Outboard Motor Lubrication System Downstream Oil Return Path
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Solution Overview
Problem
Conventional lubrication systems for outboard motors cannot return lubrication oil accumulated downstream of the oil filter to the oil pan, leading to oil leakage and soiling when the oil filter is removed.
Innovation Solution
A lubrication system with an oil return path that guides lubrication oil from the oil passage downstream of the oil filter back to the oil pan, including configurations such as an oil return path disposed below the oil filter, connected to the main gallery, and an electromagnetic valve to control oil flow, minimizing manufacturing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lubrication system without downstream oil return path is used, then device complexity is reduced, but lubrication oil accumulates downstream of oil filter and flows outside when filter is removed
Solution Approach 1:
The oil return system is segmented into two independent paths: one for upstream oil (before filter) and one for downstream oil (after filter). This allows each path to be optimized independently and enables the downstream return path to be added without redesigning the entire system, thus maintaining ease of manufacture while solving the oil containment problem.
Solution Approach 2:
A downstream oil return path acts as an intermediary mechanism that captures and redirects oil accumulating after the filter. This intermediary path prevents oil from reaching the exterior when the filter is removed, solving the containment issue without adding complex sealing mechanisms or modifying the filter itself.
2Reliability
If oil return path is added downstream of oil filter, then lubrication oil is prevented from flowing outside, but device complexity increases
Solution Approach 1:
The downstream oil return path is merged with the existing oil pan and integrated into the lubrication system's natural oil circulation. By combining the new return path with existing components rather than adding completely separate systems, the patent achieves oil containment while minimizing the increase in device complexity.
Solution Approach 2:
The downstream oil return path utilizes the system's own oil pressure and gravity to automatically return oil to the oil pan without requiring external pumps or complex control mechanisms. This self-service approach achieves reliable oil containment while keeping the system structure simple.
3Ease of repair
If oil filter is removed for replacement, then maintenance is enabled, but accumulated oil flows back and soils outboard motor
Solution Approach 1:
The downstream oil return path is established in advance before filter removal. When the filter is removed for maintenance, the return path is already in place to immediately capture and redirect any oil that accumulates, preventing it from flowing outside. This preliminary action eliminates the need for temporary containment measures during filter replacement.
4Productivity
If vertically communicating oil return holes are formed in bearing components, then oil return efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent extracts the oil return function from the bearing components and implements it separately through the downstream oil return path. This separates the oil return efficiency requirement from the bearing component manufacturing, allowing bearing components to be manufactured with standard precision while achieving high oil return efficiency through the dedicated return path.
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
Prevents lubrication oil from flowing to the outside, ensuring the outboard motor remains clean even when the oil filter is removed, by effectively returning oil accumulated downstream of the filter to the oil pan.
Implementation Method 1
an oil pump arranged to pump the lubrication oil into the oil passage
Implementation Method 2
an oil filter arranged to filter the lubrication oil to be guided to the movable member
Implementation Method 3
an oil return path arranged to return the lubrication oil that is accumulated in a portion of the oil passage downstream of the oil filter to an oil pan
Data Source
AI summary
In an outboard engine, an upstream oil return path is connected to an oil passage upstream of an oil filter to return lubrication oil that is accumulated in the oil passage upstream of the oil filter to an oil pan. A downstream oil return path is connected to an oil passage downstream of the oil filter to return lubrication oil that is accumulated in oil passages and a main gallery downstream of the oil filter to the oil pan. The lubrication oil accumulated in a portion of an oil passage downstream of the oil filter is hindered from flowing to the outside even if the oil filter is removed when the engine is stopped.