Overlapping Piston Ring Taper Profile for Leakage Control
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Solution Overview
Problem
Piston rings in large engines face wear and leakage issues due to extreme conditions, with long tapers providing pressure relief but increasing the risk of leakage at the overlapping region.
Innovation Solution
A piston ring design with a longer axial taper along most of the circumference and a shorter taper adjacent to the overlapping region, featuring a varying outer peripheral profile to maintain pressure cancellation while reducing leakage risk, incorporating a non-tapered or shorter taper at the overlapping region and a larger taper angle to compensate for the shorter extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a long axial taper is provided on the outer peripheral surface, then pressure cancellation function is improved, but the risk of leakage at the overlapping region increases
Solution Approach 1:
The patent applies local quality by providing different taper configurations in different circumferential regions of the piston ring. The first circumferential region (opposite the overlapping region) has a long axial taper for pressure cancellation, while the second circumferential region (at the overlapping region) has a shorter taper to prevent leakage. This localized differentiation resolves the contradiction between pressure relief and sealing effectiveness.
Solution Approach 2:
The outer peripheral surface is segmented into distinct circumferential regions with different taper characteristics. The first region provides long taper for pressure distribution, while the second region provides short taper for sealing. This segmentation allows each region to optimize its function independently, resolving the contradiction between pressure cancellation and leakage prevention.
2Duration of action of stationary object
If a tapered running profile is provided to relieve high pressure, then the service life of the piston ring is extended, but the sealing effect at the overlapping region is compromised
Solution Approach 1:
The patent implements local quality by varying the taper length across different circumferential regions. The long taper in the first region extends service life through pressure relief, while the short taper in the second region maintains sealing effect. This localized approach allows both contradictory requirements to be satisfied in their respective regions.
3Reliability
If the taper start is varied in the vicinity of the overlapping region, then leakage risk is reduced, but the pressure relief function may be compromised
Solution Approach 1:
The patent applies local quality by positioning the taper start at different axial locations in different circumferential regions. In the second region (overlapping area), the taper start is positioned to reduce leakage risk. In the first region (opposite overlapping area), the taper start is positioned to optimize pressure cancellation. This localized positioning resolves the contradiction between leakage prevention and pressure relief.
Data Source
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AI summary
A piston ring is provided. The piston ring comprises a main section extending along a circumferential direction around a geometrical axis, a first tongue section and a second tongue section, wherein, in use, the first tongue section is configured to overlap the second tongue section to form a contacting interface. At the main section, said outer peripheral suface comprises a tapering first surface portion extending in the circumferential direction, wherein said tapering first surface portion has a taper start. Adjacent to said first tongue section, said taper start is located proximally relative to the location of said taper start at the rest of the main section.