Offset-Gap Piston Ring Assembly for Hydrogen Blow-By Control
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Solution Overview
Problem
Internal combustion engines face challenges with hydrogen fuel due to issues like air/fuel mixture flow into the crankcase, presence of lubricating oil in the combustion chamber, and increased risk of unintended ignition, leading to reduced efficiency and increased emissions.
Innovation Solution
A piston ring assembly comprising two annular ring elements with gaps that are out of alignment, twisted at an angle to create a labyrinth sealing effect, and designed to minimize friction and prevent oil leakage, thereby enhancing engine efficiency and safety when using hydrogen fuel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single annular piston ring with a gap is used, then assembly is easier and tension is provided to keep contact with the cylinder, but gas flows through the gap causing blow-by that reduces engine efficiency and allows fuel into the crankcase
Solution Approach 1:
The single annular piston ring is segmented into two separate annular ring elements, each with its own gap. This segmentation allows each ring element to be independently assembled while creating a multi-stage sealing system that reduces gas flow through the gaps, thereby maintaining assembly ease while improving sealing efficiency and reducing blow-by.
Solution Approach 2:
The gaps of the two annular ring elements are positioned at different angular positions around the ring circumference, creating a two-dimensional sealing pattern. This angular offset arrangement prevents gas from flowing through both gaps simultaneously, effectively blocking the blow-by path while maintaining the functional benefits of gapped ring design.
2Reliability
If piston rings with gaps are used to allow assembly and provide tension, then the rings can be installed and maintain contact with the cylinder, but gas flows through the gaps leading to unwanted fuel presence in the crankcase
Solution Approach 1:
By dividing the sealing function into two separate annular ring elements with gaps at different angular positions, the system maintains reliable contact stability of each individual ring while creating a more effective barrier against fuel migration. The segmented design ensures that fuel cannot pass through both gaps simultaneously, reducing harmful fuel presence in the crankcase.
3Adaptability or versatility
If hydrogen is used as fuel, then carbon-neutral operation is achieved, but the risk of unintended ignition increases due to higher air/fuel concentrations and oil presence in the combustion chamber
Solution Approach 1:
The dual annular ring element design with offset gaps creates a more effective seal that reduces the presence of oil and air/fuel mixture in the crankcase. This segmentation-based sealing improvement minimizes the conditions that could lead to unintended hydrogen ignition, thereby reducing ignition risk while maintaining carbon-neutral fuel capability.
4Reliability
If oil is present in the combustion chamber for lubrication, then moving parts are protected, but oil ignites with hydrogen generating carbon-dioxide and particulate emissions
Solution Approach 1:
The two annular ring elements with angularly offset gaps create a more effective sealing barrier that reduces oil migration into the combustion chamber. This segmented sealing approach maintains adequate lubrication protection for moving parts while minimizing oil presence that would otherwise ignite and generate harmful carbon-dioxide and particulate emissions during hydrogen combustion.
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 piston ring assembly effectively minimizes blow-by and oil film presence in the combustion chamber, improving engine efficiency and ensuring safe operation with hydrogen fuel by preventing unintended ignition and reducing emissions.
Implementation Method 1
A piston ring assembly comprising two annular ring elements with gaps that are out of alignment, twisted at an angle to create a labyrinth sealing effect
Implementation Method 2
designed to minimize friction and prevent oil leakage, thereby enhancing engine efficiency
Data Source
AI summary
A piston ring assembly includes a first annular ring element having a first gap. The piston ring assembly further includes a second annular ring element having a second gap. The first annular ring element is located above the second annular ring element and is contacting the second annular ring element such that the first gap and the second gap are out of alignment. The first annular ring element has a first radial outer face with a first outer radius and the second annular ring element has a second radial outer face with a second outer radius such that the second outer radius is greater than or equal with the first outer radius.