Aircraft having a redundant and efficient bleed system
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Solution Overview
Problem
Commercial aircraft environmental control systems that rely on bleed air from jet engines reduce engine efficiency, and existing solutions either require significant redesign or additional components, increasing costs and complexity.
Innovation Solution
An aircraft with an auxiliary supply unit that provides compressed air and electricity, using a fuel cell and compressor to operate independently of the main engines, allowing the environmental control system to function without bleed air, while maintaining redundancy through bleed air from the engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bleed air is tapped from the jet engine compressor section to operate the environmental control system, then the environmental control system can be operated with proven and reliable components, but the engine efficiency decreases due to fuel consumption for compressing air that is then taken away from the combustion and thrust process
Solution Approach 1:
The air supply system is segmented into two independent sources: the jet engine bleed air system and the auxiliary supply unit. This allows the environmental control system to receive compressed air from either source or both simultaneously, enabling operation without engine bleed air when the auxiliary unit is available, thus improving engine efficiency while maintaining system reliability
Solution Approach 2:
The auxiliary supply unit acts as an intermediary compressed air source between the environment and the environmental control system. It provides compressed air independently of the jet engine, serving as a mediator that allows the control system to function without extracting air from the engine's combustion process, thereby resolving the conflict between reliability and energy efficiency
2Loss of energy
If additional cooling means or additional compressors are added to support an air-cycle process without bleed air, then engine efficiency is improved, but system complexity and costs increase
Solution Approach 1:
The auxiliary supply unit is designed as a multi-functional device that provides compressed air for the environmental control system while being dimensioned to exclusively operate this system. This universal unit replaces the need for additional cooling means or compressors, achieving the goal of improving engine efficiency without increasing system complexity
Solution Approach 2:
The auxiliary supply unit is self-contained and provides its own compressed air generation capability without requiring integration with the jet engine's existing systems. It independently performs the function of supplying compressed air to the environmental control system, avoiding the need for additional complex integration with engine systems
3Loss of energy
If the auxiliary supply unit is dimensioned to exclusively operate the environmental control system, then engine load is reduced and efficiency is improved, but redundancy is reduced compared to having full bleed air availability
Solution Approach 1:
The system is designed with dynamic switching capability between the auxiliary supply unit and engine bleed air sources. The auxiliary unit is dimensioned to exclusively operate the environmental control system under normal conditions, but the system can dynamically switch to or combine with engine bleed air when needed, providing both efficiency improvement and redundancy
Solution Approach 2:
The auxiliary supply unit provides beforehand cushioning by being pre-dimensioned to fully operate the environmental control system independently. This prior preparation ensures that when the auxiliary unit is available, engine load is reduced, while the possibility of switching to engine bleed air provides a safety cushion for redundancy when the auxiliary unit is unavailable
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 solution enhances aircraft efficiency by reducing the load on jet engines and minimizing system modifications, allowing the environmental control system to operate efficiently with minimal additional costs or redesign, while ensuring redundancy through bleed air supply.
Implementation Method 1
The auxiliary supply unit comprises a fuel cell and a compressor, which is coupled with an electric motor supplied with electrical energy through the fuel cell
Implementation Method 2
The auxiliary supply unit comprises a fuel cell and a compressor, which is coupled with an electric motor supplied with electrical energy through the fuel cell
Data Source
AI summary
An aircraft having at least one thrust providing jet engine and a fuselage with an integrated pressurized cabin includes an environmental control system having at least one pneumatic air cycle air conditioning unit, a bleed air port in the at least one thrust providing jet engine, a non thrust providing auxiliary supply unit configured to provide electricity and compressed air on ground and during flight, and at least one compressed air line. The at least one compressed air line is coupled with the bleed air port and the auxiliary supply unit. The environmental control system is coupled with the at least one compressed air line. Further, the auxiliary supply unit is dimensioned to exclusively operate the environmental control system by delivering compressed air, and bleed air from the bleed air port is selectively providable to the environmental control system for redundancy.