Dual-Web Oil Scraper Ring for Directional Oil Control
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Solution Overview
Problem
Existing oil scraper piston rings for internal combustion engines do not optimize oil scraping behavior equally during both the upstroke and downstroke of the piston, leading to inefficiencies in oil management.
Innovation Solution
An oil scraper piston ring design featuring two webs with distinct geometries, where the lower web is optimized for maximum downward oil scraping and the upper web is designed to float on a residual oil film during the upward stroke, with a conical and then parallel profile, and both webs optionally coated with wear-resistant layers like PVD or CVD for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional oil scraper piston ring with uniform web geometry is used, then the structure is simple and easy to manufacture, but the oil scraping behavior is not optimized for both upward and downward strokes
Solution Approach 1:
The piston ring is segmented into two distinct webs with different geometries - a first web optimized for downward stroke oil scraping and a second web optimized for upward stroke oil scraping. This segmentation allows each web to perform its specific function independently, resolving the contradiction between optimization and complexity by dividing the ring into functional segments rather than using a uniform design.
Solution Approach 2:
Different regions of the piston ring (the two webs) are given different local qualities - the first web has geometry optimized for maximum downward scraping while the second web has geometry optimized for minimal upward oil pushing. This local differentiation allows each part to have the specific properties needed for its function, improving overall oil scraping efficiency without requiring complete redesign of the entire ring.
2Productivity
If the lower web is designed for maximum downward oil scraping, then oil removal efficiency improves, but the upper web may push oil upward during the upward stroke
Solution Approach 1:
The second web is specifically designed with geometry that minimizes upward oil pushing during the upward stroke, creating a local quality difference between the two webs. While the first web maximizes downward scraping, the second web's geometry is optimized to reduce harmful upward oil transport, thus resolving the contradiction between downward scraping efficiency and upward oil pushing.
Solution Approach 2:
The two webs are designed with asymmetric geometries relative to each other - the first web has a profile optimized for downward force while the second web has a different profile optimized for reduced upward force. This asymmetry allows the ring to perform differently during upward and downward strokes, eliminating the harmful effect of uniform geometry that causes both webs to push oil upward equally.
3Reliability
If a wear-resistant coating is applied to the running surface, then durability and scraping performance improve, but manufacturing complexity and cost increase
Solution Approach 1:
The wear-resistant coating is applied selectively to specific regions of the piston ring - primarily to the running surfaces of both webs where contact with the cylinder wall occurs. This localized coating approach provides wear protection and enhanced scraping performance exactly where needed, while minimizing the overall manufacturing complexity compared to coating the entire ring.
Solution Approach 2:
The wear-resistant coating is applied during the manufacturing process as a preliminary step before the ring is installed in the engine. This preliminary application ensures that the protective layer is already in place when the ring begins service, maximizing its durability and performance from the start without requiring additional maintenance or intervention during operation.
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
This design achieves optimized oil scraping behavior in both directions, with the lower web ensuring maximum oil removal downward and the upper web minimizing oil push upward, while the wear-resistant coatings enhance durability and efficiency.
Implementation Method 1
both webs are provided with different web geometries such that the lower web takes over the predominant part of the scraping action in the downward stroke and the upper web essentially floats on a residual oil film on the counter-running surface in the upward stroke, wherein the upper web, starting from its upper flank, runs conically towards the counter-running surface and then over a part of the web height approximately parallel to the counter-running surface and is then provided at least over a part of the web height with an asymmetrically convex running surface profile
Implementation Method 2
both webs are provided with different web geometries such that the lower web takes over the predominant part of the scraping action in the downward stroke and the upper web essentially floats on a residual oil film on the counter-running surface in the upward stroke, wherein the upper web, starting from its upper flank, runs conically towards the counter-running surface and then over a part of the web height approximately parallel to the counter-running surface and is then provided at least over a part of the web height with an asymmetrically convex running surface profile
Implementation Method 3
the upper web essentially floats on a residual oil film on the counter-running surface in the upward stroke, wherein the upper web, starting from its upper flank, runs conically towards the counter-running surface
Data Source
Figure 1~2
AI summary
The invention relates to an oil control ring (1) for an internal combustion engine, having two webs (3, 4) arranged axially one over the other in the region of the running surface (5, 6) of the oil control ring, wherein both webs form the running surface (5, 6) when in contact with a counter running surface (10) and the webs (3, 4) are provided with a profile (11, 13, 14) on the counter-running-surface side, which profile has an at least partial coating (13, 15) if necessary, wherein the two webs (3, 4) are provided with different web geometries in such a way that the lower web (4) takes on most of the scraping action in the downward stroke and the upper web (3) substantially floats on a residual oil film on the counter running surface (10) during the upward stroke.