Aircraft Oil Circuit Leak Detection Using Pressure-Balanced Piston

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing leak detection methods for aircraft engine lubrication oil circuits are unreliable, empirical, and unable to detect leaks in real-time during engine operation, often only intervening after significant foreign fluid has entered the oil circuit.

Innovation Solution

A leak detection device with a piston mechanism and calibrated orifices placed at strategic points in the lubrication oil circuit, equipped with a position sensor to detect any imbalance caused by leaks, and connected to a diagnostic system for alerting anomalies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If empirical leak detection methods (examining oil tank level stability, checking for fuel odors or fires) are used, then the device complexity is low, but the reliability of leak detection is poor and real-time detection during engine operation is not achieved

Engineering Contradiction:
Improveleak detection reliabilityVSAvoiddetection device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical sensor systems with a simple piston-based pressure balance mechanism. The piston automatically moves in response to pressure differences caused by leaks, converting a complex detection problem into a simple mechanical displacement that can be detected by basic sensors, thereby achieving high reliability with low device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection device uses the leak itself (the pressure difference caused by fuel entering the oil circuit) as the driving force to move the piston. The system self-activates when a leak occurs, eliminating the need for external power sources or complex active sensing systems, thus improving reliability while keeping the device simple.

Inventive Principle:
Principle #25Self-service

2Reliability

If drainage devices are used to mitigate leak consequences, then the device can intervene after leaks occur, but it only acts after significant foreign liquid has entered the oil circuit and the construction is relatively complex

Engineering Contradiction:
Improvereal-time leak detection capabilityVSAvoiddetection and mitigation device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary detection by positioning the piston to detect even small pressure differences caused by initial leaks. The system is designed to trigger an alarm before significant amounts of fuel contaminate the oil circuit, enabling preventive action rather than reactive drainage, thus achieving real-time detection with a simple mechanism.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If multiple plates and chambers are used in the piston mechanism, then the measurement precision of leak detection is improved, but the device complexity increases

Engineering Contradiction:
Improveleak detection precisionVSAvoidpiston mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the detection mechanism into multiple sealed chambers and plates within the piston, each contributing to the overall pressure balance. This segmentation allows the system to detect leaks with high precision by comparing pressures across multiple points, while the modular design keeps each individual component simple and manageable.

Inventive Principle:
Principle #1Segmentation

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

The device can detect leaks as soon as they begin, providing real-time alerts and preventing oil circuit overflow and pollution, thus ensuring continuous engine operation and safety.

Implementation Method 1

a piston formed of a plurality of plates stepped on a movable rod which connects said plates, a plurality of fixed chambers in which the plates slide respectively by dividing each into two separate compartments, two calibrated orifices located respectively at two distinct positions of the circuit, the two compartments of each of the chambers being respectively connected to the circuit by two respective and distinct connecting conduits terminating on the circuit on either side of a calibrated orifice

Methodology Applied
Scientific EffectPressure difference detection: Pressure Gradient

Data Source

PatentEP4359651B1Device for detecting leaks in an aircraft engine lubricating oil circuit
Publication Date: 2025.04.16 SAFRAN AIRCRAFT ENGINES SAS
  • EP4359651B1 patent drawingFigure 1~2
  • EP4359651B1 patent drawingFigure 3~4
  • EP4359651B1 patent drawingFigure 5

AI summary

Leaks in an oil lubrication circuit, in particular through a heat exchanger (5) communicating with another circuit (8), are measured by the movements of a piston (12) that is sensitive to variations in flow rates and pressure drops at two calibrated ports (9, 10) on either side of the predicted location of the leak. In one intended application, the second circuit (8) contains over-pressurised fuel which is used to constantly cool the oil.