Fuel Tank Vent Valve Float Guidance to Prevent Fuel Leakage
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Solution Overview
Problem
Existing fuel storage systems face challenges in safely venting fuel vapors while preventing unintentional leakage of liquid fuel, especially under conditions such as over-filling, inclined surfaces, and aggressive vehicle motion.
Innovation Solution
A vent valve assembly comprising a housing with a float that translates relative to the housing, guided by alignment features to prevent rotation and ensure proper alignment with a flapper, which seals the vapor release passage to prevent liquid fuel leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the float is allowed to translate freely in the chamber, then the vapor venting function is improved, but the float may rotate or misalign causing liquid fuel leakage
Solution Approach 1:
The patent applies local quality by providing guiding features at specific locations on the float and housing that constrain rotation only where needed, while allowing free translation for vapor venting. The guide channels and guide nobles are positioned to provide localized guidance without restricting the overall float movement required for vapor release.
Solution Approach 2:
The guiding features act as intermediaries between the float and housing, mediating the float's movement. These features transmit and control the float's translation while preventing rotation, serving as a mechanical intermediary that reconciles the need for both free movement and alignment control.
2Manufacturing precision
If guiding features are added to prevent float rotation, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the guiding features directly into the existing float and housing structures. The guide channels are formed as integral parts of the housing, and the guide nobles are provided on the float itself, combining multiple functions (structural support and alignment guidance) into unified components rather than adding separate alignment mechanisms.
Solution Approach 2:
The guiding features utilize thin-walled structures and flexible sealing elements that can deform slightly to accommodate manufacturing tolerances while maintaining alignment precision. The guide channels and sealing surfaces are designed with appropriate clearances and flexibility to ensure proper float guidance without requiring extremely tight manufacturing tolerances.
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 vent valve assembly effectively manages fuel vapor release while maintaining a seal against liquid fuel leakage, ensuring safe operation under various conditions and reducing the risk of fuel loss or contamination.
Implementation Method 1
a float located inside the chamber and configured to be translatable relative to the housing along an axis
Data Source
AI summary
A vent valve assembly for use with a fuel tank may comprise a housing having outer and inner wall structures that define a chamber therebetween, and a float located inside the chamber and configured to be translatable relative to the housing along an axis. The float has an orifice extending along the axis. The inner wall structure of the housing is disposed within the orifice of the float, facing an inner surface of the orifice. The vent valve assembly also comprises one or more guiding features located on the inner surface of the orifice, and one or more mating guiding features located on the inner wall structure of the housing and configured to mate with the guiding features. The guiding features and mating guiding features cooperate to guide translation of the float relative to the housing along the axis and restrict rotation of the float about the axis.