Hybrid Piston Manufacturing for Strength and Cooling Channel Freedom
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Solution Overview
Problem
Existing methods for producing pistons for internal combustion engines face challenges with additive manufacturing, resulting in lower strength in high-stress areas, leading to increased weight and fuel consumption due to the need for reinforcement.
Innovation Solution
A method combining conventional casting or forging for the upper piston part, which includes the piston crown and cooling channel, with additive laser melting for the lower piston part, allowing for the production of thermally and mechanically stressed areas with high strength while using additive processes for less stressed areas, enabling complex cooling channel designs and weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additive manufacturing is used for the entire piston, then design freedom and complex cooling channel shapes are improved, but strength in high-stress areas deteriorates
Solution Approach 1:
The piston is divided into two parts: the piston crown (upper part) is manufactured by conventional casting to ensure high strength in high-stress areas, while the piston lower part is manufactured by additive manufacturing to achieve design freedom and complex cooling channel shapes. This segmentation allows each part to be optimized for its specific requirements.
Solution Approach 2:
Different manufacturing methods are applied to different regions of the piston based on local requirements. The piston crown, which experiences high thermal and mechanical stresses, is made with high strength through conventional casting. The piston lower part, which has less stress but requires complex cooling channels, is made with design freedom through additive manufacturing.
2Adaptability or versatility
If additive manufacturing is used for the entire piston, then complex cooling channel designs are improved, but piston weight increases
Solution Approach 1:
The piston is segmented into two manufacturing zones: the piston crown made by conventional casting and the piston lower part made by additive manufacturing. This allows the complex cooling channels to be implemented only where needed in the lower part without adding unnecessary weight throughout the entire piston.
Solution Approach 2:
Additive manufacturing with its design freedom is applied locally to the piston lower part where complex cooling channels are required, while the piston crown uses conventional manufacturing. This localized application of additive manufacturing achieves the cooling channel design goals without the penalty of increased weight across the entire piston.
3Ease of manufacture
If additive manufacturing is used for the entire piston, then manufacturing flexibility is improved, but long-term reliability deteriorates
Solution Approach 1:
The piston is divided into two manufacturing sections: the piston crown manufactured by conventional casting for high reliability in high-stress areas, and the piston lower part manufactured by additive manufacturing for manufacturing flexibility. This segmentation ensures that critical areas maintain long-term reliability while non-critical areas benefit from manufacturing flexibility.
Solution Approach 2:
Different manufacturing approaches are applied to different regions based on their functional requirements. The piston crown, which requires high reliability under high thermal and mechanical stresses, is made by conventional casting. The piston lower part, which has less stress exposure, is made by additive manufacturing to achieve manufacturing flexibility.
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 approach enhances the strength of high-stress areas while reducing the overall weight of the piston, improving heat transfer and cooling efficiency through complex cooling channel designs, and allowing for the production of components that were difficult or impossible with conventional methods.
Implementation Method 1
the part of the cooling channel arranged in the piston upper part is closed by means of an additive process, specifically by means of laser melting, in which the aluminum in powder form is applied in a thin layer to the piston upper part and is completely remelted locally using laser radiation
Data Source
Figure 1
Figure 2~4
AI summary
The present invention relates to a method for manufacturing a piston (1) for an internal combustion engine from a piston crown (2) and a piston lower (3). The method comprises the following process steps: - manufacturing a piston crown (6), at least parts of a ring section (12) and at least a part (7) of a cooling channel (8), for example by forging or casting, - manufacturing the piston lower (3) and closing the part (7) of the cooling channel (8) arranged in the piston crown (2) by means of an additive process, - finishing the piston (1) by producing at least one ring groove (4) in the ring carrier (5) for receiving a piston ring.This makes it possible to create a piston (1) which has greater strength in its thermally and mechanically highly stressed piston upper part (2) than in its thermally and mechanically less stressed piston lower part (3) and allows greater manufacturing freedom with regard to the shape of the piston lower part (3).