Piston Compression Ring Tapered Surface Oil Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing piston devices for internal combustion engines continue to experience unsatisfactory oil consumption during high-speed and high-load conditions, despite previous designs featuring compression rings with reduced gaps and notches, as oil tends to rise due to axial parallel surfaces and arc-shaped notches.
Innovation Solution
The piston device incorporates a second compression ring with a tapered outer surface and notches on the lower surface, where the gap at the notch is larger than the first compression ring, and the radial thickness decreases towards the upper or lower side, preventing oil rise by allowing blow-by gas to escape and reducing the oil scraping effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the outer circumferential surface is formed as an axial parallel surface, then the manufacturing is simplified, but oil consumption increases during high-speed and high-load driving
Solution Approach 1:
The outer circumferential surface is divided into two regions with different properties: an upper tapered surface (with taper angle 5-15 degrees) and a lower axial parallel surface. The tapered surface is located in the oil rise prevention region while the parallel surface is in the oil scraping region, allowing each region to perform its specific function optimally
Solution Approach 2:
The compression ring structure is segmented into functional zones: the outer circumferential surface is divided into tapered and parallel sections, and the lower surface is divided into regions with different gap sizes (larger gap at notch, smaller gap elsewhere), enabling differentiated performance in different areas
2Device complexity
If arc-shaped notches are formed on the lower surface of ring ends, then the ring structure is modified, but oil rises upward along the arc-shaped surface increasing oil consumption
Solution Approach 1:
Instead of using arc-shaped notches that cause oil to rise upward, the invention uses rectangular notches with horizontal bottom surfaces. This inverted approach prevents oil from rising along the notch surface, and the rectangular shape with larger gap at the notch provides a pathway for blow-by gas to escape, counteracting the oil rise tendency
3Reliability
If the gap between ring ends is reduced to minimum, then compression effectiveness is improved, but blow-by gas cannot escape causing pressure rise and oil upward movement
Solution Approach 1:
The gap distribution is made non-uniform: the gap at the rectangular notch is intentionally made larger than the gap at other sections. This localized larger gap provides an escape path for blow-by gas, while the overall small gaps maintain compression effectiveness. The different gap sizes are positioned at specific locations to address different functional requirements
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 design effectively reduces oil consumption by preventing pressure rise and upward oil movement during high-speed and high-load conditions, while maintaining effective oil scraping and blow-by gas entry.
Implementation Method 1
The second compression ring has a tapered surface on the upper section of the ring outer circumference which serves to suppress the oil scraping effect when the ring is rising so that oil consumption can be reduced further
Implementation Method 2
When the second compression ring makes contact with the lower surface of the ring groove of the piston during driving at high-speeds and high-loads, the blow-by gas flowing into the ring groove escapes from the inner circumferential side of the ring by way of the notch on the lower surface of the ring end to the outer side, so that a rise in pressure at the piston land above the second compression ring can be prevented and therefore the oil can be prevented from rising upwards
Data Source
Figure 1~2
Figure 3~6
Figure 7~12
AI summary
A piston device for internal combustion engines includes a first compression ring (6) and a second compression ring (7) in an outer circumference of a piston (2), wherein the second compression ring (7) includes a notch extending from the inner circumference to the outer circumference on a lower surface (7a) of at least one of a pair of ends of the ring, and a gap between the ring ends at the notch on the second compression ring (7) is larger than a gap between the ring ends of the first compression ring (6), and a gap between the ring ends at the section other than the notch on the second compression ring (7) is the same or smaller than the gap between the ring ends of the first compression ring (6), and the second compression ring (7) contains an outer circumferential surface (12) comprised of a tapered surface (10) decreasing the ring radial thickness towards the upper side, and an axial parallel surface (11) formed below the tapered surface (10). Instead of the axial parallel surface (11), the second compression ring (7) may utilize a tapered surface with a taper angle smaller than the taper angle of the above tapered surface (10); or may utilize a tapered surface decreasing the ring radial thickness towards the lower side.