Outboard Motor Integrated Cooling Structure for Exhaust Noise Reduction
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Solution Overview
Problem
Existing outboard motor designs with separate components for cooling and exhaust gas management result in increased manufacturing costs, noise, and potential water intrusion issues, requiring larger casings and more complex configurations.
Innovation Solution
An integrated cooling structure within the outboard motor that combines an oil case, upper separator, and extension case to form an exhaust gas channel and cooling water flow portion, allowing for efficient cooling and noise reduction by mixing exhaust gas and cooling water, while reducing component count and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If separate components (exhaust tube, cooling water discharge path) are disposed within the case, then the exhaust gas can be cooled by cooling water, but the number of components increases and manufacturing costs increase
Solution Approach 1:
The exhaust tube and cooling water discharge path are merged into a single integrated case structure. The case itself is formed with an exhaust gas channel and a cooling water flow portion that surrounds it, eliminating the need for separate exhaust tubes and cooling water discharge paths. This integration maintains the cooling function while reducing component count and manufacturing complexity.
2Device complexity
If the exhaust tube extends for a short distance in the case, then the structure is simplified, but cooling water easily intrudes into the exhaust tube to corrode it
Solution Approach 1:
The exhaust gas channel is nested within the case structure, with the cooling water flow portion surrounding it. The integrated formation ensures proper spacing and positioning, preventing cooling water from intruding into the exhaust gas channel while maintaining structural simplicity. The case walls act as protective barriers that prevent direct contact between cooling water and the exhaust gas channel.
3Ease of operation
If connection portions between the case and exhaust structure are added, then exhaust gas flow is enabled, but the case size increases
Solution Approach 1:
The exhaust gas channel is formed as an integral part of the case structure, eliminating the need for separate connection portions between the case and exhaust structure. The exhaust gas flows directly through the channel formed within the case, reducing the overall case size while ensuring proper exhaust gas flow path.
4Adaptability or versatility
If cases and tubes of different sizes are molded for different outboard motor sizes, then engine capacity variations are accommodated, but manufacturing costs increase
Solution Approach 1:
The case is divided into separable first case and second case portions that can be selectively assembled. This segmentation allows for modular configuration where cases of different sizes can be combined or single cases used depending on the outboard motor size requirements, reducing the need to mold completely different cases for each engine capacity while maintaining adaptability.
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 integrated cooling structure effectively suppresses exhaust noise, prevents water intrusion, and allows for downsizing and cost reduction by eliminating the need for separate exhaust tubes and simplifying the design, while accommodating varying engine sizes with adjustable case configurations.
Implementation Method 1
the exhaust gas of the exhaust gas channel is cooled by the cooling water flow portion on an outer side in the first case
Implementation Method 2
the exhaust gas and cooling water are mixed in the second case
Data Source
AI summary
An outboard motor is provided with an upper separator disposed on the lower side of an oil case for storing a lubricating oil of an engine, and an extension case which is separably connected on the lower side of the upper separator. The upper separator has a central exhaust passage through which exhaust gas flows, and a cooling water flow part through which cooling water flows on the outside of the central exhaust passage, the central exhaust passage and the cooling water flow part forming an integrated structure. The exhaust gas and the cooling water are caused to mix in the extension case.