Oil Control Ring Side Rail Geometry for High-Speed Oil Sealing
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Solution Overview
Problem
Internal combustion engines experience increased oil consumption when operating at high rotation speeds, which is not effectively addressed by existing oil control ring designs.
Innovation Solution
A side rail with a vertically symmetrical shape and specific curvature conditions for its inner peripheral surface, combined with a spacer expander, to stabilize the side rail's behavior and improve sealing performance at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inner peripheral surface is rounded in a semicircular shape, then the side rail can be easily manufactured, but the oil consumption amount increases at high rotation speeds
Solution Approach 1:
The invention changes the geometric parameters of the inner peripheral surface from a conventional semicircular shape to a specific shape where the curvature radius R1 satisfies 0.7 ≤ R1/h0 ≤ 1.1. This parameter optimization stabilizes the side rail's behavior during high-speed reciprocation, improving sealing performance and reducing oil consumption without complicating the manufacturing process
2Power
If the engine operates at higher rotation speed, then power output increases, but oil consumption amount increases
Solution Approach 1:
By optimizing the curvature radius parameter R1 of the inner peripheral surface to satisfy 0.7 ≤ R1/h0 ≤ 1.1, the invention stabilizes the side rail's dynamic behavior during high-speed operation. This reduces the dominant influence of inertial force on the oil control ring, improving sealing performance and suppressing oil consumption increase even when the engine operates at high rotation speeds for increased power output
3Manufacturing precision
If the inner tip portion curvature radius is small, then the side rail fits better in the groove, but the behavior becomes unstable at high speeds
Solution Approach 1:
The invention identifies and optimizes the curvature radius parameter R1 of the inner tip portion to satisfy 0.7 ≤ R1/h0 ≤ 1.1. This optimal parameter range ensures both adequate fitting precision in the piston groove and stable dynamic behavior during high-speed reciprocation, preventing excessive influence of inertial forces that would cause instability
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 solution effectively suppresses oil consumption even at high engine rotation speeds by ensuring better abutment of the side rail with the piston groove, reducing oil leakage.
Implementation Method 1
the influence of the inertia force is more dominant than the influence of the frictional force. Since the inner tip portion satisfies Condition 1, the center of gravity is shifted to an inner peripheral surface side compared to the side rail of the related art
Implementation Method 2
the behavior of the side rail is affected by frictional force with a cylinder and inertial force associated with reciprocation
Data Source
AI summary
A side rail forms an oil control ring together with a spacer expander, and includes: an outer peripheral surface; an inner peripheral surface having a vertically symmetrical shape in an axial cross section; a first side surface; and a second side surface. The inner peripheral surface includes an inner tip portion satisfying following Condition 1 in an axial cross section.0.7≤R1/h0≤1.1 Condition 1:In the expression, R1 represents a curvature radius (unit: mm) of a curve forming the inner tip portion, and h0 represents a height (unit: mm) of the side rail.