Fuel Cap Seal Carrier Dynamics for Vibration Resistance
Solution Overview
Problem
Fuel tank caps in commercial vehicles fail to maintain an airtight seal under harsh environmental conditions, including extreme weather and vibrations, and may leak during sudden impacts, posing risks of fuel spillage and fire or explosion.
Innovation Solution
A fuel cap design featuring a movable seal carrier with two seals, where a spring biases the seal carrier to ensure airtight and fluid-tight seals between the cap and the fuel filler neck assembly, with features like O-ring seals and a cantilevered biasing mechanism to reduce friction and wear, and accommodate manufacturing imperfections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed seal design is used, then the structure is simple, but the seal fails under vibrations and impacts
Solution Approach 1:
The seal carrier is made movable relative to the cap body, allowing the seal to dynamically adjust its position in response to vibrations and impacts. The spring mechanism enables the seal carrier to move axially, maintaining continuous contact with the fuel filler neck assembly despite external disturbances, thereby resolving the contradiction between seal reliability and structural simplicity.
Solution Approach 2:
The sealing system is divided into separate functional components: a movable seal carrier, a spring mechanism, and the cap body. This segmentation allows each component to perform its specific function independently - the seal carrier provides sealing, the spring provides biasing force, and the cap body provides structural support - improving overall reliability without excessive complexity.
2Reliability
If a single seal is used, then the device complexity is low, but the sealing effectiveness under harsh conditions is insufficient
Solution Approach 1:
The sealing function is divided between two separate seals positioned at different locations on the seal carrier. The first seal contacts the cap body while the second seal contacts the fuel filler neck assembly. This segmentation of the sealing function provides redundant sealing paths, ensuring that if one seal is compromised, the other maintains the airtight barrier.
Solution Approach 2:
The dual-seal design provides a buffer zone against potential seal failures. By having two seals in series, the system creates a redundant barrier that cushions against the harsh environmental conditions, manufacturing imperfections, and dynamic loads, thereby improving sealing effectiveness without requiring overly complex individual seal components.
3Manufacturing precision
If a rigid seal structure is used, then manufacturing is simple, but the seal cannot accommodate manufacturing imperfections
Solution Approach 1:
The movable seal carrier with spring biasing allows the seal to dynamically adjust to manufacturing variations in the cap body and fuel filler neck assembly. The spring mechanism absorbs dimensional tolerances by allowing axial movement, enabling the seal to maintain contact and achieve proper sealing despite manufacturing imperfections, without requiring ultra-precise manufacturing.
Solution Approach 2:
The spring mechanism changes the positional parameter of the seal carrier, allowing it to move within a range that accommodates manufacturing tolerances. This parameter adjustment capability enables the seal to adapt to variations in component dimensions while maintaining effective sealing, resolving the contradiction between tolerance to variations and manufacturing simplicity.
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 design effectively maintains a secure, airtight seal under various conditions, including vibrations and impacts, reducing fuel loss and the risk of fire or explosion, while being cost-effective and durable.
Implementation Method 1
The seal carrier is movably biased by a spring positioned within the fuel cap
Data Source
AI summary
A fuel tank cap including a body, a seal carrier movably positioned within the body, a first seal positioned on the seal carrier and configured for sealably engaging a filler tube opening of a fuel tank, and a second seal positioned on the seal carrier and configured for sealably engaging the body.