Dual-Channel Cylinder Liner Cooling for Uneven Combustion Heat

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Solution Overview

Problem

Existing internal combustion engines face uneven heat distribution in cylinder liners due to higher temperatures at the top portion during combustion, leading to inefficiencies in cooling and potential durability issues.

Innovation Solution

A dual-channel cylinder liner design with a first annular coolant channel closer to the top end and a second channel below, separated by an annular ridge, enhances cooling by allowing coolant to efficiently reach and manage heat in both high-temperature and other areas, utilizing smooth surfaces and engineered interfaces to maintain coolant flow without additional seals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single coolant passage is used in the cylinder liner, then the cooling system structure is simple, but the heat distribution management is insufficient due to uneven heat generation in the cylinder liner

Engineering Contradiction:
Improveheat distribution managementVSAvoidcoolant passage structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single coolant passage is divided into two separate passages: a first coolant passage in the upper portion and a second coolant passage in the lower portion. This segmentation allows independent optimization of cooling for different heat zones, with the upper passage addressing combustion heat and the lower passage addressing conduction heat, thereby improving overall heat distribution management without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different coolant passages are provided for different regions of the cylinder liner based on their specific thermal characteristics. The upper coolant passage is positioned to address the high-temperature combustion zone, while the lower coolant passage addresses the heat conduction zone. This local quality approach ensures each region receives appropriate cooling tailored to its thermal profile.

Inventive Principle:
Principle #3Local quality

2Reliability

If coolant passages are positioned away from the top end, then the manufacturing is easier, but the cooling efficiency for the high-temperature combustion zone is reduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcoolant passage positioning
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The first coolant passage is positioned in the upper portion of the cylinder liner, closer to the top end than conventional designs, to proactively cool the combustion zone before heat accumulation reaches problematic levels. This preliminary cooling action prevents excessive temperature rise and maintains combustion efficiency, while the passage geometry is designed to be manufacturable through standard machining processes.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the cylinder liner is designed with features to increase coolant contact surface, then the cooling capacity is improved, but the manufacturing complexity and potential leakage points increase

Engineering Contradiction:
Improvecooling capacityVSAvoidcoolant passage configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Instead of creating a single complex passage with increased surface area, the cooling system is segmented into two separate passages with simpler geometries. Each passage has a relatively simple cross-sectional configuration, reducing manufacturing complexity and potential leakage points while collectively providing sufficient cooling capacity through the distributed cooling approach.

Inventive Principle:
Principle #1Segmentation

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 dual-channel design effectively manages heat distribution, improving engine reliability and operating life by ensuring thorough cooling without compromising durability, even in extreme conditions.

Implementation Method 1

Coolant may be directed through the coolant passage to cool the liners and carry heat energy away from the cylinders

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a coolant pump that pumps coolant into coolant passages of the engine

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3865699B1Internal combustion engine with dual-channel cylinder liner cooling
Publication Date: 2026.04.22 CATERPILLAR INC
  • EP3865699B1 patent drawingFigure 1
  • EP3865699B1 patent drawingFigure 2
  • EP3865699B1 patent drawingFigure 3

AI summary

A cylinder liner (100) is provided that includes a cylinder bore (106) capable of housing a piston (212), a top end (102) having an annular flange (108), a first cylindrical section (114), a second cylindrical section (116), and an annular ridge (112) that separates the first cylindrical section and the second cylindrical section. When employed in a liner bore (210) of an engine block (200), the cylinder liner provides for two channels that allow for coolant to be supplied to the cylinder liner.