Fuel Tank Vent Valve Diagnosis via Vehicle Position Adjustment
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Solution Overview
Problem
Passively operated fuel tank vent valves in vehicles can be improperly operated, leading to issues such as fuel vapor migration to the canister, reducing its effectiveness, or vacuum development in the fuel tank, causing deformation, due to inadequate control over their opening and closing based on the vehicle's position and the road grade.
Innovation Solution
A method involving adjusting the vehicle's position to diagnose the operation of passively controlled fuel tank vent valves by using a controller to change the vehicle's orientation on a surface with a significant grade, allowing for the differentiation of the operation of first and second grade vent valves, thereby evaluating their functionality without the need for additional position sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vent valve is held open, then fuel vapors can exit the fuel tank, but liquid fuel may migrate to the fuel vapor storage canister, saturating the canister and reducing its ability to trap fuel vapors
Solution Approach 1:
The system performs preliminary diagnosis by adjusting the vehicle position to a second position where the vent valve should be closed, then evaluates whether the valve is properly closed before allowing normal operation. This preliminary check prevents fuel vapor migration to the canister by ensuring the valve is functioning correctly.
Solution Approach 2:
The system continuously monitors vent valve operation by comparing the actual valve state with the expected state based on vehicle position and fuel level. When a discrepancy is detected, the system can trigger diagnostic routines or alert the driver, providing feedback to ensure proper valve operation and prevent harmful fuel vapor migration.
2Reliability
If the vent valve is held closed, then fuel is prevented from exiting the fuel tank, but vacuum may develop within the fuel tank causing deformation
Solution Approach 1:
The system performs preliminary diagnosis by adjusting the vehicle position to a second position where the vent valve should be closed, then evaluates whether the valve is properly closed. This ensures the valve is functioning correctly before normal operation, preventing harmful vacuum development.
Solution Approach 2:
The system continuously monitors vent valve operation by comparing the actual valve state with the expected state based on vehicle position and fuel level. When a discrepancy is detected, the system can trigger diagnostic routines or alert the driver, providing feedback to ensure proper valve operation and prevent harmful vacuum development.
3Measurement precision
If position sensors are added to detect positions of grade vent valves, then individual diagnosis of vent valves is enabled, but system cost increases
Solution Approach 1:
The system uses existing vehicle components (controller, actuator, vehicle position adjustment capabilities) to perform vent valve diagnosis without requiring additional position sensors. The controller automatically adjusts vehicle position and evaluates valve operation, allowing the system to self-diagnose using resources already available.
Solution Approach 2:
The existing controller and actuator systems are made multi-functional by having them perform both normal vehicle operations and vent valve diagnosis functions. The controller not only manages engine operations but also controls vehicle position adjustment and evaluates vent valve status, eliminating the need for dedicated position sensing hardware.
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 approach enables individual diagnosis of vent valves responding to the vehicle's position, reduces system costs, and ensures proper operation of fuel tank vent valves, preventing fuel vapor migration and tank deformation.
Implementation Method 1
The area in a fuel tank that is occupied by fuel may change with a grade that the vehicle is parked on so that the passively operated grade vent valves may open or close depending on the grade of the surface that the vehicle is parked on
Data Source
AI summary
Methods and systems are presented for diagnosing operation of passive grade vent valves of a fuel system. The methods and systems include adjusting a position of a vehicle so that fuel in a fuel tank may cause a first grade vent valve to open and a second grade vent valve to close.