Hybrid-Electric Propulsion Gearbox for Take-Off and Cruise Power Split
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Solution Overview
Problem
Aircraft engines are oversized for cruising, leading to inefficient power usage and increased size and weight, as they are designed for maximum thrust during take-off but require less power during the rest of the flight.
Innovation Solution
A hybrid propulsion system combining a heat engine and an electric motor with a transmission system that includes various gearbox configurations to optimize rotational power input from both engines, allowing for efficient power distribution to drive turbines and compressors at different speeds, thereby improving fuel efficiency and reducing engine size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine is sized for maximum thrust during take-off, then take-off performance is improved, but the engine becomes oversized and inefficient for cruising flight
Solution Approach 1:
The propulsion system is segmented into two independent power sources: a heat engine optimized for high-power take-off operations and an electric motor optimized for efficient cruising operations. This segmentation allows each component to operate at its optimal efficiency point for its intended flight phase, resolving the contradiction between take-off performance and cruising fuel efficiency
Solution Approach 2:
The system dynamically switches between heat engine-only operation during take-off, electric motor-only operation during cruising, and combined operation during transition phases. This dynamic operation allows the system to adapt to varying power requirements and maintain optimal efficiency across different flight conditions
2Power
If the engine is sized for maximum thrust during take-off, then take-off performance is improved, but engine size and weight increase
Solution Approach 1:
The propulsion system is segmented into two independent power sources: a heat engine optimized for high-power take-off operations and an electric motor optimized for efficient cruising operations. This segmentation allows each component to operate at its optimal efficiency point for its intended flight phase, resolving the contradiction between take-off performance and cruising fuel efficiency
Solution Approach 2:
The system merges a heat engine and an electric motor into a hybrid propulsion system that shares common components such as the transmission system, turbine, and compressor. This merging allows the system to achieve the high power of the heat engine while using the lighter electric motor for cruising, effectively reducing overall system weight compared to a heat engine sized for maximum take-off thrust
3Use of energy by moving object
If a single engine operates at reduced power during cruising, then fuel efficiency improves, but the engine remains oversized and complex
Solution Approach 1:
The propulsion system is segmented into two independent power sources: a heat engine optimized for high-power take-off operations and an electric motor optimized for efficient cruising operations. This segmentation allows each component to operate at its optimal efficiency point for its intended flight phase, resolving the contradiction between take-off performance and cruising fuel efficiency
Solution Approach 2:
The electric motor is extracted as a separate power source specifically for cruising operations, allowing the heat engine to be downsized and optimized for take-off only. This extraction eliminates the need for the heat engine to operate inefficiently at reduced power during cruising, simplifying its design and improving overall system efficiency
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
The hybrid propulsion system enhances fuel efficiency by optimizing power usage across different flight phases, reducing engine size and weight, and eliminating the need for variable inlet guide vanes, while allowing for independent operation of turbine and compressor components.
Implementation Method 1
A heat engine is configured to drive a heat engine shaft
Implementation Method 2
An electric motor is configured to drive an electric motor shaft
Implementation Method 3
A turbine can be connected to the heat engine to be driven by exhaust form the heat engine
Data Source
AI summary
A hybrid propulsion system includes a heat engine configured to drive a heat engine shaft. An electric motor is configured to drive an electric motor shaft. A transmission system includes at least one gearbox. The transmission system is configured to receive rotational input power from each of the heat engine shaft and the electric motor shaft and to convert the rotation input power to output power.