Piston Ring Flank Depressions for Wear Reduction
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Solution Overview
Problem
Piston rings in modern internal combustion engines face durability issues due to corrosive and abrasive attacks on their lower flanks, exacerbated by reduced lubricating oil, leading to increased wear and potential failure.
Innovation Solution
The piston ring features varying depth profile depressions on its flanks, which can be filled with soft materials like copper or molybdenum, designed to enhance lubrication and protect against corrosion, with sinusoidal or wavy shapes ensuring effective oil flow and wear reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If lubricating oil is reduced to avoid oil pumping, then harmful emissions are reduced, but wear and corrosion on piston ring flanks increase
Solution Approach 1:
A soft material layer is introduced as an intermediary between the piston ring flank and the groove surface. This layer acts as a mediator that reduces friction and wear while allowing controlled oil distribution, thus protecting the piston ring without requiring excessive lubrication that would cause oil pumping
Solution Approach 2:
The piston ring flank is equipped with depressions at specific locations where soft material is applied. This creates local zones of improved lubrication and corrosion protection exactly where wear occurs most severely, without affecting the overall oil consumption or causing oil pumping
2Reliability
If uniform depth depressions are provided on piston ring flanks, then initial protection is achieved, but protective effect is lost quickly due to wear
Solution Approach 1:
The depressions in the piston ring flank have a contoured, curved bottom shape rather than being flat or uniform. This curved geometry allows the soft material to be distributed and replenished more effectively during operation, maintaining the protective effect for longer periods
Solution Approach 2:
The varying depth profile of the depressions creates periodic variations in oil distribution and material transfer during the piston cycle. This periodic action helps continuously replenish the soft material layer, extending the duration of protective effect
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 significantly improves durability by reducing wear and corrosion on both the lower and upper flanks, maintaining protective effects over a longer period and ensuring efficient lubrication, thus reducing blow-by values and extending piston ring lifespan.
Implementation Method 1
a soft material is placed in one or more of the at least one depression... the soft material comprises a material selected from a group consisting of copper, molybdenum, titanium, chromium, cobalt, nickel, tin, zinc, tungsten, or alloys thereof
Data Source
Figure 1~2B
Figure 3~4
AI summary
The invention relates to a piston ring for an internal combustion engine, comprising at least one recess provided on a ring flank of the piston ring, the at least one recess having a varying depth profile in the peripheral direction of the piston ring.