Cooling Duct Piston Lining Part Bridging Design
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Solution Overview
Problem
Existing cooling duct piston designs for combustion engines are complex, costly, and prone to contamination from lost core materials in the engine oil circuit, with thermal and mechanical stresses at attachment points facing the combustion chamber.
Innovation Solution
A cooling duct piston design featuring an encircling depression on the piston basic body, bridged by a lining part that forms the cooling duct, eliminating the need for a lost core and providing a robust, cost-effective solution with a cast joint or material bond connection, using materials with varying thermal properties to manage temperature dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a lost core is used to form the cooling duct, then the cooling duct can be produced, but material may remain in the cooling duct causing contamination of the engine oil circuit
Solution Approach 1:
The invention extracts the harmful lost core material from the production process entirely. Instead of using a lost core that needs to be removed, the cooling duct is formed by creating an encircling depression in the piston basic body and bridging it with a lining part. This eliminates the source of contamination (lost core material) while still achieving the desired cooling duct geometry.
Solution Approach 2:
The invention replaces the permanent lost core with a temporary molding approach where the encircling depression is formed during piston basic body production, and the lining part is subsequently added. This disposable-like approach (where the depression form is abandoned after use) avoids the contamination risks of reusable lost cores.
2Strength
If attachment points are provided in the surface facing the combustion chamber, then the lining part can be connected to the piston basic body, but thermal and mechanical stresses from operating temperature stress these attachment points
Solution Approach 1:
The invention moves the connection from a surface-level attachment (2D) to a volumetric integration (3D). The lining part is molded directly into the encircling depression, creating a cast joint that distributes stresses throughout the volume of the depression and surrounding material, rather than concentrating stresses at surface attachment points.
Solution Approach 2:
The invention merges the lining part and piston basic body into a single integrated structure through the cast joint formed by molding the lining part into the encircling depression. This eliminates the interface between separate components, thereby eliminating attachment points that would be subject to thermal and mechanical stresses.
3Reliability
If a multi-part steel piston with annular element is used, then cooling duct can be formed, but the design becomes more complex and materials must be adjusted for thermal and mechanical properties
Solution Approach 1:
The invention segments the piston into two functional parts: the piston basic body (providing structural support) and the lining part (providing combustion chamber surface and cooling duct formation). This segmentation allows each part to be optimized for its specific function while simplifying the overall design compared to multi-part steel pistons with separate annular elements.
Solution Approach 2:
The lining part serves multiple functions: it forms the combustion chamber-facing piston surface, creates the encircling depression for the cooling duct, and provides the bridging structure to close the cooling duct. This multi-functionality reduces the need for separate specialized components, simplifying the overall piston design.
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 design simplifies production, reduces contamination risks, and enhances mechanical and thermal robustness without attachment points in the combustion chamber, achieving efficient temperature management and cost savings.
Implementation Method 1
the material of the lining part has a higher level of heat conductivity than the material of the piston basic body, in order to dissipate the temperatures occurring on the combustion chamber side from the piston basic body
Data Source
AI summary
A cooling duct piston (1) for combustion engines. The cooling duct piston has a piston basic body (2) that is connected to a lining part (3), which is facing an assigned combustion chamber. Here, the lining part (3) completely forms the piston surface (4) of the cooling duct piston (1) that faces the combustion chamber. An encircling depression (5) is provided in the surface of the piston basic body (2) facing the combustion chamber. The lining part (3) provides a permanent connection at least with the surface of the piston basic body (2) facing the combustion chamber, and thus bridges the encircling depression (5), such that the encircling depression (5), with the lining part (3) that bridges it, forms a cooling duct (6).