Method of diagnosing level sensor failure in fuel cell water trap and control unit using the same
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Solution Overview
Problem
Diagnosing level sensor failure in a fuel cell water trap is challenging because the level sensor failure does not result in an immediate change in the water level reading, making it difficult to determine if the drain valve is malfunctioning or if the level sensor itself has failed.
Innovation Solution
A method involving a controller that determines if the water level has changed, adds a charge based on operating time, compares it to a threshold, and forcibly opens the drain valve if channel voltage is abnormal, diagnosing sensor failure based on voltage recovery after valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a level sensor is used to determine condensate level in the water trap, then the drain valve can be controlled to discharge condensate, but when the level sensor fails, the level reading does not change making it impossible to distinguish sensor failure from drain valve malfunction
Solution Approach 1:
The patent introduces an intermediary diagnostic mechanism that uses channel voltage as a mediator to indirectly assess the actual condensate level. Instead of relying solely on the potentially failed level sensor, the system measures channel voltage which changes in response to actual condensate level changes, thereby mediating between the sensor output and the true system state to enable accurate failure diagnosis
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors channel voltage and compares it against threshold values to determine actual condensate levels. This feedback loop allows the system to detect discrepancies between level sensor readings and actual conditions, enabling the diagnosis of both level sensor failures and drain valve malfunctions through voltage threshold comparisons
2Reliability
If the drain valve is opened based on level sensor reading, then condensate can be discharged, but when the level sensor fails the valve may open unnecessarily causing water loss and reduced productivity
Solution Approach 1:
The channel voltage serves as an intermediary verification mechanism before triggering drain valve operation. The controller uses voltage threshold comparisons as an intermediate check to confirm actual condensate levels match sensor readings, preventing unnecessary valve opening and water loss while maintaining reliable condensate discharge when needed
Solution Approach 2:
The patent applies partial action by using voltage threshold comparisons only when sensor readings are questioned or ambiguous. The system does not continuously open the valve based on every voltage fluctuation, but rather uses threshold-based partial verification to confirm the need for drainage, avoiding excessive valve operations that would waste water and reduce productivity
Data Source
AI summary
A method of diagnosing level sensor failure in a fuel cell water trap, the method may include: determining whether a water level of a level sensor is changed in a fuel cell water trap, adding an amount of charge according to an operating time and comparing the added amount of charge with a preset threshold amount of charge, according to the result of the forcibly opening a drain valve according to determining whether a channel voltage of a specific channel is abnormal as the result of the comparison, and diagnosing a failure of the level sensor according to determining whether the channel voltage of the specific cell is recovered as a normal state when the drain valve is opened.