Galleryless Monolithic Piston Cooling With a Concave Undercrown
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Solution Overview
Problem
Current piston designs face challenges in achieving increased compression loads and operating temperatures while maintaining a compact and lightweight engine, as they require steel construction and complex joining processes, which increase manufacturing costs and weight.
Innovation Solution
A monolithic steel piston with a galleryless design, featuring a concave undercrown surface for enhanced cooling and reduced compression height, eliminating the need for joining processes and cooling galleries, thus allowing for improved durability, reduced weight, and increased fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling galleries are added to the piston design, then the piston operating temperature is reduced, but the piston weight and compression height increase
Solution Approach 1:
The patent removes the cooling gallery feature from the piston design entirely, extracting the harmful element that caused increased weight and compression height while maintaining acceptable operating temperatures through alternative means
Solution Approach 2:
The patent changes the material parameter by using aluminum alloy instead of steel, which has different thermal properties that allow for reduced cooling requirements and lower weight
2Temperature
If cooling galleries are added to the piston design, then the piston operating temperature is reduced, but the manufacturing cost increases
Solution Approach 1:
The patent eliminates the cooling gallery structure and the associated joining processes, thereby removing the manufacturing complexity and cost associated with bonding multiple parts together
Solution Approach 2:
The patent merges the piston into a single monolithic structure, eliminating the need for separate upper and lower parts that would require joining processes, thus simplifying manufacturing and reducing costs
3Strength
If the piston is constructed from steel, then the piston strength and durability are improved, but the piston weight increases
Solution Approach 1:
The patent changes the material parameter from steel to aluminum alloy, which has a lower density and weight while providing sufficient strength for the application through optimized design
Solution Approach 2:
The patent uses aluminum alloy as a composite material that provides an optimal balance between weight and strength, potentially incorporating different aluminum alloys or treatments to achieve required mechanical properties
4Length of moving object
If the piston compression height is reduced, then the engine compactness is improved, but the piston may not withstand increased compression loads
Solution Approach 1:
The patent changes the material parameters by using aluminum alloy with optimized mechanical properties that provide sufficient strength in a reduced compression height configuration
Solution Approach 2:
The patent applies local quality optimization by strategically designing the piston crown and bowl geometry to concentrate strength where needed while maintaining overall compact dimensions
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 solution provides a strong, durable, and lightweight piston that effectively manages high performance demands, reduces manufacturing costs, and enhances engine compactness and fuel efficiency by eliminating the need for complex cooling galleries and joining processes.
Implementation Method 1
the undercrown surface includes a concave center portion located along the central longitudinal axis which channels oil from one side of the piston to the opposite side
Implementation Method 2
the undercrown surface comprises an expansive area for contact by cooling oil while the piston is in use
Data Source
AI summary
A galleryless piston for an internal combustion engine is provided. The piston has a monolithic piston body including an upper wall forming an upper combustion surface with first and second portions. The first portion extends annularly along an outer periphery of the upper wall and the second portion includes a combustion bowl. The first portion can also include valve pockets formed therein to reduce weight. The upper wall has an undercrown surface directly opposite the second portion of the upper combustion surface. To enhance cooling, a center portion of the undercrown surface is concave, such that oil is channeled during reciprocation of the piston from one side to the opposite side of the piston. The concave center portion is axially offset from the surrounding area of the undercrown surface.