Profiled Cover Plate for Piston Cooling Gallery
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Solution Overview
Problem
Internal combustion engine pistons face challenges in efficiently cooling the piston crown due to severe thermal stresses, which can lead to reduced durability and increased operating temperatures.
Innovation Solution
The implementation of a variable profile cover plate in the cooling gallery of the piston, which alters the fixed volume of the gallery by extending outwardly or inwardly, allowing for a larger or smaller cross-sectional area. This design optimizes the heat exchange efficiency by displacing fluid and varying the gallery's volume profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a constant volume cooling gallery is used, then the piston structure is simple, but the heat exchange efficiency is insufficient under severe thermal stresses
Solution Approach 1:
The cover plate is designed with a variable profile that creates a variable volume cooling gallery, allowing the cooling chamber volume to change dynamically with piston position. This dynamic volume variation optimizes heat exchange efficiency under severe thermal stresses while managing the complexity through a relatively simple cover plate geometry.
2Temperature
If the cover plate extends outwardly to increase cross-sectional area, then heat exchange efficiency improves, but the piston crown height increases
Solution Approach 1:
The cover plate with variable profile is nested within the piston crown structure, with the cooling gallery volume varying within the existing piston envelope. The profiled cover plate creates internal volume variation without significantly increasing the external piston dimensions, effectively nesting the variable volume chamber within the piston crown.
3Quantity of substance
If the cover plate extends inwardly to decrease cross-sectional area, then fluid flow is optimized, but heat exchange surface area is reduced
Solution Approach 1:
The cover plate profile is designed with varying cross-sectional areas at different locations, creating local volume variations that optimize fluid flow in specific regions. The profiled geometry provides enlarged cross-sectional areas in regions requiring enhanced fluid circulation while maintaining adequate heat exchange surface area in other regions, applying different qualities to different parts of the cooling gallery.
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 variable profile cover plate enhances the heat exchange efficiency of the cooling gallery, effectively reducing piston temperature and increasing piston life by optimizing the fluid flow and heat transfer within the gallery.
Implementation Method 1
at least part of the heat of the piston crown portion is transferred to the oil
Implementation Method 2
the reciprocating motion of the piston during engine operation generally moves the oil up and down within the cooling gallery
Data Source
AI summary
An internal combustion engine piston includes a crown defining an annular cavity between an inner wall and an outer wall. The annular cavity includes an opening opposite a top wall and at least partially defines a cooling gallery. A cover plate is assembled with the annular cavity and the piston crown to form a lower boundary of the cooling gallery and thereby enclose the cooling gallery within the piston crown. The cover plate includes a plurality of crests separated by a plurality of troughs wherein the crests and troughs are arranged to create a variable volume profile of the cooling gallery. The variable volume profile of the cooling gallery can increase or decrease annularly around the piston based on a cross-sectional shape of the cover plate. Optionally, the cover plate includes one or more inlets or outlets for exchanging fluid in the cooling gallery.