Patent Description:
This disclosure relates to aircraft and engines therefor, and more particularly to hybrid electric aircraft engines.

Aircraft engines vary in efficiency and function over a plurality of parameters, such as thrust requirements, air temperature, air speed, altitude, and the like. Aircraft require the most thrust at takeoff, wherein the demand for engine power is the heaviest. However, during the remainder of the mission, the aircraft engines often do not require as much thrust as during takeoff. The size and weight of the engines allows them to produce the power needed for takeoff, however after take-off the engines are in effect over-sized for the relatively low power required to produce thrust for cruising in level flight.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved aircraft engines. The present disclosure provides a solution for this need.

<CIT> discloses a hybrid electric engine control module according to the preamble of claim <NUM>.

<CIT> discloses a propulsion system for an aircraft.

The present invention provides a hybrid electric engine control module (ECU) as set forth in claim <NUM>.

The present invention also provides a computer implemented hybrid electric aircraft powerplant control method as set forth in claim <NUM>.

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a powerplant system in accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments and/or aspects of this disclosure are shown in <FIG>.

Referring to <FIG>, a hybrid electric aircraft powerplant (HEP) system <NUM> can include a heat engine system <NUM> configured to provide torque to an air mover <NUM> (e.g., a propeller, fan, or any other suitable propulsion device). The heat engine of the HEP <NUM> can be a heat engine of any type, e.g., a gas turbine, spark ignited, diesel, rotary, or reciprocating engine of any fuel type and with any configuration. Any suitable heat engine system can include any suitable turbomachinery elements, either turbocharger, turbosupercharger, supercharger, and exhaust recovery turbo compounding, either mechanically, electrically, hydraulically or pneumatically driven, for example. An example of a rotary engine suitable for this application is disclosed in <CIT>.

The powerplant system <NUM> can also include an electric motor system <NUM> configured to provide torque to the air mover <NUM> in addition to and/or independently of the heat engine system <NUM>. The electric motor system <NUM> and the heat engine system <NUM> can be sized and configured to produce any amount of total horsepower (e.g., <NUM> horsepower total, <NUM> horsepower each). The electric motor system <NUM> can include any suitable components as appreciated by those having ordinary skill in the art in view of this disclosure (e.g., an electric motor, an electrical supply subsystem including a battery and a battery management system).

The system <NUM> includes a hybrid electric engine control module (ECU) <NUM> operatively connected to the heat engine system <NUM> and the electric motor system <NUM> to control a torque output from each of the heat engine system <NUM> and the electric motor system <NUM>. The ECU <NUM> is an embodiment of an ECU disclosed herein. The ECU <NUM> is configured to receive a torque command (e.g., a power lever angle from a power lever (PLA) <NUM> and/or other module) and split output power between the electric motor system <NUM> and the heat engine system <NUM>. Additionally, the ECU <NUM> is configured to balance a total torque against a second total torque of a second aircraft powerplant <NUM> (e.g., as shown in <FIG>). The ECU <NUM> can additionally and/or alternatively be configured to receive any suitable sensor measurements or status information (e.g., rotor speed, temperature, and pressure at various engine stations, battery state of charge, etc.) for processing the splitting of output power. In certain embodiments, the torque split can be an adaptive split that changes in real-time as a function of one or more parameters (e.g., battery state of charge, torque command, sensor information, etc.).

In certain embodiments, the torque splitting logic may use parameters that are not directly measured and may need to be synthesized in some way (e.g. temperature or pressure at various engine stations). In certain embodiments, the torque split calculation may account for various operational constraints of the heat engine system, electrical machinery, and/or energy storage, or example.

Referring additionally to <FIG>, the ECU <NUM> includes a torque splitting module <NUM> configured to receive a total torque value (e.g., Qtot as shown in <FIG> from a total torque module <NUM> or, in examples not presently being claimed, directly from the PLA <NUM> based on a setting of the PLA <NUM>, for example). The ECU is configured to determine a torque split of the total torque value between the electric motor system <NUM> and the heat engine system <NUM>. The torque splitting module <NUM> is configured to control (e.g., directly or indirectly) the electric motor system <NUM> and the heat engine system <NUM> to produce the total torque value in accordance with the determined torque split (e.g., while meeting transient and steady-state operational constraints for the heat engine, electrical motor, and battery subsystem).

In certain embodiments, the torque splitting module <NUM> can be configured to determine the torque split as a function of stored correlation data. In certain embodiments, for a given total torque value, lookup table or other suitable data can be used to output a correlated split between heat engine torque value (Qh) and electric motor torque value (Qe), which values ultimate control the output of the respective engine systems. For example, during takeoff, the PLA <NUM> may be set to a maximum power setting (e.g., <NUM> horse, and the torque splitting module <NUM> can output a maximum Qh and a maximum Qe (e.g., <NUM> horsepower from the electric motor system <NUM> and <NUM> horsepower from the heat engine system <NUM>). In certain embodiments, for PLA settings less than maximum power, the torque splitting module <NUM> can output a smaller Qe (e.g., <NUM> electric horsepower) and maintain a maximum Qh (e.g., <NUM> horsepower). In certain embodiments, at PLA settings where the demanded total horsepower is equal to or less than a maximum Qh (e.g., less than or equal to <NUM> horsepower), the torque splitting module <NUM> can be configured to output a Qe value of zero, thereby causing the heat engine system <NUM> to produce all required power which can conserve battery for situations where greater than maximum Qh is required (e.g., climb, go around).

In certain embodiments, the electric motor system <NUM> or the heat engine system <NUM> may not be able to provide a normal share of power in accordance with the torque split, e.g., due to reaching an operational limit (e.g., such as a temperature or pressure limit). For example, a torque split in cruise may be commanding full power from the heat engine system <NUM> (e.g., <NUM> horsepower from heat engine) and less or no power from the electric motor system (e.g., <NUM> horespower), but due to transient maneuver or condition, the power output of the heat engine system <NUM> is briefly limited (e.g., for about <NUM> minute or less) either by the system or by the condition (e.g., heat engine system horsepower drops to 950HP). The ECU <NUM> can determine that total commanded torque is not available under the existing torque split and the torque splitting module can cause the electric motor system <NUM> to make up for the transient loss in horsepower from the heat engine system <NUM> (e.g., by providing <NUM> horsepower from the electric motor system <NUM>) thereby maintaining the commanded total torque value. The reverse scenario can also be employed in certain embodiments where the heat engine system <NUM> can compensate for the electric motor system <NUM>.

In certain embodiments, the torque splitting module <NUM> can additionally be configured to split torque as a function of a manual input from a pilot. For example, a manual input lever for selecting an amount of electric power to be utilized can be used by a pilot. Any suitable manual control is contemplated herein.

The ECU <NUM> includes a total torque module <NUM> configured to receive one or more input values including at least a power lever setting, e.g., from the PLA <NUM>. The total torque module <NUM> is configured to determine the total torque value (Qtot) as a function of the one or more input values and output the total torque value to the torque splitting module <NUM>. The one or more input values can further include at least one of an altitude, a total temperature, air density, a condition lever (CLA) <NUM> setting, and/or the second total torque of the second aircraft powerplant. Any other suitable input values for determining total torque is contemplated herein.

In certain embodiments, referring additionally to <FIG>, the hybrid electric powerplant system <NUM> can be utilized on a multiengine aircraft <NUM> (e.g., a retrofit Bombardier Dash-<NUM>). In certain embodiments, the aircraft <NUM> may utilize a traditional powerplant (e.g., a turbomachine). The total torque module <NUM> can be configured to determine a total torque value using a locally stored torque map (e.g., as shown) to match or approximate the second total torque of the second aircraft powerplant <NUM> at a same power lever setting. In certain embodiments, an actual second total torque value can be provided to the total torque module <NUM> (e.g., from a torque sensor or other control unit) on the second powerplant <NUM> such that the actual second torque can be used by the total torque module <NUM> to determine the total torque value Qtot. Any other suitable data from any other suitable source can be utilized to allow the total torque module <NUM> to match or approximate the total torque of the second aircraft powerplant to reduce or eliminate asymmetric thrust.

In certain embodiments, the ECU <NUM> can include a torque rate limit module <NUM> configured to match or approximate a rate of torque change to the second aircraft powerplant <NUM> to match or approximate dynamic response of the second aircraft powerplant <NUM>. The torque rate limit module <NUM> can limit torque increase and/or decrease as a function of any suitable data and/or inputs (e.g., based on the one or more input values and stored data such as a look up table). In embodiments where the hybrid electric powerplant system <NUM> is used in a multiengine aircraft that also has a second powerplant <NUM> that is a traditional powerplant (e.g., a turbomachine), the second powerplant may respond slower to PLA <NUM> setting changes than the hybrid electric aircraft powerplant system <NUM> responds to PLA <NUM> setting changes. Since the PLA <NUM> and the PLA <NUM> can be disposed together and operated simultaneously as appreciated by those having ordinary skill in the art, to avoid dynamic mismatch when changing the settings of PLA <NUM> and PLA <NUM> together, the torque rate limit module <NUM> can control the time of increase or decrease of the total torque value that is provided to the torque splitting module <NUM> when there is a change in total torque value output by the total torque module <NUM>. In certain embodiments, the torque rate limit module <NUM> can receive the PLA setting and rate-limit the PLA setting change into the total torque module <NUM>. Any other suitable way of rate limiting is contemplated herein.

The ECU <NUM> can include a fuel flow control module <NUM> configured to control fuel flow in the heat engine system <NUM> to control torque output of the heat engine system <NUM> as a function of heat engine torque value (Qh) output by the torque splitting module <NUM>. In certain embodiments, the torque splitting module <NUM> can be configured to output an electric motor torque value (Qe) to a motor control module (MC) <NUM> of the electric motor system <NUM>. The MC can be configured to control an electric motor <NUM> of the electric motor system <NUM> as a function of the Qe. While the MC <NUM> is shown as part of the electric motor system <NUM>, it is contemplated that the motor control module <NUM> can be at least partially integrated with the ECU <NUM> or be in any other suitable location. In certain embodiments, the fuel flow control module <NUM> can be separate from the ECU <NUM> (e.g., contained within the heat engine system <NUM>).

Embodiments of a HEP disclosed herein are applicable to any suitable multiengine propulsion system distribution. In examples not presently being claimed, a single engine aircraft can include a single HEP <NUM>. While certain embodiments shown, e.g., as in <FIG>, show a single HEP <NUM> and a single traditional powerplant <NUM>, it is contemplated that more than two powerplants can be used on an aircraft. It is also contemplated that both powerplants in a dual powerplant system (e.g., as shown in <FIG>) can be a HEP, e.g., HEP <NUM> as disclosed herein. Any suitable number (e.g., all) of powerplants in a system having a plurality of powerplants can be a HEP, e.g., HEP <NUM> as disclosed herein. One or multiple engines can be the same HEP or a different HEP or different full combustion or different full electric.

Any suitable control scheme according to the appended claims, for a single or multi HEP system is contemplated herein (e.g., a power setting map), e.g., similar to and/or the same as disclosed above.

Certain embodiments may provide a recharge function which may require coordination of the ECU <NUM>, electric motor controller MC and the battery management system BMS. In certain embodiments, recharge can be done at any point where power demand is below <NUM>% heat engine power, for example. In certain embodiments, the heat engine can be oversized to provide recharge capability at cruise, for example. In certain embodiments, aircraft speed can be reduced slighted (e.g., about <NUM> kts, about <NUM>% power, or any suitable amount reduction) so the battery can be recharged without the engine being oversized by flying slower and using the freed power to recharge. Regeneration can also be implemented during certain portions of the descent flight leg, for example. Regeneration during descent can allow downsizing of the battery without loss of mission fuel burn reduction due to heat engine recharge, which burns fuel.

Certain embodiments allow torque splitting to match one or more other aircraft engines in takeoff and climb operations, and throttling back of heat engine (e.g., combustion) power may only occur at level or descending flight conditions or slower climb rate. Embodiments can manage the electric energy to climb up to altitude. The BMS can know how much energy is left and monitor the storage/discharge. Embodiments can measure remaining battery, make calculations on impact to flight, and adjust power output of the electric motor system accordingly. Any suitable sensors, sources, and data calculation to provide this information is contemplated herein (e.g., one or more sensors connected to the ECU <NUM> and/or BMS <NUM>).

Embodiments can calculate and display the maximum altitude, or the maximum climb rate that can be achieved with current energy storage (e.g., based on a fixed correlation, or based on additionally on one or more flight variables, e.g., as density altitude, selected airspeed, or any other suitable factors). Certain embodiments can regenerate electricity in any suitable manner (e.g., by windmilling the propeller and/or by recharge in cruise if the heat engine is sized to be large enough to both cruise at a desired speed and provide enough excess energy to charge the battery). In certain embodiments, a pilot may have the option to reduce airspeed and use excess heat engine power to charge the battery. In certain embodiments, the ECU can command recharge of the battery in at least one portion of flight when excess power is available. The at least one portion of flight can include at least one of descent, low speed cruise, slow climb, or higher altitude cruise, for example. In certain embodiments, the ECU can command regenerating the battery with windmilling during descent or partial descent as a function of descent rate from a pilot command, flight control command, or ECU calculated rate of descent based on any other suitable parameter that the ECU can use as an input.

Any module disclosed herein can include any suitable hardware (e.g., circuitry, microprocessor, etc.) and/or software (e.g., any suitable computer code) configured to perform one or more disclosed functions of the respective module. Also, any module disclosed herein can be at least partially commonly hosted and/or integral with or at least partially separate from any other module disclosed herein as appreciated by those having ordinary skill in the art in view of this disclosure. For example, embodiments can include a separate torque split module that implements the torque split and a separate engine control module that controls the thermal engine. In certain embodiments, the can be hosted together in any suitable manner (e.g., on the same hardware and/or software).

The electric motor system <NUM> can include any suitable components (e.g., electric motor <NUM>, a battery <NUM>, a battery management system <NUM>), and can be configured to supply any suitable type of power supply (e.g., <NUM> phase as shown). The heat engine system <NUM> can include any suitable type of heat engine. The powerplant system <NUM> can include a combining gear box <NUM> configured to combine the outputs of the electric motor system <NUM> and the heat engine system <NUM> to combine torque to the air mover <NUM>. As appreciated by those having ordinary skill in the art, any other suitable components for the hybrid power plant system <NUM> is contemplated herein (e.g., a reduction gear box <NUM>, a propeller control unit, a propeller).

While this disclosure refers to certain levers (PLA, CLA, manual lever), the term lever is not limited to a physical lever, and includes any suitable control structure. For example, certain embodiments of levers can include a dial, a digital interface, or any other suitable control for use by a pilot in commanding inputs.

In accordance with at least one aspect of this disclosure, a computer implemented hybrid electric aircraft powerplant control method includes receiving one or more power input values including at least a power lever command, determining a total torque demand based on the one or more power input values to create a total torque value, and splitting the total torque value into an electric motor torque value and heat engine torque value. The method includes controlling an electric motor system as a function of the electric motor torque value and controlling a heat engine system as a function of the heat engine torque value to cause the powerplant to meet the total torque demand.

The method includes matching or approximating the total torque value to a second total torque of a second aircraft powerplant at a same power setting. The method can include controlling torque change rate to match or approximate a second torque change rate of a second aircraft powerplant. The one or more power input values further include at least one of an altitude, a total temperature, a condition lever setting, and/or the second total torque of the second aircraft powerplant, for example.

In accordance with at least one aspect of this disclosure, an aircraft <NUM> can have a hybrid-electric powerplant system as disclosed above in place of a traditional powerplant, and a second powerplant that is a traditional powerplant. Embodiments can include propulsion delivered by a propeller driven by both an electric motor system and a heat engine system. Certain embodiments include <NUM>/<NUM> power split between the electric motor and heat engine power lanes (such that each engine/motor provides the same maximum power). Any other power split is contemplated herein. The electric motor control module can selectively provide energy from the battery to the electric motor. The battery can be located in the aircraft cabin, for example.

In embodiments, the battery, the BMS system and motor control module can be located in the cabin. A high voltage (e.g., about <NUM> kV) AC distribution system can transmit electrical power from the motor control module to the electric motor that is mechanically parallel with the heat engine. The propeller condition lever (CLA) can control the propeller control unit (PCU) as appreciated by those having ordinary skill in the art. In certain embodiments, the CLA command may be optionally read by the ECU. The ECU can be the master Power Management System (PMS) and can control the total power request and limits as well as torque split between the heat engine and the electric motor.

Embodiments of an ECU can calculate the total torque demand for the HEP based on the PLA power demand and flight operating conditions to mimic a traditional engine (e.g., turbomachine) steady response and transient torque response. The ECU can then calculate the torque split between the heat engine and the electric motor. The torque split may include electric compensation during a transient or limited power condition (e.g., temperature, boost compressor running line) of the heat engine. The ECU can then send the electric torque command to the electric motor control module via any suitable communication pathway (e.g., a digital communication link). The motor control module then command proper AC voltage and current to the electric motor. The raw PLA setting input can also be read by the motor control module for health assessment of the ECU and for direct control based on the PLA settings in certain degraded operational modes (e.g., wherein ECU is not functional).

Embodiments can balance torque between two powerplants on aircraft (e.g., a combination of one or more HEP and one or more traditional engines) such that either the HEP matches sensed torque output of a traditional engine, or calculates what torque setting should be to match or approximate the traditional engine torque (e.g., based on throttle inputs, altitude, etc.). Embodiments can balance torque between two or more HEP powerplants (e.g., as shown in <FIG>), or any other suitable combination of at least one HEP powerplant and at least one of any other type of powerplant (e.g., a turbomachine, piston, hybrid, full electric). Embodiments include a torque rate limiter for when power lever is moved since the HEP system acheives torque faster than a traditional engine (e.g., a turbomachine) to slow torque changes to match or approximate torque changes of the traditional engine. Embodiments as disclosed herein provide fuel use reduction among other benefits.

Aspects of the this disclosure may be described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of this disclosure. It will be understood that each block of any flowchart illustrations and/or block diagrams, and combinations of blocks in any flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in any flowchart and/or block diagram block or blocks.

Claim 1:
A hybrid electric engine control module (<NUM>) configured to be operatively connected to a hybrid electric aircraft powerplant (<NUM>) having a heat engine system (<NUM>) and an electric motor system (<NUM>) to control a torque output from each of the heat engine system (<NUM>) and the electric motor system (<NUM>), the hybrid electric engine control module (<NUM>) being configured to receive a torque command and split output power between the electric motor system (<NUM>) and the heat engine system (<NUM>), characterised in that:
the hybrid electric engine control module further comprises a torque splitting module (<NUM>) configured to:
receive a total torque value;
determine a torque split of the total torque value between the electric motor system (<NUM>) and the heat engine system (<NUM>); and
control the electric motor system (<NUM>) and the heat engine system (<NUM>) to produce the total torque value in accordance with the determined torque split; and
the hybrid electric engine control module further comprises a total torque module (<NUM>) configured to:
receive one or more input values including at least a power lever setting;
determine the total torque value as a function of the one or more input values; and
output the total torque value to the torque splitting module (<NUM>), wherein the total torque module (<NUM>) is configured to match or approximate the total torque value to a second total torque of a second aircraft powerplant (<NUM>) at a same power lever setting, to balance a total torque against the second total torque of the second aircraft powerplant (<NUM>).