Fuel Tank Cap Closure Detection Using Pressure Equalization
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Solution Overview
Problem
There is a need for a reliable method to determine if the fuel tank cap of a motor vehicle is fluid-tightly mounted on the filler neck after refueling, as existing methods may wear out or provide incorrect notifications due to mechanical stress or dirt accumulation.
Innovation Solution
A method involving a device that measures the pressure in the fuel tank's gas chamber by opening a recirculation line and comparing the initial and subsequent pressures to determine if the tank cap is closed, without relying on sensors or mechanical devices on the tank cap, using a pressure sensor and data processing to assess the closure status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors or mechanical devices are mounted on the tank cap to detect closure status, then the closure status can be detected, but the devices wear out due to constant mechanical stress or provide incorrect notifications due to dirt accumulation
Solution Approach 1:
The patent replaces mechanical sensors and contact sensors on the tank cap with a pressure-based detection system. A pressure sensor measures pressure changes in the fuel tank's gas chamber, and a data processing device determines closure status based on these pressure variations. This substitution eliminates mechanical wear and contamination issues associated with contact sensors while maintaining reliable detection of whether the tank cap is properly closed.
2Reliability
If additional sensors or mechanical devices are added to the tank cap system, then closure status can be detected, but the device complexity increases
Solution Approach 1:
The patent utilizes the existing recirculation line in the fuel tank system, which normally serves for vapor recovery, to also function as a pathway for pressure equalization during closure detection. By opening the recirculation line controlled by a recirculation line control valve, the system creates a pressure difference that can be measured by the pressure sensor to determine closure status. This multi-functional use of existing components avoids adding separate detection hardware, thereby reducing overall system complexity.
3Reliability
If the recirculation line is opened to equalize pressure for detection, then closure status can be determined, but fuel vapor may escape from the tank
Solution Approach 1:
The system performs closure status detection at a specific moment in the refueling process - immediately after refueling completion but before the filler neck is removed. At this timing, the tank cap is already in place and the recirculation line is normally closed. The system briefly opens the recirculation line under controlled conditions to create a pressure difference for detection, then quickly closes it again. This timing-based approach minimizes the window for vapor escape while still enabling accurate closure status determination.
Solution Approach 2:
The system uses a data processing device that continuously monitors pressure sensor readings and provides feedback to determine closure status. When the recirculation line is opened, the system monitors the pressure change in real-time. If the tank cap is properly closed, a characteristic pressure drop is observed; if not closed, a different pressure pattern occurs. This feedback mechanism enables automatic determination of closure status and can trigger warnings to the user, ensuring proper closure while minimizing vapor loss through controlled, brief recirculation line opening.
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
This method effectively determines the closure status of the fuel tank cap without wear or incorrect notifications, ensuring the fuel tank is sealed correctly before driving, thus preventing fuel vapor escape and reducing the need for additional hardware on the tank cap.
Implementation Method 1
obtaining a value for a first pressure which is present in the gas chamber of the fuel tank of the motor vehicle
Implementation Method 2
By connecting the three atmospheres mentioned above, the pressure in the gas chamber of the fuel tank drops substantially to at most a pressure that corresponds to the pressure in the atmosphere
Data Source
AI summary
A method for detecting the closure status of a fuel tank closure of a motor vehicle and to a device for carrying out this method.