Gap Member for Internal Combustion Engine Sealing
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Solution Overview
Problem
Internal combustion engines face challenges in improving fuel economy, achieving low emissions, and preventing cylinder liner breakage due to fuel and lubricating oil entering gaps between the cylinder head and liner, leading to abnormal combustion.
Innovation Solution
The introduction of a gap member with a lower Young's modulus than the seal portion, disposed between the cylinder head and cylinder liner, suppresses fuel and oil entry into these gaps, allowing the fastening force to primarily act through the seal portion, reducing shearing forces on the cylinder liner and enhancing assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal member is sandwiched between the cylinder block and cylinder head to provide high sealing performance, then sealing performance is improved, but fuel and lubricating oil may still enter the gap between cylinder head and cylinder liner causing abnormal combustion
Solution Approach 1:
The sealing system is divided into two distinct components: a seal member for sealing between the cylinder block and cylinder head, and a gap member for preventing fuel and oil entry into the gap between cylinder head and cylinder liner. This segmentation allows each component to specialize in its specific sealing function, improving overall reliability while preventing harmful factors.
Solution Approach 2:
The gap member acts as an intermediary component placed in the gap between the cylinder head and cylinder liner. This mediator prevents direct contact between fuel/oil and the gap space, blocking the harmful effect before it can cause abnormal combustion, while not interfering with the primary sealing function of the seal member.
2Strength
If fastening force is applied by bolts to secure cylinder head and cylinder block, then assembly strength is improved, but shearing force may act on the cylinder liner causing breakage
Solution Approach 1:
The gap member is extracted as a separate component that specifically addresses the shearing force problem. By placing this compliant element in the gap, it absorbs and distributes the shearing forces generated by bolt fastening, preventing these forces from being transmitted directly to the cylinder liner while maintaining overall assembly strength.
Solution Approach 2:
The gap member is designed with specific material parameters (Young's modulus, thickness) that differ from the rigid seal member. By changing the mechanical parameters of the component in the gap, it provides compliance that reduces shearing forces on the cylinder liner while still maintaining sufficient fastening strength through the seal portion.
3Reliability
If a rigid seal portion is used to prevent fuel entry, then sealing performance is improved, but assembly efficiency decreases due to difficulty in fitting
Solution Approach 1:
Different parts of the sealing system have different mechanical properties: the seal member has high rigidity for sealing performance, while the gap member has lower rigidity (lower Young's modulus) for ease of assembly. This local differentiation of material properties allows each component to optimize its function while improving overall manufacturability.
Solution Approach 2:
The sealing system uses composite construction with two different members: a rigid seal member for sealing and a more compliant gap member for assembly ease. This composite approach combines materials with different mechanical properties to simultaneously achieve high sealing performance and easy assembly, resolving the contradiction between rigidity and assembly efficiency.
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
This solution improves fuel economy, achieves low emissions, and reduces cylinder liner breakage by preventing fuel and oil from entering the combustion chamber and minimizing shearing forces on the liner.
Implementation Method 1
the gap member is disposed in the gap between the cylinder head and the cylinder liner on the inner circumferential side of the seal portion, it is possible to suppress a fuel from entering this gap
Implementation Method 2
The seal member is sandwiched between the cylinder head and the cylinder block and pressed by an axial force of the bolt fastening the cylinder head and the cylinder block and exerts high sealing performance
Implementation Method 3
the gap member has a lower Young's modulus than the seal portion. Therefore, when a pressing force is applied by fastening the cylinder body and the cylinder head with a bolt or the like, a repulsive force generated at the seal portion is larger than a repulsive force generated by the gap member being fitted therebetween
Data Source
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AI summary
An engine (10) includes a cylinder liner (21), a cylinder block (20), a cylinder head (30A), a seal portion (41A), and a gap member (50). The seal part (41A) is provided to surround the outer circumferential side of the cylinder liner (21) and configured to seal between the cylinder block (20) and the cylinder head (30A). At a position on the inner circumferential side of the seal part (41A), the gap member (50) fills the gap between the cylinder head (30A) and the end surface of the inner peripheral side of the cylinder liner (21), and is made of a material having a lower Young's modulus than the seal part (41A).