Hydrophobic Membrane Fuel Cap for Marine Vapor Venting
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Solution Overview
Problem
Existing fuel cap systems for marine vessels fail to prevent contamination from water and other substances while allowing adequate fuel vapor venting, leading to potential engine damage and environmental issues during refueling and boat movement.
Innovation Solution
A fuel cap with a hydrophobic membrane coated with materials like Teflon, integrated with a deflection shield to create a treacherous path for liquids, allowing effective venting of fuel vapors and atmospheric air while preventing water and contaminants from entering the fuel tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the vent passageway is made small to prevent water ingress, then water prevention is improved, but fuel vapor venting effectiveness deteriorates
Solution Approach 1:
The patent employs a hydrophobic membrane as the vent passageway structure. This membrane contains numerous microscopic pores that allow fuel vapors and atmospheric air to pass through while blocking liquid water due to surface tension effects. The porous structure provides sufficient total venting area despite having small individual pore sizes, thus resolving the contradiction between preventing water ingress and maintaining effective vapor venting.
Solution Approach 2:
The vent passageway incorporates a hydrophobic coating on the inner surface that creates locally different properties - the surface is hydrophobic at the microscopic level to repel water while remaining permeable to gases. This local quality differentiation allows the same structure to simultaneously prevent water ingress and maintain effective vapor venting.
2Stress or pressure
If a separate vent tube is used to prevent fuel pressure buildup, then pressure equalization is improved, but environmental contamination from liquid fuel venting deteriorates
Solution Approach 1:
The patent combines the vent tube and filling device into a single integrated structure. The vent passageway is formed within the filling device body, eliminating the need for a separate vent tube. This merged structure allows pressure equalization while the hydrophobic membrane prevents liquid fuel from escaping through the vent, thus resolving the contradiction between pressure management and contamination prevention.
Solution Approach 2:
The filling device is designed to perform multiple functions: it serves as both the fuel filling conduit and the venting mechanism. The hydrophobic membrane within the filling device simultaneously enables atmospheric air intake for pressure equalization and blocks liquid fuel escape, providing universal functionality that resolves the contradiction between separate venting and contamination control.
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 solution provides a fuel cap with a sufficient venting area for effective fuel vapor release and air flow, while preventing the ingress of water and contaminants, thus protecting the engine and environment, and allowing for higher manufacturing tolerances and lower costs.
Implementation Method 1
a vent passageway that prevents water and liquid contaminants from passing through and allows the flow of fuel vapors and atmospheric air
Data Source
Figure 1A~2A
Figure 1B
Figure 2B
AI summary
Fuel cap apparatus for use with fuel venting systems are described. An example fuel cap apparatus includes a body having a central cavity and a flange. A membrane is coupled to the body to form a passageway therethrough and coated with a material to substantially prevent the flow of liquid and permit the flow of gas through the passageway.