Aircraft Engine Oil Reservoir Filling With Air-Triggered Shutoff
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Solution Overview
Problem
Existing oil tank filling systems for aircraft engines face inaccuracies and potential overfilling due to the limitations and reliability issues of oil level probes, leading to uncertainties in filling levels and potential engine performance degradation.
Innovation Solution
A device with a supply duct, pump, and a shut-off valve independent of the probe, combined with overfill and nominal fill indicators, ensures accurate filling to an optimum level by interrupting oil supply when the optimum level is reached, eliminating the need for visual checks and detecting malfunctions in the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If oil level probes with electrical switches and magnetic floats are used to measure filling level, then the filling process can be automated and visual checks eliminated, but measurement inaccuracies and probe failures occur leading to underfilling or overfilling
Solution Approach 1:
The patent introduces an intermediary optical system consisting of a light source and photodetector that mediates the measurement process. Instead of relying directly on electrical switches and magnetic floats, the optical intermediary provides a more reliable measurement mechanism that is less susceptible to thermal, mechanical, and chemical degradation, thereby resolving the contradiction between automation and measurement precision.
Solution Approach 2:
The patent replaces the mechanical-electrical probe system (electrical switches and magnetic floats) with an optical measurement system. This substitution eliminates the mechanical and electrical components that are prone to failure from thermal cycles, vibrations, and chemical alteration, while maintaining automated filling control, thus resolving the contradiction between automation and measurement precision.
2Productivity
If filling is performed quickly to improve productivity, then oil supply efficiency increases, but the risk of overfilling increases due to system inertia and measurement uncertainties
Solution Approach 1:
The patent implements a feedback mechanism where the optical measurement system continuously monitors the oil level and provides real-time information to the control system. This feedback loop allows the system to adjust the filling rate dynamically, enabling fast filling while maintaining reliable control by compensating for system inertia and preventing overfilling.
Solution Approach 2:
The patent introduces dynamic control of the filling process, where the filling rate can be adjusted in real-time based on optical measurements. The system transitions from static, slow filling to dynamic, adaptive filling that optimizes productivity while maintaining reliability through continuous monitoring and adjustment of the filling rate.
3Manufacturing precision
If probe measurement uncertainties are reduced to achieve precise filling, then filling accuracy improves, but the complexity and cost of the measurement system increases
Solution Approach 1:
The patent extracts the measurement function from the complex mechanical-electrical probe system and implements it through a simpler optical system. By taking out the problematic electrical switches and magnetic floats and replacing them with optical components, the system achieves higher precision while actually reducing overall complexity, as the optical system has fewer moving parts and is more reliable.
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 ensures precise filling without overfilling, reduces the risk of underfilling, and allows for reliable detection of system faults, ensuring optimal engine performance and extended autonomy.
Implementation Method 1
an air duct (22) connecting to the tank (15) above the level at which the supply duct (17) connects, and passing through the shut-off valve (21) to control it, the air duct (22) being sealable by the oil (37) at the outlet (38) of the air duct (22) when the oil (37) reaches an optimum fill level (H2) of the tank (15)
Implementation Method 2
a pump (18) placed on the supply duct (17) and arranged so as to be able to force an oil flow from the aeroplane tank (16) to the engine tank (15)
Data Source
AI summary
In order to fill a reservoir while avoiding laborious manual filling operations, there is added to the existing device, including a supply duct, a pump and a measuring probe, a stop valve designed to interrupt the filling as soon as the desired level has been reached, which is detected for example by an air intake which controls the closure of the valve. Two level indicators are added and make it possible to ascertain either that optimum filling has been achieved or that a malfunction is present in the system. Application to the systems for oil filling of aircraft engine reservoirs from another reservoir arranged within the aircraft, generally common to all the engines.