Forged Piston Oil Gallery Shape for Uniform Crown Cooling
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Solution Overview
Problem
Conventional piston oil galleries struggle to effectively cool non-traditional, complex-shaped combustion bowls in diesel engines, leading to potential overheating and 'hot spots' due to non-uniform wall thickness, which can cause piston failure and engine issues.
Innovation Solution
The development of forged steel oil galleries with complex shapes matching the combustion bowls, formed through a combination of forging and machining processes, ensuring uniform wall thickness and efficient cooling by maintaining the oil gallery's shape in sync with the combustion bowl's complex geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional annular or ring-shaped cooling galleries with constant cross-sections are used, then the manufacturing process is simple and straightforward, but the galleries cannot effectively cool complex-shaped combustion bowls, leading to non-uniform wall thickness and hot spots
Solution Approach 1:
The patent applies asymmetry by transitioning from traditional symmetric annular galleries with constant cross-sections to asymmetric galleries with variable cross-sections that adapt to the complex shape of the combustion bowl. The gallery cross-section varies along its length, being thicker in areas requiring more cooling and thinner in areas where less cooling is needed, thereby achieving uniform wall thickness throughout the piston crown while matching the asymmetric geometry of modern complex-shaped combustion bowls.
Solution Approach 2:
The patent implements local quality by varying the gallery cross-sectional dimensions at different locations along the gallery path. The gallery width and depth are locally adjusted to match the local requirements of the combustion bowl geometry, providing enhanced cooling where needed and maintaining uniform wall thickness in critical areas, thereby addressing the non-uniform cooling problem of complex-shaped bowls.
2Temperature
If the oil gallery shape does not match the complex combustion bowl shape, then conventional machining operations can be used, but the wall thickness becomes non-uniform causing overheating and hot spots
Solution Approach 1:
The gallery is designed with asymmetric variable cross-sections that mirror the asymmetric geometry of the complex combustion bowl. This asymmetric design allows the gallery to conform precisely to the bowl shape, ensuring uniform wall thickness distribution and preventing localized overheating that would occur with symmetric constant-cross-section galleries.
Solution Approach 2:
The patent applies parameter changes by varying the gallery cross-sectional parameters (width, depth, area) continuously along the gallery length. These parameter variations are specifically tailored to match the combustion bowl geometry, ensuring that the wall thickness remains uniform throughout. The cross-sectional area is increased in regions requiring more cooling and decreased in regions where the bowl geometry demands thinner walls, thereby maintaining optimal temperature distribution.
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 minimizes overheating risks, prevents piston failure, and maintains acceptable temperature limits, enhancing engine reliability and efficiency while reducing emissions and weight.
Implementation Method 1
The oil circulates through the gallery and cools parts of the piston which are susceptible to damage from the heat of combustion
Data Source
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AI summary
A steel piston with an oil gallery, and process for forming a steel piston oil gallery channel, which corresponds to the complex shape of the combustion bowl in the piston crown. The oil gallery channel is first forged to the basic shape that corresponds to the shape of the walls of the combustion bowl. Machine-turning surfaces in the oil gallery channel can be machine-finished as desired. Surfaces in the oil gallery which cannot be machined with conventional turning operations, such as recesses and protrusions into the channel, are left in the original forged condition.