Resistive Non-Metallic Wire Shielding for Fuel Tank EMI
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Solution Overview
Problem
In fuel tanks, existing technologies face challenges in preventing electromagnetic interference (EMI) while maintaining the integrity of electrically conductive materials, particularly in confined spaces where fuel level sensing probes are installed, as traditional non-metallic materials are insufficient in shielding against high current flows and sparks that could ignite fuels.
Innovation Solution
The implementation of a system using resistive non-metallic wires for both excitation and return signal wires, accompanied by grounded guard wires, which are configured to shield the return signal wires from electromagnetic interference, thereby preventing sparks and ensuring safe operation within the fuel tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional non-metallic conductive materials are used for shielding, then cost and installation complexity are reduced, but electromagnetic interference shielding effectiveness is insufficient against high current flows and sparks
Solution Approach 1:
The wiring shield is segmented into multiple individual resistive non-metallic wires rather than using a continuous metallic shield. Each wire provides localized EMI protection while maintaining flexibility and reducing overall system complexity. The segmented approach allows the shield to be integrated into existing wire bundles without requiring complete system redesign.
Solution Approach 2:
The patent uses composite resistive non-metallic materials that combine electrical resistance properties with shielding capabilities. These composite materials provide both structural integrity and EMI protection, replacing traditional separate metallic shield components with an integrated non-metallic solution that is equally effective against high current flows and sparks.
2Reliability
If metallic conductive materials are used for wiring shields, then EMI shielding effectiveness is improved, but the risk of electrical discharge and sparks within the fuel tank increases
Solution Approach 1:
The patent converts the potentially harmful effect of electrical conductivity into a beneficial protective feature by using resistive non-metallic materials. These materials have controlled resistance that dissipates electrical energy as heat rather than allowing high current flows and sparks, transforming what would be a hazard into a safety mechanism that protects against electrical discharge while maintaining EMI shielding effectiveness.
Solution Approach 2:
The resistive non-metallic wiring shield creates an inherently safer electrical environment within the fuel tank by eliminating metallic conductors that could generate sparks. This inert approach to electrical conduction ensures that even under transient electric field conditions, the system maintains protection without introducing ignition risks.
3Reliability
If multiple separate shielding components are installed, then EMI protection is improved, but installation complexity and time increase
Solution Approach 1:
The patent merges the EMI shielding function with the existing exciter and return signal wire bundles by integrating resistive non-metallic wires directly into these bundles. This consolidation eliminates the need for separate shielding components and their associated installation steps, reducing installation time while maintaining comprehensive EMI protection throughout the fuel level sensing system.
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 effectively reduces electromagnetic interference by routing grounded guard wires alongside excitation and return signal wires, reducing installation complexity and cost, while ensuring the safety of the fuel tank by preventing electrical discharges and maintaining accurate fuel level measurements.
Implementation Method 1
The grounded guard wire of the return signal wire bundle and the grounded guard wire of the exciter wire bundle are configured to shield the return signal wire from electromagnetic interference
Implementation Method 2
When exposed to transient electric fields these materials are resistant to the high current flows and sparks that would ignite fuels
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A system includes a fuel level sensing probe inside a fuel tank and an exciter wire bundle to connect the fuel level sensing probe to a power source outside the tank. The exciter wire bundle includes an excitation wire and a grounded guard wire. The excitation wire and the grounded guard wire each include a resistive non-metallic wire. The system also includes a return signal wire bundle to connect the fuel level sensing probe to a device configured to measure a quantity of fuel within the tank. The return signal wire bundle includes a return signal wire and a grounded guard wire. The grounded guard wire of the return signal wire bundle and the grounded guard wire of the exciter wire bundle are configured to shield the return signal wire from electromagnetic interference. The return signal wire and the grounded guard wire each include a resistive non-metallic wire.