Segmented Oil Ring With Coil Expander For Friction Reduction
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Solution Overview
Problem
Existing internal combustion engine oil rings face challenges in reducing axial width to minimize friction and oil consumption while maintaining effective oil scraping and preventing oil from entering the combustion chamber, as current designs either deform easily or increase friction, leading to inefficiencies and increased oil consumption.
Innovation Solution
The oil ring design features a generally I-shaped cross-section with a coil expander and oil return grooves that include a semicircular recess and straight/curved line configuration, optimizing the radius of curvature and tension to ensure stable pressing force and efficient oil return, thereby reducing oil consumption and improving fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the axial width of the oil ring main body is reduced to minimize friction and oil consumption, then fuel efficiency is improved, but the tension of the oil ring is reduced too much causing deterioration in oil-scraping performance
Solution Approach 1:
The oil ring is divided into two separate components: an oil ring main body and a coil expander. The coil expander is inserted into the oil ring main body and provides additional tension through its spring action, compensating for the reduced tension caused by the narrowed axial width of the main body. This segmentation allows each component to be optimized independently for its specific function.
2Loss of substance
If the axial width of the oil ring main body is reduced, then the amount of oil consumption is reduced, but the oil ring deforms easily during machining and operation
Solution Approach 1:
By separating the oil ring into a main body and a coil expander, the structural integrity is maintained through the coil's elastic properties while the main body can be optimized for reduced width. The coil expander acts as a reinforcement element that prevents deformation.
Solution Approach 2:
The axial width of the oil ring main body is specifically controlled within the range of 1.0 mm to 2.5 mm, and the web thickness is maintained at 0.3 mm or more. These parameter changes optimize the balance between reducing oil consumption and maintaining structural stability during machining and operation.
3Device complexity
If the coil expander is arranged in intimate contact with the inner periphery of the oil ring main body, then the oil ring structure is compact, but most oil return holes are closed inhibiting oil from escaping quickly
Solution Approach 1:
The coil expander is designed to contact the inner periphery of the oil ring main body at specific locations while leaving other areas clear. This local contact approach allows the coil to provide tension without blocking the oil return holes, maintaining both structural compactness and oil return efficiency.
4Productivity
If oversized oil return holes are formed in the oil ring main body to improve oil return, then oil can escape quickly, but the strength of the oil ring main body is reduced
Solution Approach 1:
The oil return holes are designed with specific dimensional parameters that optimize both oil return efficiency and structural strength. The holes are sized and positioned to provide adequate oil passage while maintaining the integrity of the oil ring main body, particularly the web section.
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 configuration stabilizes the pressing force against the cylinder inner wall, prevents oil from entering the combustion chamber, and reduces oil consumption, enhancing fuel efficiency in both gasoline and Diesel engines by ensuring long-term effective oil scraping and return.
Implementation Method 1
The coil expander is intended to improve the oil-scraping performance of the oil ring by pressing and biasing the oil ring main body radially outward
Implementation Method 2
Respective outer peripheral sliding surfaces of the upper rail and lower rail slide over a cylinder inner wall surface through an oil film when a piston reciprocates
Data Source
Figure 1~2
Figure 3~3(a)
Figure 4~5
AI summary
An object of this invention is to provide an internal combustion engine oil ring which stably retains, for a long period, the function of scraping excess oil from a cylinder inner wall surface and letting the excess oil flow down to an underside of a piston and ensures reduction in the amount of oil consumption when an internal combustion engine is driven. In order to achieve the object, there is adopted an internal combustion engine oil ring, wherein an oil ring main body includes, along an inner peripheral surface, a coil expander receiving recess having a generally semicircular shape in cross-section in an oil ring axial direction, an inner peripheral surface of the coil expander receiving recess has an oil return groove formed along an inner peripheral direction for smoothly returning scraped oil to an underside of a piston, and an outer peripheral shape of the oil return groove is composed of a straight line and a curved line continuous with the straight line in cross-section in the oil ring axial direction.