Integrated Fuel Density Compensation With Single-Cable Sensing
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Solution Overview
Problem
The existing aviation fuel level sensing systems require multiple cables for fuel density and dielectric value measurements, leading to increased weight and cost due to electromagnetic interference concerns and the need for redundant detectors in aircraft fuel tanks.
Innovation Solution
An integrated densitometer-compensator system that combines fuel density and dielectric value measurement within a single unit, using a chassis for electromagnetic interference shielding and a single external power and communication link to an avionics computer, reducing the number of cables needed by using a single interface cable for power and signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate density and dielectric detectors are used to measure fuel characterization values, then measurement precision is improved, but device complexity and weight increase due to multiple cables and detectors
Solution Approach 1:
The patent combines separate density and dielectric detectors into a single integrated densitometer-compensator unit. This consolidation maintains the ability to measure both fuel density and dielectric value while reducing the number of cables and detectors needed, thereby decreasing system complexity and weight without sacrificing measurement precision
Solution Approach 2:
The integrated densitometer-compensator performs multiple functions within a single device: it measures both fuel density and dielectric value, provides electromagnetic interference shielding, and communicates through a single interface cable. This multi-functionality eliminates the need for separate detectors and multiple cables, resolving the contradiction between measurement precision and device complexity
2Reliability
If shielded cables are used to reduce electromagnetic interference, then reliability is improved, but weight and cost increase
Solution Approach 1:
The patent integrates the electromagnetic interference shielding function directly into the densitometer-compensator housing rather than relying on separate shielded cables. This approach maintains signal reliability by providing EMI protection at the source while significantly reducing cable weight and complexity
Solution Approach 2:
The integrated unit acts as an intermediary that processes and shields signals before transmission. By combining the detectors, processing electronics, and shielding into a single housed unit, the system reduces the need for heavy shielded cables while maintaining signal integrity and reliability
3Reliability
If multiple pairs of detectors are installed in each fuel tank for redundancy, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent consolidates multiple detector functions into a single integrated densitometer-compensator unit that can serve multiple fuel tanks. This approach maintains measurement redundancy and reliability while reducing the total number of detectors and cables required across the aircraft's fuel 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 reduces the number of cables required, thereby decreasing the weight and cost associated with them, while maintaining accurate fuel mass calculations and mass distribution assessments in aircraft fuel tanks.
Implementation Method 1
a capacitive sensing device that produces a signal representative of the fuel level as a result of the dielectric value of the fuel immersing the sensor
Implementation Method 2
The integrated densitometer-compensator is shielded against electromagnetic interference
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An integrated densitometer-compensator system for providing a digital indication of the dielectric value and density of a fluid in a tank includes a dielectric capacitive measuring device, a vibrating spool fluid density measuring device, a signal processor, a power supply, and a remote computing device. The signal processor produces a digital signal representing the dielectric value and density of the fluid, and includes a serial driver that transmits the digital signal as a serial word by modulating a carrier signal. An unshielded interface cable transmits the serial word, which can contain a unique identifier, and also provides power to the system. Transmission can be electrically, optically, or wirelessly. The exemplary system measures aviation fuel characteristics in fuel tanks onboard an aircraft.