Segmented Thermal Barrier Coating for Piston Heat Management

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Solution Overview

Problem

Internal combustion engine pistons face challenges with heat build-up and material degradation due to high temperatures, which are exacerbated by traditional thermal barrier coatings that distribute heat unevenly, leading to increased stress and potential coating delamination.

Innovation Solution

A thermal barrier coating is applied to select circumferentially spaced surface parts of the piston bowl surface, using ceramic materials like zirconium oxide, with varying thickness and placement to manage heat distribution and reduce material stress, while leaving uncoated areas to absorb heat, thereby distributing heat more evenly and reducing maximum temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thermal barrier coating is applied to the entire piston surface, then the piston material is protected from high temperatures, but heat builds up in surrounding parts of the combustion chamber in an uncontrolled manner

Engineering Contradiction:

Improvepiston material protectionVSAvoidheat build-up in surrounding parts

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The thermal barrier coating is divided into multiple separate coating zones rather than covering the entire piston surface. This segmentation allows different regions to have different thermal characteristics, enabling controlled heat distribution between the piston and surrounding combustion chamber parts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the piston surface are assigned different coating properties - some areas have thermal barrier coating for protection, while other areas remain uncoated to allow heat transfer. This local differentiation optimizes both piston protection and heat management in surrounding parts.

Inventive Principle:

Principle #3Local quality

2Reliability

If a thermal barrier coating is applied to the piston surface, then material degradation and oxidation are reduced, but the coating experiences high thermal stress leading to crack and delamination

Engineering Contradiction:

Improveresistance to material degradationVSAvoidthermal stress in coating

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The coating is segmented into discrete zones separated by uncoated regions. This segmentation reduces the continuous thermal stress path, allowing stress relief at the boundaries between coated and uncoated areas, thereby reducing the risk of crack propagation and delamination.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design accounts for differential thermal expansion between the coating and piston material by creating uncoated transition zones that accommodate expansion stresses, reducing the likelihood of coating failure.

Inventive Principle:

Principle #37Thermal expansion

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

This approach reduces material degradation and coke build-up, enhances durability, and prolongs piston longevity by evenly distributing heat and minimizing thermal stress on the coating and underlying material.

Implementation Method 1

the piston bowl surface being provided with a thermal barrier coating layer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the piston according to this disclosure is assimilating more heat energy such that surrounding parts of the combustion chamber is exposed to less heat

Methodology Applied

Scientific EffectHeat absorption: Absorption (EM radiation)

Implementation Method 3

The thermal expansion of the piston material and the coating may be different causing high stresses in the coating

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10801439B2Piston for a cylinder for an internal combustion engine

Publication Date: 2020.10.13 VOLVO TRUCK CORP

AI summary

A piston for a cylinder for an internal combustion engine has a piston bowl surface adapted for facing a combustion chamber of the cylinder, the piston bowl surface being provided with a thermal barrier coating layer, wherein the thermal barrier coating layer is provided on a plurality of circumferentially spaced surface parts of the piston bowl surface. A method for producing a piston for a cylinder for an internal combustion engine includes the steps of providing a piston for a cylinder for an internal combustion engine, the piston having a piston bowl surface adapted for facing a combustion chamber of the cylinder, and providing the piston bowl surface with a thermal barrier coating layer, wherein the step of providing the thermal barrier coating layer is made on a plurality of circumferentially spaced surface parts of the piston bowl surface.