Fuel Tank Connector With Segmented Gas Barrier Shell
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Solution Overview
Problem
Preventing the outflow of fuel evaporative gas through the melt-bonded portion while maintaining adequate connection strength to a resin-made fuel tank is challenging due to the permeability of polyethylene materials.
Innovation Solution
A connector design featuring a main portion made of synthetic resin that minimizes gas permeation, combined with a shell that allows easier gas passage and is melt-bonded to the fuel tank, incorporating a flange part with a wall section for melt-bonding that narrows the distance between the connector and the tank to reduce gas permeation without compromising melt-bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the connector is made of polyethylene to enable melt-bonding to the fuel tank, then the connection strength is improved, but the gas permeation increases causing fuel evaporative gas to pass through easily
Solution Approach 1:
The connector is divided into two distinct portions: a shell portion made of polyethylene for melt-bonding to the fuel tank, and a main body portion made of gas-barrier resin to prevent gas permeation. This segmentation allows each portion to perform its specific function optimally without compromising the other.
Solution Approach 2:
Different portions of the connector are made of different materials with different properties. The shell portion uses polyethylene for its melt-bonding capability, while the main body portion uses gas-barrier resin for its low gas permeability. This local differentiation of material properties resolves the contradiction between bonding strength and gas barrier performance.
2Strength
If the wall section for melt-bonding is thickened to improve connection strength, then the melt-bonding strength is improved, but the gas permeation volume increases
Solution Approach 1:
The connector structure separates the bonding function (shell portion) from the gas barrier function (main body portion). This allows the shell to be sufficiently thick for strong bonding without compromising gas barrier performance, as the gas must pass through the thin gas-barrier resin layer rather than the thick shell.
Solution Approach 2:
The shell portion acts as an intermediary that provides the melt-bonding interface with the fuel tank, while the main body portion acts as the intermediate gas barrier layer. This intermediary structure allows thick bonding sections without increasing gas permeation volume.
3Object-affected harmful factors
If the distance between the main portion and the gas barrier layer is decreased to reduce gas permeation, then the gas barrier effectiveness is improved, but the melt-bonding strength is reduced
Solution Approach 1:
The connector is segmented into a shell portion for bonding and a main body portion for gas barrier function. This segmentation allows the gas barrier layer to be positioned close to the fuel tank aperture for effective gas blocking, while the shell portion maintains sufficient thickness and volume for strong melt-bonding.
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 connector effectively reduces fuel evaporation gas outflow while ensuring sufficient melt-bonding strength by optimizing the geometry of the melt-bonding portion to balance gas barrier effectiveness and connection integrity.
Implementation Method 1
a shell which is formed in an outer side of the main portion and is made of a synthetic resin through which the gas passes easier than the main portion and can be melt-bonded to the outer surface of the fuel tank
Data Source
AI summary
A connector to connect a fluid path to a fuel tank includes a main portion made of a synthetic resin through which a gas produced from fuel hardly passes, and a shell formed outside the main portion and made of a synthetic resin through which the gas passes easier than the main portion and which can be melt-bonded to the outer surface of a fuel tank. The main portion includes a flange part in the outer periphery. The shell has a wall section for a melt-bonding portion which extends around from the top surface side of the flange part and covers the bottom side of the flange part. The undersurface of the flange part is provided with an inclination having the peripheral edge side of the flange part upside thereof.