Flared Cylinder Liner for Thermal Expansion Management
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Solution Overview
Problem
The design of internal combustion engines with jacketed cylinders faces challenges in maintaining homogeneous contact surfaces between the cylinder block and cylinder head due to thermal expansion and stress, leading to potential cracking and compromised sealing, especially in the space between neighboring cylinders where cooling is difficult and thermal expansion of light metal alloys causes pressure on the cylinder head gasket and liners.
Innovation Solution
A cylinder liner design with a flared outer wall and striations to improve contact with the cylinder block, allowing for expansion compensation and maintaining minimal space between liners, ensuring homogeneous contact and reduced thermal stress, while the flared section can be conical or domed to accommodate manufacturing constraints and thermal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cylinder liner is used to provide rigidity and resistance to friction, then the cylinder becomes sufficiently hard to resist piston friction, but thermal expansion of the light metal alloy cylinder block causes non-homogeneous contact surfaces and potential cracking
Solution Approach 1:
The invention applies different properties to different parts of the cylinder liner: the upper part has a flared outer wall to accommodate thermal expansion and maintain contact surface homogeneity, while the lower part maintains the traditional cylindrical shape for rigidity and friction resistance. This local differentiation resolves the contradiction between strength and sealing reliability.
2Volume of moving object
If the space between neighboring cylinders is minimized to improve structural compactness, then the engine becomes more compact, but thermal expansion causes pressure on the cylinder head gasket and liners leading to cracking
Solution Approach 1:
The invention changes the geometric parameter of the cylinder liner's outer wall in the upper part, creating a flared shape that provides expansion space. This parameter change allows the liner to accommodate thermal expansion without causing excessive pressure on the cylinder head gasket, while maintaining minimal space between cylinders for structural compactness.
3Weight of moving object
If the cylinder block is made of light alloy to reduce weight, then the engine becomes lighter, but the contact surface between cylinder block and cylinder head becomes non-homogeneous due to thermal expansion
Solution Approach 1:
The flared outer wall design applies locally to the upper part of the cylinder liner where contact with the cylinder head occurs. This local modification compensates for thermal expansion effects in the light alloy cylinder block, ensuring homogeneous contact surfaces at the critical sealing interface while maintaining the overall lightweight construction.
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 design enhances the structural integrity and sealing efficiency by minimizing space between cylinder liners, reducing thermal stress, and maintaining a consistent contact surface for the cylinder head gasket, thereby improving the engine's resistance to operational stresses and thermal expansion.
Implementation Method 1
The outer wall (4) of the cylinder liner is provided with striations (8) in order to improve the intimate connection between the cylinder block (C) and the liner (2)
Implementation Method 2
the outer wall (4) of the cylinder liner comprises an upper part (6) flared towards the upper edge (5) of the liner
Data Source
Figure 1~7
Figure 3
AI summary
The invention relates to a cylinder sleeve (2) for lining the cylindrical wall of a cylinder (A1) of an internal combustion engine. The inventive sleeve (2) comprises an inner wall (3) which is intended to guide a piston in translation and an outer wall (4) which is intended to rest on the cylindrical wall of the cylinder. The outer wall (4) of the sleeve of the cylinder (2) comprises an upper part (6) which is flared toward an upper edge (5) of the sleeve (2), which is defined between the inner (3) and outer (4) walls of the cylinder sleeve. The invention also relates to a cylinder block of an internal combustion engine, comprising at least two cylinders (A1, B1) which are each equipped with one such cylinder sleeve.