Hybrid Electric Multi-Shaft Core With Variable Gear Ratio Speed Control
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Solution Overview
Problem
Traditional gas turbine engines face inefficiencies in operational stages requiring different power sources, such as electrical versus fuel, and lack flexibility in rapidly adjusting compressor speed to enhance performance and prevent stalls.
Innovation Solution
A hybrid electric engine with a variable gear ratio gearbox and an electric motor connected to the gearbox, allowing selective acceleration or deceleration of the compressor relative to the turbine, enhancing speed control and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a traditional gas turbine engine uses fuel combustion to drive the turbine and compressor, then the engine can operate continuously, but the ability to rapidly adjust compressor speed is limited and fuel efficiency varies during different operational stages
Solution Approach 1:
The patent combines a fuel-based turbine-compressor system with an electric motor-compressor system into a hybrid configuration. The electric motor is coupled to the compressor via a gearbox, allowing it to directly drive the compressor independently of the turbine. This merging of two different power sources (fuel combustion and electrical power) enables the system to select the most efficient power source for each operational stage, thereby improving overall fuel efficiency while maintaining rapid speed adjustability through the electric motor.
2Power
If the compressor speed is increased rapidly to increase engine airflow and power, then engine power output improves, but the risk of engine surge increases
Solution Approach 1:
The control system continuously monitors engine operating parameters including compressor speed, turbine speed, and airflow conditions. Based on this feedback, the controller dynamically adjusts the electric motor speed and torque output, as well as fuel flow to the combustor, to maintain optimal operating conditions. This feedback control prevents the compressor from entering surge conditions by detecting approaching surge margins and reducing power input accordingly, while still enabling rapid power increases when operating within safe margins.
3Adaptability or versatility
If an electric motor is added to drive the compressor independently, then rapid speed adjustment capability improves, but the device complexity increases
Solution Approach 1:
The electric motor-gearbox assembly is designed to serve multiple functions: it can drive the compressor during electrical power mode, assist the turbine during hybrid mode, and potentially generate electrical power during turbine-driven mode if configured as a generator. The gearbox is designed with variable ratio capability to optimize compressor speed across different operating conditions. This multi-functionality justifies the added complexity by providing operational flexibility and potential fuel efficiency improvements.
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
Enables rapid thrust or power increase during engine stalls, improves fuel efficiency, and reduces the risk of engine surges by dynamically controlling compressor speed, thus optimizing engine performance and reducing noise.
Implementation Method 1
a combustor configured to drive the turbine via a flow of combustion products
Implementation Method 2
An electric motor is operably connected to the variable gear ratio rear box and configured to input rotational energy into the gearbox
Implementation Method 3
a variable gear ratio gearbox... The input of rotational energy into the gearbox from the electric motor changes a rotational speed of one of the compressor or the turbine
Data Source
AI summary
A hybrid electric engine of an aircraft includes a compressor, a turbine operably connected to the compressor via a variable gear ratio gearbox and a combustor configured to drive the turbine via a flow of combustion products. An electric motor is operably connected to the variable gear ratio rear box and configured to input rotational energy into the gearbox. The input of rotational energy into the gearbox from the electric motor changes a rotational speed of one of the compressor or the turbine relative to the other of the compressor or the turbine.