Recessed Coke Scraping Ring for Uniform Piston Pressure
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Solution Overview
Problem
Existing coke scraping rings in gas engines cause pressure choking and dead space, leading to piston deformation and reduced fatigue strength due to the narrow clearance between the cylinder piston and the coke scraping ring.
Innovation Solution
A coke scraping ring with a recessed design that provides a widened fluid path and recesses on the combustion-facing side, allowing for a more homogeneous pressure distribution and reduced dead space, preventing piston deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the clearance between the cylinder piston and the coke scraping ring is reduced to minimize dead space, then the dead space volume is reduced, but the pressure distribution becomes non-uniform causing piston deformation
Solution Approach 1:
The coke scraping ring incorporates recesses at specific locations on its inner surface, creating local variations in the clearance geometry. These recesses are strategically positioned to allow pressure equalization in critical areas while maintaining minimal overall dead space volume, thus resolving the contradiction between minimizing dead space and ensuring uniform pressure distribution.
Solution Approach 2:
The invention introduces a radial dimension variation through the recesses in the coke scraping ring, transforming the previously uniform axial clearance into a multi-dimensional pressure distribution pathway. This allows pressure to equalize radially through the recesses while maintaining minimal axial dead space, solving the pressure uniformity issue without increasing overall volume.
2Stability of the object's composition
If the clearance between the cylinder piston and the coke scraping ring is increased to improve pressure distribution, then the pressure distribution becomes more uniform, but the dead space volume increases
Solution Approach 1:
Rather than uniformly increasing the clearance, the invention applies local clearance variations through recesses only where pressure equalization is needed. This maintains minimal dead space volume overall while providing sufficient pressure distribution uniformity in the critical regions where the recesses are located.
3Volume of stationary object
If a narrow clearance is used between the cylinder piston and the coke scraping ring, then the dead space is minimized, but the pressure becomes choked leading to piston deformation and reduced fatigue strength
Solution Approach 1:
The coke scraping ring is segmented with multiple recesses distributed around its circumference, creating multiple pressure equalization pathways. This segmentation allows pressure to be relieved in a distributed manner rather than through a single choke point, maintaining minimal dead space while preventing pressure-induced piston deformation and preserving fatigue strength.
Solution Approach 2:
Recesses are strategically positioned at locations where pressure buildup would most affect piston integrity, providing localized pressure relief exactly where needed to maintain piston fatigue strength without increasing overall dead space volume.
Data Source
AI summary
The present invention pertains to a coke scraping ring for a cylinder liner of a cylinder used in a gas engine, for scraping carbonaceous residuals (R) off a top land of a piston, comprising a ring body, a top end, a bottom end, and a combustion-facing side configured to be in direct contact with combustion products during operation. The coke scraping ring further comprises a scraping ring section at the bottom end and a recess ring section, configured to provide a recess in the combustion-facing side. The present invention further pertains to a cylinder liner comprising such scraping ring, to a cylinder comprising such cylinder liner, to a gas engine comprising such cylinder and to a gas engine operation method comprising continuous scraping carbonaceous residuals off a top land of a cylinder piston, comprising the steps of assembling a cylinder piston, a coke scraping ring, a cylinder liner, a cylinder crank case and a cylinder head to obtain a ready-to-operate cylinder, operating the cylinder while scraping excess carbonaceous residuals off the top land of a cylinder piston, and observing no pressure-induced deformation on the cylinder piston.