Split Ring Side Rail Protrusion for Engine Oil Control
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Solution Overview
Problem
Conventional side rails in multi-piece oil rings for internal combustion engines face challenges in effectively scraping off oil without increasing friction and fuel consumption, as they either reduce oil scraping efficiency with large radius surfaces or enhance scraping but increase friction with small radius surfaces.
Innovation Solution
A side rail with a split ring shape and a protrusion on its outer peripheral surface, offset from the axial center, which contacts the cylinder inner surface with high pressure to enhance oil scraping during piston downstroke and reduces friction by maintaining a smaller contact width, while the protrusion's design and coating help in sealing and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the outer peripheral surface is formed in a curved surface with a large radius, then friction between the outer peripheral surface and the cylinder inner surface is reduced, but oil scraping-off action is insufficient causing increased oil consumption
Solution Approach 1:
The outer peripheral surface is divided into multiple functional zones: a first curved surface portion with a larger radius for reduced friction during upstroke, a second curved surface portion with a smaller radius for enhanced oil scraping during downstroke, and an axial end surface for sealing. This segmentation allows each portion to perform its specific function optimally without compromising the others.
Solution Approach 2:
Different regions of the outer peripheral surface are given different geometric properties tailored to their specific functions. The first curved surface portion has a larger radius for low-friction sliding during compression and exhaust strokes, while the second curved surface portion has a smaller radius for aggressive oil scraping during intake and combustion strokes. This local differentiation resolves the contradiction between friction reduction and oil control.
2Loss of substance
If the outer peripheral surface is formed in a curved surface with a small radius, then oil scraping-off action is enhanced reducing oil consumption, but surface pressure applied to the cylinder inner surface increases causing increased friction
Solution Approach 1:
The outer peripheral surface is segmented into distinct zones with different radii of curvature. The first curved surface portion uses a larger radius to minimize friction during upstroke, while the second curved surface portion uses a smaller radius to maximize oil scraping efficiency during downstroke. This spatial segmentation allows the side rail to achieve both low friction and effective oil control.
Solution Approach 2:
The side rail exploits the periodic reciprocating motion of the piston to switch between different surface portions. During upstroke (compression and exhaust), the first curved surface portion with larger radius contacts the cylinder wall for low-friction operation. During downstroke (intake and combustion), the second curved surface portion with smaller radius engages for aggressive oil scraping. This periodic utilization of different surface zones resolves the friction-oil control contradiction.
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
The side rail effectively reduces oil and fuel consumption by enhancing oil scraping efficiency and minimizing friction, maintaining sealing properties and reducing wear, thereby improving engine performance.
Implementation Method 1
the outer peripheral surface of the side rail slides on the cylinder inner surface, forming an oil film with an appropriate thickness on the cylinder inner surface and scraping off excess oil adhered to the cylinder inner surface
Implementation Method 2
the outer peripheral surface of the side rail slides on the cylinder inner surface, forming an oil film with an appropriate thickness on the cylinder inner surface
Data Source
AI summary
A side rail (1) is formed in a sprit ring shape with an opening (10) and to be mounted on a space expander (2) in an annular shape to constitute, together with the space expander (2), a multi-piece oil ring (3) used in an internal combustion engine. The side rail (1) includes an outer peripheral surface (14) facing radially outward, an inner peripheral surface (13) facing radially inward, a first axial surface (11) facing a crankcase, a second axial surface (12) facing a combustion chamber and parallel to the first axial surface (11), and a protrusion (20) formed on the outer peripheral surface (14) in a position offset from an intermediate position between the first axial surface (11) and the second axial surface (12) toward the first axial surface (11) and protruding radially outward from the outer peripheral surface (14).