Piston Scraper Ring Uniform Twist Design
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Solution Overview
Problem
Existing oil control ring designs in internal combustion engines face challenges with non-uniform distortion leading to excessive wear, oil consumption, and blowby, particularly due to uneven twisting and scraping motions during piston operation.
Innovation Solution
A scraper ring design with a constant circumferential twist about its entire circumference, achieved through a cross-sectional profile with parallel upper and lower surfaces and strategically angled surfaces, which flexes uniformly during operation to maintain consistent scraping and sliding performance, minimizing wear and optimizing oil control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a conventional twisted ring design with chamfer is used, then oil consumption is reduced, but non-uniform distortion causes excessive wear at maximum twist location
Solution Approach 1:
The patent applies local quality by varying the cross-sectional geometry along the circumferential direction of the ring. Different sections of the ring have different thickness distributions to compensate for the non-uniform twist, ensuring uniform contact pressure and wear distribution across the entire ring circumference while maintaining effective oil scraping.
Solution Approach 2:
The patent changes the geometric parameters of the ring cross-section, specifically the thickness distribution along the circumferential direction. By adjusting these parameters, the ring achieves uniform twist characteristics that balance oil scraping performance with wear reduction across all circumferential positions.
2Stability of the object's composition
If material is removed from inner/uppermost corner to reduce non-uniform distortion, then twisting uniformity improves, but insufficient contact occurs near the break during upstroke
Solution Approach 1:
The patent applies local quality by strategically varying the cross-sectional geometry at different circumferential positions. The thickness distribution is optimized so that sections near the break have adequate material for contact during upstroke, while other sections have reduced thickness to achieve uniform twist and prevent excessive wear.
Solution Approach 2:
The patent incorporates dynamic characteristics by designing the ring to flex and twist uniformly during operation. The varying cross-sectional geometry allows the ring to adapt its shape during the piston cycle, maintaining optimal contact characteristics during both downstroke (scraping) and upstroke (sliding) phases.
3Productivity
If ring distortion is increased during downstroke, then scraping effect is improved, but excess scraping occurs at maximum twist location
Solution Approach 1:
The patent applies local quality by creating non-uniform cross-sectional geometry that compensates for the non-uniform twist distribution. This ensures that the scraping effectiveness is distributed evenly around the ring circumference, preventing both insufficient scraping and excessive scraping at any particular location.
Solution Approach 2:
The patent changes the geometric parameters of the ring cross-section to control the twist distribution. By carefully selecting the thickness variation along the circumference, the ring achieves uniform contact pressure that maintains consistent oil scraping performance across all positions while avoiding excessive wear.
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 design enhances oil scraping efficiency during the downstroke and improves sliding motion during the upstroke, reducing wear and enhancing engine performance by maintaining a consistent radial twist and minimizing excessive oil consumption and blowby.
Implementation Method 1
the scraper ring to become bound within groove 218 during the scraping motion... the scraper ring flexes uniformly during operation
Implementation Method 2
the oil control rings scrape oil from the cylinder wall during the downstroke... On the upstroke the oil control rings slide over the oil to avoid scraping it
Data Source
AI summary
A piston assembly for an internal combustion engine includes a cylinder bore and a piston having a plurality of ring grooves, and a ring positioned within a ring groove. The ring includes a cross-section having a lower surface and an outer radial surface that form a scraping corner, an inner radial surface, and an upper surface. The upper surface and the lower surface are generally parallel with one another, and both upper and lower surfaces form a positive first angle with respect to a radial axis, and the outer radial surface forms a second positive angle with respect to a central axis. A constant twist occurs in the ring about a rotational center of the cross-section, the constant twist occurring at each cross-sectional location of the ring about the circumference of the ring and between adjacent free ends of the ring.