Cylinder Liner Texture and Wall Thickness for Bore Temperature Uniformity
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Solution Overview
Problem
Internal combustion engines face challenges with non-uniform bore wall temperatures in cylinder liners, leading to distortion and reduced engine efficiency due to varying thermal expansion, which results in increased blow-by, lubricant consumption, noise, and decreased fuel economy.
Innovation Solution
A cylinder liner with varying specific surface areas and diameters along its axial length, featuring different textures and thermal conductivities to manage temperature uniformity, is integrated into the engine block, providing a controlled thermal conductivity profile that complements engine operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a uniform cylinder liner is used, then manufacturing is simple, but bore wall temperature becomes non-uniform leading to distortion
Solution Approach 1:
The cylinder liner incorporates varying wall thicknesses at different axial positions, with the lower portion having a greater wall thickness than the upper portion. This local variation in structural properties compensates for the non-uniform temperature distribution, maintaining more uniform bore wall temperatures throughout the liner length.
Solution Approach 2:
The liner's geometric parameters are changed along its length, specifically the wall thickness varies axially to control thermal conductivity and heat distribution. This parameter variation allows the liner to adapt to different thermal conditions at different heights, improving overall temperature uniformity.
2Temperature
If cooling jacket is added, then thermal management is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The cooling jacket is integrated directly into the cylinder block structure, merging the cooling function with the structural component. This eliminates the need for separate cooling components and reduces overall device complexity while maintaining effective thermal management.
Solution Approach 2:
The cylinder block serves multiple functions: it provides structural support for the engine and simultaneously acts as a cooling system through the integrated cooling jacket. This multi-functionality reduces the number of separate components needed and simplifies the overall device structure.
3Shape
If bore wall temperature is non-uniform, then thermal expansion varies causing distortion, but uniform temperature requires complex thermal management
Solution Approach 1:
The liner wall thickness is locally optimized at different axial positions, with thicker walls in the lower portion and thinner walls in the upper portion. This local structural differentiation compensates for temperature variations and maintains bore cylindrical shape without requiring complex active thermal control systems.
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 solution achieves a more uniform bore wall temperature, reducing distortion and friction, thereby improving engine efficiency, reducing blow-by and lubricant consumption, and enhancing fuel economy.
Implementation Method 1
a cylinder block commonly has a cooling jacket with a circulating fluid flowing therethrough to cool the block and the cylinder liners in the block
Implementation Method 2
a cooling jacket with a circulating fluid flowing therethrough to cool the block
Implementation Method 3
A specific surface area and a diameter of the outer surface vary with an axial position on the liner to provide a thermal conductivity that varies with the axial position
Data Source
AI summary
A method of forming an engine is provided. A liner is cast with an outer surface with a first texture extending circumferentially from a first end to a second end of the liner. A section of the outer surface of the liner is machined to provide a second texture extending circumferentially about the liner and spaced apart from the first end, wherein the second texture has a lower specific surface area than the first texture. An engine and a cylinder liner for the engine are provided. The liner has first and second ends with an outer surface extending therebetween. An outer surface of the liner has axial sections defining different textures to form material interfaces with the block with different thermal conductivities thereacross.