Cuff-ring Top End Protrusions Cylinder Head Contact
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Solution Overview
Problem
The clearance distance between the carbon scraping ring and the cylinder head in internal combustion engines creates a crevice volume, leading to incomplete combustion and increased emissions, while reducing this distance risks deformation or misalignment due to potential contact between the cuff-ring and the cylinder head during thermal expansion.
Innovation Solution
A cuff-ring with a top end featuring protrusions or recesses is designed to minimize the contact surface with the cylinder head, reducing the compression force and risk of deformation by creating a smaller contact area, potentially a line contact, thereby maintaining alignment and reducing material wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the clearance distance between the carbon scraping ring and the cylinder head is reduced to improve combustion efficiency and reduce emissions, then the crevice volume is minimized, but the risk of contact between the cuff-ring and cylinder head during thermal expansion increases, leading to deformation or misalignment
Solution Approach 1:
The cuff-ring top end is designed with non-uniform geometry featuring protrusions and recesses, creating localized variations in the contact surface. This allows certain areas to make contact with the cylinder head while other areas remain clear, distributing the thermal expansion stresses and preventing uniform deformation that would lead to misalignment.
Solution Approach 2:
The cuff-ring top end incorporates asymmetric features with protrusions extending in specific directions and recesses positioned to create an uneven contact pattern. This asymmetric design allows the ring to accommodate thermal expansion asymmetrically, maintaining alignment while enabling close clearance for improved combustion.
2Object-generated harmful factors
If the cuff-ring is positioned closer to the cylinder head to minimize crevice volume, then emissions are reduced, but the compression force and contact stress increase, causing deformation
Solution Approach 1:
The protrusions and recesses create localized contact zones rather than uniform contact across the entire top end. This concentrates the compression forces on specific areas with enhanced local strength, while other areas provide clearance to prevent stress accumulation that would cause deformation.
Solution Approach 2:
The protrusions and recesses are pre-formed during manufacturing to anticipate and accommodate thermal expansion forces. This preliminary geometric configuration prepares the cuff-ring to handle compression stresses before they occur during engine operation, preventing deformation under load.
3Stability of the object's composition
If the contact surface between the cuff-ring and cylinder head is increased to improve stability, then alignment is maintained, but material wear increases due to higher friction
Solution Approach 1:
The continuous contact surface is segmented into discrete contact zones defined by the protrusions and recesses. This segmentation reduces the total contact area while maintaining stability through distributed contact points, thereby reducing friction and material wear compared to a large continuous contact surface.
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 cuff-ring effectively reduces the risk of deformation and misalignment, minimizing material wear and maintaining engine functionality by optimizing the contact surface between the cuff-ring and the cylinder head, thus improving combustion efficiency and reducing emissions.
Implementation Method 1
to avoid contact between the cylinder head and the carbon scraping ring due to thermal expansion and tolerances of other related engine parts
Data Source
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AI summary
The present disclosure relates to a cuff-ring (12) for a cylinder liner (3) of an internal combustion engine (1). The cuff-ring (12) may comprise a cuff-ring axis (A), a circumferential outer side (13) extending about the cuff-ring axis (A) and configured to contact the cylinder liner (3), a circumferential inner side (14) extending about the cuff-ring axis (A) and being configured to scrape off deposits accumulated on a piston (2) of the internal combustion engine (1). The cuff-ring (12) may further comprise a top end (17) extending in radial direction between the circumferential inner side (14) and the circumferential outer side (13), and a bottom end (23) opposite the top end (17). The top end (17) may include at least one of a protrusion (18) or a recess (25).