Stern Drive Cooling System with Side Wall Water Outlet
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Solution Overview
Problem
Conventional cooling systems for stern drives, such as those described in U.S. Pat. Nos. 6,808,432 and 5,871,380, face inefficiencies due to the insulating effect of oil in the housing and water accumulation in the water jacket, which reduces the ram effect and cooling efficiency.
Innovation Solution
A cooling system for stern drives that includes a conduit with a water outlet directing ambient water towards the gear and clutch housing, a removably attachable cover with a drain section, and protruding features like ribs and a periphery wall section to enhance heat removal, ensuring efficient water discharge and drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water is discharged through the top of the housing using ram pressure, then cooling is attempted, but the space between oil level and housing top acts as heat insulator reducing cooling efficiency
Solution Approach 1:
The water outlet is positioned at a specific location on the side wall of the housing, near the gear and clutch, rather than at the top. This local positioning ensures water is discharged directly at the heat generation source, bypassing the heat insulating oil space and improving heat removal efficiency from the gear and clutch components.
2Temperature
If water jacket is provided on the back of the housing, then cooling is attempted, but water accumulates in the water jacket increasing water pressure and inhibiting the ram effect
Solution Approach 1:
The water discharge function is extracted from the traditional water jacket location and relocated to a side wall outlet. This extraction prevents water accumulation in a confined space, maintains the ram effect by avoiding pressure buildup, and directs water flow more effectively at the heat generation source.
3Productivity
If water outlet is directed horizontally along the side wall, then water discharge is improved, but water may not reach the heat generation area effectively
Solution Approach 1:
The water outlet is positioned at a specific location on the side wall, near the gear and clutch, with the outlet directed horizontally along the side wall. This local positioning combined with horizontal direction ensures water is discharged both efficiently and directly at the heat generation source, achieving both water discharge efficiency and effective heat removal.
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 described cooling system improves heat removal efficiency by directing water close to heat-generating components and utilizing protruding features to increase the heat removal effect, even at low propulsion speeds, thereby enhancing overall cooling performance.
Implementation Method 1
The water is taken from ambient water of the drive unit, and the water is discharged using water pressure generated by the propulsive speed due to the so-called ram effect.
Implementation Method 2
improves heat removal efficiency by directing water close to heat-generating components
Data Source
AI summary
The subject invention provides a cooling system for a stern drive, including: a conduit having a water outlet for discharging ambient water, which is introduced by using a water current generated by propulsion of a boat to which said stern drive is mounted, the water outlet being directed toward a side wall of a housing containing a gear and a clutch where heat is generated, at a location near the gear and the clutch; and a cover removably attachable to the housing, the conduit being contained between the cover and the housing, the cover defining a space to which water is discharged from the water outlet and a drain section for draining the water.