Fuel Quantity Measurement Using Drain Valve Pressure Sensor
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Solution Overview
Problem
Existing methods for determining fuel quantity in aircraft fuel tanks on the ground are costly, weight-additive, and risky due to multiple penetration points and potential magnetic float detachment, and require aircraft power, making them unsuitable for maintenance and regulator compliance without a secondary system.
Innovation Solution
Utilizing the existing drain valve as a penetration point for a pressure sensor to measure fuel depth and volume, with a look-up table or conversion equations accounting for tank geometry, and optionally including temperature and attitude corrections, allowing for independent fuel quantity measurement without additional structural reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple penetration points with magnetic floats are used for fuel quantity measurement, then measurement capability is improved, but device complexity and weight increase due to structural reinforcement requirements
Solution Approach 1:
The existing drain valve penetration point is used for multiple purposes: its original function of draining water and debris from the fuel tank, and the new function of fuel quantity measurement by inserting a pressure sensor probe through the same opening. This eliminates the need for separate dedicated measurement penetration points and their associated structural reinforcement.
Solution Approach 2:
The existing drain valve infrastructure serves the measurement function without requiring additional penetration points. The system uses the already-present opening and structural features to accommodate the pressure sensor probe, making the existing structure serve both its original purpose and the new measurement function.
2Measurement precision
If multiple penetration points are created for fuel quantity measurement, then measurement capability is improved, but weight increases due to local structural reinforcement
Solution Approach 1:
The existing drain valve penetration point is used for multiple purposes: its original function of draining water and debris from the fuel tank, and the new function of fuel quantity measurement by inserting a pressure sensor probe through the same opening. This eliminates the need for separate dedicated measurement penetration points and their associated structural reinforcement.
3Measurement precision
If multiple penetration points are used for fuel quantity measurement, then measurement capability is improved, but reliability decreases due to increased leak paths
Solution Approach 1:
The existing drain valve penetration point is used for multiple purposes: its original function of draining water and debris from the fuel tank, and the new function of fuel quantity measurement by inserting a pressure sensor probe through the same opening. This eliminates the need for separate dedicated measurement penetration points and their associated structural reinforcement.
4Measurement precision
If magnetic floats are used for fuel quantity measurement, then measurement capability is improved, but safety decreases due to risk of float detachment and damage within the tank
Solution Approach 1:
The mechanical magnetic float system is replaced with a pressure sensor probe that measures fuel pressure to determine fuel quantity. This substitution eliminates the risk of float detachment and damage while providing accurate measurement through pressure-based calculation of fuel level and volume.
5Measurement precision
If primary fuel quantity systems are used during flight, then measurement capability is improved, but operational flexibility decreases because they require aircraft power
Solution Approach 1:
The fuel quantity measurement capability is extracted from the powered primary system and made available through a separate, passive measurement method using the pressure sensor probe. This allows measurement to occur independently of aircraft power status, enabling use during ground operations, maintenance, and recovery scenarios where the primary system cannot operate.
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
Enables accurate and cost-effective fuel quantity measurement using existing infrastructure, reducing weight and risk, and allowing operation independent of aircraft power, meeting regulatory requirements.
Implementation Method 1
the pressure measured by the pressure sensor can be used to calculate the depth of fuel at the drain valve location
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention provides a method, device and apparatus for determining a quantity of fuel within a fuel tank having a drain valve penetrating a lower boundary of the fuel tank. The method includes inserting a pressure measurement probe having a pressure sensor into the drain valve to permit contact between the pressure sensor and fuel within the tank, and measuring a pressure of the fuel with the pressure sensor. The measured pressure is used to determine the quantity of fuel within the tank, e.g. by consulting look-up tables comprising data indicating the relationship between measured pressure and fuel quantity, or by using one or more conversion equations.