Outboard Motor Intake Duct Split Cover Design
Solution Overview
Problem
Existing outboard motors face challenges in assembling efficiency, miniaturization, and corrosion prevention due to complex intake device structures and difficulty in draining water and air separation during sailing.
Innovation Solution
The outboard motor design features a split engine cover allowing for easy assembly, an intake pathway with upstream and downstream ducts that prevent interference and facilitate air circulation, and a configuration that separates water from air before it enters the engine, including an exhaust port and suction port arrangement to direct air to the throttle body while draining water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple opening portion is provided at the engine cover for introducing outside air, then the structure is simple, but the air temperature increases due to heat from the engine
Solution Approach 1:
The engine cover is divided into an upper cover and a lower cover that can be separated. The intake pathway is configured to pass through both covers, with the upstream duct fixed to the upper cover and the downstream duct fixed to the lower cover. This segmentation allows the intake pathway to extend below the engine cover, away from heat sources, while maintaining structural simplicity.
Solution Approach 2:
The intake pathway is extended in the vertical dimension by passing through both the upper and lower engine covers. The downstream duct extends downward below the engine cover level, creating a longer intake path that bypasses the engine's heat zone. This dimensional extension allows cool air intake without complex additional components.
2Temperature
If an intake device with silencers is provided to reduce air temperature, then the air intake temperature decreases, but the device complexity increases
Solution Approach 1:
The silencer function is extracted from a separate component and integrated into the downstream duct itself. The downstream duct is designed with an internal structure that provides silencing functionality while maintaining a simple overall intake device configuration. This eliminates the need for additional separate silencer components.
Solution Approach 2:
The intake pathway, silencing function, and water drainage function are merged into a single integrated downstream duct structure. This multi-functional design reduces the number of separate components needed while achieving temperature reduction, noise control, and water drainage simultaneously.
3Ease of manufacture
If the engine cover is made into one piece, then the structure is simple, but the assembling operation takes more time and labor
Solution Approach 1:
The engine cover is segmented into an upper cover and a lower cover that can be assembled separately and then joined. This segmentation allows the intake pathway to be pre-assembled with the respective cover, enabling parallel manufacturing and reducing final assembly time. Each cover can be manufactured and prepared independently before being joined together.
4Volume of moving object
If the ducts are positioned close together to reduce size, then miniaturization is achieved, but the ducts interfere with each other during assembly
Solution Approach 1:
The ducts are arranged in different vertical levels rather than being positioned close together horizontally. The upstream duct is positioned in the upper cover while the downstream duct extends below the engine cover, creating vertical separation. This dimensional arrangement minimizes the overall footprint while preventing interference during assembly operations.
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
This design simplifies the assembling process, reduces engine intake temperature, increases engine output, and prevents corrosion by ensuring efficient air and water separation, allowing for miniaturization without size increase.
Implementation Method 1
the upstream side duct being fixed to the engine upper cover of the engine cover so that air can circulate downward in the upstream side duct, the downstream side duct being fixed to the engine side in parallel with the upstream side duct so that air can circulate upward in the downstream side duct
Data Source
AI summary
[Problem] To perform an assembling operation easily while attaining improvement in engine efficiency.[Solution] An outboard motor 10 according to the invention includes an upstream side duct 42 which is fixed to an engine upper cover 27, and a downstream side duct 43 which is fixed to an engine 14 side. The upstream side duct 42 includes an exhaust port 52 which is opened at its side face. The downstream side duct 43 includes a downstream side lower duct 59 and a downstream side upper duct 60. In the downstream side lower duct 59, a suction port 61 is provided at a position opposed to the exhaust port 52 and separately at a predetermined distance from the exhaust port 52. In the downstream side upper duct 60, an exhaust port formed toward a throttle body 36 of the engine 14 is provided above the downstream side lower duct 59. The upstream side duct 42 and the downstream side duct 43 are formed so as not to interfere with each other when the engine upper cover 27 is moved vertically.