Split Range Control for Aircraft Fuel Tank Pressurization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for pressurizing aircraft fuel tanks face challenges in rapidly adapting to changing ambient pressures while minimizing weight and maintaining a relative air pressure, as they often require excessive pressurized air and are prone to structural damage due to rapid pressure changes.
Innovation Solution
A system with two regulators and ejectors, along with check valves, that dynamically adjusts airflow to maintain a specified pressure interval by using a first regulator for primary pressure control and a second regulator for high-demand situations, minimizing the need for pressurized air and ensuring system reliability and low weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a large opening is used for air flow to rapidly change pressure inside the tank, then the speed of pressure adaptation is improved, but the amount of pressurized air required increases significantly
Solution Approach 1:
The air flow path is segmented into two separate paths: a first path with a first regulator for normal pressure control, and a second path with a second regulator for rapid pressure equalization. This segmentation allows the system to use a large opening in the second path only when needed for rapid adaptation, while keeping the first path closed during normal operation to minimize pressurized air consumption.
Solution Approach 2:
The system dynamically switches between two operating modes by controlling two separate regulators. During normal operation, only the first regulator is active with a small opening. When rapid pressure adaptation is needed, the second regulator opens with a large opening. This dynamic switching optimizes both speed and pressurized air usage based on real-time conditions.
2Manufacturing precision
If a closed regulating system is used with active regulation on both air inflow and outflow, then the pressure control precision is improved, but the device complexity increases
Solution Approach 1:
The closed regulating system is segmented into two independent but coordinated regulation paths. The first regulator handles normal pressure control with fine adjustment, while the second regulator handles rapid pressure equalization. This segmentation allows each regulator to be optimized for its specific function, maintaining high precision while managing complexity through functional separation.
Solution Approach 2:
The system uses partial action by activating only the necessary regulator based on current conditions. During normal operation, only the first regulator is active. During rapid pressure changes, the second regulator is activated in addition to or instead of the first. This partial activation reduces the effective complexity of the system at any given moment while maintaining the capability for high-precision control when needed.
3Ease of manufacture
If a static throttling size is used to block outflow, then the ease of manufacture is improved, but the adaptability to varying pressure conditions deteriorates
Solution Approach 1:
While each individual throttling remains static for ease of manufacture, the system achieves adaptability through dynamic control of two separate throttles. The first throttle is optimized for normal operation, while the second throttle is optimized for rapid pressure equalization. The system dynamically switches between these two static configurations based on pressure conditions, achieving both manufacturability and adaptability.
Solution Approach 2:
The single adaptive throttle is segmented into two separate static throttles, each optimized for specific operating conditions. This segmentation allows each throttle to be manufactured with fixed dimensions for ease of production, while the system as a whole achieves adaptability through coordinated control of both throttles based on real-time pressure conditions.
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 system efficiently manages pressure changes with reduced pressurized air usage, maintains system reliability, and minimizes weight, while also preventing tank explosions through a security valve.
Implementation Method 1
using the airflow through the first ejector to suck in additional ambient air through the first ejector and add it to the first airflow into the volume
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention aims at pressurising a volume (2) that needs to have a relative air pressure, in comparison with an ambient pressure, where the ambient air pressure can change rapidly and with large amplitude and where the access to pressurised air is limited. This is solved by a half open system comprising two parallel regulators (9) and (17) and two ejectors (15) and (19) working according to a split range control principle. When the relative air pressure difference is above a desired value of the second regulator (17), only the first regulator and the first ejector work. When the relative air pressure difference is below the desired value of the second regulator (17), both regulators (9) and (17) and ejectors (15) and (19) work. In this way the pressure inside the volume (2) can adapt rapidly to the changes in the ambient pressure, without leaking too much air during a static condition.