PAEK Sealing Ring for Spark Plug Dielectric Strength

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Solution Overview

Problem

Existing spark plugs experience undesirable voltage flashovers due to metallic inside seals, leading to misfires and reduced dielectric strength, as they are not adequately resistant to temperature and thermal conductivity, limiting their service life.

Innovation Solution

A spark plug design featuring a sealing ring made of polyaryl ether ketone (PAEK) or polyether ether ketone (PEEK) with added fillers like boron nitride and glass/carbon fibers, which enhances dielectric strength, thermal conductivity, and mechanical strength, reducing electric field intensity and thermal stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic inside seals are used, then sealing function is achieved, but voltage flashovers occur between metal shell and center electrode

Engineering Contradiction:

Improvesealing functionVSAvoidvoltage flashover

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A polymer sealing ring is introduced as an intermediary component between the metal shell and the insulator. This polymer ring serves as an electrical insulator that prevents voltage flashovers while simultaneously providing the necessary sealing function. The polymer material acts as a mediator that combines both sealing and electrical insulation properties, eliminating the harmful flashover effect that occurs with metallic seals.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing ring is made from composite materials, specifically polymer materials that combine sealing capability with high electrical insulation properties. This composite approach allows the sealing ring to fulfill both the sealing function and the electrical insulation requirement, preventing voltage flashovers between the metal shell and center electrode while maintaining effective sealing.

Inventive Principle:

Principle #40Composite materials

2Reliability

If metallic inside seals are used, then sealing is achieved, but dielectric strength is reduced

Engineering Contradiction:

ImprovesealingVSAvoiddielectric strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The polymer sealing ring acts as an intermediary component that provides both sealing and electrical insulation. By positioning this insulating polymer ring between the metal shell and the insulator, the design maintains the sealing function while significantly improving the overall dielectric strength of the spark plug, preventing electrical breakdown paths.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the material parameter of the sealing ring from conductive metal to insulating polymer. This parameter change fundamentally alters the electrical properties of the sealing component, transforming it from a potential flashover path to an electrical insulator that enhances dielectric strength while maintaining sealing effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Strength

If polymer sealing rings are used, then dielectric strength is increased, but temperature resistance must be sufficient

Engineering Contradiction:

Improvedielectric strengthVSAvoidtemperature resistance

Core Design Contradiction:

StrengthVSTemperature

Solution Approach 1:

The invention selects polymer materials with specific parameter characteristics that provide both high dielectric strength and adequate temperature resistance. By carefully choosing polymer materials with appropriate thermal and electrical properties, the sealing ring achieves the necessary temperature resistance while maintaining enhanced dielectric strength compared to metallic seals.

Inventive Principle:

Principle #35Parameter changes

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 significantly increases dielectric strength, reduces electrode wear, and ensures a secure seal with improved thermal management, resulting in a longer service life and reliable ignition performance.

Implementation Method 1

the sealing ring has polyaryl ether ketone (PAEK)... significantly increases dielectric strength... reduces electric field intensity

Methodology Applied

Scientific EffectDielectric strength: Dielectric

Implementation Method 2

enhances dielectric strength, thermal conductivity... improved thermal management

Methodology Applied

Scientific EffectThermal conductivity: Conduction (thermal)

Implementation Method 3

sealing ring made of polyaryl ether ketone (PAEK) or polyether ether ketone (PEEK) with added fillers like boron nitride and glass/carbon fibers... enhances... mechanical strength

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Data Source

PatentUS10651631B2Spark plug with polymer sealing ring

Publication Date: 2020.05.12 FEDERAL MOGUL IGNITION GMBH

AI summary

A spark plug is specified, having a metal shell with an axial bore and a threaded section, having an insulator with an axial bore that is located at least partially inside the axial bore of the metal shell; a center electrode that is accommodated at least partially inside the axial bore of the insulator; a ground electrode that is held by the metal shell, wherein an end region of the ground electrode forms, together with the center electrode, an ignition gap, and having a sealing ring that extends at least between an outside shoulder of the insulator and an inside shoulder of the metal shell, wherein the sealing ring has polyaryl ether ketone (PAEK), preferably polyether ether ketone (PEEK).