Aircraft APU Engine Assembly with Integrated Turbine
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Solution Overview
Problem
Existing aircraft auxiliary power units (APUs) are often heavy and complex, making them unsuitable for aircraft applications due to their ground-based design.
Innovation Solution
A compact engine assembly for aircraft APUs, comprising an internal combustion engine, a generator, a compressor, and a turbine configuration that includes a first and second stage turbine in driving engagement, optimized for efficient power generation and air compression, with a Wankel engine core for high cycle efficiency and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If ground-based APU design is used, then power generation capability is achieved, but weight and complexity increase
Solution Approach 1:
The patent combines the compressor and turbine into a single integrated assembly where the turbine is directly coupled to the compressor shaft. This merging of components reduces the overall number of parts, eliminates intermediate coupling mechanisms, and decreases weight while maintaining power generation capability. The integrated design allows the turbine to directly drive the compressor, creating a compact unit suitable for aircraft applications.
Solution Approach 2:
The engine assembly serves multiple functions: the internal combustion engine generates power, the compressor compresses air for engine intake and aircraft systems, and the turbine recovers energy from exhaust gases. This multi-functionality reduces the need for separate systems, thereby reducing overall weight and complexity while maintaining comprehensive power generation and air supply capabilities.
2Power
If ground-based APU design is used, then power generation capability is achieved, but device complexity increases
Solution Approach 1:
The patent integrates the turbine and compressor into a single assembly with direct mechanical coupling, eliminating the need for separate mounting structures, intermediate shafts, and additional coupling mechanisms. This merging reduces device complexity while maintaining the ability to generate power and compress air simultaneously.
Solution Approach 2:
The engine assembly is segmented into distinct functional modules: the internal combustion engine, the integrated compressor-turbine assembly, and the exhaust system. This modular segmentation allows for simplified assembly, easier maintenance, and reduced overall complexity compared to integrated ground-based designs.
3Weight of moving object
If compact engine assembly is used, then weight is reduced, but power density must be maintained
Solution Approach 1:
The direct coupling of the turbine to the compressor creates a compact power train that maximizes power density. By eliminating intermediate components and reducing the overall assembly size, the patent achieves high power output relative to the weight and volume of the engine assembly.
Solution Approach 2:
The patent optimizes the operating parameters of the internal combustion engine, including compression ratio and combustion chamber design, to maximize power output per unit weight. The integrated compressor-turbine assembly is designed with optimized geometry to efficiently convert thermal energy into mechanical work, maintaining high power density in a compact configuration.
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 solution provides a lightweight, efficient, and compact APU that can power aircraft systems effectively, reducing weight and complexity while maintaining high power density and combustion efficiency, suitable for aircraft use.
Implementation Method 1
at least one internal combustion engine in driving engagement with an engine shaft
Implementation Method 2
a turbine having an inlet in fluid communication with an outlet of the at least one internal combustion engine
Implementation Method 3
a compressor having an outlet in fluid communication with an inlet of the at least one internal combustion engine
Data Source
AI summary
An auxiliary power unit having internal combustion engine(s) in driving engagement with an engine shaft, a generator having a generator shaft drivingly engaged to the engine shaft, a compressor having an outlet in communication with the internal combustion engine inlet, and a turbine having an inlet in communication with the internal combustion engine outlet. The turbine may be a first stage turbine, and the assembly may include a second stage turbine having an inlet in communication with the first stage turbine outlet. A method of providing electrical power to an aircraft is also discussed.