Oil Mist Detector Transparent Window Dirt Detection

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Solution Overview

Problem

Existing oil mist detectors face challenges in reliably detecting dirt on transparent windows, leading to decreased transmittance and detection errors due to oil mist adherence, which requires periodic washing without sensitivity perception.

Innovation Solution

An oil mist detector with a zero point shifting structure and a controller that compares detection signal values to a preset dirt abnormal value, allowing for automatic dirt detection and alarm, minimizing background scattering light and enabling reliable detection of dirt on the transparent window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a transparent window is used in the oil mist detector, then light transmission for detection is enabled, but oil mist adheres to the window causing decreased transmittance and detection errors

Engineering Contradiction:
Improvedetection reliabilityVSAvoidoil mist adhesion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the transparent window from the detection chamber by providing a separate detection chamber with a transparent window, isolating it from direct contact with oil mist while maintaining optical detection capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary substance (silicone oil or fluorocarbon oil) with high oil repellency between the oil mist and the transparent window, preventing oil mist adhesion while allowing light transmission

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the transparent window is kept clean for accurate detection, then detection precision is maintained, but periodic washing is required which reduces productivity

Engineering Contradiction:
Improvedetection precisionVSAvoidoperational continuity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies an oil repellent coating on the transparent window that provides self-cleaning functionality by preventing oil mist adhesion, eliminating the need for periodic manual washing and maintaining continuous operation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses composite materials combining the transparent window with an oil repellent coating layer, creating a surface that simultaneously maintains optical clarity and resists oil adhesion

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If background scattering light is minimized for accurate oil mist detection, then detection sensitivity is improved, but the zero point detection becomes difficult

Engineering Contradiction:
Improvedetection sensitivityVSAvoidzero point signal
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the detection system into separate functional chambers: a detection chamber for oil mist detection and a zero point detection chamber free from oil mist interference, allowing independent optimization of each function

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses a light guide or optical fiber as an intermediary to transmit light between the detection chamber and the photodetector, enabling separate placement of the zero point detection chamber away from oil mist contamination

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

The solution allows for easy and reliable detection of dirt on the transparent window, preventing detection errors and maintaining sensitivity by automatically judging and alarming dirt presence, thus reducing the need for periodic washing.

Implementation Method 1

a light emitting device and a light receiving device that are so arranged as to face the outer side of a transparent window provided in the oil mist introduction chamber... receiving, by the light receiving device through the transparent window, scattering light generated from the irradiated light hitting the oil mist present in the detection region

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP1936358B1Oil mist detector
Publication Date: 2015.05.06 HORIBA LTD
  • EP1936358B1 patent drawingFigure 1
  • EP1936358B1 patent drawingFigure 2
  • EP1936358B1 patent drawingFigure 3

AI summary

Dirt on a transparent window (W) of an oil mist detector (1) is to be detected easily and reliably. An oil mist detector includes: a casing (6) having an oil mist introduction chamber arranged in a crankcase (C) of an internal combustion engine; and a light emitting device (2) and a light receiving device (3) so arranged as to face an outer side of a transparent window (W) provided in the oil mist introduction chamber. The light emitting device (2) irradiates light to a predetermined detection region (S) in the oil mist introduction chamber through the transparent window (W) and the light receiving device (3) receives through the transparent window (W) scattering light (LS) generated from the irradiated light (LB) hitting oil mist present in a detection region (S), thereby achieving oil mist detection. A zero point shifting structure is provided which makes a given amount of background scattering light (BLS) from the casing (6) incident on the light receiving device (3) under absence of oil mist in the oil mist introduction chamber.