Undulating Cooling Jacket Base for Cylinder Liner Distortion
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Solution Overview
Problem
Existing cooling jacket designs for internal combustion engines face issues with liner distortion, mechanical stress, and inadequate cooling due to concentrated load introduction and thermal gradients, especially in high-performance engines with increasing specific output.
Innovation Solution
The cooling jacket's bottom is designed with a steeply rising and falling structure, featuring flat sections parallel to the cylinder head plane and inclined sections normal to the cylinder axes, distributing mechanical and thermal loads uniformly and maximizing the cooling effect across the cylinder liner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cooling jacket bottom is located at a large distance from the cylinder head gasket plane, then the cylinder head bolts have no negative impact on the cylinder liner, but the cooling jacket volume increases and warm-up time increases
Solution Approach 1:
The cooling jacket bottom is segmented into alternating raised and recessed sections, creating a structured pattern that distributes bolt loads across multiple zones while maintaining compact overall dimensions. This segmentation allows the cooling jacket to achieve both structural support and space efficiency.
Solution Approach 2:
The cooling jacket bottom features locally varying geometry with raised sections positioned to receive bolt loads and recessed sections providing cooling passages. This local differentiation optimizes both mechanical strength at load points and thermal management in cooling zones.
2Ease of manufacture
If the cooling jacket bottom is made flat, then manufacturing is simplified, but bolt force transfer causes local stress concentrations and liner distortion
Solution Approach 1:
The cooling jacket bottom incorporates curved transitions between raised and recessed sections, eliminating sharp corners that would concentrate stress. The curved geometry distributes bolt loads more evenly while maintaining manufacturing feasibility through standard casting or machining operations.
3Strength
If the cooling jacket bottom has a wave-like structure, then bolt load distribution improves, but coolant flow separation occurs and cooling efficiency decreases
Solution Approach 1:
The transitions between raised and recessed sections use curved surfaces with optimized radii to guide coolant flow smoothly around the structured bottom. This curvature prevents flow separation and turbulence while maintaining the load-distributing wave-like pattern.
Solution Approach 2:
The dimensions of the raised and recessed sections, including their widths, heights, and transition radii, are specifically optimized to balance mechanical load distribution with coolant flow characteristics. These parameter adjustments ensure both structural integrity and thermal efficiency.
4Loss of time
If the cooling jacket volume is reduced, then warm-up time decreases, but inadequate cooling occurs in cylinders furthest from the coolant supply
Solution Approach 1:
The structured bottom creates multiple localized cooling zones distributed across the cylinder block, with recessed sections positioned to cool specific cylinder areas. This segmentation ensures all cylinders receive adequate cooling regardless of distance from the main coolant supply.
Solution Approach 2:
The cooling strategy transitions from relying solely on coolant flow path length to utilizing the vertical dimension created by the structured bottom. Raised and recessed sections create three-dimensional cooling pathways that reach all cylinder zones efficiently within a compact volume.
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 minimizes liner deformation and thermal constriction, ensuring efficient heat dissipation and reduced mechanical stress, while maintaining optimal coolant flow and reducing piston friction.
Implementation Method 1
the water jackets for cylinder liner cooling in the cylinder block extend over the entire height of the cylinder liner. This enables complete liner cooling with only minimal liner distortion due to thermal effects during combustion.
Implementation Method 2
adequate cooling of all cylinders in the cylinder block area cannot be satisfactorily ensured
Implementation Method 3
The load transfer from the cylinder head bolts into the cylinder block in the piston-running area causes liner distortion and strength problems. This bolt force transfer leads to local stress concentrations in the cooling jacket bottom.
Implementation Method 4
Due to the differing temperature gradient along the longitudinal axis of the cylinder liner and the cooling jacket bottom's position in the piston-running area, mechanical and thermal compression of the liner occurs, resulting in liner distortion and load-bearing capacity issues.
Data Source
Figure 1~4
AI summary
The invention relates to a liquid-cooled internal combustion engine comprising at least one cylinder block which has a cooling jacket (1) and comprises multiple cylinders (2). The cooling jacket (1) has a base (3) facing a crankcase and a cover (4) facing a cylinder head sealing plane (4a), and the base (3) has an undulating course when seen in a lateral view of the cylinder block. A first spacing (H2) between two adjacent cylinders (2) in the region of at least one first motor transverse plane (8) is larger than a second spacing (H2) between the base (3) of the cooling jacket (1) and the cover (4) in the region of at least one second motor transverse plane (10) containing the cylinder axis (9) when measured in the direction of the cylinder axis (9) in both cases. In order to minimize cylinder deformations, the base (3) of the cooling jacket (1) has at least one first flat section (12) arranged on a first reference plane (ε1) in the region of the first motor transverse plane (8), wherein the first reference plane (ε1) is preferably formed parallel to the cylinder head sealing plane (4a) of the cylinder block. Thus, the base (3) has a roof-like shape starting from the flat section in the region between the screws in the free cylinder lining region (the cylinder tube between the tapped holes).