Helicopter Hybrid Propulsion Coupling and Decoupling Mechanism
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Solution Overview
Problem
Current turboshaft engines in helicopters, particularly those with linked turbines, have a less complex structure but are limited to a single optimal operating point, leading to inefficiencies when operating outside this point, and existing propulsion systems are complex, costly, and heavy due to their architecture.
Innovation Solution
A hybrid propulsion system combining a turboshaft engine with a linked turbine and an electric machine, featuring means for coupling and decoupling between the rotors, allowing the turboshaft engine to operate near its optimal point and the electric machine to provide additional power, especially during take-off and landing, while also serving as a redundancy in case of failure, and enabling starting without a dedicated auxiliary electric motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a turboshaft engine with a linked turbine is used, then the structure is less complex, but the engine can only operate at one optimal operating point causing significant efficiency drop at other speeds
Solution Approach 1:
The patent applies multi-functionality by enabling the turboshaft engine to operate in multiple modes: as a standalone engine and as part of a hybrid propulsion system with an electric machine. This allows the engine to maintain simplicity while adapting to different operating conditions through the electric machine supplementation, effectively resolving the contradiction between structural simplicity and operating versatility.
2Adaptability or versatility
If a free turbine engine is used, then the engine can operate close to optimum efficiency over a wide range of operating speeds, but the structure is more complex with greater number of parts and higher mass
Solution Approach 1:
The patent segments the propulsion system into two independent power sources: a simple linked-turbine turboshaft engine and an electric machine. This segmentation allows each component to be optimized independently - the turboshaft engine maintains its simple structure while the electric machine provides the additional adaptability needed to operate efficiently across a wide speed range, avoiding the complexity of a free turbine architecture.
Solution Approach 2:
The patent merges a linked-turbine turboshaft engine with an electric machine into a hybrid propulsion system. This combination allows the system to achieve the wide operating range and efficiency of a free turbine while maintaining the structural simplicity of a linked turbine, as the electric machine supplements the turboshaft engine rather than requiring a complex free turbine design.
3Ease of operation
If a dedicated auxiliary electric motor is added to start the turboshaft engine, then the starting function is ensured, but the device complexity and mass increase
Solution Approach 1:
The patent makes the electric machine multi-functional by using it for both starting the turboshaft engine and providing supplemental power during transient phases. This eliminates the need for a separate auxiliary starting motor, as the same electric machine performs both functions, thereby reducing overall system complexity and mass while maintaining full starting capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces complexity, cost, and mass, improves efficiency by allowing operation near the turboshaft engine's optimal point, provides additional power during critical phases, and ensures redundancy and faster starting, while passive coupling and decoupling mechanisms enhance reliability.
Implementation Method 1
an electric machine capable of operating as an electric motor
Implementation Method 2
a turboshaft engine with a linked turbine
Data Source
AI summary
A propulsion system (1) for a helicopter, comprising a turboshaft engine (2) with a linked turbine and an electric machine (3) capable of operating as an electric motor, the turboshaft engine (2) and the electric machine (3) being capable of driving in rotation at least one main rotor (5) intended to be coupled to a rotating wing (6) characterised in that it comprises means of coupling and decoupling (14) in rotation between a rotor (3a) of the electric machine (3) and a rotor (2a) of the turboshaft engine (2), the means of coupling and decoupling (14) being capable of allowing the rotor (2a) of the turboshaft engine (2) to be driven in rotation with the aid of the electric machine (3), in a first state of the propulsion system (1), and capable of allowing the rotor (2a) of the turboshaft engine (2) and the rotor (3a) of the electric machine (3) to be decoupled in rotation, in a second state of the propulsion system (1).