Capless Fuel Filler Assembly with Nested Sealing Flaps
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Solution Overview
Problem
Capless refueling systems are more expensive than conventional cap-type systems due to increased complexity and cost, particularly in ensuring a secure seal without a threaded cap.
Innovation Solution
A capless fuel filler assembly featuring a main flap unit and a shutter unit, both pivotally connected to the fuel filler pipe, which engage cooperatively to seal the filling end and prevent fuel leakage, utilizing a radial flange and mating surface interference fit for sealing contact without a gasket, reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capless refueling systems are used, then the refueling system eliminates the need for a removable cap, but the system becomes more expensive due to increased complexity
Solution Approach 1:
The closure mechanism is divided into two separate pivotally mounted closures (first closure and second closure) positioned at different locations along the filler tube. Each closure independently seals a portion of the filler tube, allowing the system to achieve complete sealing through segmented rather than monolithic design, thereby reducing complexity while maintaining capless operation.
Solution Approach 2:
The first closure is positioned upstream from the second closure along the filler tube, creating a nested arrangement where the closures work in sequence. The refueling nozzle must pass through the first closure to reach the second closure, with each closure providing a layer of sealing. This nested structure achieves complete sealing with simpler individual components.
2Reliability
If multiple pivotally mounted closures are provided in series, then complete closure of the filler tube is ensured, but the manufacturing cost increases
Solution Approach 1:
Each pivotally mounted closure is designed as a simple, inexpensive component with basic pivot mounting and biasing mechanisms. Rather than using a single complex closure system, the patent employs multiple simpler closures that can be manufactured more cheaply and assembled in series, achieving reliable sealing through redundancy rather than complexity.
3Ease of operation
If a refueling nozzle is inserted into the filler tube, then the pivotally mounted closures are opened against biasing, but the system requires complex biasing mechanisms
Solution Approach 1:
The biasing mechanisms (such as springs) are integrated into the closure assembly itself, with each closure having its own biasing element that automatically urges it toward the closed position. The refueling nozzle itself provides the opening force by simply being inserted and pushed through the closures, eliminating the need for separate actuation mechanisms. The system serves itself by using the nozzle's insertion motion to overcome the integrated biasing forces.
Data Source
AI summary
A fuel filler assembly for a vehicle includes a main flap unit connected to a fuel filler pipe adjacent a filling end thereof and a main flap pivotally disposed on the main flap unit for selectively closing access to the filling end of the fuel filler pipe. The fuel filler assembly further includes a shutter unit connected to the fuel filler pipe adjacent the filling end thereof and engaging the main flap unit, and a shutter pivotally disposed on the shutter unit for selectively closing access to the filling end of the fuel filler pipe. Cooperative engagement (e.g., an interference fit) between the main flap unit and the shutter unit seals the main flap unit and the shutter unit together and prevents fuel from leaking therebetween.