Leak Detection in Fuel Cell Systems

Diagnosing cause of hydrogen leakage in fuel cell vehicles by supercharging air and comparing hydrogen concentration before and after. If hydrogen sensor detects leakage, it controls an air compressor or radiator fan to supercharge air for a duration. Then it diagnoses leak cause based on ratio of hydrogen concentration before vs after air supercharge. This allows distinguishing between issues like hydrogen backflow, valve leakage, and sensor offset.

Source

Locating leaks in fuel cell systems by analyzing hydrogen sensor signals. If a hydrogen sensor in the exhaust system detects hydrogen after switching to a diagnostic mode where cathode inputs are closed, it indicates a leaky membrane. If the hydrogen level stays constant or increases, it indicates a leaky purge valve. By excluding cathode gas, the hydrogen source can be determined.

Source

Fault detection for fuel cells in vehicles that improves accuracy by combining historical and real-time data. The method involves obtaining current fuel cell power, pressure, and flow, historical values, sensor errors, calculating corrected pressures and flows, and using them along with current values to determine fuel cell faults. This provides better fault detection compared to just using real-time values, reducing false positives and improving stability.

Source

A method for diagnosing faults in solid oxide fuel cell (SOFC) systems using oxygen sensors. The method involves continuously monitoring oxygen concentration at the cathode and anode using sensors. If the cathode oxygen concentration decreases below a threshold, it indicates a possible stack fault. The method further involves analyzing the anode oxygen concentration to determine the location of the fault. If the anode oxygen concentration increases, the fault is in the stack. If the anode oxygen concentration decreases, the fault is in the fuel cell balance of plant (BoP).

Source

Diagnostic method for detecting faults in hydrogen sensors in fuel cell systems. The method involves opening a drain valve between the anode and cathode subsystems and monitoring pressure in the anode subsystem. If pressure falls below a threshold within a certain time after opening the drain valve, it indicates a fault in the hydrogen sensor as hydrogen should have transferred to the cathode subsystem. The drain valve opening also validates the fluid connection between the subsystems.

Source

Locating leaks in a fuel cell system by analyzing hydrogen sensor signals. When a hydrogen sensor in the exhaust system indicates elevated hydrogen levels, the fuel cell system is diagnostically operated to isolate the leak source. If the hydrogen signal drops during diagnostics, it indicates a leaky fuel cell membrane. But if the signal stays high, it indicates a leaky purge valve in the anode line system.

Source

Locating leaks in fuel cell systems using hydrogen sensors in the exhaust. The method involves purging the anode line, monitoring hydrogen in exhaust afterward, and diagnosing leaks based on hydrogen signal behavior. If hydrogen signal is constant after purging, it indicates a leaky fuel cell membrane. If hydrogen signal decreases after purging, it indicates a leaky anode line valve.

Source

Fuel cell system that can detect hydrogen leaks even when the system is powered off or the vehicle is not running. The system uses multiple hydrogen sensors to continuously monitor for leaks. If leaks are detected, an onboard control unit receives the sensor data and determines if hydrogen is actually leaking. If so, it can take appropriate actions like stopping the fuel cell or battery power supply. This allows the system to detect and respond to hydrogen leaks even when the vehicle is not running, which addresses a shortcoming of conventional hydrogen leak detection systems that require power to operate.

Source

Fuel cell fault detection method with improved accuracy by comprehensively analyzing temperature, pressure, flow, and gas leakage data. The method involves determining if the fuel cell temperature is normal, then checking pressure and flow to see if they are normal. If pressure or flow is abnormal, it indicates a fault. The gas leakage alarm is also checked to identify sensor failures. By combining multiple indicators, it reduces misdiagnosis compared to using single indicators.

Source

Method for diagnosing failures of fuel cell systems using digital twins to provide more reliable and efficient fault detection and isolation compared to traditional methods. The method involves collecting digital twin data from the fuel cell system, training neural networks using this data, generating virtual sensor readings from the digital twin, calculating residuals between physical and virtual sensor values, and using a second neural network to classify the residuals as faults. This allows fault detection and isolation using learned models rather than relying solely on physical sensor data.

Source

Efficiently detecting leaks in the hydrogen supply valve of a fuel cell system. The method involves checking for leaks in a fuel cell's hydrogen supply valve by supplying hydrogen to the valve while closed, then opening the cathode exhaust valve and running the blower to circulate oxygen. If the fuel cell stack voltage exceeds a predetermined threshold, it indicates a leaky hydrogen valve.

Source

Detecting hydrogen leaks in a fuel cell system to avoid flammable gas releases by monitoring voltage discharge during shutdown. An abnormal rate of voltage discharge indicates a hydrogen leak in the anode, external components, or crossover through the membrane. The leak detection is based on comparing discharge rates to expected values.

Source

A fuel cell system that properly detects a cross-leak, where hydrogen gas from the fuel side penetrates the electrolyte membrane to the oxidant side, without triggering false alarms. The system includes a fuel cell, oxidant supply, fuel supply, and a controller that monitors hydrogen concentration in the oxidant exhaust to detect cross leaks. To reduce false alarms, it varies the hydrogen detection threshold based on the amount of fresh air bypassing the fuel cell. If more bypass air is used (which can dilute the hydrogen concentration), it increases the threshold for cross-leak detection.

Source

Diagnosing valve failure in a fuel cell system without using a valve position sensor. The method diagnoses and determines whether an integrated discharge valve is opened or closed and fails in a direct way of using a sensor, etc. rather than indirectly checking and diagnosing whether an integrated discharge valve is opened or closed. The diagnostic method uses pressure sensors to detect failure states where a valve does not open when commanded to. It involves controlling hydrogen pressure to a set level and monitoring if an integrated discharge valve opens within a certain time. If not, the valve is diagnosed as failed.

Source

A hydrogen leak sensing device and method for a fuel cell vehicle that can detect hydrogen leaks even when the vehicle's electronic systems are powered off. The sensing device calculates the state of fuel (SOF) in the hydrogen tank when the valve is closed versus open to determine if there has been a leak. If the SOF decreases when the valve is closed, it indicates a leak.

Source

A hydrogen leakage detection system for fuel cell systems that enables quicker detection of hydrogen leakage by strategically placing sensors. The detection system includes an outer shell housing the fuel cell stack and hydrogen tanks, with a hydrogen sensor inside the shell. A porous sheet separates the shell into upper and lower regions. The fuel cell components are in the lower region beneath the sheet, while the sensor is in the upper region. The sheet allows hydrogen permeation. If there's a leak in the lower fuel cell area, the porous sheet lets the leaked hydrogen diffuse upwards, increasing the concentration around the sensor for faster detection.

Source

Fuel cell vehicle detection system to accurately determine if a fuel cell has experienced a leak and the severity of the leakage. The system uses a two-stage detection process. In the preliminary stage, a leak sensor detects if the cell leaks. If so, the current and power signals of the cell are analyzed. If the current changes significantly or power drops, it indicates a serious leak. In the reconfirmation stage, the power change is calculated and if it's high, it confirms a serious leak. This two-stage process provides accurate leak detection without continuous monitoring and false alarms. The emergency and reminder signals are sent to the ECU.

Source

Leak detection system for hydrogen fuel systems in aircraft to improve safety by detecting hydrogen leaks that are difficult to visually detect due to hydrogen's colorless and odorless nature. The system uses sensors to monitor components like fuel tanks, delivery systems, and generators for signs of hydrogen leakage. If a leak is detected, the system alerts the crew and takes mitigating actions like venting the area or shutting down the engine. The system can also have indicators like displays in the cockpit to show leak warnings.

Source

Diagnostic device for fuel cells that can detect stack leakage after shutdown to improve maintenance efficiency and extend stack life. The device allows leakage detection of fuel cells without the need for continuous power-on operation. After the fuel cell is shut down, the device purges the cathode side to create a nitrogen atmosphere, then applies a potential scan to obtain seepage current. If seepage exceeds a threshold, the cell needs repair.

Source

Fuel cell system and method for detecting hydrogen leaks and faults that addresses the issue of false alarms and short sensor life caused by always-on hydrogen sensors. Instead, it uses other sensors to detect leaks and faults. The method involves monitoring the hydrogen inlet and outlet pressures of the fuel cell stack using pressure sensors. By comparing the actual pressures with the normal pressures for a target power level, leakage can be detected without always-on hydrogen sensors. Faults like stack overheating or low cell voltage are detected by monitoring stack parameters like temperature and cell voltages. The controller activates the hydrogen sensor only when needed for startup or diagnostics. This reduces sensor wear and false alarms.

Source