Variable Thickness Cylinder Liner Coatings for Wear Reduction

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Solution Overview

Problem

Existing cylinder liner coatings for internal combustion engines are expensive and inefficient in reducing friction and wear, particularly at high-pressure and high-temperature regions such as the top and bottom dead centers, where galling and wear are most severe, due to uniform coating distribution that does not account for varying lubrication conditions throughout the piston stroke.

Innovation Solution

A variable thickness coating is applied to the cylinder liner, with thicker coatings at the top and bottom dead center regions and a thinner coating at the midstroke region, utilizing methods like plasma spraying or chemical vapor deposition, to optimize friction reduction and wear resistance while minimizing material usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a uniform thickness coating is applied to the cylinder liner, then the manufacturing process is simple, but the friction and wear resistance is insufficient at critical regions like top and bottom dead centers

Engineering Contradiction:
Improvefriction and wear resistanceVSAvoidcoating thickness distribution
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies different coating thicknesses to different regions of the cylinder liner based on local wear conditions. The top and bottom dead center regions receive thicker coatings (first and second thicknesses) to withstand high pressure and temperature, while the midstroke region receives a thinner coating (third thickness). This local differentiation optimizes friction and wear resistance without requiring complex variable thickness application equipment.

Inventive Principle:
Principle #3Local quality

2Reliability

If a thicker coating is applied to provide better wear resistance, then the durability is improved, but the material cost and manufacturing complexity increase

Engineering Contradiction:
Improvewear resistanceVSAvoidcoating material usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent strategically applies thicker coatings only to the top and bottom dead center regions where wear is most severe, while using a thinner coating in the midstroke region. This localized approach ensures adequate wear resistance at critical points while minimizing overall material consumption and reducing manufacturing complexity compared to applying a uniformly thick coating throughout.

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 variable thickness coating significantly reduces friction and wear at critical regions, minimizing material costs and enhancing the durability and performance of the cylinder liner by aligning coating thickness with the varying lubrication conditions and wear patterns throughout the piston stroke.

Implementation Method 1

Among the coating technologies that may be used are plasma spraying, high velocity oxygen fuel spraying, laser coating and chemical vapor deposition

Methodology Applied
Scientific EffectPlasma spraying: Plasma Spray

Implementation Method 2

Among the coating technologies that may be used are plasma spraying, high velocity oxygen fuel spraying, laser coating and chemical vapor deposition

Methodology Applied
Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentEP2677152B1Variable thickness coatings for cylinder liners
Publication Date: 2017.08.09 GENERAL ELECTRIC CO
  • EP2677152B1 patent drawingFigure 1
  • EP2677152B1 patent drawingFigure 2
  • EP2677152B1 patent drawingFigure 3

AI summary

A cylinder liner for an internal combustion engine (11) includes a liner body (21) defining a longitudinal axis coated with a coating (31) on the interior surface of the liner body that varies in thickness along the longitudinal axis. The coating on the interior surface is thicker in a region of the interior surface corresponding to a top dead center (33) or a bottom dead center (35) of a piston.