Oil Scraper Ring Gap Structure for Pressure Relief and Oil Control
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Solution Overview
Problem
Existing oil scraper rings in internal combustion engines face instability due to high gas pressure from narrow annular gaps, leading to reduced performance and increased oil entry into the combustion chamber, especially during throttled or overrun operations, which affects particulate emissions.
Innovation Solution
The oil scraper ring features an uneven annular gap design with a larger gap at the top and a smaller gap at the bottom, incorporating recesses that widen the upper gap to allow freer gas flow and direct blowby gases into the crankcase, reducing oil flow towards the combustion chamber and stabilizing the middle piston ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a narrow annular gap is used in the oil control ring, then oil scraping performance is improved, but gas pressure builds up causing ring instability
Solution Approach 1:
The patent applies local quality by creating different gap widths at different locations of the annular gap. The gap width varies along the circumferential direction, with narrower sections for oil scraping and wider sections for pressure relief, allowing each local region to serve its specific function optimally
Solution Approach 2:
The annular gap is segmented into multiple sections with different widths rather than being a uniform narrow gap. This segmentation allows the gap to simultaneously provide oil scraping control in narrow sections and pressure equalization in wider sections, resolving the contradiction between oil control and stability
2Stability of the object's composition
If a larger annular gap is used to prevent pressure buildup, then ring stability is improved, but oil control performance deteriorates
Solution Approach 1:
Different sections of the annular gap have different widths tailored to their specific functions. Narrower sections maintain oil scraping effectiveness while wider sections provide pressure relief, achieving both stability and oil control without compromise
3Object-generated harmful factors
If a small annular gap is used for maximum oil control, then oil scraping effect is maximized, but gas pressure above the ring increases
Solution Approach 1:
The annular gap is divided into functional segments with varying widths. Small-gap sections maximize oil scraping while larger-gap sections serve as pressure relief channels, allowing the system to achieve maximum oil control without excessive pressure buildup
4Object-generated harmful factors
If the annular gap is reduced to control oil flow, then oil entry into combustion chamber is reduced, but blowby gas flow is restricted
Solution Approach 1:
The annular gap width varies locally to differentiate between oil control zones and gas flow channels. Narrower sections control oil flow while wider sections facilitate blowby gas passage, achieving oil control without significantly restricting gas flow
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 reduces oil entry into the combustion chamber, improves ring stability, and decreases particulate emissions by effectively managing gas pressure and blowby gases, ensuring efficient operation across various engine conditions.
Implementation Method 1
The respective recess thus extends into the region in which the one corner, which would have been formed from the surface of the outer ring surface or a web, the respective abutting surface, and the upper ring flank, would be located. The two opposite recesses located on both sides of the annular gap widen the annular gap, particularly between the edges of the upper wiper web. One of the two recesses is located at each of the butt ends.
Implementation Method 2
The oil control ring, with its irregular annular gap, is also designed to channel a portion of the blowby into the space between the two piston ring scraper lands, allowing a portion of the blowby to flow inward through radial openings in the oil control ring into the ring groove base, from where it is channeled into the crankcase via oil drainage channels or the underlying axial clearance.
Implementation Method 3
Furthermore, the invention attempts to reduce oil flow in an upward direction, i.e., toward the combustion chamber, during throttled operation or overrun.
Implementation Method 4
The two opposite recesses located on both sides of the annular gap widen the annular gap, particularly between the edges of the upper wiper web. This allows the remaining annular gap to be made (significantly) smaller by a factor of 2 to 3 than would be possible with conventional rings. The annular gap on the upper flank surface is a factor of 2 to 5 larger than the annular gap in the installed state.
Data Source
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AI summary
The invention relates to an oil scraper ring (4) comprising a ring element (6), having an upper ring edge (8), a lower ring edge, a ring inner side and a ring outer side (14), wherein the ring element (6) is provided with two opposing contact surfaces (20), between which there is a ring gap (18), wherein the ring element (6) is provided with at least one scraper bar (24, 26) on the ring outer side (14), and wherein the oil scraper ring (4) is provided with two recesses (28), each arranged on each contact surface (20), and each adjoining at least on the ring outer side (14),the respective contact surface (20) and the upper ring edge (8).