Fuel Tank Oblique Pump Mount Reduces Pitch Moment
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Solution Overview
Problem
In saddle-ride type four-wheeled vehicles, the existing fuel tank arrangement generates a large moment at the fuel pump's fixing position due to pitch motion, which is exacerbated by the low rigidity of resin fuel tanks, leading to potential mechanical stress and reduced fuel tank capacity.
Innovation Solution
The fuel tank is designed with a deep bottom portion positioned forward of the head cover and an inclined upper surface that extends rearward and obliquely downward, with the fuel pump fixed to this inclined portion and extending forward and obliquely downward, reducing the moment at the pump's fixing position and increasing tank capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the fuel tank is located over the head cover and the fuel pump is suspended vertically from the upper surface, then the fuel pump can be easily installed, but a large moment is generated at the fixing position during pitch motion
Solution Approach 1:
The fuel pump is repositioned from a vertical suspension arrangement to an oblique arrangement extending from the inclined upper surface toward the deep bottom portion. This dimensional change in pump orientation reduces the moment arm during pitch motion, thereby decreasing the moment generated at the fixing position while maintaining installation feasibility.
Solution Approach 2:
The upper surface of the fuel tank is designed with an inclined portion that extends rearward and obliquely downward. This geometric parameter change creates a more favorable fixing position for the fuel pump, allowing it to be positioned where it experiences reduced moment during vehicle pitch motion, while still enabling practical installation procedures.
2Volume of stationary object
If the deep bottom portion is positioned further rearward than the head cover, then the fuel tank capacity can be increased, but the moment acting on the fuel pump during pitch motion increases
Solution Approach 1:
The fuel tank design incorporates an asymmetric configuration where the deep bottom portion is positioned forward of the head cover, and the upper surface includes an inclined portion extending rearward and obliquely downward. This asymmetric arrangement allows the fuel pump to be positioned in a location that maximizes tank capacity while minimizing the moment arm during pitch motion, resolving the contradiction between capacity and structural strength.
3Weight of moving object
If the fuel tank is made of resin to reduce weight, then the vehicle weight is reduced, but the rigidity of the fuel tank is not high making it unsuitable for large moment generation
Solution Approach 1:
The fuel tank design incorporates specific geometric parameters including an inclined upper surface and a deep bottom portion positioned forward of the head cover. These parameter changes optimize the structural distribution of forces within the resin tank, reducing stress concentration at the fuel pump fixing position and enabling the use of lightweight resin material while maintaining sufficient rigidity to withstand operational loads.
Data Source
AI summary
A saddle-ride type four-wheeled vehicle has a structure that increases a tank capacity of a fuel tank and reduces a moment acting on a fixing position of a fuel pump disposed in the fuel tank. The saddle-ride type four-wheeled vehicle includes a fuel tank located above the head cover of the engine, and a fuel pump disposed in the fuel tank. The lower surface portion of the fuel tank includes, at a more forward position than the head cover, a deep bottom portion situated at a lowest position in the lower surface portion. The upper surface portion of the fuel tank includes, at a more rearward position than the deep bottom portion, an inclined portion arranged to extend rearward and obliquely downward. An upper end of the fuel pump is fixed to the inclined portion, and the fuel pump is arranged to extend forward and obliquely downward from the inclined portion toward the deep bottom portion.