Aircraft Fuel Tank Inerting Gas Generator Control
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Solution Overview
Problem
Conventional aircraft fuel tank inerting systems consume excess energy and fuel by continuously generating inerting gas, even when oxygen levels are below the ignition threshold, leading to increased operational costs and reduced efficiency.
Innovation Solution
Implementing an inerting gas generator that starts when oxygen levels exceed 10% and stops when they fall below 8%, with a management unit controlling the system to restart before descent, optimizing gas distribution based on real-time oxygen measurements and flight phase information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inerting gas generator operates continuously to maintain oxygen levels below the ignition threshold, then safety is improved, but energy consumption and fuel consumption increase
Solution Approach 1:
The inerting gas generator operates periodically rather than continuously, activating only when oxygen levels exceed the high threshold (10%) and deactivating when levels fall below the low threshold (8%). This periodic operation maintains safety requirements while significantly reducing energy and fuel consumption compared to continuous operation.
Solution Approach 2:
The system dynamically adjusts the generator operation based on real-time oxygen level measurements and flight phase information. The control system monitors oxygen concentration continuously and modulates generator activity to match actual inerting needs, optimizing the balance between safety and energy efficiency.
2Use of energy by moving object
If the inerting gas generator is stopped when oxygen levels are low, then energy consumption is reduced, but oxygen levels may rise above safe thresholds
Solution Approach 1:
The system restarts the inerting gas generator a predetermined time before the descent phase begins, regardless of current oxygen levels. This beforehand action ensures that oxygen levels are reduced to safe thresholds before descent, when safety requirements are most stringent, while avoiding unnecessary continuous operation during other flight phases.
Solution Approach 2:
The control system performs preliminary inerting action by restarting the generator before descent phase, anticipating the increased safety requirements of this flight phase. This preliminary action ensures safe oxygen levels are achieved in advance of when they are most critically needed.
3Reliability
If the inerting gas generator is restarted before descent phase, then safety during descent is improved, but energy consumption increases
Solution Approach 1:
The system performs preliminary inerting by restarting the generator before descent phase, ensuring safe oxygen levels are achieved in advance of when they are most critically needed. This targeted preliminary action concentrates energy consumption on the specific time period when safety requirements are most stringent.
Solution Approach 2:
The generator operates periodically with scheduled restarts before descent phases, aligning energy consumption with specific high-safety-requirement periods rather than maintaining continuous operation. This periodic scheduling optimizes the balance between safety assurance and energy 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
This approach reduces energy and fuel consumption by only generating inerting gas when necessary, extending equipment lifespan and ensuring safety during descent preparations.
Implementation Method 1
The OBIGGS system comprises at least one air separation module containing, for example, permeable membranes, such as polymer membranes, through which an air flow passes. Due to the different permeabilities of the membrane to nitrogen and oxygen, the system divides the air flow in such a way that an air flow with a high nitrogen content and an air flow with a high oxygen content are obtained.
Data Source
Figure 1
AI summary
Method of inerting at least one fuel tank (2) of an aircraft, by means of at least one inerting gas generator (3), notable in that the inerting gas generator (3) is started when at least one oxygen sensor (5) present in the tank (2) measures an oxygen level above a high threshold value.