Spark Plug Terminal Electrode Recess Geometry for Identifier Readability

Solution Overview

Problem

Conventional spark plugs with conical recesses in terminal electrodes face issues with irregular light reflection, making identifiers on the bottom surface difficult to read due to conical shape.

Innovation Solution

Designing spark plugs with terminal electrodes having recesses with parallel side surfaces, allowing for better light control and easier reading of identifiers on the bottom surface, and incorporating features like data matrix codes or QR codes for information storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a conical recess is formed in the terminal electrode, then the identifier can be stored on the bottom surface, but irregular light reflection occurs making the identifier difficult to read

Engineering Contradiction:

Improveidentifier readabilityVSAvoidirregular light reflection

Core Design Contradiction:

Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional conical recess design by using a cylindrical recess with parallel side surfaces instead. This inversion of the geometric form eliminates the irregular light reflection problem while maintaining the identifier storage function on the bottom surface.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the geometric parameters of the recess from a conical shape with angled surfaces to a cylindrical shape with parallel side surfaces. This parameter change modifies the light reflection characteristics, making the identifier readable while preserving information storage capability.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a conical recess is used, then the structure is simple, but the identifier is hard to read due to light reflection issues

Engineering Contradiction:

Improverecess structureVSAvoididentifier detection

Core Design Contradiction:

Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent inverts the conventional conical recess design by using a cylindrical recess with parallel side surfaces instead. This inversion of the geometric form eliminates the irregular light reflection problem while maintaining the identifier storage function on the bottom surface.

Inventive Principle:

Principle #13The other way round (Inversion)

3Loss of information

If more information is stored in the identifier, then the information capacity increases, but the reading difficulty increases due to light reflection

Engineering Contradiction:

Improveinformation storage capacityVSAvoididentifier reading

Core Design Contradiction:

Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent changes the geometric parameters of the recess from a conical shape with angled surfaces to a cylindrical shape with parallel side surfaces. This parameter change modifies the light reflection characteristics, making the identifier readable while preserving information storage capability.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11398717B2Spark plug and method for manufacturing the same

Publication Date: 2022.07.26 DENSO CORP

AI summary

A spark plug includes a terminal electrode extending in an axial direction of the spark plug. The terminal electrode has an end in the axial direction, and has a recess formed in the end of the terminal electrode. The recess has a bottom surface and an identifier on the bottom surface. The recess has a side surface parallel to the axial direction.