Intermediate Piston Ring with Segmented Gas Guidance
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Solution Overview
Problem
Existing piston rings face challenges in preventing top ring flutter due to increased inter-ring pressure while maintaining effective oil scraping and reducing reverse blow-by, as the larger gap in traditional intermediate rings compromises oil control.
Innovation Solution
The improved intermediate piston rings feature combustion gas guidance with angled end faces and unidirectional gas flow features, such as chamfers and undercuts, to control gas passage and minimize reverse blow-by, while maintaining a minimized outer gap for enhanced oil scraping performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the gap between ring ends of the second piston ring is increased to relieve gas pressure and prevent top ring flutter, then the top ring flutter is reduced, but the oil scraping capability of the second ring deteriorates
Solution Approach 1:
The second piston ring is segmented into multiple functional zones: a first portion with a larger gap for gas pressure relief and flutter prevention, and a second portion with a smaller gap for effective oil scraping. This segmentation allows each zone to independently perform its specific function without compromising the other.
Solution Approach 2:
Different portions of the second piston ring are given different gap sizes tailored to their specific functions. The first portion (dealing with gas pressure) has a larger gap, while the second portion (dealing with oil control) has a smaller gap, optimizing local performance for each requirement.
2Stress or pressure
If the gap between ring ends of the second piston ring is increased to relieve inter-ring gas pressure, then the gas pressure relief is improved, but the reverse blow-by resistance deteriorates
Solution Approach 1:
The second piston ring is divided into functional segments where the first portion handles gas pressure relief with a larger gap, while the second portion maintains a smaller gap to prevent reverse blow-by, allowing both pressure management and seal integrity.
Solution Approach 2:
The design converts the potentially harmful large gap (which would increase blow-by) into a beneficial feature by strategically positioning it in the first portion for gas pressure relief, while the second portion's smaller gap compensates to maintain reverse blow-by resistance.
3Loss of substance
If the gap between ring ends of the second piston ring is minimized to improve oil scraping, then the oil scraping capability is improved, but the top ring flutter increases due to increased inter-ring pressure
Solution Approach 1:
The second piston ring is segmented into a first portion with minimized gap for oil scraping and a second portion with larger gap for gas pressure relief, allowing simultaneous optimization of both oil control and flutter prevention.
Solution Approach 2:
The second piston ring exhibits local quality variations with different gap sizes in different portions, where the oil-contacting portion has a smaller gap for scraping while the gas-pressure-exposed portion has a larger gap for pressure relief.
Data Source
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AI summary
100461 An improved piston ring (20) for use as an intermediate piston ring in a piston assembly having three or more piston rings is provided. The piston ring includes a piston ring body which extends through an arcuate shape between opposite end faces (22). The piston ring body has at least one combustion gas guidance feature (22, 32) for allowing a greater flow of combustion gasses to pass the piston ring body when the piston is moving in one direction and for allowing a lesser flow of combustion gasses to pass the piston ring body when the piston is moving in an opposite direction. This allows for the ring gap at the outer diameter of the piston ring (20) to be minimized without creating flutter in another piston ring above the intermediate piston ring during operation of an engine.