics can slowly ramp up the voltage of the components before fully connecting to the HV bus or other power source. In various embodiments, the HV bus can be a DC bus or an AC bus, or there can be multiple buses that are either DC or AC buses. If an AC bus is used, AC power can be output directly from the motor / generator to the AC bus. If a DC bus is used, an inverter can be used to convert the AC power from the motor / generator to DC power and output to the DC bus.

[0032] The sensors 260 may include various sensors for monitoring different components of the flexible architecture 201. Such sensors may include, for example, temperature sensors, tachometers, fluid pressure sensors, voltage sensors, current sensors, status sensors, etc., to determine the current state of the clutch 250, or other types of sensors. For example, voltage and / or current sensors may be used to indicate the function and settings of the motor / generator, to inform the clutch of the selected state, or to adjust other components of the system. Status sensors may also indicate the particular mode in which the flexible architecture is being used, and the system may receive input (e.g., from the pilot, from an automatic flight control) to change the system to a different state or mode for a particular upcoming flight phase. 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 a position relative to the ground and / or known / mapped structures.

[0033] The components within the dashed lines of flexible architecture 201 in FIG. 2A may be associated with the flexible architecture described herein, while aircraft main controller 220 may be associated with a broader aircraft system. In other words, aircraft main controller 220 may control aspects of the aircraft other than flexible architecture 201, while controller 205 may control aspects of the aircraft related to flexible architecture 201. Aircraft main controller 220 and controller 205 may communicate with each other to coordinate the powering of various propulsion mechanisms of the aircraft. For example, aircraft main controller 220 may send signals to control device 205 requesting a particular power output level for one or more particular propulsion mechanisms. Controller 205 may receive such control signals and determine how to coordinate flexible architecture 201 (e.g., which mode to enter, how to control elements of flexible architecture 201) to output the desired power level based on the control signals from aircraft main controller 220. In various embodiments, aircraft main controller 220 may send signals related to the control of particular aspects of flexible architecture 201. In other words, in addition to or instead of transmitting a desired power output signal to controller 205, controller 205 can function as a repeater to retransmit control signals from aircraft main controller 220 to the components of flexible architecture 201, and controller 205 determines from the control signals how to control the individual components of flexible architecture 201.

[0034] In various embodiments, aircraft main controller 220 may also transmit control signals related to future desired power output, future flight phases, flight plan information, etc. In this manner, controller 205 may receive information regarding the anticipated power requirements of the aircraft and use it to determine how to control aspects of flexible architecture 201, both now and in the future. For example, flight plan information may be used to determine when to use battery power, when to charge batteries, etc. In another example, if a large power demand is anticipated, controller 205 may ensure that engines 230 are running before beginning to provide the desired level of power.

[0035] In various embodiments, controller 205 may also communicate with one or more batteries to monitor their charge levels, control when the batteries are charged or discharged, control when the batteries are used to power generators / motors 235, and control when the batteries are used to directly power other aspects of the aircraft. However, in other embodiments, aircraft main controller 220 may communicate with the aircraft's batteries and / or relay information regarding the batteries and their control to controller 205. Similarly, in cases where the aircraft's batteries are controlled using aircraft main controller 220 rather than controller 205, controller 205 may send control signals related to the batteries to the aircraft main controller such that the batteries may be controlled as necessary or desired for the functioning of flexible architecture 201.

[0036] In various embodiments, the power I / O 245 may include two different outputs (e.g., a high voltage (HV) output and a low voltage (LV) output) associated with two different windings of the generator / motor 235. Thus, two different voltages (e.g., HV and LV) may be output and controlled by the controller 205 and / or the aircraft main controller 220. The power I / O 245 may additionally or alternatively have voltage conversion components (e.g., DC / DC converters) to enable it to output two or more different voltages. In such an embodiment, the two different outputs may be achieved without using two separate windings. The two different outputs may be output to different power buses of the aircraft, such as, for example, an HV bus and an LV bus. The two outputs of the power I / O 245 may also be independently controlled by the controller 205. Thus, the outputs may be turned off (e.g., by turning off the field current of the motor / generator, thereby allowing the generator's power shaft and rotor to rotate or freewheel relative to the rest of the motor / generator). In various embodiments, the power shaft may not actually freewheel within the generator / motor 235. Instead, the power shaft may rotate the rotor of the motor / generator 235 while the stator remains stationary, but the controller 205 may be used to control the output such that little or no power is actually output by the motor / generator 235. In various embodiments, the controller 205 may control the motor / generator 235 to output a desired or threshold level of power from the motor / generator 235 while the remaining power is output by the power shaft (e.g., to a propulsion mechanism). For example, the controller 205 may control the motor / generator 235 to generate as electrical power between 0% and 100% of the power output by the engine to the power shaft.For example, the controller 205 may cause the motor / generator 235 to generate 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99%, or 100% of the power from the power shaft as electrical power.

[0037] In some embodiments, the accessory pads may not be controlled by controller 205 and / or aircraft main controller 220. The accessory pads may simply be on all the time when engines 230 are running, or may be controlled separately (e.g., by a manual switch toggled by a user) to control when and how power is provided to the aircraft accessories.

[0038] In some embodiments, controller 205 may communicate with a wireless transceiver that may be onboard an aircraft or aerospace vehicle, thereby allowing controller 205 to communicate with other computing devices that are not hardwired to system 200. In this manner, instructions or inputs for implementing the various modes of the flexible architecture described herein may also be received wirelessly from remote computing devices. In other embodiments, system 200 may communicate only with components onboard an aircraft.

[0039] Figure 2B illustrates a block diagram representing a second aircraft control system 275 used with the flexible architecture for an aerospace hybrid system, according to an example embodiment. In the example of Figure 2B, system 275 does not have a separate aircraft main controller as in Figure 2A. Instead, the entire aircraft has the flexible architecture and a single main controller 280 that controls all aspects of the aircraft (including, for example, the aircraft's propulsion mechanism 255).

[0040] The controller 285 may communicate with and control one or more propulsion mechanisms 255 on the aircraft. The controller 285 may also communicate with one or more sensors 270 on the aircraft or aerospace vehicle, which may be aircraft sensors and flexible architecture sensors. In particular, the sensors 260 may be embedded in any of the components of Figures 1A and / or 1B described above, and thus may be used to inform how the devices of Figures 1A and / or 1B are controlled and / or how the modes described herein are implemented as described herein.

[0041] 2A or 2B, controller 205, controller 285, and / or aircraft main controller 220 may also be in communication with a cooling system configured to cool and / or heat any component of the flexible architecture, one or more batteries, or other aspects of the aircraft, such that the cooling system may also be controlled in conjunction with other systems and methods described herein.

[0042] Described below are five particular modes that may be implemented using various embodiments of the flexible architectures described herein (including, for example, the flexible architectures shown in and described with respect to Figures 1A, 1B, 2A, and 2B).

[0043] In a first mode, which may be referred to herein as a hybrid generator mode, a clutch (e.g., clutch 115 of FIG. 1A and / or clutch 175 of FIG. 1B) may be controlled to engage an engine (e.g., engine 105 of FIG. 1A and / or engine 155 of FIG. 1B) with a power shaft (e.g., power shaft 111 of FIG. 1A and / or clutch output / power shaft 180) extending from the clutch to a generator / motor (e.g., generator / motor 121 of FIG. 1A and / or generator / motor 185 of FIG. 1B), causing the engine to rotate a power shaft in the generator / motor to generate electrical power that is supplied to other systems on the aircraft, such as propulsion mechanisms / systems, via a power I / O (e.g., power I / O 125 of FIG. 1A). For example, such propulsion mechanisms / systems may be powered using an electric motor, and the electrical power output by the generator / motor in the first mode may be used to drive such propulsion mechanisms / systems. That is, in a first mode, the clutch can be used to engage the engine with a power shaft to drive a generator / motor, which can then output electrical power.

[0044] In a second mode, which may be referred to herein as a direct drive engine mode, a clutch (e.g., clutch 115 of FIG. 1A and / or clutch 175 of FIG. 1B) may engage an engine (e.g., engine 105 of FIG. 1A and / or engine 155 of FIG. 1B) output to a power shaft (e.g., power shaft 111 of FIG. 1A and / or clutch output / power shaft 180) that extends through a generator / motor (e.g., generator / motor 121 of FIG. 1A and / or generator / motor 185 of FIG. 1B) to provide mechanical power to a propulsion mechanism, such as a propeller of an aircraft. In such a mode, the magnetic field may be removed from the generator / motor (e.g., the generator / motor may be controlled to be off or disengaged) such that the generator / motor power shaft and rotor rotate or freewheel and thus the generator / motor power I / O (e.g., power I / O 125 of FIG. 1A) is disengaged and does not output power. That is, in the second mode, the engine can drive the power shaft to mechanically or otherwise power the propulsion mechanism, while the power shaft rotates in the generator / motor without receiving or outputting electrical power at the power I / O. As described herein, the controller can also be used to control how much electrical power the generator / motor generates and outputs at the power I / O, while allowing the remaining power on the power shaft to be output as mechanical power to the propulsion device. The propulsion device can be, for example, a rotor, a propeller, a fan, or any other means of providing thrust. Thus, for example, when the aircraft's batteries are fully charged and the aircraft's electric motors are not being used, it may be desirable to output only mechanical power to the propulsion device and not convert any of the power on the power shaft to electrical power. In other examples, it may be desirable to convert only a portion of the mechanical power from the power shaft to electrical power.For example, the controller may cause the motor / generator to convert a certain percentage of power from the power shaft into electrical power, or may monitor the power shaft to ensure that a minimum threshold of mechanical power is output to the propulsion mechanism (e.g., to maintain a particular airspeed or RPM of the propulsion mechanism) and then convert the remaining power from the power shaft into electrical power (e.g., to charge batteries or other energy storage devices onboard the aircraft). Thus, various embodiments described herein may be controlled such that the generator / motor outputs a certain amount of electrical power or no / very little electrical power even while the motor / generator power shaft and rotor are rotating, which may help prevent overcharging of batteries onboard the aircraft, reduce overall fuel consumption, etc. In various embodiments, this may be controlled by the controller to control how much electrical energy is output using the generator, or by disengaging or partially disengaging the power shaft from the rotor of the motor / generator (or vice versa).

[0045] In a third mode, which may be referred to herein as an augmented thrust mode, a clutch (e.g., clutch 115 of FIG. 1A and / or clutch 175 of FIG. 1B) may engage an engine (e.g., engine 105 of FIG. 1A and / or engine 155 of FIG. 1B) to a power shaft (e.g., power shaft 111 of FIG. 1A and / or clutch output / power shaft 180) that extends through a generator / motor (e.g., generator / motor 121 of FIG. 1A and / or generator / motor 185 of FIG. 1B), which is used as a motor drawing power via a power I / O (e.g., power I / O 125 of FIG. 1A) from an external source such as a battery pack. This provides a higher mechanical power output to the power shaft than the engine or generator / motor can provide. That is, in the third mode, both the engine and the generator / motor are used to simultaneously drive the power shaft to deliver power (electricity) to the propulsion mechanism.

[0046] In a fourth mode, which may be referred to herein as a direct drive generator / motor mode, a clutch (e.g., clutch 115 of FIG. 1A and / or clutch 175 of FIG. 1B) may disengage the engine (e.g., engine 105 of FIG. 1A and / or engine 155 of FIG. 1B) from the generator / motor (e.g., generator / motor 121 of FIG. 1A and / or generator / motor 185 of FIG. 1B), such that power may be provided to the generator / motor via the power I / O (e.g., power I / O 125 of FIG. 1A) to drive the generator / motor as a motor and provide mechanical power to the power shaft (e.g., power shaft 111 of FIG. 1A and / or clutch output / power shaft 180). That is, in the fourth mode, only the generator / motor may provide power (electricity) to the propulsion mechanism based on the power received at the power I / O.

[0047] In a fifth mode, which may be referred to herein as an engine power split mode, a clutch (e.g., clutch 115 of FIG. 1A and / or clutch 175 of FIG. 1B) may engage an engine (e.g., engine 105 of FIG. 1A and / or engine 155 of FIG. 1B) with a generator / motor (e.g., generator / motor 121 of FIG. 1A and / or generator / motor 185 of FIG. 1B), such that the engine may not only rotate the generator / motor as a generator to provide power to other systems on the aircraft via the power I / O (e.g., power I / O 125 of FIG. 1A), but may also provide mechanical power to a power shaft (e.g., power shaft 111 of FIG. 1A and / or clutch output / power shaft 180) to drive a system such as a propeller. That is, in the fifth mode, the engine may be used to drive a power shaft and generator / motor to output power (electricity) via the power I / O and power shaft.

[0048] As described herein, any of these five modes (or variations thereof) may be used with the single flexible architecture described herein. Furthermore, particular modes and / or combinations of modes may be beneficial for particular aircraft or aerospace vehicle types, particular propulsion types, particular flight phases of an aircraft or aerospace vehicle, etc.

[0049] For example, in a hybrid electric vertical take-off and landing (VTOL) aircraft with electric motor-driven propellers, the flexible architecture herein may be used only as a power source such that the flexible architecture can power the aircraft in a first mode (e.g., hybrid generator mode) during any portion of the flight phase in which the aircraft's power bus or one or more of the aircraft's motors must be powered.

[0050] In another example, in an aircraft with a single large main pusher propeller (e.g., at the rear of the aircraft fuselage) and an array of electric motors / propellers (e.g., on the aircraft wings), the flexible architecture can be used in a fifth mode (e.g., engine power split mode) during takeoff to mechanically power the main pusher propeller and electrically power the wing-mounted motors. Figures 3 and 4 show two examples of such aircraft 300 and 400 that can use the flexible architecture for aerospace hybrid systems according to exemplary embodiments. For example, aircraft 300 has a main pusher propeller 305 and aircraft 400 has a main pusher propeller 405 in the form of a ducted propulsion fan. In both examples, the fifth mode described herein can be used to mechanically power the main pusher propellers 305 and 405 from a power shaft. Additionally, the wing-mounted electric motors / propellers 310 and 410 can be driven with electrical power from a motor / generator as described herein.

[0051] Alternatively, the flexible architecture described herein may be used to power configurations such as those shown in Figures 3 and 4 in a third mode (e.g., augmented mode) by the battery pack powering both wing-mounted motors at takeoff to augment engine power to the power shaft driving the main propulsion propeller. During cruise flight, the aircraft may use the second mode (e.g., direct drive engine mode) to drive only the main propulsion propeller. In another example, during cruise flight, the aircraft may include a clutch between the power shaft and the propulsion propeller, and the controller may operate the aircraft in a first mode (e.g., hybrid generator mode) driving the wing-mounted motor by disengaging the power shaft from the propulsion propeller and outputting power from the generator / motor to the wing-mounted motor. In another example (e.g., emergency situations such as engine failure), the propulsion prop may be driven in a fourth mode (e.g., direct drive generator / motor mode) using power input to a power I / O such as one or more batteries.

[0052] In another example, the aircraft may be a VTOL aircraft with a gyrocopter-type main rotor that can operate powered or unpowered and may have wing-mounted forward thrust motors and propellers. In one embodiment, the flexible architecture may be used entirely in a first mode (e.g., hybrid generator mode) where power provided from the power input / output (and generator / motor) drives motors coupled to the gyrocopter-type main rotor and power is used to drive wing-mounted motors. In one embodiment, the aircraft may be configured with a clutch between the power shaft and the gyrocopter-type main rotor such that the flexible architecture may use a second mode (e.g., direct drive engine mode) or a third mode (e.g., augmented thrust mode) to spin the gyrocopter-type main rotor (e.g., to bring the gyrocopter-type rotor up to takeoff speed). In such an example, the controller may switch the flexible architecture to the first mode (e.g., hybrid generator mode) after the gyrocopter-type rotor has reached speed (e.g., switch to the first mode for cruise flight). A fourth mode (e.g., direct drive generator / motor mode) can be used again in the event of engine failure, using electrical power to drive a powered shaft (and thus a gyrocopter-type rotor) from a power source such as one or more batteries.

[0053] 5 illustrates another example aircraft 500 that may employ a flexible architecture for an aerospace hybrid system, according to an example embodiment. For example, the aircraft 500 may include multiple (e.g., eight) electric motor / propellers 505 on a tilt wing that may be powered using a first mode (e.g., hybrid generator mode) described herein, in which an engine may be engaged with a power shaft using a clutch to drive a generator / motor that may output power to the various electric motor / propellers 505 on the tilt wing.

[0054] Thus, described herein is an advantageous flexible architecture for an aircraft that can achieve various modes for powering the propulsion. While a particular aircraft and propulsion configuration may not utilize each of the modes described herein for which the flexible architecture is capable, the flexible architecture can still be implemented in different aircraft to achieve different modes. Similarly, while one example of a flexible architecture having five different modes for powering the propulsion is described in detail herein, other flexible architectures having fewer, more, or different modes for powering the propulsion are also contemplated herein.

[0055] For example, the flexible architecture may not have a clutch as described herein and still achieve the various modes described herein when it is desirable to couple the engine output to the motor / generator and / or power output shaft of the system. For example, in a first mode, the engine may rotate a power shaft to generate electricity via a generator. In a second mode, the engine may directly drive, for example, mechanical propulsion components, but it is not necessary to disengage the engine from the motor / generator or power shaft because the motor / generator can be turned off or the motor / generator power shaft and rotor can be allowed to freewheel within the motor / generator. In a third mode, the engine and motor / generator are used to drive the power shaft, so it is not desirable to disengage the engine and motor / generator using a clutch. In a fifth mode, the engine may rotate a power shaft to generate electricity via a generator, which mechanically powers the propulsion mechanism. Thus, in an aircraft utilizing any of the first, second, third, and / or fifth modes described above, it is not necessary to disengage the power shaft from the engine output. Thus, in embodiments using any combination of the first, second, third, and / or fifth modes (but not the fourth mode), a clutch may not be used since the system may always connect the engine output to the motor / generator power shaft, which may be of value since clutches may be heavy and / or unreliable.

[0056] 6 is a flow chart illustrating a first exemplary method 300 for using a flexible architecture of an aerospace hybrid system in different flight phases of an aircraft with a main propulsion propeller, according to an exemplary embodiment. In particular, the aircraft may be an aircraft with a single larger propulsion propeller and an array of electric motors and corresponding smaller propellers on the wings. During the takeoff flight phase at 602, the fifth mode described herein may be used to mechanically power the main propulsion propeller and to provide electrical power to the wing-mounted motors. During the cruise flight phase at 604, the second mode described herein may be used to mechanically power only the main propulsion propeller and not provide electrical power to the smaller electric motors / propellers.

[0057] FIG. 7 is a flow chart illustrating a second exemplary method 400 for using a flexible architecture of an aerospace hybrid system in different flight phases of an aircraft with a main propulsion propeller, according to an exemplary embodiment. In particular, the aircraft may be an aircraft with a single larger propulsion propeller and an array of electric motors and corresponding smaller propellers on the wings. During the takeoff flight phase at 702, a third mode described herein, called thrust augmentation, may be used to power the main propulsion propeller via a generator / motor (drawing power from the battery) and to mechanically power the main propulsion propeller directly from the engine. Additionally, power (generated by the generator / motor and / or generated directly from the battery) may also be provided to the electric motors on the wings during takeoff. During the cruise flight phase at 704, a second mode described herein may be used to mechanically power only the main propulsion propeller and not the smaller electric motors / propellers.

[0058] 1A , when engine 105 applies power to power shaft 111 and clutch 115 is engaged such that generator / motor 121 is not running or turned on, power shaft 111 may freewheel within generator / motor 121 (e.g., in the second mode described above). Similarly, power shaft 180 of FIG. 1B may freewheel within generator / motor 185 in various embodiments. However, engine 105 and / or engine 155 may generate torque pulses on power shaft 111 and / or power shaft 180 that may be dangerous to generators such as generator / motor 121 and / or generator / motor 185 when clutch 115 and / or clutch 175 engage the respective power shafts 111 and / or 180. In other words, a large torque pulse on the shaft, similar to that which can occur when certain types of engines (e.g., diesel piston internal combustion engines) fire, can cause high angular accelerations that can cause fatigue or damage to the components of the generator / motor 121 and / or generator / motor 185 coupled to the power shafts 111 and / or 180. As such, components to mitigate this torque can smooth the torque on the power shafts 111 and / or 180, such as using a flywheel or other heavy damping or spring coupling system.

[0059] FIG. 8 illustrates an example of a flexible architecture 800 for an aerospace hybrid system having a flywheel for absorbing vibration torque, according to an exemplary embodiment. In particular, the flexible architecture 800 includes similar or identical components as those shown in and described with respect to FIG. 1B, but includes a flywheel 195 rigidly connected to an output flange 165 using bolts 170. The flywheel 195 is further rigidly connected to one side of a clutch 175 by bolts 198. Thus, rotational motion can be transferred from the engine 155 through the crankshaft 160, the output flange 165, and the flywheel 195 to the clutch 175. The clutch 175 can engage or disengage the power shaft 180 to selectively convert the rotational motion received from the flywheel 195 to the power shaft 180. The flywheel 195 can also be, for example, a dual mass flywheel or a spring coupling.

[0060] In various other embodiments, a flywheel may not be used. For example, further embodiments of damping systems and damping devices are described herein that may dampen torque on a power shaft (e.g., power shaft 111) but do not include a flywheel. Additionally, in various embodiments, a flywheel and other damping systems or components may be used in combination to dampen or smooth the torque applied to the power shaft.

[0061] For example, a power shaft or rotor within the generator / motor itself may be rigidly coupled to the crankshaft of the generator / motor. In this manner, the crankshaft and rotor may together dampen torque pulses on the power shaft or rotor, reducing tangential acceleration due to torque pulses from the engine. In such an embodiment, a clutch may be omitted. As such, the damping system is internal to the generator / motor, and the damping system's footprint and weight may be smaller than a flywheel or other damping system that may be external to the generator / motor. In particular, a rigid coupling of the power shaft or rotor to the crankshaft may increase the inertia of the power shaft or rotor, whereby that additional inertia helps to prevent the power shaft from slowing down or otherwise rotating in a manner that is susceptible to acceleration due to torque pulses of the engine. In such an embodiment, the power shaft or rotor and crankshaft may function similarly to a flywheel.

[0062] In various embodiments, a generator / motor may be used that has a stationary inner portion and a rotating outer portion, which increases the inertia of the rotating portion and may allow magnets in the generator / motor to rotate and avoid being dislodged by the Torx spike. In other words, since the magnets may already be rotating on the outer portion, a constant stabilizing radial force may be applied in addition to the tangential inertial force due to the torque spike acceleration.

[0063] The torque damping system may also be configured as part of the power shaft or rotor that connects the engine output to the generator / motor. For example, the hub between the generator / motor power shaft or rotor may include a coupling with torsional spring and / or damping properties. The torsional damping coupling may include an elastomeric part or spring (e.g., made of steel or another metal) that reduces the transmission of potentially harmful torque impulses from the engine output to the generator power shaft or rotor. The torsional damping coupling may be similar to or referred to as a resonant damping coupling. For example, such a torsional damping coupling may reduce the weight and size of the overall system as opposed to a system that uses a flywheel or other bulky damping system. One or more torsional damping couplings may be installed in the engine, between the engine and the clutch, in the clutch, between the clutch and the generator, and / or in the generator to achieve damping before the power shaft or rotor damages components of the generator itself.

[0064] Other methods of damping torque on the generator's power shaft or rotor may also be used. For example, the magnetic field on the generator may be pulsed and controlled to act on the generator's power shaft or rotor to counter some or all of the torque pulses imparted to the power shaft or rotor by the engine. Such pulses on the generator's magnetic field may be controlled based on measurements of torque pulses applied by the engine, so that generator components are not damaged by the diesel engine. For example, in the third mode described above, where both the engine and the generator / motor provide power to the power shaft, pulses may be provided from the generator to the power shaft to provide power to the power shaft and prevent damage to the generator components. In other modes described herein, the generator may be used to apply pulses to the power shaft whenever the power shaft is being driven in part by the engine overall. Thus, to adequately protect the generator's components in such a manner, the pulses applied by the generator's magnetic field to the power shaft or rotor may be configured to correlate with and appropriately counteract the torque pulses of the engine.

[0065] FIG. 14 illustrates an example of a flexible architecture 1400 for an aerospace hybrid system with a flywheel and spring coupling to absorb vibration torque, according to an exemplary embodiment. In particular, the flexible architecture 1400 includes similar or identical components as shown in and described with respect to FIG. 8, but includes a spring coupling 199 rigidly connected to the flywheel 195 and the power shaft 180. The size, weight, etc. of the flywheel 195 and the characteristics of the spring coupling 199 can be adjusted according to the power output of the engine 155 and the characteristics of each other, so that the vibration torque can be reduced as desired and / or as possible. For example, different engines may generate different amounts of vibration torque, so various embodiments herein include flywheels and / or spring couplings with different characteristics to reduce vibrations transmitted from the crankshaft 160 to the power shaft 180. In various embodiments, the flexible architecture 1400 may not have a clutch, such that the crankshaft 160 and the power shaft 180 are always coupled to each other. In various embodiments, a flexible architecture similar to that of FIG. 14 may also include a clutch such that the output of the engine 155 can eventually be releasably disengaged from the power shaft 180. In various embodiments, such a clutch may be connected between the spring coupler 199 and the power shaft 180, or the power shaft may be split into multiple shafts with clutches connected to the multiple shafts, or the clutch may be located anywhere between the engine 155 and the generator / motor 185 such that the output of the engine 155 can be selectively disengaged from the portion of the power shaft 180 that travels through the generator / motor 185. In various embodiments, a clutch may additionally or alternatively be located after the generator / motor 185 such that the power shaft 180 can be disengaged from the load (e.g., the propulsion system of the aircraft).

[0066] Further, examples of how the flexible architectures described herein can be packaged and / or used in actual aircraft are described below. For example, certain aircraft may use electric motors to drive their propulsion systems and therefore must have sufficient on-board electrical energy to drive those propulsion systems or be provided with a method to generate such on-board electrical energy. Furthermore, regulations in certain jurisdictions may require sufficient reserve energy to comply with aircraft operating regulations. The flexible architectures described herein can provide such electrical energy and / or reserve energy to the propulsion systems such that the systems described herein can operate in a variety of electric aircraft. For example, embodiments herein provide efficient conversion of jet fuel (or other liquid or gas fuels) to electricity such that widely available fuel sources can be used to power electric aircraft.

[0067] Figure 9 illustrates a perspective view 900 of an example flexible architecture for an aerospace hybrid system, according to an exemplary embodiment. This hybrid unit can be used as a core powerplant for a variety of aircraft types and implementations. The hybrid unit of Figure 9 is a tightly integrated powerplant that may include some, all, and / or additional elements shown and described in Figures 1A, 1B, 2A, 2B, and / or 8.

[0068] Additionally, the hybrid unit may include an integrated cooling system 905 for cooling various aspects of the hybrid unit, heat exchangers associated with the hybrid unit, or heat sinks such as finned attachments on any aspect of the hybrid unit. The power output 910 may be or may connect to a power shaft (e.g., power shaft 110 of FIG. 1A, power shaft 180 of FIG. 1B or FIG. 8) such that rotational power is output from the hybrid unit to a propulsion system or other aspects of the aircraft. The electrical connector 915 may be used to output electrical power (or input electrical power) as described herein. The electrical connector 915 may be, for example, an Amphenol Surlok Plus™ connector or equivalent, or any other type of suitable connector. In this manner, a main bus, such as a direct current (DC) bus of the hybrid unit, may be connected via the electrical connector 915 (e.g., power input / output 125 of FIG. 1, power I / O 245 of FIG. 2A or FIG. 2B). These or other connectors may also facilitate connection and control of components of the hybrid unit, such as through the use of a Controller Area Network (CAN) bus, a CAN 2.0 bus, and / or an SAE J1939 bus. Such communication buses may operate at different speeds, such as 250 kilobytes per second (kbps), 500 kbps, 1000 kbps, etc. In various embodiments, the electrical connector 915 and / or other connectors may be customized for a given application, such as different types of aircraft and the communications and power systems those aircraft use.

[0069] By virtue of the power output 910 and electrical connector 915, the hybrid unit of FIG. 9 can output mechanical power via the power output 910 and / or output electrical power via the electrical connector 915 and a DC bus within the hybrid unit (e.g., power input / output 125 of FIG. 1 , power I / O 245 of FIG. 2A or FIG. 2B ). Similarly, just as mechanical power is received via the power output 910 to generate electricity for output via the electrical connector 915, electrical power can be received via the electrical connector 915 to drive the power output 910. For example, if the aircraft has one or more batteries, additional power from the batteries can be received via the electrical connector 915 to boost the power (electrical power) applied to the power output 910, such that the power output 910 is driven by both the engine and electrical power from the aircraft's batteries, as described herein.

[0070] The hybrid unit of FIG. 9 may further include a connector 925 for connecting the engine to a fuel source. The connector 925 may be a quick fuel connection, such as an AN6 quick fuel connection. In this manner, the engine may be supplied with fuel to power the power output 910 and / or generate electricity that is output via the electrical connector 915. The hybrid unit of FIG. 9 may further include mounting hardware 920 for mounting the hybrid unit to the aircraft. Although the mounting hardware 920 is shown on the top of the hybrid unit in FIG. 9, in other embodiments, the mounting hardware 920 may additionally or alternatively be located on either the top, bottom, side, etc. of the hybrid unit such that the hybrid unit may be mounted to the aircraft as desired.

[0071] Figure 10 illustrates a top view 1000 of the example flexible architecture of Figure 9 in accordance with an exemplary embodiment. Figure 11 illustrates a side view 1100 of the example flexible architecture of Figure 9 in accordance with an exemplary embodiment.

[0072] Thus, the hybrid units described herein can be used to power electric or hybrid electric aircraft and can provide better power than battery packs alone. For example, hybrid units such as those shown in FIGS. 9-11 can provide better energy density than batteries (e.g., 5-7 times better energy density). For example, the hybrid units described herein can have an equivalent energy density of 600-1200 or more watt-hours per kilogram (Wh / kg). Additionally, the hybrid units described herein advantageously have better fuel economy than other systems (e.g., 40% better fuel economy than turbine engines) and can use readily available fuels such as Jet-A, diesel, kerosene, biofuel alternatives, or other suitable or desired fuels. In other words, the hybrid units herein can include an engine, generator, inverter, and thermal management using air cooling in a compact package, thereby allowing aircraft equipped with a flexible architecture to advantageously utilize these components as a power plant. Various voltage outputs (e.g., 400 volts (V), 800V, 1000V, 1200V, etc.) are provided from the hybrid architecture, as well as connections for other accessory or system power (e.g., 28V). The flexible architecture described herein can be quieter than other systems (e.g., quieter than turbine engine systems). For example, noise levels can be less than 70 decibels (dB) at distances of 100 feet or less from current systems.

[0073] The flexible architecture described herein may also be scalable. For example, a larger aircraft may use two or more of the flexible architectures described herein. The flexible architecture may also be used for a variety of aircraft designed for different functions and purposes. For example, the flexible architecture described herein may be useful in Urban Air Mobility (UAM) systems such as electric vertical take-off and landing (eVTOL) aircraft, electric short take-off and landing (eSTOL) aircraft, conventional electric take-off and landing (eCTOL) aircraft, etc. One example of a flexible architecture such as that shown in Figures 9-11 may have the specifications shown in Table 1 below. [Table 1] *Maximum burst shaft power depends on battery configuration. **Dry mass includes engine, generator, inverter, and thermal system.

[0074] As shown above, a 185 kW hybrid unit can be provided, and thus two hybrid units can be provided on a given aircraft to provide 370 kW of power.

[0075] Figure 12 illustrates a perspective view 1200 of another example of a flexible architecture for an aerospace hybrid system in accordance with an illustrative embodiment. The flexible architecture of Figure 12 includes an engine 1205 and a generator, which are hidden or not visible due to other components of the system, such as cooling ducts. However, similar to the hybrid units of Figures 9-11, a mechanical power output 1210 and an electrical output 1220 (both of which can optionally receive electrical power as well) are provided.

[0076] In this manner, various embodiments herein provide a hybrid power plant that can be integrated into a variety of different types of aircraft in the aerospace market. In doing so, aircraft manufacturers may not need to build their own systems of engines, generators, power electronics, cooling systems, and / or control systems to power the aircraft. This can be advantageous because the development process to create a power generation system and make it aerospace standard can take four or more years and cost more than $10 million.

[0077] In this manner, the hybrid power plant or flexible architecture described herein may be designed, manufactured, etc., separate from the design of the aircraft. Some aspects of the flexible architecture may be customized according to the desires of the aircraft manufacturer, but in a manner that does not result in a redesign or reconfiguration of the entire system. Thus, embodiments herein provide an integrated unit that includes an engine, generator, power electronics, cooling system, and / or control system in one package that is installed on the aircraft. Combining these elements into a single standalone unit may further advantageously allow the unit to go through the Federal Aviation Administration (FAA) certification process as a system. This would allow multiple aircraft manufacturers to use the certification system, reducing the certification burden and development burden on aircraft developers, as well as improving efficiency by eliminating the need for multiple aircraft manufacturers to certify many different power generation systems specifically designed for their aircraft.

[0078] By providing a combined unit with engines, generators, power electronics, cooling systems, and / or control systems, the hybrid flexible architecture described herein can be optimized as an entire system rather than as separate components. Optimize the whole system rather than optimizing the parts. Furthermore, such hybrid units can be used in multiple aircraft designs, but the systems designed as part of the aircraft design process are configured in a way that makes them difficult to reapply elsewhere. Having a hybrid unit that can be applied to multiple market segments and aircraft designs with common power requirements expedites the development of production aircraft, with major components of the aircraft already certified (e.g., hybrid units or flexible architectures, etc.).

[0079] Aviation hybrid electric systems have historically been designed from the ground up for each application / aircraft. Such a process is inefficient and is addressed by embodiments herein. For example, some aircraft are equipped with unique power plants designed specifically for that aircraft. Such solutions may include custom engines, generators, power electronics, control systems, cooling systems, battery packs, propulsion motors, and / or propellers. Embodiments herein provide a compact hybrid system for an aircraft that may constitute two separate halves within an aircraft's power and propulsion system, i.e., one half of the upstream end and one half of the downstream end of a powertrain (such as the hybrid powertrain described herein).

[0080] 13 illustrates examples of downstream components 1305, 1310 and upstream components 1315, 1320 for propelling an aircraft 1300, according to an exemplary embodiment. For example, the downstream components 1305, 1310 of an aircraft system may include motors, rotors / propellers, attitude control components, etc., as may be relevant depending on the particular design of the aircraft. The upstream components 1315, 1320 of the aircraft, which may be repeatable within different aircraft, may include any of the engines, generators, batteries, power distribution, fuel, generator noise abatement, etc.

[0081] Specifically, the upstream end of the powertrain may include hybrid powertrain elements responsible for generating electrical power. Such components may include an engine, a generator, power electronics, a control system (for the upstream power generating components), a cooling system (for the upstream components), a battery pack, and / or fuel. The downstream end of the powertrain may include hybrid powertrain elements responsible for converting electrical power into thrust, attitude control, and / or active control of aerodynamics. These downstream components may further include electric motors, propellers, motor controllers, and / or control systems for the propulsion system.

[0082] Thus, there may be a need for a common upstream powertrain across very different electric aircraft designs with similar size and total power requirements. However, because downstream powertrains have little consistency between aircraft, these components may not be standardized to work across many aircraft designs as the upstream components. Furthermore, upstream elements that aid in standardization may include components related to power requirements rather than total energy requirements. In the case of engines, generators, power electronics, cooling systems, and / or control systems, these elements of the upstream powertrain may be sized to fit the specific power requirements (kW or hp) of the aircraft. However, the amount of fuel and the size of the battery pack may be determined by the total energy requirements (kWh or hp hr), which may vary from aircraft to aircraft. In such an embodiment, the volume of fuel may be adjusted by changing the size of the fuel tank to fit the requirements of the aircraft design, and the capacity of the battery pack in kWh may be adjusted by adjusting the number of parallel stacks of cells in the battery pack or by adding additional battery packs.

[0083] Accordingly, embodiments are provided herein for providing a hybrid power plant that tightly integrates an engine, generator, power electronics, control system (for the power generation system), and / or cooling system in a weight- and space-efficient manner, where the hybrid power plant can be certified as a stand-alone unit that is separable from the aircraft and designed to provide propulsion.

[0084] Additionally, as described herein, the rotor in the generator can be optimized to serve multiple purposes in the context of a hybrid power plant. A conventional internal combustion engine may have a flywheel mass attached to the rotating shaft to enhance smoothness of operation. However, in the context of an aerospace system, adding extra mass may be undesirable. As described herein, when the engine is coupled to the generator of a hybrid power plant, the rotor of the generator may be designed to withstand torque impulses from the engine and to be the rotating mass that the engine utilizes to smooth operation.

[0085] Additionally, while auxiliary power units are known in the art, these systems may be designed for purposes other than as the primary propulsion source for an aircraft and therefore may not have a control system that can be certified to standards required for use in propulsion. Additionally, such systems may be designed without a cooling system, which is left to the airframe designer. As such, these systems are not Part 33 (FAA regulations for aircraft power plants) certified. Additionally, these auxiliary power unit systems are designed as light-weight auxiliary systems that are used intermittently, rather than as highly efficient propulsion systems used during all phases of flight. Additionally, while auxiliary power units may be designed to generate alternating current (AC) power, the hybrid power plants described herein are capable of generating direct current (DC) power, and therefore the hybrid power plants may be coupled to large propulsion battery packs, as the battery packs are powered and charged using a DC source.

[0086] Turbogenerators are one type of adaptive auxiliary power unit proposed for hybrid power. Such systems lack cooling system integration that provides airframe developers with a cooling system that is part of the hybrid power plant. As such, airframe developers may need to design their own cooling system along with the use of turbogenerators. Using embodiments herein may be advantageous in that a separate cooling system for cooling the hybrid power plant described herein does not need to be designed or developed for a particular airframe, since such a cooling system is already included in the flexible architecture described herein.

[0087] As such, the flexible architectures and hybrid power plants described herein advantageously provide an engine for converting liquid fuel (or gaseous fuel) into rotary mechanical power, a generator coupled to the engine configured to convert the rotary mechanical power into electricity, and / or power electronics coupled to the generator configured to convert a direct AC output of the generator into high voltage DC power. The flexible architectures and hybrid power plants described herein further advantageously provide a control system configured to vary the power output of the engine to match the power demands of the aircraft's main propulsion electric bus to meet the power demands of the aircraft.

[0088] The hybrid power plant control system, power electronics, generator, and / or engine designs described herein may further comply with regulatory requirements for the reliability of aerospace propulsion systems (e.g., probability of failure is 10 -6or 10 to the power of minus 6). The flexible architecture and hybrid power plant may further include a control interface that allows the flexible architecture or hybrid power plant to communicate with a vehicle level flight control system to provide propulsion commands from the vehicle level flight control system to the hybrid power plant control system, which may also advantageously provide status messages back to the vehicle level flight control system (e.g., feedback for use in controlling the flexible architecture or hybrid power plant). The flexible architecture and hybrid power plant may further include a cooling system that maintains a temperature range of the generator, power electronics, and / or engine over the full range of operating power outputs of the flexible architecture and hybrid power plants described herein.

[0089] Various embodiments of the flexible architecture or hybrid power plants described herein may further include a control system that varies the power output by varying the engine torque and / or maintains a substantially constant revolutions per minute (RPM) over a significant range of the power output. Such embodiments may provide faster response of the flexible architecture or hybrid power plant by eliminating throttle lag and longer response times associated with the rotational inertia of the system.

[0090] Various embodiments of the flexible architecture or hybrid power plants described herein may further include an option to provide a portion of the engine's power output as mechanical shaft power and a portion as DC power. Various embodiments of the flexible architecture or hybrid power plants described herein may further include embodiments in which the engine may be a piston engine, a diesel piston engine, a turbine engine, a rotary engine, or other form of combustion engine. Various embodiments of the flexible architecture or hybrid power plants described herein may further include examples in which the rotor of the generator is designed to be the flywheel of the engine. Various embodiments of the flexible architecture or hybrid power plants described herein may further include a clutch between the engine and the generator so that the generator can be operated as a motor while the engine is shut down in some types of parallel hybrid installations described herein.

[0091] FIG. 15 is a diagram of an example of a computing environment including a general-purpose computing system environment 100, such as a desktop computer, laptop, smartphone, tablet, or other similar device capable of executing instructions, such instructions being stored in a non-transitory computer-readable medium. The various computing devices disclosed herein (e.g., processor / controller 205, aircraft main controller 220, processor / controller 280, or any other computing device in communication with these controllers, which may be part of other components of the aircraft or a control system of the aircraft, whether onboard the aircraft or remote from the aircraft) may be similar to computing system 100 or may include some components of computing system 100. Also, while described and illustrated in the context of a single computing system 100, those skilled in the art will appreciate that the various tasks described below may also be performed in a distributed environment having multiple computing systems 100 linked via a local or wide area network. And, executable instructions may be associated with and / or executed by one or more of the multiple computing systems 100.

[0092] 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 devices (removable and / or non-removable), including, but not limited to, magnetic or optical disks, tape drives, and / or flash drives. Such additional memory devices may be made accessible to the computing system environment 100, for example, by a hard disk drive interface 112, a magnetic disk drive interface 114, and / or an optical disk drive interface 116. As will be appreciated, each of these devices are linked to the system bus 306 and enable reading and writing to the hard disk 118, the removable magnetic disk 120, and / or the removable optical disk 122, such as a CD / DVD ROM or other optical media. 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. Moreover, those skilled in the art will appreciate that other types of computer readable media capable of storing data can 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 and / or read only memory, and / or other methods or techniques 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.

[0093] 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 into the computing environment 100, as needed, for example, via a network connection.

[0094] 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. Other input devices, not shown, may include a microphone, joystick, game pad, scanner, etc. These and other input devices are typically connected to the processing unit 102 by a peripheral interface 138 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, a game port, Firewire, or a universal serial bus (USB). For viewing information from the computing system environment 100, a monitor 140 or other type of display device may 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 a printer.

[0095] 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, for example 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 the memory storage devices of the computing system environment 100.

[0096] The computing system environment 100 may also include location determination hardware 186 for determining a location of the computing system environment 100. In some cases, the location determination hardware 156 may include, for example, a GPS antenna, an RFID chip or reader, a WiFi antenna, or other computing hardware that may be used to capture or transmit signals that may be used to determine the location of the computing system environment 100.

[0097] Although the present disclosure has described specific embodiments, 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 present disclosure is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the present disclosure. Furthermore, in the detailed description of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be apparent to one 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.

[0098] Some portions of the detailed description 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 reasons of 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 connection with the various presently disclosed embodiments.

[0099] 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, and as will be apparent from the discussion herein, throughout the discussion of the present embodiments, discussions utilizing terms such as "determine", or "output", or "transmit", or "record", or "locate", or "store", or "display", or "receive", or "recognize", or "utilize", 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 (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 described herein or otherwise understood by those skilled in the art.

[0100] 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, can cause a computing device to perform an operation.

[0101] 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 appended claims and their equivalents.

Claims

1. A hybrid powertrain system for an aircraft, the hybrid powertrain system comprising: The engine, an electric machine having a power shaft therein; The electric machine further includes an electric input / output; the power shaft is mechanically attached to a propulsion device and configured to provide mechanical power to the propulsion device; The power shaft is configured to be rotated by the output of the engine; the engine and the electric machine are configured to operate in a first mode in which the electric machine is controlled to convert a variable amount of power from rotation of the power shaft by the engine into a first electrical power, while the power shaft is configured to output the remaining mechanical power of the power shaft to the propulsion device; the engine and the electric machine are configured to operate in a second mode in which both the engine and the electric machine drive the power shaft, the electric machine driving the power shaft based on a second electrical power received via the electrical input / output. Hybrid powertrain system.

2. The hybrid powertrain system of claim 1 , wherein the first electrical power is configured to be output to an electric propulsion device of the aircraft.

3. 3. The hybrid powertrain system of claim 2, wherein the electric propulsion device of the aircraft includes at least one battery and at least one electric motor used for electric propulsion of the aircraft, the at least one battery and the at least one electric motor being mounted on the aircraft.

4. In the first mode, the electric machine: does not convert power from the power shaft to the first electrical power; converting all power from the power shaft into the first electrical power; or 2. The hybrid powertrain system of claim 1, controlled to convert some between 0% and 100% of said power on said power shaft to said first electrical power.

5. The hybrid powertrain system of claim 4 further comprising a controller configured to cause the electric machine to vary a percentage of electrical power converted by the electric machine from the power shaft to the first electrical power.

6. 2. The hybrid powertrain system of claim 1, further comprising a controller configured to control the engine and the electric machine to output a first desired amount of the mechanical power to a propulsion mechanism and to output a second desired amount of the first electrical power from the propulsion mechanism.

7. The hybrid powertrain system of claim 1 further comprising a flywheel connected to at least one of the power shaft or the output of the engine.

8. 8. The hybrid powertrain system of claim 7, further comprising a spring coupling connected to the flywheel, the spring coupling configured to reduce vibrations transmitted from the flywheel to the power shaft.

9. The hybrid powertrain system of claim 1 , wherein the second electrical power is received from one or more batteries of the aircraft during the second mode.

10. The hybrid powertrain system of claim 1 , wherein the first electrical power is output to at least one of an electric motor or a battery.

11. The hybrid powertrain system of claim 1 , wherein at least one of the power shaft or the output of the engine further provides rotational power to a cooling system of the hybrid powertrain system.

12. A method for controlling a hybrid powertrain system of an aircraft, the method comprising: Controlling the engine and an electric machine having a power shaft therein to operate in a first mode, the first mode including: configured to drive the power shaft with the engine and rotate the power shaft with the output of the engine; and outputting a first electrical power from the electric machine via an electrical input / output of the electric machine based on the rotation of the power shaft by the engine; controlling the engine and the electric machine to operate in a second mode, the second mode including simultaneously driving the power shaft by the engine and the electric machine; the electric machine drives the power shaft based on a second electrical power received via the electrical input / output. method.

13. 13. The method of claim 12, wherein the first electrical power is output to drive electric propulsion motors of the aircraft or is output to propulsion batteries of the aircraft, which are used to power the electric propulsion motors.

14. The method of claim 12 , wherein the power shaft is mechanically attached to a propulsion device and configured to provide mechanical power to the propulsion device.

15. 13. The method of claim 12, wherein during the first mode, a first portion of rotational force applied to the power shaft by the engine is converted to electrical power by the electric machine and a second portion of the rotational force is delivered via the power shaft to a propulsion device.

16. 13. The method of claim 12, further comprising engaging a clutch during both the first mode and the second mode, the clutch configured to releasably engage the output of the engine to the power shaft.

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