DM-i configuration multi-mode power system and method for tiltrotor aircraft

Abstract

The application discloses a DM-i configuration multi-mode power system and method suitable for a tilt-rotor aircraft. The power system comprises a double-rotor driving through shaft, a first driving bevel gear, a first driven bevel gear, a second driving bevel gear, a second driven bevel gear, an engine speed reducer, an electric motor speed reducer, a two-stage speed reducer, a power coupling intermediate shaft, an engine, a clutch, an electric motor, a generator, a control module and a battery. The application is a super hybrid power system of five power modes. During operation, the engine can independently provide power through the control of the clutch, can drive the generator to generate power at a global highest working efficiency point, and the electric motor can recover kinetic energy into electric energy during landing and deceleration. The application does not need a disposable backup battery, thereby avoiding extra load.

Description

Technical Field

[0001] This invention relates to the field of aviation propulsion, and more particularly to a DM-i configuration multi-mode propulsion system and method suitable for tiltrotor aircraft. Background Technology

[0002] The tiltrotor aircraft revolutionarily combines the vertical takeoff and landing (VTOL) capability of a helicopter with the high-speed cruise performance of a fixed-wing aircraft, achieving a leap in mission capabilities for a single platform. Through a unique tilting mechanism, it converts its rotor into a propeller configuration during cruise, flying like a turboprop aircraft, thereby increasing its cruise speed to 500-600 km / h and significantly extending its range, enabling rapid long-range deployment. Simultaneously, it retains the full VTOL / Short takeoff and landing capabilities of a helicopter. It requires no runway and can take off and land in confined areas such as ship decks and field sites, offering extremely high deployment flexibility, making it particularly suitable for forward-deployed areas or regions with limited infrastructure. The combination of "high-speed cruise" and "VTOL" makes it an irreplaceable "force multiplier" and mission innovator in key areas such as rapid military long-range deployment, combat search and rescue, and civilian long-range emergency response.

[0003] Because tiltrotor aircraft rely entirely on the two large rotors at the wingtips for lift, the failure of one engine will immediately generate devastating asymmetric lift and torque, causing the aircraft to roll out of control within seconds. The core function of the cross-drive system is to integrate the power of the two engines into a single "power pool" through mechanical linkage. In the event of a single engine failure, the remaining engine can instantly continue driving both rotors via the drive shaft, maintaining basic balance and control, and buying the pilot valuable time to react and achieve a safe landing or mode switch. Without this system, a single engine failure is almost tantamount to a catastrophic accident; therefore, it is the cornerstone of ensuring the survivability of this unique aircraft configuration.

[0004] However, this redundant system, designed to ensure safety, also comes at a significant performance cost. The extra-long driveshaft, complex gearbox, and multiple clutches required to achieve power interconnection constitute a huge amount of additional weight. This "dead weight" directly encroaches on the aircraft's payload space, reducing its ability to carry passengers or cargo. At the same time, the complex transmission path introduces additional mechanical friction and energy loss, reducing power transmission efficiency and meaning that more fuel is needed to perform the same task, thus weakening its range and economy.

[0005] The overall efficiency of traditional gas turbine aircraft engines is typically below 40%. While pure electric propulsion systems have the potential for zero emissions, their development is limited by the energy density bottleneck of current electrochemical energy storage technologies. To balance efficiency and range, hybrid power systems have emerged. By integrating the core advantages of gas turbine engines and electric propulsion systems, these systems allow the engine to operate continuously in its high-efficiency range, thereby significantly reducing fuel consumption and emissions. However, existing hybrid-powered aircraft mostly employ distributed electric propulsion configurations, resulting in a tight coupling relationship where one electric motor corresponds to one propulsion unit. This leads to complex system structures, difficulties in multi-motor coordinated control, long power transmission paths, and low transmission efficiency. Furthermore, the failure of a single motor can also affect flight safety.

[0006] In summary, this invention addresses the aforementioned problems by proposing a DM-i configuration multi-mode power system suitable for tiltrotor aircraft. It fundamentally optimizes the power architecture by integrating the electric motor with the engine and transmission system, thus resolving the core contradictions faced by traditional tiltrotor aircraft, such as the bulky safety redundancy system, significant efficiency losses, and the complex control of existing hybrid power systems. This provides a more efficient and reliable power solution for the future development and application of tiltrotor aircraft. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the deficiencies mentioned in the background art by providing a multi-mode propulsion system and method for the DM-i configuration of tiltrotor aircraft.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] The DM-i configuration multi-mode power system suitable for tiltrotor aircraft includes a dual-rotor drive through shaft, a first active bevel gear, a first driven bevel gear, a second active bevel gear, a second driven bevel gear, an engine reducer, an electric motor reducer, a two-stage reducer, a power coupling intermediate shaft, an engine, a clutch, an electric motor, a generator, a control module, and a battery.

[0010] The first driven bevel gear and the second driven bevel gear are coaxially fixed to the left rotor shaft and the right rotor shaft of the tiltrotor aircraft, respectively.

[0011] The two ends of the dual-rotor drive shaft are coaxially fixed to the first driving bevel gear and the second driving bevel gear, respectively, and the first driving bevel gear meshes with the first driven bevel gear, and the second driving bevel gear meshes with the second driven bevel gear;

[0012] The driven gear of the secondary reducer and the dual-rotor drive through shaft are coaxially fixed at the midpoint of the dual-rotor drive through shaft, and the driving gear of the secondary reducer and the power coupling intermediate shaft are coaxially fixed at the midpoint of the power coupling intermediate shaft.

[0013] The driven gear of the engine reducer is coaxially and fixedly connected to one end of the power coupling intermediate shaft, and the driving gear of the engine reducer is coaxially and fixedly connected to the output end of the clutch.

[0014] The output shaft of the engine and the input end of the clutch are coaxially and fixedly connected.

[0015] The driven gear of the motor reducer is coaxially and fixedly connected to the other end of the power coupling intermediate shaft, and the driving gear of the motor reducer is coaxially and fixedly connected to the output shaft of the motor.

[0016] The input shaft of the generator and the output shaft of the engine are coaxially and rigidly connected.

[0017] The control module is electrically connected to the clutch, generator, motor, and battery respectively, and is used to control the operation of the clutch, generator, motor, and battery.

[0018] This invention also discloses a method for operating the DM-i configuration multi-mode propulsion system suitable for tiltrotor aircraft, comprising the following steps:

[0019] If pure electric drive is required: the control module controls the clutch to disengage, and simultaneously controls the engine and generator to stop working, controlling the battery to directly supply power to the electric motor; the electric motor outputs power to drive the rotor to rotate;

[0020] If a generator is used for power generation: the control module controls the clutch to disengage and controls the engine to drive the generator to generate electricity; when the effective power of the engine is greater than the power required to drive the rotor, the control module will generate a portion of the electrical energy to drive the electric motor, which in turn drives the rotor; at the same time, the remaining electrical energy will be stored in the battery; when the effective power of the engine is less than the power required to drive the rotor, the control module will use all the electrical energy generated by the generator to drive the electric motor and control the battery to discharge to make up for the power gap.

[0021] If direct engine drive is used: the control module controls the clutch to close, controls the electric motor to stop working, and controls the engine to work to directly drive the rotor; when the power provided by the engine is greater than the power required by the aircraft, the control module will use the excess power to drive the generator to generate electricity and store the electrical energy in the battery to charge the battery;

[0022] If the engine and electric motor are driven in parallel: the control module controls the clutch to close, and the engine and electric motor are mechanically coupled. When the effective power of the engine is less than the power required to drive the rotor, the control module controls the engine to drive the rotor to rotate. At the same time, the control module controls the battery to supply power to the electric motor, and the electric motor outputs auxiliary power to drive the rotor together with the engine. When the effective power of the engine is greater than the power required to drive the rotor, the control module controls the engine to use the excess power to drive the generator to generate electricity and store the electrical energy in the battery.

[0023] If energy recovery is required: the control module controls the clutch to disengage, controls the engine and generator to stop working, during the aircraft deceleration and braking process, the rotor is driven by aerodynamic drag or inertia to reverse the electric motor, so that the electric motor is in generator mode, converting the mechanical energy of the rotor into electrical energy, and the control module transmits the generated electrical energy to the battery for storage.

[0024] This invention is a super hybrid power system with five power modes. Through clutch control, the engine can provide power independently and also drive the generator to generate electricity at its highest global operating efficiency point. During descent and deceleration, the electric motor can recover kinetic energy and convert it into electrical energy, eliminating the need for a primary backup battery and avoiding additional load. Compared with traditional single-power systems and series / parallel hybrid power systems, this invention has the following comprehensive advantages:

[0025] 1. The power distribution mode can realize five modes: pure electric, direct drive, series, parallel and energy recovery. The power hybridization degree is very high, which can adapt to the energy saving, emission reduction and safety requirements of various complex flight conditions, and the engine and motor arrangement is flexible.

[0026] 2. The motor, engine, and transmission system are integrated, sharing a power transmission path, thus avoiding the complexity of coordinating multiple motors. The motor and engine jointly drive the rotor via a drive shaft, resulting in a short power transmission path and high transmission efficiency. In the event of motor failure, the engine can provide the necessary power to ensure safety, reducing the coordination and control time required in the event of a single motor failure.

[0027] 3. During normal operation and in the event of a single power source failure, the through shaft connecting the two rotors can be fully utilized, preventing it from becoming an additional load on the aircraft. The torque and speed of the two rotors remain the same. When one of the engines or electric motors fails, the other power source can ensure the safe landing of the aircraft. This is suitable for the emergency mode of dual-rotor aircraft and significantly improves safety.

[0028] 4. The bevel gear transmission on both sides ensures that the two rotors rotate in opposite directions, with the same speed and torque, which is suitable for the dynamic balance of a twin-rotor aircraft.

[0029] 5. The driven bevel gear can rotate along the driving bevel gear. The rotor tilting process does not affect the transmission efficiency. Moreover, only the driven bevel gear of the rotor rotates during the tilting process. The tilting load is small and the tilting energy consumption is low, making it suitable for tilt rotor aircraft.

[0030] 6. The use of a three-stage reduction gear (with bevel gears as the third stage reducer) can reduce the size and weight of each reducer, resulting in a simple and reliable power transmission structure that can increase the payload of the hybrid-powered aircraft. Attached Figure Description

[0031] Figure 1This invention provides a schematic diagram of a DM-i configuration multi-mode power system suitable for tiltrotor aircraft.

[0032] In the diagram, 1-left rotor, 2-right rotor, 3-left rotor shaft, 4-driven gear of the second-stage reducer, 5-dual rotor drive through shaft, 6-right rotor shaft, 7-first driven bevel gear, 8-second driven bevel gear, 9-first driving bevel gear, 10-second driving bevel gear, 11-driven gear of the engine's first-stage reducer, 12-driving gear of the second-stage reducer, 13-power coupling intermediate shaft, 14-driven gear of the electric motor's first-stage reducer, 15-engine, 16-clutch, 17-driving gear of the engine's first-stage reducer, 18-driving gear of the electric motor's first-stage reducer, 19-electric motor, 20-generator, 21-battery, 22-control module. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0034] This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0035] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, and / or parts, these elements, components, and / or parts are not limited by these terms. These terms are merely used to distinguish elements, components, and / or parts from one another. Therefore, the first element, component, and / or part discussed below may be a second element, component, or part without departing from the teachings of this invention.

[0036] In the description of this invention, it should be understood that the terms "horizontal," "vertical," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and should not be construed as limiting this invention; the terms "installation," "connection," "fixing," etc., should be interpreted broadly, for example, they can refer to a fixed connection, a detachable connection, or an integral connection, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components; for those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0037] In the description of this application, unless otherwise expressly specified or limited, the terms "installation," "connection," and "linking" should be interpreted broadly, for example, as a fixed connection, an integral connection, or a detachable connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium, or as communication between two components, etc. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] like Figure 1 As shown, the present invention discloses a

[0039] The DM-i configuration multi-mode power system suitable for tiltrotor aircraft includes a dual-rotor drive through shaft, a first active bevel gear, a first driven bevel gear, a second active bevel gear, a second driven bevel gear, an engine reducer, an electric motor reducer, a two-stage reducer, a power coupling intermediate shaft, an engine, a clutch, an electric motor, a generator, a control module, and a battery.

[0040] The first driven bevel gear and the second driven bevel gear are coaxially fixed to the left rotor shaft and the right rotor shaft of the tiltrotor aircraft, respectively.

[0041] The two ends of the dual-rotor drive shaft are coaxially fixed to the first driving bevel gear and the second driving bevel gear, respectively, and the first driving bevel gear meshes with the first driven bevel gear, and the second driving bevel gear meshes with the second driven bevel gear;

[0042] The driven gear of the secondary reducer and the dual-rotor drive through shaft are coaxially fixed at the midpoint of the dual-rotor drive through shaft, and the driving gear of the secondary reducer and the power coupling intermediate shaft are coaxially fixed at the midpoint of the power coupling intermediate shaft.

[0043] The driven gear of the engine reducer is coaxially and fixedly connected to one end of the power coupling intermediate shaft, and the driving gear of the engine reducer is coaxially and fixedly connected to the output end of the clutch.

[0044] The output shaft of the engine and the input end of the clutch are coaxially and fixedly connected.

[0045] The driven gear of the motor reducer is coaxially and fixedly connected to the other end of the power coupling intermediate shaft, and the driving gear of the motor reducer is coaxially and fixedly connected to the output shaft of the motor.

[0046] The input shaft of the generator and the output shaft of the engine are coaxially and rigidly connected.

[0047] The control module is electrically connected to the clutch, generator, motor, and battery respectively, and is used to control the operation of the clutch, generator, motor, and battery.

[0048] The DM-i multi-mode powertrain system is divided into five modes based on the energy source configuration, power transmission path, and control strategy: pure electric mode, series mode, direct drive mode, parallel mode, and energy recovery mode. The working principles and applicable scenarios for each mode are as follows:

[0049] 1. Pure Electric Drive Mode: With the clutch disengaged, the engine and generator are not operating. The battery serves as the sole energy source, directly supplying power to the electric motor under the control of the control module. The electric motor outputs power to drive the rotor through a reduction gear mechanism, resulting in zero fuel consumption and exhaust emissions throughout the entire process. This mode is suitable for zero-emission short-haul flights and low-noise takeoffs and landings, such as short-haul low-altitude flights in urban areas, takeoffs and landings around residential areas, and operations in noise- and emission-sensitive areas (such as urban emergency rescue and low-altitude inspections).

[0050] 2. Series Drive Mode: With the clutch disengaged, the engine drives the generator to produce electricity. When the engine's effective power exceeds the power required to drive the rotor, the control module generates a portion of the electrical energy to drive the electric motor, which in turn drives the rotor via a reduction gear. Simultaneously, the remaining electrical energy charges the battery. When the engine's effective power is less than the power required to drive the rotor, the control module uses all the electrical energy generated by the generator to drive the electric motor and controls the battery to discharge to compensate for the power shortfall. This ensures that the engine always operates at its optimal efficiency point. This mode is suitable for long-endurance cruise flights when the battery's SOC (State of Charge) is below a threshold, or when the electric motor needs to continue operating and the battery is low on power (such as long-distance cargo transport or long-term low-altitude monitoring).

[0051] 3. Engine Direct Drive Mode: The clutch is engaged, and the electric motor stops working. In the engine's high-efficiency operating range, engine power is directly transmitted to the rotor via a mechanical transmission chain. When the engine's power exceeds the aircraft's power requirements, the excess power drives a generator to produce electricity, which is then stored in the battery by the control module for charging. In this mode, the engine cruises at high efficiency and high power output, operating at its peak efficiency. There are no energy conversion stages in the power transmission path, reducing energy loss during power transmission. The tilt rotor adjusts its angle according to cruise requirements, optimizing aerodynamic efficiency and achieving high-speed flight. This mode is suitable for medium- to long-range high-altitude cruise and stable flight phases requiring no additional power assistance (such as intercity transport and long-distance ferry flights).

[0052] 4. Parallel Drive Mode: With the clutch engaged, both the engine and the electric motor can directly drive the rotor, achieving power coupling mechanically. When the engine's effective power is less than the power required to drive the rotor, the engine directly outputs power to the rotor via mechanical transmission. Simultaneously, the control module controls the battery to supply power to the electric motor, which outputs auxiliary power and integrates into the powertrain, working in conjunction with the engine's power to drive the rotor. When the engine's effective power exceeds the power required to drive the rotor, the engine can use the excess power to drive the generator, and the electrical energy is charged into the battery via the control module. This mode maintains the engine within its high-efficiency range through power distribution, offering high flexibility but complex control. It is suitable for scenarios requiring high power, such as vertical takeoff, rapid climb, and headwind flight (e.g., heavy-load takeoff, rapid climb across complex terrain).

[0053] 5. Energy Recovery Mode: The clutch is disengaged, and the engine and generator are not operating. During aircraft deceleration and braking, the rotor, driven by aerodynamic drag or inertia, reverses the direction of the power coupling device to drive the electric motor. At this time, the electric motor switches to generator mode, and the control module transfers the generated electrical energy to the battery for storage. This converts the rotor's mechanical energy into electrical energy, achieving deceleration through energy recovery while reducing energy waste. This mode is suitable for deceleration during landing, scenarios requiring active deceleration during flight (such as approaching landing or deceleration when avoiding obstacles), and ground driving scenarios.

[0054] When a single power source fails, such as an engine malfunction, the clutch disengages, and the battery powers the electric motor, which then drives the rotor to rotate via the transmission system. If the electric motor malfunctions, the system enters engine direct drive mode.

[0055] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0056] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multi-mode propulsion system for DM-i configuration tiltrotor aircraft, characterized in that, It includes a dual-rotor drive through shaft, a first driving bevel gear, a first driven bevel gear, a second driving bevel gear, a second driven bevel gear, an engine reducer, an electric motor reducer, a two-stage reducer, a power coupling intermediate shaft, an engine, a clutch, an electric motor, a generator, a control module, and a battery; The first driven bevel gear and the second driven bevel gear are coaxially fixed to the left rotor shaft and the right rotor shaft of the tiltrotor aircraft, respectively. The two ends of the dual-rotor drive shaft are coaxially fixed to the first driving bevel gear and the second driving bevel gear, respectively, and the first driving bevel gear meshes with the first driven bevel gear, and the second driving bevel gear meshes with the second driven bevel gear; The driven gear of the secondary reducer and the dual-rotor drive through shaft are coaxially fixed at the midpoint of the dual-rotor drive through shaft, and the driving gear of the secondary reducer and the power coupling intermediate shaft are coaxially fixed at the midpoint of the power coupling intermediate shaft. The driven gear of the engine reducer is coaxially and fixedly connected to one end of the power coupling intermediate shaft, and the driving gear of the engine reducer is coaxially and fixedly connected to the output end of the clutch. The output shaft of the engine and the input end of the clutch are coaxially and fixedly connected. The driven gear of the motor reducer is coaxially and fixedly connected to the other end of the power coupling intermediate shaft, and the driving gear of the motor reducer is coaxially and fixedly connected to the output shaft of the motor. The input shaft of the generator and the output shaft of the engine are coaxially and rigidly connected. The control module is electrically connected to the clutch, generator, motor, and battery respectively, and is used to control the operation of the clutch, generator, motor, and battery.

2. The operating method of the DM-i configuration multi-mode propulsion system for tiltrotor aircraft as described in claim 1, characterized in that, Includes the following steps: If pure electric drive is required: the control module controls the clutch to disengage, and simultaneously controls the engine and generator to stop working, controlling the battery to directly supply power to the electric motor; the electric motor outputs power to drive the rotor to rotate; If a generator is used for power generation: the control module controls the clutch to disengage and controls the engine to drive the generator to generate electricity; when the effective power of the engine is greater than the power required to drive the rotor, the control module will generate a portion of the electrical energy to drive the electric motor, which in turn drives the rotor; at the same time, the remaining electrical energy will be stored in the battery; when the effective power of the engine is less than the power required to drive the rotor, the control module will use all the electrical energy generated by the generator to drive the electric motor and control the battery to discharge to make up for the power gap. If direct engine drive is used: the control module controls the clutch to close, controls the electric motor to stop working, and controls the engine to work to directly drive the rotor; when the power provided by the engine is greater than the power required by the aircraft, the control module will use the excess power to drive the generator to generate electricity and store the electrical energy in the battery to charge the battery; If the engine and electric motor are driven in parallel: the control module controls the clutch to close, and the engine and electric motor are mechanically coupled. When the effective power of the engine is less than the power required to drive the rotor, the control module controls the engine to drive the rotor to rotate. At the same time, the control module controls the battery to supply power to the electric motor, and the electric motor outputs auxiliary power to drive the rotor together with the engine. When the effective power of the engine is greater than the power required to drive the rotor, the control module controls the engine to use the excess power to drive the generator to generate electricity and store the electrical energy in the battery. If energy recovery is required: the control module controls the clutch to disengage, controls the engine and generator to stop working, during the aircraft deceleration and braking process, the rotor is driven by aerodynamic drag or inertia to reverse the electric motor, so that the electric motor is in generator mode, converting the mechanical energy of the rotor into electrical energy, and the control module transmits the generated electrical energy to the battery for storage.

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