Coaxial Capacitive Sensor for Engine Oil Particle Monitoring

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing online monitoring methods for lubricating oil abrasive particles in aeroengines are ineffective in accurately detecting the number, size, and morphology of particles due to environmental factor interference and limitations in capacitive sensor design.

Innovation Solution

A coaxial capacitive sensor with a circular truncated cone or cylindrical configuration, featuring planar and curved electrodes, divides the sensor interior into detection sub-spaces to form non-parallel and parallel capacitors, allowing for real-time monitoring and diagnosis by extracting signal characteristics from time-frequency domains, and compensating for environmental influences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional capacitive sensors arrange electrodes on the outer surface of the lubricating oil pipeline, then online monitoring of abrasive particles can be achieved, but the detection results are easily affected by environmental factors

Engineering Contradiction:

Improvedetection accuracyVSAvoidenvironmental factor interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sensor interior is divided into multiple detection sub-spaces by electrode support insulating substrates and a center bearing. Each sub-space contains electrode plates that form independent capacitive detection units, allowing segmented monitoring of abrasive particles while reducing environmental interference through spatial distribution

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Electrode support insulating substrates serve as intermediaries between the electrode plates and the external environment. These insulating substrates electrically isolate the electrodes from the pipeline wall while providing mechanical support, thereby preventing environmental factors from directly affecting the capacitive detection

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If offline detection analysis methods are used for lubricating oil abrasive particles, then fast response and high precision can be achieved, but timely and effective feedback cannot be provided

Engineering Contradiction:

Improvedetection precisionVSAvoidfeedback time delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The capacitive sensor is pre-installed within the lubricating oil pipeline system, with electrode plates positioned to detect abrasive particles as they pass through. This preliminary positioning enables continuous real-time monitoring without requiring sample collection and laboratory analysis, providing immediate feedback on wear conditions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical sample collection and laboratory analysis system with an electromagnetic capacitive detection system. The capacitive sensor detects changes in dielectric properties caused by abrasive particles, substituting physical sample handling with non-contact electromagnetic measurement for real-time monitoring

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If optical methods are used for online monitoring of lubricating oil abrasive particles, then multiple detectable parameters can be obtained, but the method is easily affected by bubbles and only suitable for low flow rates

Engineering Contradiction:

Improvedetectable parametersVSAvoidbubble interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The capacitive sensor uses electrical fields as an intermediary to detect abrasive particles, replacing optical detection methods. The capacitive measurement principle is not affected by bubbles or light scattering issues, enabling reliable detection in high-flow lubricating oil systems where optical methods fail

Inventive Principle:

Principle #24Intermediary (Mediator)

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 efficient online monitoring and diagnosis of lubricating oil abrasive particles, providing quantitative and morphological characteristics, thus predicting wear state severity and ensuring engine reliability.

Implementation Method 1

coaxial capacitive sensor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

electrode plates are attached onto the electrode support insulating substrates, respectively

Methodology Applied

Scientific EffectElectric Field: Electric Field

Data Source

PatentUS11061010B2Coaxial capacitive sensor and a method for on-line monitoring and diagnosing engine lubricating oil abrasive particles

Publication Date: 2021.07.13 XIAMEN UNIV

AI summary

A coaxial capacitive sensor includes a sensor lubricating oil inlet and a sensor lubricating oil outlet. The sensor lubricating oil inlet and the sensor lubricating oil outlet separately communicate with the interior of the coaxial capacitive sensor. The interior of the coaxial capacitive sensor is provided with a center bearing, electrode support insulating substrates, and electrode plates. The plurality of electrode support insulating substrates and the center bearing divide the interior of the coaxial capacitive sensor into a plurality of detection sub-spaces, and the electrode plates are attached onto the electrode support insulating substrates, respectively. The coaxial capacitive sensor provided by the present invention can be arranged in a lubricating oil pipeline to avoid the influences of environmental factors on the testing results, and can on-line detect the characteristics of the lubricating oil abrasive particles efficiently.