External Refueling Switch for Hybrid Vehicles
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Solution Overview
Problem
Hybrid electric vehicles (HEVs) face challenges in depressurizing the fuel tank before refueling, leading to inconvenient and unintuitive refueling processes, which can result in fuel vapors escaping into the atmosphere and potential liquid fuel splashing during refueling.
Innovation Solution
A system and method that allows for external refueling request initiation, where the fuel tank is depressurized and the refueling door is unlocked only when the pressure drops below a threshold, enabling all refueling steps to be performed outside the vehicle, simplifying the design and reducing complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the refuel request button is located on the dashboard inside the vehicle, then the refueling process can be initiated, but the operation becomes inconvenient and unintuitive requiring driver re-entry
Solution Approach 1:
The refuel request functionality is extracted from the dashboard interior and relocated to the exterior refueling door area. The refuel request button or sensor is positioned where the refueling operator can access it without entering the vehicle, allowing initiation of the depressurization sequence from outside.
Solution Approach 2:
The refueling door assembly serves as an intermediary structure that houses both the access control mechanism and the refuel request initiation device. This intermediary location allows the operator to interact with the system externally while maintaining the necessary control functions.
2Ease of operation
If the refueling door is unlocked before fuel tank depressurization, then access to the fuel fill line is available, but fuel vapors escape into the atmosphere
Solution Approach 1:
The system performs preliminary depressurization of the fuel tank before unlocking the refueling door. When the refuel request is initiated, the control sequence automatically opens the fuel tank isolation valve to vent vapors to the canister first, then waits for pressure equalization before allowing door unlock and refueling access.
Solution Approach 2:
The control system monitors fuel tank pressure and uses this feedback to control the unlocking sequence. The refueling door remains locked during the depressurization process and only unlocks when the pressure differential is reduced to a safe level, preventing vapor escape.
3Ease of operation
If the refueling door is unlocked while fuel tank pressure is high, then access is available, but liquid fuel may splash out of the tank
Solution Approach 1:
The system performs preliminary pressure reduction before allowing refueling access. The fuel tank isolation valve is opened in advance to equalize pressure, and the refueling door remains locked during this process. Only after pressure equalization is confirmed does the system unlock the door, preventing liquid fuel splashing.
4Reliability
If multiple refueling control components are distributed throughout the vehicle, then functionality is maintained, but design complexity and cost increase
Solution Approach 1:
The patent combines multiple refueling control functions into the refueling door assembly. The door incorporates the refuel request initiation mechanism, the locking/unlocking control, and serves as the access point to the fuel fill line. This consolidation integrates what would otherwise be separate dashboard and fuel system components into a single modular assembly, reducing overall system complexity.
Data Source
AI summary
A method for a vehicle, comprising: depressurizing a fuel tank while restricting access to a fuel fill line responsive to receiving a refueling request from a refueling request module located external to a vehicle cabin; and allowing access to the fuel fill line responsive to the fuel tank pressure decreasing below a threshold. In this way, all of the steps of a refueling procedure can be carried out entirely outside of a vehicle.