Fuel Cell Sensor Abnormality Detection via Pressure Reference
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Solution Overview
Problem
Fuel cell systems face challenges in accurately determining abnormality in pressure sensors due to pressure decreases in the filling flow path after hydrogen tank filling, often caused by foreign matter, leading to erroneous sensor readings.
Innovation Solution
A fuel cell system with a control unit that calculates maximum filling pressure and differences between supply start pressure and maximum filling pressure, using temperature and flow rate sensors to determine sensor normalcy, thereby reducing erroneous abnormality determinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure comparison method is used to detect sensor abnormality, then sensor abnormality detection capability is improved, but measurement precision deteriorates due to pressure decrease in filling flow path
Solution Approach 1:
The system records the maximum filling pressure during the filling process before pressure decrease occurs. By capturing the pressure peak in advance and using it for comparison with supply flow path pressure, the system avoids the problem of pressure decrease affecting measurement accuracy while maintaining the ability to detect sensor abnormalities.
Solution Approach 2:
The system creates a reference value (maximum filling pressure) that represents the true pressure state in the fuel tank. This copied reference value is then used for comparison with the supply flow path pressure sensor readings, allowing accurate abnormality detection without being affected by subsequent pressure decreases in the filling flow path.
2Reliability
If pressure comparison between filling and supply flow paths is performed, then sensor abnormality detection is enabled, but false abnormality determination occurs due to pressure decrease
Solution Approach 1:
The control unit identifies and records the maximum pressure value during filling before pressure decrease occurs. This preliminary capture of the pressure peak ensures that the reference value used for abnormality detection reflects the true pressure state, preventing false abnormality determinations caused by subsequent pressure drops.
Solution Approach 2:
The system continuously monitors pressure in both filling and supply flow paths, comparing the supply flow path pressure against the recorded maximum filling pressure. This feedback mechanism enables accurate detection of sensor abnormalities while filtering out normal pressure variations that occur after filling completion.
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 configuration improves the accuracy of abnormality detection for pressure sensors by accounting for pressure changes and flow conditions, reducing the likelihood of false abnormality readings.
Implementation Method 1
a first pressure sensor that is mounted on the filling flow path and that detects a pressure in the filling flow path; a second pressure sensor that is mounted on the supply flow path and that detects a pressure of the fuel gas at an outlet of the fuel tank
Implementation Method 2
a temperature sensor that detects a temperature in the fuel tank
Data Source
AI summary
The present disclosure relates to a fuel cell system. In abnormality detection control, a control unit of the fuel cell system obtains a maximum filling pressure that is a maximum value of the pressure in a filling flow path during filling, and determines that both of first and second pressure sensors are normal when the difference between a supply start pressure and the maximum filling pressure is equal to or smaller than a reference value. When this difference is larger than the reference value, the control unit determines that there is a possibility that at least one of the first and second pressure sensors may be abnormal. The supply start pressure is a detection value of the second pressure sensor at the time when supply of fuel gas to a fuel cell is started for the first time after filling of a fuel tank with the fuel gas is finished.