Gap-Covered Piston Ring Assembly for Hydrogen Blow-By Sealing

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Solution Overview

Problem

Internal combustion engines face challenges with hydrogen fuel, including air/fuel mixture flow into the crankcase, lubricating oil presence in the combustion chamber, and high blow-by and oil leakage due to the flammability of hydrogen and its interaction with engine components.

Innovation Solution

A piston ring assembly design featuring an annular basic body with a gap covered by a cover element, which includes protrusions to block gases and secure the cover element in place, minimizing blow-by and oil leakage even at high engine speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a traditional piston ring with a gap is used, then assembly is easier and the ring can be installed in the piston groove, but gas leakage (blow-by) increases and fuel enters the crankcase

Engineering Contradiction:

Improveassembly easeVSAvoidsealing performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The piston ring is divided into two separate components: a basic body (annular ring) and a cover element. The basic body can be easily assembled in the piston groove with its gap, while the cover element seals the gap to prevent gas leakage. This segmentation allows each component to fulfill its specific function optimally.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover element is positioned over the gap of the basic body, with the cover element containing recesses that receive protrusions from the basic body. This nested arrangement creates a sealed structure while maintaining ease of assembly, as the components fit together like nested dolls.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If a lock section is added to the piston ring to prevent opening, then sealing improves, but at high engine speeds the lock section cannot maintain locking and blow-by occurs

Engineering Contradiction:

Improvering stabilityVSAvoidengine speed performance

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The connection between the basic body and cover element uses dynamic protrusions and recesses that can accommodate high-speed vibrations and movements. The protrusions fit into the recesses with sufficient clearance to allow for dynamic movement at high engine speeds while maintaining the sealed structure.

Inventive Principle:

Principle #15Dynamics

3Reliability

If the gap in the piston ring is reduced to minimize blow-by, then sealing improves, but assembly becomes more difficult and tension application is compromised

Engineering Contradiction:

Improvesealing performanceVSAvoidassembly ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By separating the sealing function (cover element) from the structural function (basic body), the design allows the basic body to maintain a practical gap size for assembly and tension application, while the cover element provides the sealing barrier.

Inventive Principle:

Principle #1Segmentation

4Adaptability or versatility

If hydrogen is used as fuel, then carbon-neutral operation is achieved, but air/fuel mixture flow into the crankcase and oil presence in combustion chamber increase due to blow-by

Engineering Contradiction:

Improvefuel type compatibilityVSAvoidflammability and emissions

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The piston ring assembly uses simple metal components (basic body and cover element) that can be manufactured cost-effectively and replaced if needed, providing a practical solution for hydrogen fuel compatibility without requiring expensive specialized materials.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4571149A1Piston ring assembly

Publication Date: 2025.06.18 MAHLE INT GMBH

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AI summary

The invention relates to a piston ring assembly (10) comprising an annular basic body (15) having a gap (17) and comprising a cover element (16) covering the gap (17) of the basic body (15), whereas the annular basic body (15) having a first end (18) and a second end (19) being arranged adjacent to another separated by the gap (17), the basic body (15) having a radial outer face (20, 28) and a radial inner face (21), the basic body (15) having a first axial face (22) and a second axial face (23), whereas the basic body (15) has a first recess (24) at the first end (18) and has a second recess (25) at the second end (19) such that the first and second recesses (24, 25) leave a respective protrusion (26) at the first end (18) and at the second end (19), whereas the cover element (16) having a first lateral portion (33), a middle portion (34) and a second lateral portion (35), the middle portion (34) is located between the lateral portions, the first lateral portion (33) and the second lateral portion (35) each having a third recess (36), whereas the cover element (16) is located at basic body (15) such that the middle portion (34) of the cover element (16) covers the gap (17) of the basic body (15) and each protrusion (26) of an end (18, 19) of the basic body (15) is located in a third recess (36) of a lateral portion of the cover element (16).