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, presence of lubricating oil in the combustion chamber, and high risk of unexpected ignition due to hydrogen's flammability and oil combustion, leading to efficiency losses and emissions.

Innovation Solution

A piston ring assembly with an annular basic body and a cover element that seals the gap, minimizing blow-by and oil leakage, while maintaining stability and positioning at high engine speeds, suitable for hydrogen fuel operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a traditional piston ring with a gap is used, then assembly is easier and the ring can provide tension to stay in contact with the cylinder, but gas blow-by increases and fuel leaks into the crankcase

Engineering Contradiction:

Improveassembly easeVSAvoidgas blow-by

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The piston ring is divided into a basic body with a gap and a separate cover element that closes the gap. The basic body provides assembly ease while the cover element eliminates gas blow-by by sealing the gap area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The cover element is extracted as a separate component that specifically addresses the gap sealing function, allowing the basic body to maintain its simple open-ring structure for easy assembly while the cover provides the sealing function.

Inventive Principle:

Principle #2Taking out (Extraction)

2Adaptability or versatility

If the engine operates with hydrogen fuel, then carbon-neutral operation is achieved, but the risk of unexpected ignition increases due to hydrogen's high flammability

Engineering Contradiction:

Improvefuel compatibilityVSAvoidignition safety

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The cover element transforms the potentially harmful gap (which causes blow-by and fuel leakage) into a sealed structure that prevents hydrogen from entering the crankcase, thereby converting a design feature that could lead to ignition risks into a safety-enhancing element.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The cover element proactively prevents hydrogen from reaching the crankcase by sealing the gap before any potential ignition can occur, addressing the safety concern in advance rather than reacting to it.

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If lubricating oil is present in the combustion chamber, then the piston can be lubricated, but oil combustion generates carbon-dioxide and particulate emissions

Engineering Contradiction:

Improvelubrication functionVSAvoidemissions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The cover element extracts and seals the gap area where oil could leak into the combustion chamber, preventing oil combustion and associated emissions while allowing the piston ring to maintain its lubrication function through the basic body's contact with the cylinder wall.

Inventive Principle:

Principle #2Taking out (Extraction)

4Speed

If a lock section design is used for low-speed engines, then the piston ring can be secured, but at high engine speeds the lock section cannot maintain locking and blow-by occurs

Engineering Contradiction:

Improveengine speed rangeVSAvoidlocking stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The piston ring is segmented into a basic body and a cover element, where the cover element replaces the traditional lock section design. This segmentation allows the cover to provide continuous sealing without the locking mechanism failures that occur at high speeds.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a locking mechanism to secure the piston ring at high speeds, the invention inverts the approach by using a cover element that actively seals the gap, providing reliability through sealing rather than through mechanical locking.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20250198512A1Piston ring assembly

Publication Date: 2025.06.19 MAHLE INT GMBH

AI summary

A piston ring assembly is disclosed. The piston ring assembly includes an annular basic body having a gap. A cover element covering the gap of the basic body is provided. The annular basic body having a first end and a second end being arranged adjacent to another separated by the gap. A first recess disposed at the first end and a second recess disposed at the second end such that the first and second recesses leave a respective protrusion at the first end and at the second end. The cover element having a first lateral portion, a middle portion and a second lateral portion. The first and second lateral portions each having a third recess. The cover element is located at basic body such that the middle portion covers the gap and each protrusion is located in a third recess of a lateral portion of the cover element.