Flexible Seal Assembly for Fuel Fill Pipe Airflow Control
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Solution Overview
Problem
The existing fuel fill pipe design allows for unrestricted airflow during refueling, leading to air entrainment and the escape of untreated hydrocarbons into the atmosphere, which increases the size and cost of carbon canisters needed for vapor outlet systems.
Innovation Solution
A seal assembly with pliable, annular seal bodies and a cap ring is installed at the end of the fuel fill pipe, featuring inwardly projecting tabs that engage the refueling nozzle to limit airflow and provide over-fill and over-pressure relief, ensuring a tight seal during normal refueling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fuel fill pipe is made with a larger diameter to allow easy insertion and removal of the refueling nozzle, then the ease of operation is improved, but air entrainment increases leading to higher hydrocarbon emissions
Solution Approach 1:
A flexible annular seal member is positioned at the open end of the fill pipe, forming a flexible barrier that seals against the nozzle outer tube. This flexible film structure allows the nozzle to be easily inserted and removed while preventing air from entering the fill pipe during refueling operations.
Solution Approach 2:
The seal member acts as an intermediary element between the fill pipe and the nozzle. It provides a sealing interface that allows the nozzle to pass through easily during insertion and removal while blocking air entrainment during the refueling process.
2Object-generated harmful factors
If a seal assembly is added to reduce air entrainment, then hydrocarbon emissions are reduced, but the device complexity increases
Solution Approach 1:
The seal assembly uses a simple flexible annular seal member without complex mechanical structures. This flexible film approach reduces device complexity while effectively preventing air entrainment and hydrocarbon emissions during refueling.
3Object-generated harmful factors
If the seal assembly provides a tight seal to prevent air flow, then hydrocarbon emissions are reduced, but the reliability decreases due to potential over-fill and over-pressure conditions
Solution Approach 1:
The seal member is designed with flexible tabs that can dynamically adjust their position. During normal refueling, the tabs maintain a tight seal against the nozzle to prevent air entrainment. However, when over-fill or over-pressure conditions occur, the flexible tabs can deflect or deform to allow controlled air passage, providing a fail-safe mechanism that maintains reliability.
Solution Approach 2:
The flexible seal design inherently provides a cushioning effect by allowing controlled deformation under excessive pressure or fill conditions. This pre-designed flexibility acts as a safety mechanism that prevents dangerous pressure buildup while maintaining the sealing function during normal operation.
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 seal assembly significantly reduces air entrainment and hydrocarbon emissions, allowing for smaller, less costly carbon canisters by minimizing airflow through the fill pipe, while maintaining easy refueling procedures and quick, cost-effective installation.
Implementation Method 1
A seal assembly with pliable, annular seal bodies and a cap ring is installed at the end of the fuel fill pipe, featuring inwardly projecting tabs that engage the refueling nozzle to limit airflow
Implementation Method 2
A seal assembly with pliable, annular seal bodies and a cap ring is installed at the end of the fuel fill pipe, featuring inwardly projecting tabs that engage the refueling nozzle to limit airflow and provide over-fill and over-pressure relief
Data Source
AI summary
A seal assembly is provided for a fill pipe of a vehicle fuel system to provide a pliable seal between an end of the fuel pipe and a refueling nozzle inserted in the fill pipe.