Piston Ring Ceramic Coating Spalling Prevention
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Solution Overview
Problem
The existing technologies for internal combustion engines face challenges with ceramic coatings on piston rings applied via PVD, as they are prone to spalling due to folded metal on the cylinder liner's inner running face, leading to reduced engine service life and combustion chamber damage.
Innovation Solution
A running set comprising a piston ring with a ceramic coating and a cylinder liner or engine block with an inner running face having a proportion of folded metal below 3%, which reduces spalling and enhances durability by minimizing wear on the ceramic coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If honing or burnishing is performed on the inner running face of the cylinder liner to achieve appropriate surface roughness, then the coefficient of roughness is improved for correct functioning, but folded metal accrues on the treated surface causing spalling of the ceramic coating
Solution Approach 1:
The patent applies parameter changes by modifying the surface treatment parameters (honing or burnishing) to achieve a specific roughness profile that minimizes folded metal accumulation while maintaining appropriate surface characteristics for lubrication and ring functioning.
Solution Approach 2:
The patent applies local quality by creating specific surface characteristics in different zones of the running face, with controlled roughness and folded metal distribution patterns that prevent coating spalling while maintaining lubrication properties.
2Strength
If a ceramic coating is applied to the outer running face of the piston ring via PVD method, then the wear resistance is improved, but the coating is prone to spalling due to folded metal on the cylinder liner surface
Solution Approach 1:
The patent applies preliminary action by preparing the cylinder liner surface through controlled honing or burnishing before the piston ring coating is applied, creating an optimal surface profile that prevents folded metal accumulation and subsequent coating spalling during operation.
Solution Approach 2:
The patent uses the controlled surface structure of the cylinder liner as an intermediary element that mediates between the piston ring coating and the underlying metal, preventing direct contact and adhesion failure caused by folded metal.
3Reliability
If the proportion of folded metal on the inner running face is reduced below 3%, then the spalling of the ceramic coating is decreased, but the manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the honing or burnishing parameters to achieve a specific folded metal proportion threshold (below 3%) that ensures coating durability while maintaining manufacturing feasibility through controlled process parameters.
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 reduction in folded metal on the inner running face significantly decreases the wear of the ceramic coating, leading to improved durability and extended service life of the engine components, as demonstrated by comparative tests showing a substantial reduction in coating wear from approximately 4% to 2% folded metal.
Implementation Method 1
at least one part of the outer running face of the ring having a coating which consists of ceramic material and which is applied with the aid of the PVD method (physical vapor deposition)
Data Source
AI summary
A running set for an internal combustion engine may include at least one of a cylinder liner and an engine block including at least one integrated cylinder. The running set may further include at least one piston ring. The at least one piston ring may define an outer running face and the at least one of the cylinder line and the integrated cylinder may define an inner running face. At least one part of the outer running face may include a coating composed of a ceramic material. At least one part of the inner running face may include a proportion of less than three percent of a folded metal.