Segmented Cylinder Liner Roughness Control
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Solution Overview
Problem
Current cylinder liners for internal combustion engines lack optimal distribution of roughness values and lengths along their internal surface, leading to inefficiencies in wear reduction, friction, and scuffing, as previous technologies focused solely on specifying roughness values without considering the ratios of length variations in different portions.
Innovation Solution
A cylinder liner with an internal surface divided into three portions, each with specific roughness values and predefined lengths, where the ratios of these lengths are controlled to optimize wear reduction through scuffing and friction, and a constant or varying honing angle is applied to ensure uniform surface finish and effective lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the internal surface is divided into multiple portions with different roughness values, then wear reduction and friction are improved, but the manufacturing complexity increases due to the need for precise control of roughness distribution and length ratios
Solution Approach 1:
The internal surface of the cylinder liner is segmented into multiple distinct portions (first, second, and third portions) along the longitudinal axis, each with specifically controlled roughness values and length ratios. This segmentation allows optimization of lubrication and wear characteristics in different zones while maintaining manufacturability through defined geometric parameters.
Solution Approach 2:
Different portions of the internal surface are assigned different roughness qualities tailored to their specific functional requirements. The first portion near the head has one roughness characteristic, the central second portion has another, and the third portion near the crankcase has a third characteristic, enabling localized optimization of lubrication and wear resistance.
2Duration of action of stationary object
If the roughness values are optimized for wear reduction, then the working life is extended, but the manufacturing precision requirements increase due to the need for specific roughness values and length ratios
Solution Approach 1:
The invention specifies precise parameter ranges for roughness values (Ra, Rz, Rq) and length ratios (L1/L, L2/L, L3/L) for each portion of the internal surface. These parameter definitions provide clear manufacturing targets that balance wear reduction performance with achievable manufacturing precision through standard honing and finishing processes.
3Ease of operation
If the length ratios of different portions are controlled, then lubrication efficiency is improved, but the device complexity increases due to the need for precise length measurements and distribution
Solution Approach 1:
The invention transitions from controlling only roughness values to controlling both roughness and the dimensional aspect of length ratios. By defining specific length ratios (L1/L, L2/L, L3/L) along the longitudinal dimension, the patent optimizes lubrication efficiency while providing clear geometric parameters for manufacturing control.
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 solution significantly reduces wear and friction, extends engine life, and improves lubrication efficiency by optimizing the ratios of roughness lengths and honing angles, as demonstrated by tests showing reduced wear and improved scuffing resistance.
Implementation Method 1
A precise relationship between the cylinder liners, the pistons and the piston rings leads to the improvement of the performance of the engine. Usually, the cylinder liners for use in internal combustion engines are produced in cast iron with the addition of alloying elements to improve the mechanical and thermal properties thereof. As well as the addition of alloying elements, the liners of cast iron also require optimised working surfaces, contributing to the reduction in the consumption of oil and the recirculation of the gases
Implementation Method 2
having the objective of reducing the wear occurring due to scuffing and to friction
Data Source
AI summary
A cylinder liner for an internal combustion engine may include a hollow cylindrical body. The body may include an internal surface having a longitudinal/axial length. The internal surface may be divided into at least two portions along the longitudinal/axial length. The at least two portions may respectively include a specific value of roughness and a predefined length.