Variable-Height Spacer for Engine Cylinder Bore Cooling
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Solution Overview
Problem
Existing cooling structures for internal combustion engines can inadequately dissipate heat from the upper portions of pistons, leading to potential piston seizure and reduced engine performance due to excessive restriction of cooling water flow by spacers.
Innovation Solution
A spacer is fitted inside the water jacket surrounding the cylinder bore, covering the intermediate portion in the peripheral direction to thermally expand the cylinder bore, reducing friction and ensuring adequate heat dissipation while maintaining the spacer's friction-reducing effect by regulating cooling water flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the spacer excessively restricts the flow of cooling water in the upper and lower portions of the water jacket, then the friction between the piston and cylinder bore is reduced, but heat dissipation from the upper portion of the piston becomes insufficient
Solution Approach 1:
The spacer is designed with different heights at different locations: a first height in the upper portion of the water jacket and a second height in the lower portion, where the first height is greater than the second height. This local differentiation allows the upper portion to maintain better cooling water flow and heat dissipation capability while the lower portion achieves sufficient friction reduction, resolving the contradiction between heat dissipation and friction reduction.
2Force
If the spacer covers the intermediate portion of the cylinder bore, then the clearance between the cylinder bore and piston increases reducing friction, but the cooling water flow path is obstructed
Solution Approach 1:
The spacer height varies dynamically along the depth direction of the water jacket, being greater in the upper portion and smaller in the lower portion. This dynamic height variation allows the spacer to cover the intermediate portion for friction reduction while maintaining adequate cooling water flow paths, particularly preserving flow in the upper portion where heat dissipation is critical.
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 enhances heat dissipation from the upper piston portion, reduces friction between the piston and cylinder bore, improves fuel efficiency, and prevents overheating by ensuring sufficient cooling of the piston's top and skirt parts.
Implementation Method 1
the cylinder bore is thermally insulated by regulating the flow of the cooling water in the water jacket by use of the spacer
Implementation Method 2
the friction between the cylinder bore and a piston can be reduced by thermally expanding the cylinder bore
Implementation Method 3
the performance of heat dissipation from the upper portion of each piston to the cylinder bore needs to be secured
Implementation Method 4
heat dissipation from the upper portion of each piston to the cylinder bore
Data Source
AI summary
A spacer covets intermediate portions of respective cylinder bores in a depth direction of a water jacket throughout the entire peripherics of the intermediate portions in the peripheral direction. Accordingly, the intermediate portion of each cylinder bore becomes higher in temperature than any other portion, and is thermally expanded. Thereby, the clearance between the cylinder bore and the corresponding piston increases. Thus, the friction decreases to improve fuel efficiency of an internal combustion engine. Furthermore, the temperature of oil lubricating the intermediate portion of the cylinder bore rises, and the viscosity decreases. Accordingly, the effect of friction reduction is enhanced more. Furthermore, upper and lower portions of the cylinder bores in a cylinder axis direction are sufficiently cooled. Therefore, the cooling performance of a top part and a skirt part of each piston, which tends to become higher in tempera lure, is secured. Accordingly, overheat can be prevented.