Cross Fin Cooling Structure for Engine Cylinder Head Castability
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Solution Overview
Problem
Forced air-cooling type internal combustion engines face challenges in balancing castability and cooling efficiency, particularly when thin cooling fins are placed at narrow interspaces, which can lead to casting insufficiencies and reduced cooling effectiveness.
Innovation Solution
The engine design incorporates cross fins that intersect with cooling fins, with a thicker leading edge than the cooling fins, connected to the combustion chamber wall, and a fan that directs air through the shroud to enhance cooling efficiency while maintaining castability. The cross fins are angled at 45° or less relative to the fan axis and increase in thickness towards the cylinder block, optimizing heat transfer and air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thin cooling fins are placed at narrow interspaces to increase the number of cooling fins, then cooling efficiency is improved, but melt permeability around the cooling fins is lowered, causing casting insufficiencies
Solution Approach 1:
The cross fin is designed with non-uniform thickness, being thicker at the leading edge (root side) and thinner at the tip side. This local quality variation allows the root portion to ensure adequate melt permeability during casting, while the thinner tip portion maintains effective cooling surface area and heat dissipation capability.
Solution Approach 2:
The invention introduces cross fins that extend in a direction crossing the cooling fins (transverse direction), adding a new dimensional element to the traditional longitudinal cooling fin structure. This creates a three-dimensional cooling fin network that improves both castability and cooling efficiency simultaneously.
2Area of stationary object
If the thickness of cooling fins is reduced to increase the number of fins, then cooling surface area is increased, but structural strength and heat transfer capability are reduced
Solution Approach 1:
The cross fin employs variable thickness with the leading edge being thicker than the tip, concentrating structural strength and heat transfer capability where most needed (at the root connection point) while maintaining adequate cooling surface area at the thinner tip portions.
Solution Approach 2:
The combination of cross fins and cooling fins creates a composite cooling structure that integrates both longitudinal and transverse heat dissipation pathways, effectively increasing the overall cooling surface area while maintaining structural integrity through the intersecting fin pattern.
3Temperature
If narrow interspaces between cooling fins are used to pack more fins, then cooling efficiency is enhanced, but air flow between fins is restricted
Solution Approach 1:
The cross fin introduces a transverse dimension to the cooling fin structure, creating additional air flow pathways that cross between cooling fins. This three-dimensional fin arrangement allows air to flow through multiple channels, effectively increasing total air flow capacity despite narrow interspaces between individual cooling fins.
Solution Approach 2:
The cross fin divides the continuous cooling fin structure into segmented sections, creating multiple discrete air flow channels. This segmentation allows air to pass through various pathways around and between the fins, improving overall air flow distribution and cooling efficiency.
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 improves both castability and cooling efficiency by preventing melt permeability deterioration and ensuring sufficient air flow between cooling fins, allowing for effective heat transfer and efficient cooling while maintaining engine performance.
Implementation Method 1
a fan for rotating to introduce air to an inside of the shroud
Implementation Method 2
a multitude of cooling fins are provided on the surface of the internal combustion engine for improving the cooling efficiency
Data Source
AI summary
There is provided a forced air-cooling type internal combustion engine which excels in both castability and cooling efficiency of a cylinder head and/or a cylinder block. A forced air-cooling type internal combustion engine (101) includes: a cylinder block (103) molded by casting; a cylinder head (100) molded by casting and overlaid on the cylinder block; a shroud (130) covering at least a portion of the cylinder block and at least a portion of the cylinder head; and a fan (121) for rotating to introduce air to the inside of the shroud. At least one of the cylinder block and the cylinder head includes a cooling fin (10) formed at least in a portion covered by the shroud and a cross fin (20) provided so as to cross the cooling fin, the cross fin being connected to the cooling fin. A thickness ( t' ) of the cross fin at a leading edge ( 20a ) thereof is greater than a thickness ( t ) of the cooling fin at a leading edge thereof.