Laser Welded Piston Assembly Cooling Gallery
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Solution Overview
Problem
Internal combustion engine pistons face increased stress due to reduced weight and elevated pressures and temperatures, requiring effective cooling methods while minimizing manufacturing complexity and weight, and existing cooling gallery designs are complex, expensive, and difficult to form in smaller pistons.
Innovation Solution
A piston assembly with a cooling gallery ring and piston body joined via laser welding, allowing for a one-piece design with flexible weld placement and reduced heat-affected zones, minimizing material waste and post-processing needs, and enabling efficient coolant circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling galleries are added to the piston, then thermal management is improved, but device complexity increases
Solution Approach 1:
The piston is divided into two separate components: a piston body and a cooling gallery ring. This segmentation allows the cooling gallery ring to be formed independently with integrated cooling channels, then joined to the piston body via laser welding. The segmentation resolves the contradiction by enabling thermal management functionality without requiring complex integrated cooling galleries in the main piston structure.
Solution Approach 2:
The cooling gallery ring is positioned within the piston assembly, nesting the cooling functionality inside the piston structure. The cooling gallery ring fits into a recess in the piston body and is joined via laser welding, creating a compact integrated structure that provides cooling without significantly increasing overall piston complexity or dimensions.
2Reliability
If friction welding is used to form cooling galleries, then enclosed cooling galleries can be created, but piston weight and size increase
Solution Approach 1:
The patent replaces friction welding (a mechanical welding process requiring high forces) with laser welding (a thermal welding process). This substitution allows for the formation of enclosed cooling galleries without the extreme forces required by friction welding, thereby avoiding unintended deformation and enabling lighter piston components that would deform under friction welding loads.
Solution Approach 2:
The invention changes the welding process parameters from high-force mechanical friction welding to controlled thermal laser welding. This parameter change enables the use of lighter piston materials and designs that would be susceptible to deformation under friction welding forces, thus reducing overall piston weight while maintaining reliable cooling gallery formation.
3Reliability
If friction welding is used to form cooling galleries, then cooling functionality is achieved, but manufacturing precision decreases
Solution Approach 1:
The patent replaces friction welding with laser welding to eliminate the high-magnitude forces that cause piston deformation. Laser welding applies thermal energy locally without the mechanical forces required by friction welding, thereby maintaining manufacturing precision and avoiding unintended deformation of the piston and cooling gallery features.
Solution Approach 2:
Laser welding provides localized heating and joining at the interface between the piston body and cooling gallery ring, concentrating the thermal energy precisely where needed. This local quality approach minimizes the heat-affected zone and prevents widespread thermal deformation, maintaining manufacturing precision while achieving reliable cooling gallery formation.
4Temperature
If cooling galleries are added to the piston, then thermal management is improved, but manufacturing cost increases
Solution Approach 1:
By segmenting the piston into a piston body and a separate cooling gallery ring, the invention enables independent optimization and manufacturing of each component. The cooling gallery ring can be formed using cost-effective processes and then joined via laser welding, which is efficient for this application. This segmentation reduces manufacturing cost compared to forming complex integrated cooling galleries in the main piston structure.
Solution Approach 2:
Replacing friction welding with laser welding reduces manufacturing cost by eliminating the need for extremely high-strength piston components required for friction welding. Laser welding allows the use of lighter, potentially lower-cost materials and simplifies the manufacturing process by avoiding the complex setup and extreme forces required for friction welding, thereby reducing overall manufacturing cost.
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 enhanced durability and reduced weight with improved thermal management, allowing for increased power output and fuel efficiency while simplifying manufacturing and reducing material costs.
Implementation Method 1
The piston body and cooling gallery ring may be joined together via a laser welding process along both interface regions
Implementation Method 2
A coolant such as crankcase oil may be introduced to the cooling gallery, and may be distributed about the cooling gallery by the reciprocating motion of the piston, thereby reducing the operating temperature of the piston
Data Source
AI summary
An exemplary piston may include a piston body having radially inner and outer body mating surfaces. The piston may further include a cooling gallery ring cooperating with the piston body to form a continuous upper combustion bowl surface and a cooling gallery. The cooling gallery ring may have radially inner and outer ring mating surfaces abutted along their corresponding radially inner and outer body mating surfaces, such that the cooling gallery is substantially enclosed. The piston body and cooling gallery ring may be joined together along the radially inner and radially outer interface regions to form a generally one-piece piston assembly. The radially outer interface region may be elongated in a direction parallel to the piston axis, e.g., facilitating a laser welding joining process.