Piston Cooling Gallery Boss for Ring Pin Retention and Flow Splitting
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Solution Overview
Problem
In marine outboard motors, the alignment pin used to restrict piston ring rotation can fall into the cooling gallery, obstructing cooling fluid flow and affecting engine performance, leading to increased temperatures and poor emissions.
Innovation Solution
A boss is integrated within the cooling gallery that secures the alignment pin and acts as a flow splitter, directing cooling fluid flows in opposite directions to enhance retention and circulation, preventing pin obstruction and improving cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the alignment pin is secured in a throughhole extending from the ring groove into the cooling gallery, then the alignment pin can restrict piston ring circumferential displacement, but the alignment pin may fall into the cooling gallery and obstruct cooling fluid flow
Solution Approach 1:
The harmful function of the throughhole (allowing pin to fall into cooling gallery) is extracted and removed. The hole is changed from a throughhole to a blind hole that terminates before entering the cooling gallery, eliminating the risk of pin obstruction while maintaining alignment function
Solution Approach 2:
An intermediary structure (the blind hole termination point) is introduced between the ring groove and the cooling gallery. This intermediary prevents direct access of the alignment pin to the cooling gallery while still allowing the pin to perform its alignment function in the ring groove
2Reliability
If the alignment pin is correctly located in the hole in the ring groove, then piston ring circumferential movement is restricted, but if the alignment pin becomes misplaced, excessive cooling fluid flows to the ring belt via the hole
Solution Approach 1:
The harmful pathway for excessive cooling fluid flow (the throughhole) is extracted and removed. By converting to a blind hole that terminates before the cooling gallery, the uncontrolled flow path is eliminated, preventing cooling fluid loss while maintaining alignment functionality
3Temperature
If a cooling gallery is incorporated within the piston body, then piston temperature is reduced, but the alignment pin hole may interfere with cooling fluid circulation
Solution Approach 1:
The potential obstruction problem is extracted by removing the throughhole configuration that would allow pin displacement into the cooling gallery. The blind hole configuration eliminates this interference while preserving the cooling gallery's temperature reduction function
Solution Approach 2:
The hole structure is segmented into two distinct zones: the upper portion in the ring groove for alignment pin function, and the lower portion that terminates before the cooling gallery. This segmentation separates the alignment function from the cooling function, preventing interference between them
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 securely retains the alignment pin and enhances cooling fluid circulation, reducing piston temperature and emissions while maintaining proper ring alignment, thus improving engine performance.
Implementation Method 1
the boss projects into the cooling gallery opposite the fluid inlet and is shaped to provide a flow splitter surface configured to divide cooling fluid flowing through the fluid inlet during use into first and second fluid flows and to direct the first and second fluid flows in opposite directions around the cooling gallery
Implementation Method 2
a cooling fluid, such as crankcase oil, is circulated around the cooling gallery to reduce the temperature of the upper combustion surface of the piston
Data Source
Figure 1
Figure 2a~2d
Figure 3
AI summary
A piston (200) foran internal combustion engine (100) is provided. The piston includes a piston body (210) including an upper combustion surface(211), an annular side wall (213) with a ring belt region(214), and a cooling gallery (240) located within the piston body having a fluid inlet(243). A piston ring (222) is located in a ring groove (216) around the ring belt region and an alignment pin (230) is secured in a hole (231) in the piston side wall to restrict circumferential displacement of the piston ring. The piston body further includes a boss (250) within the cooling gallery into which the hole and the alignment pin extend. The boss projects into the cooling gallery opposite the fluid inlet and is shaped to provide a flow splitter surface (251) configured to divide cooling fluid flowing through the fluid inlet during use into first and second fluid flows and to direct the first and second fluid flows in opposite directions around the cooling gallery.