Stationary Piston Ring With Radial Ridges and Oil Drainage
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Solution Overview
Problem
Existing internal combustion engine piston rings face challenges in maintaining a stable seal and efficient oil drainage while allowing piston movement without compromising skirt length, particularly at the bottom dead center position.
Innovation Solution
A piston ring design featuring a ring body with radially inward ridges, a circumferentially surrounding spring for biasing the ridges against the piston body, and oil drainage ports between the ridges and the spring groove, which remains stationary in a channel of the cylinder wall to enhance stability and oil management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piston ring is designed to move with the piston body during reciprocation, then it can maintain sealing contact with the piston body, but it compromises the stability of the piston body and requires longer skirt length
Solution Approach 1:
The sealing function is segmented from the piston body by placing the piston ring in a stationary channel in the cylinder wall, separate from the moving piston body. The ring body with ridges provides sealing contact with the piston body skirt while the ring itself remains stationary, thus maintaining sealing reliability without compromising piston stability or requiring longer skirt length.
Solution Approach 2:
Instead of the conventional approach where the piston ring moves with the piston body, this invention inverts the arrangement by making the piston ring stationary in the cylinder wall channel while the piston body moves past it. This reversal allows the sealing surface to be stationary, providing stability without requiring the piston skirt to extend longer.
2Ease of operation
If oil drainage ports are added to convey oil out of the space between ridges, then oil management is improved, but the device complexity increases
Solution Approach 1:
The ring body incorporates oil drainage ports that function similarly to porous structures, allowing oil to pass through from the space between the ridges to the groove and then to the crankcase. This integrated drainage feature is built into the ring body structure itself, providing effective oil management without requiring separate external drainage systems or complex additional components.
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 provides a stable gas and oil tight seal throughout the piston's range of travel, maintains increased stability of the piston body, and allows for effective oil drainage without reducing the skirt length, even at the bottom dead center position.
Implementation Method 1
a spring which substantially circumferentially surrounds the ring body and biases the ring body in the radially inward direction for sealing the ridges on the inner face against the piston body
Implementation Method 2
at least one oil drainage port which extends radially between the valley region of the inner face and the groove on the outer surface for conveying oil out of the space between the ridges to the groove
Data Source
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AI summary
A power cylinder assembly for an internal combustion engine is provided. The power cylinder assembly includes a cylinder wall having a channel formed therein and a piston body with a skirt. A piston ring is seated within the channel of the cylinder wall and is sealed against the skirt of the piston body. Specifically, the piston ring has a ring body with an inner face that presents two radially inwardly extending ridges spaced axially from one another by a valley region, and the outer face presents a groove which receives a spring to bias the ridges into sliding engagement with the outer surface of the skirt of the piston body. The ring body also has at least one oil drainage port which extends radially between the valley region of the inner surface and the groove of the outer face for conveying oil from between the ridges into the groove.