Segmented Scraper Ring With 360-Degree Cylinder Wall Sealing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing piston rings with end gaps allow oil to leak into the combustion chamber, leading to increased oil consumption, surface deposits, emissions, and unintentional ignition in power systems.

Innovation Solution

A scraper ring with an arcuate body and split projections that form 360-degree contact with the cylinder wall to limit oil entry, featuring grooves for fluid venting between the projections to manage pressure and prevent oil ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If expandable rings with end gaps are used to seal the combustion chamber, then the piston can compress and ignite the air-fuel mixture, but oil can flow directly into the combustion chamber through the end gaps

Engineering Contradiction:
Improvecombustion chamber sealingVSAvoidoil consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The scraper ring is divided into two separate arcuate segments that can be assembled together, allowing the end gaps of individual segments to be positioned such that they do not align, thereby preventing continuous oil leakage paths while maintaining sealing effectiveness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The scraper ring acts as an intermediary component between the piston and cylinder wall, with its specific geometry and material properties designed to scrape oil from the cylinder wall and prevent it from entering the combustion chamber through the ring end gaps

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of substance

If expandable rings are used to limit oil entry into the combustion chamber, then oil consumption is reduced, but the rings still permit oil beads to flow directly into the combustion chamber due to end gaps

Engineering Contradiction:
Improveoil consumptionVSAvoidcombustion chamber sealing
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The ring is segmented into multiple arcuate portions with strategically positioned end gaps that do not align when assembled, creating a discontinuous sealing path that blocks oil flow while maintaining combustion chamber sealing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the scraper ring have different functional characteristics - the outer surface is designed for cylinder wall contact and oil scraping, while the inner surface and end gap regions are designed to manage pressure and prevent oil ingress, creating local functional zones that address different aspects of the sealing problem

Inventive Principle:
Principle #3Local quality

3Loss of substance

If the scraper ring forms 360-degree contact with the cylinder wall to prevent oil ingress, then oil consumption is reduced, but pressure buildup may occur between the ring and piston land

Engineering Contradiction:
Improveoil consumptionVSAvoidpressure between ring and piston land
Core Design Contradiction:
Loss of substanceVSStress or pressure

Solution Approach 1:

End gaps are intentionally introduced into the otherwise continuous 360-degree ring structure, extracting or removing small sections to create pressure relief pathways that prevent dangerous pressure buildup while maintaining effective oil scraping functionality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ring design incorporates specific geometric parameters including gap size, position, and cross-sectional dimensions that are optimized to balance oil sealing effectiveness with pressure management, allowing the ring to adapt to varying operating conditions

Inventive Principle:
Principle #35Parameter changes

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 scraper ring effectively reduces oil consumption, emissions, and the risk of unintentional ignition by ensuring 360-degree contact with the cylinder wall and providing a venting mechanism to relieve pressure, improving the overall performance of power systems.

Implementation Method 1

the first contact surface is configured to slidably contact the second contact surface to adjust a diameter of the scraper ring

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the outer surface, the first outer surface, and the second outer surface together define an exterior surface of the scraper ring that extends 360 degrees relative to a central axis of the scraper ring

Methodology Applied
Scientific EffectSurface tension: Surface Tension

Implementation Method 3

at least one of the first projection or the second end surface includes a groove to permit fluid to pass from the interior surface of the scraper ring to the exterior surface of the scraper ring

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4012232A1Scraper ring for a piston
Publication Date: 2022.06.15 CATERPILLAR INC
  • EP4012232A1 patent drawingFigure 1
  • EP4012232A1 patent drawingFigure 2
  • EP4012232A1 patent drawingFigure 3~4

AI summary

A scraper ring (130) for a piston (126) includes a top surface (312, 324, 414) , a bottom surface (314, 326, 416), an inner surface (308, 320, 410), and an outer surface (310, 322,412). The top surface (312, 324, 414) has a first planar portion (312, 414) and a first angled portion (324). The bottom surface (314, 326, 416) has a second planar portion (314, 326) and a second angled portion (416). The second angled portion (416) is configured to slidably contact the first angled portion (324) to adjust a diameter of the scraper ring (130). The inner surface (308, 320, 410) connects the top surface (312, 324, 414) to the bottom surface (314, 326, 416). The outer surface (310, 322, 412) is opposite to the inner surface (308, 320, 410) and is configured to form 360 degrees of contact with a wall (118) of a cylinder (102) to substantially limit an amount of oil entering a combustion chamber (136) of the cylinder (102).