Piston Combustion Coating Zones for Lean-Burn Hydrogen Protection

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Solution Overview

Problem

In internal combustion engines, fuel-lean regions in the combustion chamber lead to sub-optimal combustion efficiency and thermal dilution, causing mechanical failure due to hydrogen embrittlement of metal components.

Innovation Solution

A coating system with multiple layers on the piston's combustion surface, including a thermal barrier, hydrogen barrier, and catalyst layers, strategically positioned to manage combustion and reduce thermal dilution and hydrogen permeation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a uniform coating is applied across the entire combustion surface, then thermal protection is provided, but combustion efficiency in fuel-lean regions deteriorates due to excessive heat barrier

Engineering Contradiction:
Improvethermal dilutionVSAvoidcombustion efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies different coating types in different zones of the combustion surface. Thermal barrier coatings are applied in fuel-rich regions where thermal dilution is severe, while catalytic coatings are applied in fuel-lean regions to promote combustion. This local differentiation allows each zone to receive the appropriate treatment for its specific combustion conditions, resolving the contradiction between thermal protection and combustion efficiency.

Inventive Principle:
Principle #3Local quality

2Temperature

If thermal barrier coating is applied to protect from heat, then component temperature increases, but hydrogen embrittlement protection deteriorates due to hydrogen permeation through the coating

Engineering Contradiction:
Improvecomponent temperatureVSAvoidhydrogen embrittlement resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses composite coating structures combining thermal barrier coating materials with hydrogen barrier coating materials. The thermal barrier coating (e.g., ceramic-based) provides thermal insulation, while the hydrogen barrier coating (e.g., metallic or ceramic layer with specific properties) prevents hydrogen permeation. This composite approach allows simultaneous achievement of thermal protection and hydrogen embrittlement resistance.

Inventive Principle:
Principle #40Composite materials

3Productivity

If catalytic coating is applied to promote combustion, then combustion efficiency improves, but thermal protection deteriorates due to reduced thermal barrier properties

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidthermal dilution
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent strategically locates catalytic coatings in fuel-lean regions where combustion promotion is most needed, while maintaining thermal barrier coatings in fuel-rich regions where thermal dilution is the primary concern. This spatial differentiation ensures that catalytic activity enhances combustion efficiency without compromising overall thermal protection of the piston.

Inventive Principle:
Principle #3Local quality

4Reliability

If multiple coating layers are applied to provide comprehensive protection, then reliability improves, but manufacturing complexity increases

Engineering Contradiction:
Improvecombustion chamber protectionVSAvoidcoating system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the combustion surface into distinct zones (fuel-rich regions and fuel-lean regions) and applies different coating types to each zone. This segmentation allows for targeted protection and optimization without requiring complex multi-layer coatings across the entire surface, thereby maintaining manufacturing feasibility while improving reliability.

Inventive Principle:
Principle #1Segmentation

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

Improves fuel combustion efficiency and prevents mechanical failure by optimizing combustion patterns and protecting engine components from hydrogen embrittlement.

Implementation Method 1

a first layer configured to decrease one or more of a thermal capacity and thermal conductivity of the coating

Methodology Applied
Scientific EffectThermal barrier: Thermal Insulation

Implementation Method 2

a third layer including a catalyst configured to initiate combustion of the gaseous fuel-air mixture

Methodology Applied
Scientific EffectCatalysis: Catalysis

Implementation Method 3

a second layer configured to decrease permeability of the coating; the second layer may be configured to decrease permeation of hydrogen

Methodology Applied
Scientific EffectPermeation barrier: Permeation

Data Source

PatentEP4682370A1Coating system
Publication Date: 2026.01.21 VOLVO TRUCK CORP
  • EP4682370A1 patent drawingFigure 1~2
  • EP4682370A1 patent drawingFigure 3~5
  • EP4682370A1 patent drawing

AI summary

A coating system (200) including a coating (220) configured to be applied to a combustion surface (150) of a piston (140) and to initiate combustion of a gaseous fuel-air mixture; a first coating zone (240) including the coating, the first coating zone being configured to correspond to a first combustion position (162) on the combustion surface of the piston; and a second coating zone (240) including the coating, the second coating zone being configured to correspond to a second combustion position (162) on the combustion surface of the piston.