Patent ID: 12187448

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus, system, and method are presented herein by way of exemplification and not limitation with reference to the Figures.

FIG.1Aschematically illustrates a gas turbine engine20. The gas turbine engine20is disclosed herein as a two-spool turbofan that generally incorporates a fan section22, a compressor section24, a combustor section26and a turbine section28. Alternative engines might include other systems or features. The fan section22drives air along a bypass flow path B in a bypass duct, while the compressor section24drives air along a core flow path C for compression and communication into the combustor section26then expansion through the turbine section28. Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines including three-spool architectures.

The exemplary engine20generally includes a low speed spool30and a high speed spool32mounted for rotation about an engine central longitudinal axis A relative to an engine static structure36via several bearing systems38. It should be understood that various bearing systems38at various locations may alternatively or additionally be provided, and the location of bearing systems38may be varied as appropriate to the application.

The low speed spool30generally includes an inner shaft40that interconnects a fan42, a low pressure compressor44and a low pressure turbine46. The inner shaft40is connected to the fan42through a speed change mechanism, which in exemplary gas turbine engine20is illustrated as a geared architecture48to drive the fan42at a lower speed than the low speed spool30. The high speed spool32includes an outer shaft50that interconnects a high pressure compressor52and high pressure turbine54. A combustor56is arranged in exemplary gas turbine20between the high pressure compressor52and the high pressure turbine54. An engine static structure36is arranged generally between the high pressure turbine54and the low pressure turbine46. The engine static structure36further supports bearing systems38in the turbine section28. The inner shaft40and the outer shaft50are concentric and rotate via bearing systems38about the engine central longitudinal axis A which is collinear with their longitudinal axes.

The core airflow is compressed by the low pressure compressor44then the high pressure compressor52, mixed and burned with fuel in the combustor56, then expanded over the high pressure turbine54and low pressure turbine46. The turbines46,54rotationally drive the respective low speed spool30and high speed spool32in response to the expansion. It will be appreciated that each of the positions of the fan section22, compressor section24, combustor section26, turbine section28, and fan drive gear system48may be varied. For example, gear system48may be located aft of combustor section26or even aft of turbine section28, and fan section22may be positioned forward or aft of the location of gear system48.

The engine20in one example is a high-bypass geared aircraft engine. In a further example, the engine20bypass ratio is greater than about six (6), with an example embodiment being greater than about ten (10), the geared architecture48is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3 and the low pressure turbine46has a pressure ratio that is greater than about five. In one disclosed embodiment, the engine20bypass ratio is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor44, and the low pressure turbine46has a pressure ratio that is greater than about five 5:1. Low pressure turbine46pressure ratio is pressure measured prior to inlet of low pressure turbine46as related to the pressure at the outlet of the low pressure turbine46prior to an exhaust nozzle. The geared architecture48may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.3:1. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.

A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section22of the engine20is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet (10,688 meters). The flight condition of 0.8 Mach and 35,000 ft (10,688 meters), with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFC’)”—is the industry standard parameter of lbm of fuel being burned divided by lbf of thrust the engine produces at that minimum point. “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.45. “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram ° R)/(518.7° R)]0.5. The “Low corrected fan tip speed” as disclosed herein according to one non-limiting embodiment is less than about 1150 ft/second (350.5 m/sec).

The gas turbine engine20can be coupled to an aircraft, where the aircraft can include multiple instances of the gas turbine engine20, which can be a hybrid electric turbine engine. Particularly, aircraft can be equipped with two or more hybrid electric turbine engines to provide thrust. Some gas turbine engines, such as hybrid electric gas turbine engines, are equipped with one or more electric machines to convert mechanical energy into electrical energy or vice versa. Two-spool hybrid electric engines can be configured with two electric machines as shown inFIG.1B. For example, as shown inFIG.1B, the gas turbine engine20includes a low speed spool electric machine60(e.g., a 1.0 MW low spool motor) associated with the low speed spool30and a high speed spool electric machine62(e.g., a 0.5 MW high spool motor) associated with the high speed spool32. Each of the electric machines (e.g., one of the electric machines60,62) can receive electric power from and/or provide electric power to a battery64(e.g., a 100 kWh battery). In one or more embodiments, the connections between the electric machines (e.g., one or more of the electric machines60,62) and the battery64can include battery management, DC-DC converters, and/or other electrical components.

FIG.1Cis a partial cross-sectional view of a hybrid electric gas turbine engine (also referred to as hybrid electric propulsion system100) according to one or more embodiments described herein. The hybrid electric propulsion system100(also referred to as hybrid electric gas turbine engine100) includes the gas turbine engine20operably coupled to an electrical power system110as part of a hybrid electric aircraft in accordance with one non-limiting embodiment of the present disclosure. In this embodiment, the engine20has a power source180such as a battery, a super capacitor, an ultra-capacitor, a fuel cell with chemical storage, or an equivalent thereof, which supplies power to a motor182, which is connected to an engine accessory gearbox184that is operably coupled to the high speed spool32such that the motor182, when operated will provide power assist to the high speed spool32via the accessory gearbox184. In other words, the accessory gearbox will have at least one component (e.g., a gear train or other equivalent device) operably coupled to the high speed spool32and the motor182such that operation of the motor182will rotate the component which in turn will rotate the high speed spool32. The power assist to the high speed spool32via the motor182will add enough stability to the high pressure compressor in order to allow, for example, re-starting without external power assist which may be provided by an auxiliary power unit (APU).

In one non-limiting embodiment, the motor182may be configured to provide power assist to the high speed spool32. Alternatively, the motor182may be part of a different configuration or system configured to only provide power assist to the high speed spool32in order to expand an in-flight re-start envelope. In yet another example, the motor182may be configured to provide power assist to the low speed spool30. For example, in an alternative embodiment, the motor182may be operatively coupled to the low speed spool30via accessory gearbox184in order to provide additional thrust to the engine20. In one or more examples, power can be extracted from the electric motor182(e.g., from one or more of the low spool or high spool) at block186to power engine accessories, aircraft loads such as environmental control systems, etc.

According to an embodiment, the power source180and the motor182of the power assist system186are under the full authority of a full authority digital engine control (FADEC)156, which controls the power source and the engine. The FADEC156is an example of a controller that can include a processing system160, a memory system162, and an input/output interface164. The processing system160can include any type or combination of central processing unit (CPU), including one or more of: a microprocessor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like. Thus, the FADEC156can be said to include processing circuitry. The memory system162can store data and instructions that are executed by the processing system160. In embodiments, the memory system162may include random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic, or any other computer readable medium onto which is stored data and algorithms in a non-transitory form. The input/output interface164is configured to collect sensor data from the one or more system sensors and interface with various components and subsystems, such as components of motor drive electronics, rectifier electronics, an energy storage management system, an integrated fuel control unit, actuators, and/or other components of the hybrid electric propulsion system100. The FADEC156provides a means for controlling hybrid electric system control effectors168based on a power transfer control166that is dynamically updated during operation of the hybrid electric propulsion system100. The means for controlling the hybrid electric system control effectors168can be otherwise subdivided, distributed, or combined with other control elements.

The FADEC156can also include various operational controls, such as a power transfer control that controls hybrid electric system control effectors. The power transfer control166can apply control laws and access/update models to determine how to control and transfer power to and from the hybrid electric system control effectors168. For example, sensed and/or derived parameters related to speed, flow rate, pressure ratios, temperature, thrust, and the like can be used to establish operational schedules and transition limits to maintain efficient operation of the gas turbine engine20.

Additionally or alternatively, the hybrid electric propulsion system100can include a hybrid electric controller210, which may be integrated into or separate from the FADEC156. The hybrid electric controller210is communicatively coupled to the power source180, the motor182, and/or any other suitable components. The features and functionality of the hybrid electric controller210are described in more detail herein with respect toFIG.2.

An aircraft can selectively power a hybrid electric engine, such as the hybrid electric gas turbine engine100ofFIG.1C, by providing electric power from a battery source and/or liquid fuel (jet fuel). During certain stages during a flight plan (e.g., taxi, cruise), electric power may be more efficient. However, during other stages (e.g., takeoff, climb), it may be more efficient to power the engine with liquid fuel. For example, during taxi, electric power may be more efficient, and thus the battery may be utilized to power the hybrid electric engine during taxi. In some examples, the hybrid electric controller210can selectively provide electric power or liquid fuel (jet fuel) based on considerations other than efficiency (e.g., engine health, operating conditions, etc.).

One use case for the hybrid electric gas turbine engine100is to use electric power from a battery source to power the hybrid electric gas turbine engine100during taxi. This is referred to as electric taxi or “e-taxi,” which has been shown to reduce energy use. In some situations, e-taxi may not be the most beneficial use of electric power from the battery source. For example, in certain situations, it may be more useful to use the electric power from the battery source to power the low speed spool electric machine60and/or the high speed spool electric machine62during flight to increase time on wing of the gas turbine engine20. Time on wing refers to the amount of time an engine (e.g., the gas turbine engine20) spends on the aircraft in operating condition as opposed to periods of service/maintenance.

One or more embodiments described herein relate to managing battery usage for a hybrid electric engine of an aircraft based on a flight plan and/or data received during the flight. Additionally and/or alternatively, one or more embodiments described herein relate to managing battery charging for a hybrid electric engine of an aircraft based on an energy reserve requirement and an e-taxi energy usage estimation. In order to increase the time on wing of an engine, one or more embodiments described herein analyze data to determine whether the engine needs electric power from the battery source for durability concerns. If so, e-taxi can be disabled/skipped and instead the electric power is used during flight to boost the low speed spool30and/or the high speed spool32, and/or other aircraft systems such as an environmental control system (ECS) that would otherwise draw from the engine. Examples of data that the present techniques can analyze to make this determination can include a flight plan, a derate setting, engine health data, operating conditions, engine cycle or flight hour count, and the like.

According to one or more embodiments described herein, the present techniques can determine not to perform e-taxi in one or more of the following scenarios: when a margin/limit is expected to be exceeded on a particular day on a particular flight point but would not be exceeded if a particular spool is boosted at the particular flight point; when a component is predicted to drive early engine removal without assistance; when the aircraft is operating in an extreme environment (e.g., high altitude, high temperature, etc.); as part of a contract; to affect in-service issues (e.g., speed keep out zones, vibes, an engine program missing hot section repair interval (HSRI) targets, etc.); during an aborted landing (instead, use electric power to boost climb); and/or based on a pilot determination/recommendation.

According to one or more embodiments described herein, a vehicle (e.g., an aircraft) can include a battery. The vehicle can be certified to operate without using at least a portion of the battery. The vehicle can be certified to operate with any output of battery energy spend logic available. At least a portion of the battery energy can be used for energy optimization or to mitigate severity of operating conditions (e.g., temperature, speed, etc.). The vehicle can receive, calculate, and/or store data on engine derate settings, ambient conditions, altitude, component life, component margin trending, manual override of energy optimization, remotely commanded override of energy optimization, etc. The vehicle can receive and/or create data indicating use of energy storage to prevent exceedance of a margin or limit. The threshold for exceedance of the margin or limit can be defined using known statistical techniques. For example, it can be defined probabilistically. A cost of the limit exceedance multiplied by a probability of limit exceedance can be compared to a cost of energy savings, and the vehicle can allocate and apply battery energy for prevention of limit or margin exceedance in response thereto. The vehicle can forgo or reduce energy optimization use of battery energy when using the battery for margin exceedance prevention. The vehicle can receive and/or calculate data indicating which component is more likely to drive engine removal for maintenance/service. The vehicle can estimate and/or receive data on which use of battery energy may most affect component degradation in the future. The vehicle can apportion battery energy to change the time or reasons for engine removal or maintenance/service based on predictive modeling of the effect of energy apportionment.

According to one or more embodiments described herein, a vehicle is provided with a capability to taxi using electric motors or combustion in gas turbine engines. The vehicle can operate an onboard model to predict outcomes of different energy usage (e.g., electric power vs. liquid fuel). The vehicle can receive data instructing a use of battery energy. The vehicle can taxi with combustion in gas turbine engines and apply battery energy to a spool of one of the gas turbine engines during a takeoff or climb.

According to one or more embodiments described herein, an aircraft is provided. The aircraft experiences a rejected/aborted landing and proceeds to take off power. The aircraft uses e-taxi-in energy for boosting spool during a go-around or rejected/aborted landing. An onboard digital twin and FADEC engine control can perform calculations to determine whether an engine should be started for taxi or whether e-taxi can be used before initiating fuel flow to the engines. An offboard prediction system can provide an e-taxi determination by assessing durability/margin. In the event that the battery energy is desired to be reserved, the e-taxi configuration can operate with one engine off and the second engine powering the fan of the first without using battery.

Referring now toFIG.2, with continued reference toFIGS.1A-1C,FIG.2is a block diagram illustrating a system200for managing battery usage for managing a hybrid electric engine of an aircraft based on engine health according to one or more embodiments described herein. The system200includes a hybrid electric controller210that is communicatively coupled to an avionics system220, a battery system230, an engine controller240, electric motor(s)250, and a remote processing system260. Although not shown, it should be appreciated that one or more of the avionics system220, the battery system230, the engine controller240, the electric motor(s)250, and the remote processing system260can be communicatively coupled directly or indirectly together independent of the hybrid electric controller210.

The hybrid electric controller210can include a processing system (PS)212and a memory system (MS)214. The processing system212can include any type or combination of central processing unit (CPU), including one or more of: a microprocessor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like. Thus, the hybrid electric controller210can be said to include processing circuitry. The memory system214can store data and instructions that are executed by the processing system212. In embodiments, the memory system214may include random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic, or any other computer readable medium onto which is stored data and algorithms in a non-transitory form.

The hybrid electric controller210receives data, such as flight plan data for a flight plan, from the avionics system220. The flight plan defines an aircrafts planned route or flight path. Examples of flight plan data include, for example, departure and arrival locations, estimated flight time, planned cruising speed and altitude, etc. The hybrid electric controller210also receives battery data from the battery system230. The battery data indicates how much electric energy (e.g., a number of kilowatt hours of electric energy) is available from one or more batteries232associated with the battery system230. The hybrid electric controller210determines waypoints, as further described herein, for when to apply electric power (also referred to as “battery energy”) from the battery system to the electric motor(s)250based at least in part on the flight plan data and the battery data. The electric motor(s)250can include any suitable electric motor, such as the low speed spool EM60ofFIG.1B, the high speed spool EM62ofFIG.1B, and/or the electric motor182ofFIG.1C, which can provide power assist to the low speed spool30and/or the high speed spool32of the gas turbine engine20.

The hybrid electric controller also receives data from the engine controller240, which is an example of the FADEC156ofFIG.1C. The data represents data about the aircraft, such as avionics information (which can alternatively and/or additionally be received directly from the avionics system220), engine power settings, etc. The hybrid electric controller210can also send data and/or commands to the engine controller240, such as to cause the engine controller240to control one or more aspects of the hybrid electric propulsion system100.

The remote processing system260can be one or more processing systems remote from the hybrid electric controller210and/or remote from the aircraft. For example, the remote processing system260can be a ground-based system(s) that can provide data, such as weather data, operating conditions data, operational recommendations, etc., to the hybrid electric controller210. The remote processing system260can include a processing system (PS)262and a memory system (MS)264. The processing system262can include any type or combination of central processing unit (CPU), including one or more of: a microprocessor, a digital signal processor (DSP), a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like. Thus, the remote processing system260can be said to include processing circuitry. The memory system264can store data and instructions that are executed by the processing system262. In embodiments, the memory system264may include random access memory (RAM), read only memory (ROM), or other electronic, optical, magnetic, or any other computer readable medium onto which is stored data and algorithms in a non-transitory form.

FIG.3Adepicts a graph300of extra margin for operating an engine, such as the engine20ofFIGS.1A-1C, according to one or more embodiments described herein. As shown, the graph300plots exhaust gas temperature (EGT) margin for the engine20for a number of cycles, where each cycle represents one flight. In this example, it is assumed that the battery system230can provide sufficient electric power to the engine20(such as via one or more of the low speed spool EM60or the high speed spool EM62ofFIG.1B) to boost takeoff. For example, a battery system that stores 100 kWh of electric energy may be able to provide about 4 MW of boost power for 82 seconds during takeoff or alternatively to power electric taxi for twenty minutes. In some cases, such as to prolong the time until engine maintenance/service is required, it is desirable to use this electric power to provide boost to the engine20while forgoing the benefits of energy savings associated with e-taxi by skipping e-taxi and taxiing instead using combustion in one or both gas turbine engines.

The graph300includes points302, which indicate in this example measured exhaust gas temperature margin recorded on previous flights. Thus, the points302inFIG.3Arepresent historical flight data. This margin may be higher on cold days and lower on hot days, but in general decreases as the engine components deteriorate over many cycles (flights). This recorded margin can be used in conjunction with other recorded parameters from those flights to predict the margin that will be available on subsequent flights, particularly when the ambient takeoff conditions or other operating parameters are known in advance of a flight. The margin trend represented by the points302can be plotted using a trend line304associated with a reference set of ambient conditions and a distribution determined using known statistical techniques to account for uncertainty in the prediction.

The graph300also includes a margin improved by the available electric boost shown as line306. This represents the calculated effect of an applied boost on the margin. For example, 1 MW of low spool boost may increase EGT margin by 20 degrees F. during takeoff.

As shown, the graph300includes a first region308, a second region310, and a third region311. During the first region308, battery energy is apportioned for energy optimization use such as e-taxi (e.g., e-taxi out) because the threshold312is not expected to be violated under any takeoff conditions when using energy optimization and no low spool boost during takeoff.

After a number of engine cycles, for example 6000 cycles, components of the engine have deteriorated enough that the engine is expected to have zero or less than zero margin on a flight based on the measured ambient conditions and the trend line304. This prediction marks the beginning of the second region310, wherein battery energy may be apportioned for boost during takeoff to achieve extra margin up to the maximum margin available with boost, line306. For ambient conditions and operating parameters predicted to result in positive margin above the threshold312, e-taxi can continue to be performed; however, for conditions predicted to result in margin below the threshold312, e-taxi is skipped or reduced in duration and the electric power of the battery system230is instead used for another purpose, such as to boost takeoff. In these cases taxi is performed using combustion of fuel in a gas turbine. The points303, which fall below the threshold312, represent predicted margin without boost. Each point303in region310has a corresponding point302that has been increased to positive margin by applying boost to takeoff. After sufficient cycles beyond region310(e.g., in region311), EGT margin may fall below threshold even while forgoing e-taxi and instead boosting takeoff with all available power. Once the EGT margin threshold312is crossed, the engine would be removed for maintenance having delayed maintenance for a significant number of additional flights beyond region308. In other embodiments any other engine performance parameter may be monitored for margin or component life assessment with and without boost of either spool.

FIG.3Bdepicts a graph320of a measured and predicted degradation of an engine component, such as the high pressure turbine of engine20ofFIGS.1A-1C, according to one or more embodiments described herein. In this example, it is shown that the decay rate of trend lines304a,304bcan change when battery energy is apportioned to assist the HPT (region310) compared to when it is used for energy optimization such as e-taxi (region308). This occurs because the HPT will deteriorate faster with higher operating temperatures and electric boost lowers operating temperatures to slow deterioration. Particularly, multiple trend line predictions304aand304bare shown. Also shown is an estimate of engine removal date due to other causes of engine removal besides end of HPT component life at the threshold316. At the cycle associated with inflection point314a, the controller estimates HPT component life progression with and without assistance from battery energy and compares to engine removal due to other reasons, e.g., the threshold316. At the inflection point314a, HPT life progression with assistance,304a, is determined to exceed another reason for removal, e.g., the threshold316, so energy continues to be used for e-taxi rather than HPT assistance on cycle314a. On cycle314b, the controller estimates that battery assistance will improve HPT life and that the HPT reaching zero life will be the reason for engine removal even with battery assistance, so battery energy is apportioned for HPT assistance on cycle314band beyond, unless some other cause is eventually predicted to drive engine removal instead. In this way, the end of component life is determined every flight and battery energy is apportioned either for energy optimization or to extend the predicted life of the component expected to drive engine removal (the point318).

FIG.4is a flow chart of a method for managing energy usage for a hybrid electric engine of an aircraft based on engine health according to one or more embodiments described herein. Managing energy usage can include managing energy provided by any suitable type of energy source, such as a battery, a fuel cell, a capacitor, etc. The method400may be performed, for example, by the hybrid electric controller210, the remote processing system260, and/or another suitable device or system.

At block402, the hybrid electric controller210receives flight data. The flight data could be data about an upcoming/next flight, historical fight data about prior flights, data about operating conditions during a prior flight(s), operating conditions excepted for an upcoming/next flight, and/or other relevant data. In one or more examples, the flight data can indicate a cycle count (e.g., number of flights). The hybrid electric controller210can receive the data from the avionics system220(e.g., flight plan data for the flight), the battery system230(e.g., battery data), the engine controller240(e.g., data about the aircraft such as avionics data, engine power settings, etc.), and/or the remote processing system260(e.g., weather data, ground conditions, airport information, etc.). In examples, the data can include one or more of ambient conditions (e.g., temperature, humidity, altitude of the departure airport, etc.), an estimated health state of the engine component (e.g., a number of cycles/flights that the engine component has undergone, an amount of time the engine component has operated, etc.), a derate setting (e.g., an indication that a full rate for takeoff is not needed), flight plan data (e.g., departure and arrival locations, estimated flight time, planned cruising speed and altitude, etc.), and/or other suitable data.

Using the data received at block402, the hybrid electric controller210calculates an engine component life expectancy for an engine component of the engine20at block406. An example of the engine component is a high pressure turbine (HPT) of the hybrid electric engine20, and in such an example, the engine component life expectancy is a HPT component life expectancy. Calculating the engine component life expectancy is performed by a method of health estimation and deterioration prediction such as calibrating a model of an engine with data received in previous flights, running that model with predictions of future flight conditions to estimate engine conditions such as rotor speed and turbine temperature in future flights, then applying those engine conditions to component life models in a process sometimes referred to as a digital twin process. Models of engines and life models may include combinations of analytical and empirical models, probabilistic modeling, and uncertainty quantification. Alternatively, calculating component life expectancy may be performed by some other form of prognostic such as referencing different pre-estimated deterioration rates with and without electrical assistance projected from an estimated current component life.

At decision block406, it is then determined whether the engine component life expectancy is indicative of a reason for removal of the engine for maintenance. That is, it is determined whether the component associated with the engine component life expectancy would be the reason for pulling the engine20for maintenance/service (e.g., the time until maintenance is based on the engine component life expectancy as opposed to another component or factor). Said another way, it is determined whether the engine component life expectancy is the limiting factor to engine maintenance.

If it is determined at decision block406that the engine component life expectancy is indicative of the reason for removal of the engine for maintenance (that is, the component is the limiting factor to engine maintenance), the method400proceeds to determine whether a use of battery energy will increase engine component life expectancy a threshold amount (e.g., an amount that is known to extend the engine component life expectancy). Specifically, at block408, an application of energy this flight that will most extend the life of the limiting component408. For example, the application of energy could be to perform e-taxi (full or partial), perform a takeoff boost, perform a climb boost, etc. At block410, that life extension (from block408) is weighed against the energy savings using trade factors that may be operator specific, such as how important it is to extend the life of the limiting component as compared to current energy savings. At block412, it is then determined whether to skip e-taxi. If it is determined to skip e-taxi at decision block412, the hybrid electric controller210apportions the electric power (e.g., the electric power from the battery system230) to extend the engine component life expectancy at block414. For example, the electric power can be used at pinch points (e.g., take off, climb, etc.) to extend the time until engine maintenance. In such cases, e-taxi is skipped. In some examples, an audible and/or visual alert (such as to a pilot on a display (not shown) of the aircraft, an operation center via the remote processing system260, a ground crew via the remote processing system260, etc.) can be issued. The method400can restart for a subsequent flight as shown by the arrow416.

If it is determined at decision block406that the engine component life expectancy is not indicative of the reason for removal of the engine for maintenance (that is, the component is not the limiting factor to engine maintenance), or if it is determined at decision block412to not skip e-taxi, the hybrid electric controller210uses the electric power from the battery system230of the aircraft to perform an e-taxi at block418. The method400can restart for a subsequent flight as shown by the arrow420.

An advantage of one or more embodiments described herein is that time on wing of an engine can be significantly extended. That is, the amount of time between engine maintenance events can be extended, such as by about 2000 cycles/flights, while still using e-taxi for many of those cycles.

While the above description has described the flow process ofFIG.4in a particular order, it should be appreciated that unless otherwise specifically required in the attached claims that the ordering of the steps may be varied.

It should be appreciated at the determination of whether to perform e-taxi or skip e-taxi in favor of apportioning electric power from the battery system of the aircraft to extend the engine component life expectancy can be performed onboard the aircraft (e.g., by the FADEC156, the hybrid electric controller210, or another suitable device/system) or offboard (e.g., by the remote processing system260).

FIG.5depicts an example method500of determining whether to skip e-taxi onboard the aircraft according to one or more embodiments described herein. At block502, an onboard controller (e.g., the FADEC156, the hybrid electric controller210, etc.) receives information, such as ambient conditions, engine/component health estimates, a derate setting, planned flight pathways, etc. At block504, the onboard controller calculates engine margins and durability projections with and without assist at each pinch point before starting an engine. For example, as shown inFIGS.3A and3B, the engine margin and durability projections are plotted based on the data received at block502. An example of a pinch point is that the aircraft is taking off from a high altitude airport on a hot day. At block504, the onboard controller determines whether to e-taxi for energy savings or whether to assist a pinch point with an electric motor. If, for example, the aircraft is taking off from a high altitude airport on a hot day, the onboard controller can determine to skip e-taxi and assist with takeoff and climb by providing electric power to the engine20. At block508, the decision from block506is indicated (such as to a pilot of the aircraft) and/or the e-taxi option is deactivated. At block510, electric power is provided at the appropriate waypoint. For example, if e-taxi is skipped and the takeoff and climb are determined to need extra power, the electric power are provided during the takeoff and climb waypoints. If, however, the e-taxi is not skipped, the electric power is provided during the e-taxi.

FIG.6depicts an example method600of determining whether to skip e-taxi offboard the aircraft according to one or more embodiments described herein. At block602, an offboard controller (e.g., the remote processing system260, etc.) receives information, such as ambient conditions, engine/component health estimates, a derate setting, planned flight pathways (path waypoints), data about the region, customer information, engine health monitoring contract information, etc. At block604, the offboard controller calculates engine margins and durability projections with and without assist at each pinch point before starting an engine. For example, as shown inFIGS.3A and3B, the engine margin and durability projections are plotted based on the data received at block602. An example of a pinch point is that the aircraft is taking off from a high altitude airport on a hot day. At block606, the offboard controller determines whether to e-taxi for energy savings or whether to assist a pinch point with an electric motor. If, for example, the aircraft is taking off from a high altitude airport on a hot day, the onboard controller can determine to skip e-taxi and assist with takeoff and climb by providing electric power to the engine20. At block608, the decision from block606is transmitted from the offboard controller to an onboard controller (e.g., the FADEC156, the hybrid electric controller210, etc.) and/or the e-taxi option is deactivated remotely by the offboard controller. At block610, electric power is provided at the appropriate waypoint. For example, if e-taxi is skipped and the takeoff and climb are determined to need extra power, the electric power are provided during the takeoff and climb waypoints. If, however, the e-taxi is not skipped, the electric power is provided during the e-taxi.

The term “about” is intended to include the degree of error associated with measurement of the particular quantity based upon the equipment available at the time of filing the application.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.

While the present disclosure has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this present disclosure, but that the present disclosure will include all embodiments falling within the scope of the claims.