Asymmetric Cylinder Liner Support for Coolant Flow and Thrust Load
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Solution Overview
Problem
Existing cylinder liners face challenges with mechanical and thermal stresses, particularly at the lower end where coolant can escape into the crankcase, leading to potential damage and reduced reliability due to inadequate support and coolant flow.
Innovation Solution
A cylinder liner design featuring a hollow cylindrical body with a lower liner support having an asymmetric configuration in the circumferential direction, providing reduced clearance around the thrust/anti-thrust plane for increased support and increased clearance around the perpendicular plane for improved coolant flow, incorporating lower seal grooves and members to manage piston side thrusts and heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a tight clearance is provided between the cylinder liner and the cylinder bore to provide structural support, then the mechanical strength and stability of the liner is improved, but the coolant flow is restricted leading to thermal stress and potential pitting
Solution Approach 1:
The patent applies local quality by providing different clearance characteristics at different locations of the cylinder liner. The lower portion (first region) has a first clearance characteristic optimized for structural support, while the upper portion (second region) has a second clearance characteristic optimized for coolant flow. This allows each region to have the appropriate clearance for its specific functional requirements without compromising the other.
Solution Approach 2:
The patent segments the cylinder liner into distinct regions with different clearance characteristics. The lower region near the crankcase is separated from the upper region, allowing independent optimization of clearance in each zone. This segmentation enables the lower portion to provide mechanical support while the upper portion maintains adequate coolant circulation.
2Ease of manufacture
If the cylinder liner has uniform clearance around the entire circumference, then the manufacturing is simplified, but the mechanical support under piston thrust is insufficient leading to liner displacement and damage
Solution Approach 1:
The patent employs asymmetry by providing different clearance characteristics at different circumferential locations of the cylinder liner. The lower portion has reduced clearance in the region corresponding to piston thrust directions to prevent liner displacement, while other regions maintain larger clearance. This asymmetric clearance distribution optimizes mechanical support where needed without uniformly complicating the manufacturing process.
3Temperature
If the clearance is increased to improve coolant flow and prevent thermal stress, then the cooling efficiency is improved, but the mechanical support is reduced leading to increased liner displacement under piston thrust
Solution Approach 1:
The patent applies local quality by providing different clearance characteristics at different locations of the cylinder liner. The lower portion (first region) has a first clearance characteristic optimized for structural support, while the upper portion (second region) has a second clearance characteristic optimized for coolant flow. This allows each region to have the appropriate clearance for its specific functional requirements without compromising the other.
4Shape
If a symmetric clearance configuration is used around the cylinder liner, then the structural balance is maintained, but the support under piston side thrust is inadequate causing liner damage
Solution Approach 1:
The patent employs asymmetry by providing different clearance characteristics at different circumferential locations of the cylinder liner. The lower portion has reduced clearance in the region corresponding to piston thrust directions to prevent liner displacement, while other regions maintain larger clearance. This asymmetric clearance distribution optimizes mechanical support where needed without uniformly complicating the manufacturing process.
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 support of the cylinder liner, reduces stress and displacement caused by piston thrusts, while ensuring effective coolant circulation and flow, thereby increasing the reliability and operating life of the engine by minimizing the risk of pitting and corrosion.
Implementation Method 1
an outer surface of the cylinder liner can form a coolant circulation space for cooling the cylinder liner
Implementation Method 2
A plurality of lower seal grooves are provided in the outer surface of the cylinder liner each of which includes a respective lower seal member. The lower seal grooves are arranged between the coolant cavity and the lower end of the cylindrical body
Implementation Method 3
The lower liner support has an asymmetric configuration in a circumferential direction such that a clearance between the sidewall of the cylinder bore and the outer surface of the cylindrical body is relatively less in a first area surrounding the thrust/anti-thrust plane
Data Source
AI summary
A cylinder liner for a cylinder bore of an internal combustion engine is provided. The cylinder liner including a hollow cylindrical body and a coolant cavity defined between a sidewall of the cylinder bore and an outer surface of the cylinder liner. A plurality of lower seal grooves are provided in the outer surface of the cylinder liner. A lower liner support is arranged between an uppermost one of the lower seal grooves and the coolant cavity. The lower liner support has an asymmetric configuration in a circumferential direction such that a clearance between the sidewall of the cylinder bore and the outer surface of the cylindrical body is relatively less in an area surrounding a thrust/anti-thrust plane and is relatively more in an area surrounding a perpendicular plane.