Fuel Cell Leak and Failure Detection Techniques

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.

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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.

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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.

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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.

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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.

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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.

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Fault detection and response for hydrogen supply in a fuel cell system. The method uses pressure sensing and consumption estimation to diagnose issues like valve failure and leaks. It estimates hydrogen supply versus consumption and checks for abnormalities. Rapid pressure drops indicate valve failure. If supply-consumption mismatch exceeds a threshold, it detects a leak. Detected faults trigger corrective actions like entering an emergency mode, reducing load, or stopping the fuel cell for inspection.

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Detecting low-level fuel injector leakage in a fuel cell system to prevent uncontrolled hydrogen release and fuel cell damage. The system monitors pressure in the anode gas loop, predicts expected pressure reduction during closed injector operation, and compares it to the actual reduction. If pressure decreases slower than expected, a leaky injector is indicated. Remedial actions include warning of the fault, reducing hydrogen from fuel lines, and preventing restart.

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Method to detect and recover from a stuck hydrogen cut-off valve in a fuel cell vehicle. It rapidly detects a stuck or closed hydrogen cut-off valve by monitoring the duty cycle of the hydrogen supply valve. If the duty cycle is maxed out, indicating the hydrogen supply line pressure is not increasing, the method opens the cut-off valve to restore hydrogen flow. If the pressure is not increasing, this implies the cut-off valve is preventing hydrogen flow.

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Detecting gas leaks from a fuel cell anode system during shutdown or startup periods. The method estimates the normal gas losses through permeation and reactions during these periods, and compares it to the actual gas loss. If the difference exceeds a threshold, it indicates an abnormal gas leak. This improves sensitivity to leaks by accounting for expected gas losses through seals and membranes.

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Diagnosing fuel cell stack failures in fuel cell electric vehicles to prevent damage due to abnormal hydrogen supply. The method involves using two hydrogen pressure sensors to detect if pressure is smooth. If the difference between sensor readings is large, it indicates hydrogen supply issues. The system shuts down if supply problems are detected, preventing stack damage.

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A fuel cell system that can detect hydrogen leaks during shutdown and reduce noise during startup. The system has a pressure sensor, valve, and pressure reducer to gradually lower the pressure in the hydrogen supply path after the fuel cell shuts down. By monitoring pressure changes at two levels, the system can distinguish between sensor errors and actual leaks.

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A method for detecting injector failures in fuel cell systems without dedicated sensors. The method uses existing pump power data. If the pump power fluctuation caused by injector activation falls within a certain range, it indicates the injector is functioning properly. If the fluctuation exceeds the range, it indicates injector failure.

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Method for controlling a fuel cell system that can diagnose whether hydrogen flows back into a stack enclosure during purging and condensate discharge, without the need to disassemble the stack enclosure and stack. The method involves detecting hydrogen inside the stack enclosure, stopping stack power generation if hydrogen is detected, purging hydrogen and discharging condensate, and then measuring hydrogen concentration inside the enclosure to determine if any backflow occurred.

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Fuel cell system with accurate hydrogen leak detection and improved ventilation without needing separate blowers. The system uses the main air compressor to draw in air through an inlet filter towards the fuel cell stack. A flow restrictor connects the inlet to the stack ventilation line. This creates a vacuum in the inlet that pulls air through the stack enclosure. A hydrogen sensor on the ventilation line detects any leaks.

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