Spark Plug Connecting Element With Oxide Composite Resistance Stability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Spark plug connecting elements in internal combustion engines face degradation due to oxidation during manufacturing and usage, leading to unstable electrical resistance and reduced durability.

Innovation Solution

A spark plug connecting element comprising specific conductive oxides, such as M1-xDxO2 and Zn1-yQyO, with a resistance element having a conductivity of 10^-3 to 10^1 S/m, and contact elements with 10^2 to 10^8 S/m conductivity, ensuring high oxidation resistance and stable electrical conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inorganic non-oxide electrically conductive materials (such as soot) are used in the spark plug connecting element, then electrical conductivity is improved, but oxidation resistance deteriorates during manufacturing and usage

Engineering Contradiction:
Improveelectrical conductivityVSAvoidoxidation resistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a composite material system combining metal oxide particles (conductive phase) embedded in a glass matrix (protective phase). This composite structure provides both electrical conductivity through the metal oxide network and oxidation resistance through the protective glass environment, resolving the contradiction between conductivity and oxidation resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters by using specific metal oxides (such as zinc oxide, bismuth oxide, tin oxide) with controlled particle sizes and concentrations. By adjusting these parameters, the material achieves optimal balance between electrical conductivity and oxidation resistance, transforming the material properties to satisfy both requirements.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If high temperatures are applied during spark plug manufacturing, then the spark plug is formed, but oxidation of conductive materials occurs leading to degradation of electrical resistance

Engineering Contradiction:
Improvemanufacturing processVSAvoidelectrical resistance stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent performs preliminary oxidation resistance treatment by embedding conductive metal oxide particles within an oxidation-resistant glass matrix before the final firing process. This preliminary protective structure prevents oxidation during high-temperature manufacturing, ensuring electrical resistance stability is maintained throughout the manufacturing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The glass matrix acts as an intermediary protective layer between the conductive metal oxide particles and the oxidizing atmosphere during high-temperature manufacturing. This intermediary structure allows the conductive materials to maintain their properties while withstanding the harsh manufacturing conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Duration of action of stationary object

If the spark plug connecting element uses materials with high oxidation resistance, then durability is improved, but electrical conductivity may be reduced

Engineering Contradiction:
Improveservice lifeVSAvoidelectrical conductivity
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent creates a composite material where metal oxide particles providing conductivity are distributed within a glass matrix providing oxidation resistance. This composite structure allows both functions to coexist - the glass protects against oxidation extending service life, while the metal oxide network maintains electrical conductivity pathways.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by having different phases perform different functions: the glass matrix provides oxidation resistance in the bulk material, while the metal oxide particles provide conductivity at specific locations where they form percolating networks. This spatial differentiation of properties allows simultaneous achievement of durability and conductivity.

Inventive Principle:
Principle #3Local quality

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 provides a spark plug with enhanced durability and a stably adjustable resistance value, maintaining high chemical and mechanical stability even under intended use conditions.

Implementation Method 1

the first contact element and the second contact element having a specific conductivity of 10^2 < S/m to 10^8 < S/m, and a resistance element, wherein the resistance element is arranged between the first contact element and the second contact element

Methodology Applied
Scientific EffectElectrical conductivity: Conduction (electrical)

Implementation Method 2

high oxidation resistance and thus a very long service life with permanently stable high electrical resistance

Methodology Applied
Scientific EffectOxidation resistance: Oxidation

Data Source

PatentEP3921902B1Spark plug connecting element and spark plug
Publication Date: 2024.05.29 ROBERT BOSCH GMBH
  • EP3921902B1 patent drawingFigure 1
  • EP3921902B1 patent drawingFigure 2

AI summary

The present invention relates to a spark plug connecting element which comprises a first contact element (9a) and a second contact element (9b), wherein a resistor element (8) is arranged between the first contact element (9a) and the second contact element (9b), the first contact element (9a) and the second contact element (9b) have a specific conductance of 102 S/m to 108 S/m, and the resistor element (8) has a specific conductance of 10-3 S/m to 101 S/m.