Dual-Layer Coated Piston Ring for Friction and Wear Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing piston rings in internal combustion engines face issues with wear and friction, leading to increased manufacturing costs and reduced performance, while existing coatings do not effectively address these concerns.

Innovation Solution

A piston ring design featuring a chromium nitride running layer applied via physical vapor deposition and a chromium flank layer applied via galvanic deposition, with overlapping portions to reduce friction and wear, is used in conjunction with a body portion made of iron-based materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-layer coating is applied to the piston ring, then the manufacturing process is simple, but the wear resistance and friction reduction are insufficient

Engineering Contradiction:

Improvewear resistanceVSAvoidcoating structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The coating is divided into two distinct layers: a chromium nitride running layer applied to the running surface for low friction and wear resistance, and a chromium flank layer applied to the flank surfaces for corrosion resistance and structural integrity. This segmentation allows each layer to be optimized for its specific functional requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different materials are applied to different surfaces of the piston ring based on their specific functional requirements. The chromium nitride coating is applied locally to the running surface where low friction is critical, while the chromium coating is applied to the flank surfaces where corrosion resistance is prioritized.

Inventive Principle:

Principle #3Local quality

2Reliability

If traditional coating methods are used, then the application process is straightforward, but the cost increases and performance improvement is limited

Engineering Contradiction:

Improvefriction reductionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Traditional mechanical coating methods are replaced with physical vapor deposition (PVD) and galvanic deposition processes. These alternative deposition methods enable precise control over coating thickness and material distribution, reducing material waste and improving coating quality while being cost-effective at scale.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The manufacturing process utilizes parameter changes in the deposition methods to optimize coating application. By controlling deposition parameters such as vapor pressure, temperature, and current density, the process achieves optimal coating properties while maintaining cost efficiency and manufacturing feasibility.

Inventive Principle:

Principle #35Parameter changes

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 coated piston ring experiences reduced friction and wear, improving engine performance and lowering manufacturing costs through the use of PVD and galvanic deposition methods.

Implementation Method 1

applying a running layer over the running surface and over at least a portion of the transition surface by a physical vapor deposition process

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

applying a flank layer over the flank surface and over at least a portion of the transition surface by a galvanic deposition process

Methodology Applied

Scientific EffectGalvanic deposition: Electrodeposition

Data Source

PatentUS12578016B2Coated piston ring for an internal combustion engine

Publication Date: 2026.03.17 TENNECO INC

AI summary

A coated piston ring for a piston is provided. The piston ring includes a running surface, a flank surface, and a transition surface therebetween. The transition surface curves or extends at an angle between the running surface and the flank surface. A running layer is disposed over the running surface and over at least a portion of the transition surface. A flank layer is disposed over the flank surface and over at least a portion of the transition surface. The running layer is applied by physical vapor deposition, and the running layer is applied by galvanic deposition. The running layer is formed of chromium nitride, and the flank layer is formed of chromium. A portion of the flank layer overlaps and is disposed outward of a portion of the running layer. During operation of the piston, the overlapping portion is spaced from both the piston and the cylinder.