Ceramic Feedthrough Pore Filling for Saline and Thermal Insulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing electrical feedthroughs in exhaust systems of internal combustion engines face issues with insufficient electrical insulation due to the absorption of saline solutions by porous ceramic layers, leading to electrolytic bridges and structural damage under humid conditions, and are prone to cracking from thermal stress due to mismatched thermal expansion coefficients.

Innovation Solution

A feedthrough design with a porous ceramic layer filled with nanoparticles as a pore filler, ensuring the pores are sealed and the thermal expansion coefficients of the ceramic layer and filler match, enhancing durability and resistance to thermal stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a porous ceramic layer is used for electrical insulation, then electrical insulation is provided, but the ceramic layer absorbs saline solutions and loses insulation effectiveness

Engineering Contradiction:
Improveelectrical insulation effectivenessVSAvoidsaline solution absorption
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a porous ceramic layer as the insulating means, utilizing the porous structure to provide electrical insulation while managing the interaction with saline environments through controlled pore filling

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent combines porous ceramic material with filling material (such as metal oxides or ceramic powders) to create a composite structure that maintains insulation properties while reducing saline solution absorption through the filled pores

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If organic sealants are used to reduce porosity, then pore filling is achieved, but durability is insufficient under operational stresses

Engineering Contradiction:
Improveporosity reductionVSAvoiddurability under stress
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent changes the material parameters by selecting inorganic filling materials with specific thermal expansion coefficients that match the ceramic layer, transforming the pore filler from organic to inorganic to achieve both porosity reduction and enhanced durability

Inventive Principle:
Principle #35Parameter changes

3Reliability

If inorganic sealants are used to fill pores, then durability is improved, but thermal expansion mismatch causes cracking

Engineering Contradiction:
ImprovedurabilityVSAvoidstructural integrity under thermal stress
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent carefully selects inorganic filling materials whose thermal expansion coefficients match those of the porous ceramic layer, eliminating thermal expansion mismatch and preventing cracking while maintaining durability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a homogeneous composite structure where the filling material is uniformly distributed within the porous ceramic matrix, ensuring consistent thermal and mechanical properties throughout the insulating means

Inventive Principle:
Principle #33Homogeneity

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 design provides durable electrical insulation and resistance to thermal stresses by preventing saline solution absorption and minimizing structural damage, maintaining effective insulation and structural integrity under varying temperatures.

Implementation Method 1

The porous ceramic used has a tendency to absorb saline solutions from the area surrounding the feedthrough. This creates an electrolytic bridge through the ceramic layer

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

Alternative inorganic sealants regularly lead to cracking under thermal stress due to different thermal expansion coefficients

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4392649B1Electrical feedthrough with porous ceramic layer and a pore filler
Publication Date: 2025.06.25 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

The invention relates to a feedthrough for an electrical conductor for electrically connecting an electrically heatable heating disc, in particular in an exhaust gas system of an internal combustion engine, through a housing, the feedthrough having an internal conductor, an external sleeve and at least one insulating means, the insulating means being arranged between the internal conductor and the external sleeve in such a manner that the internal conductor is electrically insulated from the external sleeve, wherein the insulating means is formed by a porous ceramic layer, with pores of the ceramic layer being at least partially filled with a pore filler. The invention also relates to a method for producing a feedthrough.