Aircraft Fuel Cell System Redundancy via Segmented Units
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Solution Overview
Problem
Existing aircraft fuel cell systems lack redundancy and efficiency in providing power, emergency power, and inert gas while maintaining a low weight, which is crucial for reliable operation and safety.
Innovation Solution
A dual-unit fuel cell system with independent fuel cell units capable of providing electrical power, emergency power, nitrogen-enriched air for inerting, and water, featuring redundant hydrogen and oxidant supply systems, and a switching mechanism to ensure continuous operation even if one unit fails, with each unit comprising multiple fuel cells and a shared hydrogen and oxidant supply system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fuel cell system is used to provide multiple functions (power, emergency power, inert gas), then device complexity is reduced, but reliability decreases due to lack of redundancy
Solution Approach 1:
The fuel cell system is divided into multiple independent fuel cell units (first fuel cell unit, second fuel cell unit, third fuel cell unit), each capable of providing electrical power and inert gas. This segmentation allows the system to maintain functionality even if one unit fails, thereby improving reliability while keeping the overall structure manageable through modular design.
Solution Approach 2:
Different fuel cell units are assigned different oxidant sources based on their specific functions: the first unit uses air (nitrogen-containing) for normal power generation, while the second and third units use oxygen (nitrogen-free) for emergency power and inert gas generation. This local differentiation optimizes each unit's performance for its specific purpose while maintaining system-wide reliability.
2Reliability
If multiple independent fuel cell units are used to ensure redundancy, then reliability improves, but weight increases
Solution Approach 1:
Multiple fuel cell units share common infrastructure including the hydrogen tank, oxidant supply units, exhaust switching units, and control systems. This merging of supporting components reduces the overall system weight compared to having completely separate systems, while still maintaining the redundancy benefits of multiple fuel cell units.
Solution Approach 2:
Each fuel cell unit is designed to be multi-functional, capable of providing both electrical power and inert gas depending on operational requirements. This universality reduces the need for separate dedicated systems for different functions, thereby reducing overall system weight while maintaining reliability through functional redundancy.
3Reliability
If dedicated oxygen tanks are used for emergency power, then reliability during emergency improves, but device complexity and weight increase
Solution Approach 1:
The oxidant supply system is designed to be dynamic and reconfigurable. The oxidant supply units can switch between supplying air and supplying oxygen to different fuel cell units based on operational mode (normal or emergency). This dynamic capability provides reliable emergency power while avoiding the complexity of completely separate dedicated oxygen systems.
Solution Approach 2:
The system uses its own oxidant supply infrastructure to serve multiple purposes. The same oxidant supply units that provide air for normal operation can also provide oxygen for emergency operation, eliminating the need for separate dedicated oxygen storage and distribution systems while maintaining emergency reliability.
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
Enhances reliability and safety by providing comparable or better power and inert gas capabilities while maintaining a low weight, allowing for efficient operation during normal and emergency conditions, including low-velocity flight and engine failures.
Implementation Method 1
a first fuel cell unit (4) with a first fuel cell (8) and a second fuel cell (10) and a second fuel cell unit (6) with a third fuel cell (54) and a fourth fuel cell (56)
Implementation Method 2
DE 10 2005 053 694 discloses a fuel cell system for extinguishing fires in an aircraft, wherein the fuel cell is supplied with hydrogen and air and is used for generating nitrogen enriched air
Data Source
AI summary
A fuel cell system includes a first fuel cell unit having a first fuel cell and a second fuel cell, a second fuel cell unit having a third fuel cell and a fourth fuel cell, a hydrogen tank coupled to all fuel cells, an oxygen supply unit and an air inlet. Oxidant inlets of the first fuel cell and the fourth fuel cell are couplable with the air inlet. Oxidant inlets of the second fuel cell and the third fuel cell are couplable with the oxidant supply unit couplable with at least one of the oxygen supply unit and the air inlet. Exhaust outlets of the first and fourth fuel cells are couplable with an inert gas outlet. Exhaust outlets of the second and third fuel cells are coupled with an exhaust switching unit couplable with the inert gas outlet and a water outlet.