Composite-Coated Engine Piston for Thermal Barrier and Rim Strength
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Solution Overview
Problem
Internal-combustion-engine pistons face challenges in achieving both high thermal barrier characteristics and durability, particularly at the mouth rim portion of the combustion chamber, where increased mechanical load can lead to cracking and reduced durability.
Innovation Solution
The piston is fabricated using a base material of aluminum or aluminum alloy, with a composite material portion reinforced by inorganic fibers or whiskers at the mouth rim, and an anodized aluminum coating applied to both this region and a separate area on the surface, leveraging different anodization rates to ensure even coating and enhanced mechanical and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an anodized aluminum coating is formed on the piston surface to improve thermal barrier characteristics, then thermal efficiency is improved, but the mechanical strength at the mouth rim portion decreases due to coating-induced stress and material heterogeneity
Solution Approach 1:
The patent applies different material compositions to different regions of the piston top surface. The composite material portion containing inorganic fibers or whiskers is specifically placed at the mouth rim portion where mechanical strength is critical, while other regions can have different compositions optimized for thermal barrier properties. This local differentiation allows simultaneous optimization of both strength and thermal characteristics without compromise.
Solution Approach 2:
The patent incorporates inorganic fibers or whiskers into the aluminum base material to create a composite structure. This composite material portion provides enhanced mechanical strength at the mouth rim portion while maintaining the thermal barrier properties of the anodized coating. The composite structure resolves the contradiction by combining materials with complementary properties.
2Reliability
If the mouth rim portion of the combustion chamber is strengthened to improve durability under increased mechanical load, then durability is improved, but the thermal barrier characteristics may be compromised due to material selection constraints
Solution Approach 1:
The patent implements region-specific material optimization where the mouth rim portion receives a composite material formulation with inorganic reinforcements for durability, while other areas of the piston top can be optimized for thermal management. This localized approach ensures both durability and thermal barrier characteristics are satisfied in their respective critical regions.
Solution Approach 2:
By using composite materials with inorganic fibers or whiskers at the mouth rim, the patent achieves enhanced durability without sacrificing thermal barrier performance. The composite structure provides both mechanical strength and thermal resistance, eliminating the need to compromise between these two requirements.
3Reliability
If a composite material portion is formed at the mouth rim portion to increase mechanical strength, then durability is improved, but manufacturing complexity increases due to additional material processing steps
Solution Approach 1:
The patent incorporates inorganic fibers or whiskers into the aluminum base material during the initial casting or forming process, rather than adding them as a separate post-processing step. This preliminary incorporation simplifies manufacturing by integrating the composite material creation into the base material formation process, reducing overall process complexity while achieving the durability benefits.
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 results in a piston with improved thermal barrier characteristics and durability, effectively addressing the mechanical stress and thermal efficiency requirements.
Implementation Method 1
anodized aluminum coating formed on the composite material portion and in a second region of the surface of the base material
Data Source
Figure 1
AI summary
This piston for internal combustion engines, which is capable of achieving high heat shielding properties and high durability, comprises: a base that is formed from aluminum or an aluminum alloy; a composite material part which is formed in a first region of the surface of the base, and which is formed from a composite material that is reinforced with inorganic fibers or whiskers; and an alumite coating film that is formed on the composite material part and a second region of the surface of the base, said second region being different from the first region.