Tapered Combined Oil Ring for Reduced Engine Oil Consumption
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Solution Overview
Problem
Conventional combined oil rings face challenges in reducing engine oil consumption due to increased contact area during initial sliding contact, which hampers their ability to effectively scrape off excess engine oil, leading to higher oil consumption and environmental concerns.
Innovation Solution
The combined oil ring features a pair of upper and lower side rails with a tapered cross-sectional shape along the axial direction, a curved shape near the lower end, and a barrel-shaped lower side rail, along with a spacer expander, to optimize oil scraping and reduce contact area, and includes front-back detection means and surface treatment to prevent erroneous installation and reduce sliding resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact area of the side rail is increased to improve sealing performance, then the sealing performance is improved, but the oil scraping function cannot be fully exerted and oil consumption increases
Solution Approach 1:
The side rail is designed with different cross-sectional shapes in different regions: a tapered shape in the initial contact region to reduce contact area and improve oil scraping, and a curved shape near the lower end to increase contact area for sealing. This local differentiation allows the same component to optimize both oil scraping and sealing functions in different zones.
Solution Approach 2:
The side rail's cross-sectional shape is segmented into distinct regions with different geometries - the tapered portion (with vertex within 0.15mm from lower end) and the curved portion (with curvature R0.01 to 0.5). This segmentation enables each region to perform its specific function optimally without compromising the other.
2Reliability
If the contact area increases in the initial stage of sliding contact to improve sealing, then sealing is improved, but the engine oil scraping function cannot be fully exerted
Solution Approach 1:
The tapered shape is designed to act in the preliminary stage of sliding contact (initial contact region), where it reduces contact area to enable effective oil scraping. As the ring settles into position, the curved shape near the lower end provides the necessary sealing contact, ensuring both functions are fulfilled at appropriate stages.
3Reliability
If conventional oil ring designs are used to maintain sealing performance, then sealing is maintained, but oil consumption remains high due to insufficient oil scraping
Solution Approach 1:
The invention changes the geometric parameters of the side rail cross-section, specifically implementing a tapered shape with a vertex within 0.15mm from the lower end and a curved shape with curvature R0.01 to 0.5. These parameter modifications optimize the balance between oil scraping efficiency and sealing performance, resulting in reduced oil consumption and lower energy loss.
Data Source
AI summary
Provided is a combined oil ring that further reduces engine oil consumption.A combined oil ring attached to an oil ring groove of a piston includes: a pair of upper and lower side rails each formed into a flat annular shape, and having a slide contact part that comes into sliding contact with a cylinder; and a spacer expander arranged between the pair of upper and lower side rails. In at least the upper side rail of the pair of upper and lower side rails, a cross-sectional shape of the slide contact part along an axial direction of the piston is a tapered shape linearly spreading from upper to lower parts of the piston; the tapered shape is at an angle of 5 to 30 degrees with respect to a central axis of the spacer expander, and has a vertex of the tapered shape within 0.15 mm from a lower end of the side rail; and a part closer to the lower end than the vertex is formed into a curved shape having a curvature of R0.01 to 0.5.