Wireless Fuel Quantity Measurement System for Aircraft
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Solution Overview
Problem
Aircraft fuel tanks face the risk of lightning currents entering through wired capacitive probes used for fuel measurement, which adds weight and costs due to required safety circuits and components, conflicting with the aerospace industry's goal of reducing weight and costs.
Innovation Solution
A wireless liquid quantity measurement system using electromagnetic waves is implemented, where incident waves are transmitted within a conductive enclosure, and the transfer function corresponding to the rebound waves is measured to calculate the liquid quantity, eliminating the need for wires inside the tank and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wired capacitive probes are used to measure fuel quantity, then measurement capability is achieved, but the risk of lightning currents entering the fuel tank increases
Solution Approach 1:
The patent removes the wired capacitive probe from the fuel tank environment and replaces it with a wireless electromagnetic wave-based measurement system. The measurement electronics are relocated outside the fuel tank, eliminating the physical wire that could conduct lightning currents into the tank. This extraction of the measurement function from the hazardous environment resolves the contradiction by maintaining measurement capability while eliminating the lightning current pathway.
Solution Approach 2:
The patent replaces the mechanical/wired measurement system with an electromagnetic field-based wireless system. Instead of using physical wires and capacitive probes that require electrical connections through the tank bulkhead, the system uses electromagnetic waves to measure fuel quantity. This substitution eliminates the need for wires penetrating the tank structure, thereby removing the lightning current entry risk while preserving measurement functionality.
2Reliability
If safety-related circuits and components are added to protect against lightning currents, then reliability is improved, but aircraft weight increases
Solution Approach 1:
The patent extracts the measurement electronics from inside the fuel tank and places them outside, eliminating the need for heavy safety-related circuits and components that would be required to protect wired probes from lightning currents. By removing the wires that penetrate the bulkhead, the system eliminates the need for complex protection circuits, surge protectors, and isolation components, thereby reducing aircraft weight while maintaining or improving safety.
Solution Approach 2:
The wireless electromagnetic measurement system replaces the wired system that would require heavy safety protection circuits. The electromagnetic wave-based measurement does not require electrical connections through the tank structure, eliminating the need for weight-intensive lightning protection components such as isolation transformers, surge suppressors, and protected circuitry, thus achieving both weight reduction and safety.
3Measurement precision
If wired capacitive probes are used for fuel measurement, then measurement accuracy is achieved, but device complexity and maintenance costs increase
Solution Approach 1:
The patent extracts the complex wired measurement system with its multiple capacitive probes, wiring harnesses, and associated electronics from the fuel tank and replaces it with a simplified wireless system. The wireless architecture reduces device complexity by eliminating physical connections, connectors, and the associated routing and installation complexity, while maintaining measurement precision through electromagnetic wave-based sensing.
Solution Approach 2:
The wireless electromagnetic measurement system replaces the complex wired capacitive probe system. By using electromagnetic waves instead of physical wires and capacitive sensors, the system reduces device complexity in terms of installation, wiring, connectors, and maintenance requirements, while achieving comparable or superior measurement precision through the electromagnetic interaction with the fuel.
4Ease of operation
If wires extend within the fuel tank, then capacitive probe functionality is enabled, but the risk of lightning current entry increases
Solution Approach 1:
The patent removes the wires from the fuel tank environment by implementing a wireless measurement system. The capacitive probe functionality is extracted and replaced with an electromagnetic wave-based sensing mechanism that operates without physical wires extending into the fuel tank. This extraction eliminates the lightning current pathway while preserving the essential measurement functionality.
Solution Approach 2:
The wireless electromagnetic system substitutes the wired capacitive probe mechanism. Instead of using physical wires that extend into the fuel tank to carry measurement signals, the system uses electromagnetic waves to sense fuel quantity. This substitution maintains ease of operation and measurement functionality while completely eliminating the wire-based lightning current entry risk.
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 improves aircraft safety by eliminating the risk of lightning currents and reduces weight and maintenance costs associated with traditional measurement methods, while accurately measuring fuel quantity within the tank.
Implementation Method 1
A transmitter of the interrogation assembly transmits one or more incident electromagnetic waves within a conductive enclosure and a receiver receives rebound electromagnetic waves corresponding to the incident electromagnetic waves
Implementation Method 2
an outer inductive coil and an inner inductive coil separated by the conductive enclosure capable of conducting electromagnetic waves
Data Source
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AI summary
Technologies are described herein for wirelessly measuring liquid quantity in an enclosure. According to various aspects, an incident electromagnetic wave is transmitted within a conductive enclosure. One or more rebound electromagnetic waves that correspond to the incident electromagnetic wave are received. Using the rebound electromagnetic waves, a transfer function of the rebound electromagnetic waves is measured and a quantity of liquid stored in the enclosure is calculated based on the measured transfer function.