Grooved Oil Control Ring Spacer for Sludge-Resistant Sealing
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Solution Overview
Problem
Conventional oil control rings in internal combustion engines suffer from oil sludge accumulation, leading to sticking between the spacer expander and side rails, which impairs their sealing function and increases oil consumption, especially in small-width, low-tension rings, and existing solutions are either costly or lack durability during repeated engine start-stop cycles.
Innovation Solution
The design incorporates an axially corrugated spacer expander with intermediate portions featuring grooves that extend in a circumferential direction, providing a larger volume of space between the spacer expander and side rails, facilitating easier oil flow and preventing sludge accumulation, combined with a resin or metal coating to prevent sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the axial width of the oil ring is reduced to improve followability and reduce friction loss, then the sealing performance is improved, but the space between the spacer expander and side rails becomes extremely narrow causing oil sludge accumulation and sticking
Solution Approach 1:
The spacer expander is segmented into multiple intermediate portions along its axial direction, with each intermediate portion having grooves that create separate oil flow paths. This segmentation allows oil to flow more effectively through the narrow space without accumulating, resolving the contradiction between narrow axial width and oil sludge prevention
Solution Approach 2:
Grooves are added to the intermediate portions of the spacer expander, creating a third dimension (circumferential direction) for oil flow. This allows oil to escape from the narrow radial space through the grooves in the circumferential direction, preventing sludge accumulation while maintaining the narrow axial width
2Object-affected harmful factors
If conventional coatings or hole-forming methods are used to prevent oil sludge attachment, then oil sludge accumulation is reduced, but manufacturing cost increases or durability decreases during repeated start-stop cycles
Solution Approach 1:
The spacer expander is divided into intermediate portions with grooves, creating multiple oil escape paths without requiring complex coatings or additional manufacturing steps. This structural segmentation achieves oil sludge prevention through geometry alone, avoiding increased manufacturing costs
Solution Approach 2:
The grooves in the intermediate portions enable the oil ring to self-drain oil during operation. The oil flow through the grooves automatically prevents sludge accumulation without requiring external coatings or additional components, maintaining manufacturing simplicity while improving durability
3Ease of operation
If the intermediate portions have a convex shape or specific inclination angle to prevent oil sludge accumulation, then oil flow is improved, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
The spacer expander is divided into repeating units of upper portions, intermediate portions, and lower portions. Each intermediate portion has simple grooves that guide oil flow, creating an effective oil drainage system through modular repetition rather than complex continuous geometry
Solution Approach 2:
Instead of making the intermediate portions convex or inclined to push oil away, grooves are added to the intermediate portions to actively channel oil flow. This inverted approach of creating positive flow paths rather than relying on geometric inclination simplifies the structure while improving oil drainage
Data Source
Figure 1(a)~2
Figure 3(a)~3(b)
Figure 4(a)~4(b)
AI summary
To provide a combined oil control ring comprising a pair of upper and lower side rails and an axially corrugated spacer expander having upper and lower portions for automobile engines, which is capable of keeping an excellent oil-controlling function without sticking between a spacer expander and side rails even in a long period of engine operation, the upper and lower portions of the spacer expander have tabs pushing inner peripheral surfaces of the side rails, projections supporting the side rails, and intermediate portions between the tabs and the projections; each intermediate portion opposing the side rail has at least one groove extending in a substantially circumferential direction is recessed when viewed along a radial direction.