Cylinder Liner Projections and Bore Adjacent Part for Compact Engine Cooling
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Solution Overview
Problem
In multi-cylinder engines, reducing engine size while maintaining effective cooling and ensuring adhesion between cylinder liners and blocks is challenging, especially when the inter-bore pitch is shortened, as conventional techniques compromise cooling space and adhesion during casting.
Innovation Solution
A cylinder liner design featuring projections on its outer surface for adhesion and a groove-like bore adjacent part that is inclined and positioned closer to the inner surface, reducing projections in specific areas to create space for cooling passages, allowing for compatible cooling and reduced inter-bore pitch without compromising adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If projections are formed on the outer peripheral surface of the cylinder liner to improve adhesion with the block, then adhesion is improved, but cooling space between cylinder bores is reduced
Solution Approach 1:
The invention applies local quality by providing projections only on specific portions of the outer peripheral surface of the cylinder liner, rather than uniformly across the entire surface. The projections are strategically positioned in areas where they do not interfere with the cooling passages, allowing adhesion to be improved in specific locations without compromising the overall cooling space between adjacent cylinder bores.
2Length of moving object
If the inter-bore pitch is shortened to reduce engine size, then engine length is reduced, but cooling space and adhesion are compromised
Solution Approach 1:
By concentrating projections on specific local areas of the cylinder liner's outer peripheral surface, the invention enables shorter inter-bore pitch while maintaining adhesion strength. The localized projections provide sufficient bonding area without requiring increased spacing between bores, thus allowing engine size reduction while preserving the critical adhesion property.
3Length of moving object
If the inter-bore pitch is shortened to reduce engine size, then engine length is reduced, but cooling space is reduced
Solution Approach 1:
The invention resolves this contradiction by localizing the projections to specific areas that do not encroach on the cooling passage space. This allows the inter-bore pitch to be reduced for compact engine design while the cooling passages maintain their required volume and flow characteristics, as the projections are positioned away from the cooling channels.
4Volume of stationary object
If projections are removed to create space for cooling passages, then cooling space is improved, but adhesion with the block is reduced
Solution Approach 1:
The invention applies local quality by selectively removing projections only from the portions of the outer peripheral surface that would interfere with cooling passages, while retaining projections in other areas. This selective removal maintains adhesion strength in the retained projection areas while creating sufficient cooling space in the removed projection areas, thus resolving the contradiction between cooling space and adhesion.
Data Source
AI summary
A cylinder liner that is casted in a block and defines a cylinder bore for one cylinder includes: a cylindrical liner body; a projection part including a plurality of projections on an outer peripheral surface of a part of the liner body; and a bore adjacent part inclined at a predetermined angle to an axial direction of the body and extending in the inclination direction, at a predetermined part between an upper side end and a lower side end of the body, of the outer peripheral surface of the body, which faces another cylinder bore to be adjacent when casted in the block. The outer peripheral surface of the bore adjacent part is positioned more on an inner side of the body than the outer peripheral surface above and below, and is formed such that the projections are absent on at least a part of the outer peripheral surface.