Siamesed Cylinder Liner Cooling Jacket via Lost Core Casting
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Solution Overview
Problem
Conventional cylinder blocks formed using high pressure die casting methods have structural limitations and material constraints that restrict the shape and size of the cooling jacket, affecting both thermal and structural performance, particularly in achieving a closed or semi-open deck face configuration with efficient thermal management.
Innovation Solution
A method involving siamesed cylinder liners with interbore passages and a lost core cast around them, encapsulated in a metal shell, which is then used to form a cylinder block with a cooling jacket that allows for precise control over coolant flow and thermal management, enabling a closed or semi-open deck face design with improved structural stiffness and thermal efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional high pressure die casting method is used to form the cylinder block, then the manufacturing process is simple and productive, but the shape and size of the cooling jacket are restricted by structural limitations and material selection
Solution Approach 1:
The invention divides the cylinder block into multiple segments: cylinder liners, cooling jacket, and block material. The cooling jacket is formed as a separate castable core that is inserted into the mold cavity, allowing independent design and formation of the cooling jacket shape without being constrained by the overall block casting process. This segmentation enables complex cooling jacket geometries while maintaining the simplicity of high pressure die casting for the block itself.
Solution Approach 2:
The invention introduces a castable core as an intermediary element that defines the cooling jacket shape. This core is formed separately, inserted into the mold, and then surrounded by the block material during high pressure die casting. The core acts as a mediator that transfers the desired cooling jacket geometry to the final product without requiring complex mold designs or post-casting operations.
2Strength
If the cooling jacket depth is limited by the head bolt pattern and head bolt size, then the structural stiffness is maintained, but the thermal management capability is restricted
Solution Approach 1:
The invention applies local quality by allowing the cooling jacket to have different depths and configurations in different regions of the cylinder block. The castable core enables the cooling jacket to extend deeper in areas requiring enhanced cooling while maintaining adequate structural thickness in areas requiring stiffness. This localized optimization resolves the contradiction between thermal management needs and structural requirements.
3Productivity
If a blade die with a specified draft angle is used during high pressure casting, then the manufacturing process is straightforward, but the shape of the cooling jacket is limited
Solution Approach 1:
The invention applies preliminary action by pre-forming the cooling jacket geometry using a castable core before the actual block casting occurs. The core is prepared in advance with the desired complex shape, then inserted into the mold cavity. This preliminary formation of the cooling jacket shape eliminates the need for complex draft angles or post-casting machining, maintaining high productivity while achieving sophisticated cooling jacket geometries.
Data Source
AI summary
A tool and a method of forming an engine using the tool are provided. The tool includes an insert and at least one die. The insert is formed by forming an interbore passage between first and second siamesed cylinder liners, casting a lost core, and then casting a metal shell. The insert is positioned into a die of the tool and the engine block is cast. The lost core material may then be removed to provide the cooling jacket. The engine includes a cylinder block with a cooling jacket circumferentially surrounding first and second siamesed cylinder liners intersecting a closed deck face. The cooling jacket has first and second widths in first and second axial sections, respectively. An interbore region of the first and second cylinder liners defines first and second interbore cooling passages spaced apart from the deck face and parallel to one another.