Profiled Cylinder Liner Structure for Bore Distortion Control
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Solution Overview
Problem
Cylinder liners in internal combustion engines experience distortion due to assembly, thermal expansion, and cylinder pressure, leading to radial growth, ovalization, and complex deformations that affect piston ring conformability and increase oil consumption.
Innovation Solution
A cylinder liner with a relief feature and a stiffening feature on its outer surface to resist distortion, comprising a depressed relief feature and a raised stiffening feature that counteract radial growth and complex deformations, reducing overall distortion magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the mid-stop height is shortened or liner thickness is increased to minimize radial growth, then distortion is reduced, but liner temperatures are negatively impacted
Solution Approach 1:
The patent applies local quality by introducing relief features and stiffening features at specific locations on the cylinder liner. The relief features (depressed areas) are positioned at locations prone to radial growth, while stiffening features (raised areas) are placed to provide structural support. This localized modification allows distortion control without requiring overall thickness increase, thereby maintaining thermal properties.
Solution Approach 2:
The patent transitions from modifying the liner in the radial dimension (thickness) to modifying the surface topology in the axial and circumferential dimensions. By creating relief and stiffening features that extend axially and circumferentially, the patent controls distortion through surface geometry changes rather than radial thickening, preserving heat transfer characteristics.
2Stability of the object's composition
If external rib structures are added to the cylinder block to control distortion, then distortion is reduced, but weight and cost increase
Solution Approach 1:
The patent extracts the distortion control function from the external cylinder block structure and relocates it to the cylinder liner itself. By integrating relief and stiffening features directly into the liner, the patent eliminates the need for external rib structures on the cylinder block, thereby reducing overall weight while maintaining distortion control.
Solution Approach 2:
The patent merges the distortion control function with the cylinder liner structure by integrating relief features and stiffening features into the liner body. This consolidation eliminates separate external support structures, reducing weight and simplifying the overall engine architecture while achieving the same distortion mitigation effect.
3Stability of the object's composition
If liner thickness is increased to reduce distortion, then radial growth is minimized, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of uniformly increasing liner thickness throughout, the patent applies localized thickness variations through relief and stiffening features. This selective modification provides distortion control only where needed, simplifying manufacturing compared to producing thicker liners while achieving the same structural benefit.
Solution Approach 2:
The patent changes the surface geometry parameters (creating depressed and raised features) rather than changing the fundamental thickness parameter. This approach allows distortion control through geometric modification that can be achieved through standard machining or forming processes, maintaining ease of manufacture while improving structural performance.
Data Source
Figure 1~2
Figure 3
AI summary
A cylinder liner for a cylinder bore of a cylinder of an internal combustion engine. The cylinder liner includes a cylindrical casing having an outer surface and an inner surface, wherein each surface has a respective surface area. The liner includes a liner seat positioned on the outer surface wherein the liner seat engages with the cylinder bore to position the cylindrical casing in the cylinder bore. The liner includes a relief feature positioned on the outer surface either adjacent the liner seat or above a mid-stop wherein the relief feature resists distortion of the cylindrical casing from the cylinder bore. The liner can include a stiffening feature positioned above the relief feature on the outer surface. The relief feature forms a depressed surface on the outer surface and the stiffening feature forms a raised surface on the outer surface of the cylindrical casing.