Abstract: System and methods for detecting anode contamination in a fuel cell system are presented. In certain embodiments, a high frequency resistance response of a fuel cell system may be measured at a plurality of frequencies. In some embodiments, the rate of change of high frequency resistance response over time may differ at varied frequencies based on an amount of anode contamination in the fuel cell system. Accordingly, systems and methods disclosed herein may compare high frequency resistance responses taken at a plurality of measured frequencies to detect anode contamination and initiate associated recovery procedures in the fuel cell system.

Abstract: System and methods for detecting anode contamination in a fuel cell system are presented. In certain embodiments, a high frequency resistance response of a fuel cell system may be measured at a plurality of frequencies. In some embodiments, the rate of change of high frequency resistance response over time may differ at varied frequencies based on an amount of anode contamination in the fuel cell system. Accordingly, systems and methods disclosed herein may compare high frequency resistance responses taken at a plurality of measured frequencies to detect anode contamination and initiate associated recovery procedures in the fuel cell system.

Abstract: Disclosed herein are systems and methods for monitoring and controlling a flow of air within a fuel cell stack. The fuel cell stack may include an air supply path to conduct a flow of air through the fuel cell. Sensors may be configured to determine parameters associated with the air supply path, such as pressure, flow rate, etc. A modeling system may further be configured to determine a modeled parameter associated with the air supply path. A control system may receive input from the one or more sensors and the modeling system to generate a baseline based on the measured parameter and the modeled parameter, determine a difference between the measured parameter and the modeled parameter, determine a change of the difference with respect to the baseline, determine that the change satisfies a criterion, and selectively implement a corrective action based upon satisfaction of the criterion.

Abstract: A system and method for determining if an RH sensor that measures the relative humidity of cathode inlet air provided to a fuel cell stack or an HFR circuit that measures stack water content is operating properly. The method provides the cathode inlet air through a WVT unit that increases the water content of the cathode inlet air. The method uses a water buffer model for determining the water content of the fuel cell stack based on inputs from a plurality of system components and revises a water transfer model using the HFR humidification signal or the RH signal to correct for WVT unit degradation. The method determines whether the RH sensor or the HFR circuit is operating properly, such as by determining if the HFR humidification signal is increasing at a rate that is faster than what the stack water content is able to increase.

Abstract: Disclosed herein are systems and methods for monitoring and controlling a flow of air within a fuel cell stack. The fuel cell stack may include an air supply path to conduct a flow of air through the fuel cell. Sensors may be configured to determine parameters associated with the air supply path, such as pressure, flow rate, etc. A modeling system may further be configured to determine a modeled parameter associated with the air supply path. A control system may receive input from the one or more sensors and the modeling system to generate a baseline based on the measured parameter and the modeled parameter, determine a difference between the measured parameter and the modeled parameter, determine a change of the difference with respect to the baseline, determine that the change satisfies a criterion, and selectively implement a corrective action based upon satisfaction of the criterion.

Abstract: A system and method for controlling hydrogen gas flow to an anode side of a fuel cell stack using a pressure regulator in the event that an injector that normally injects the hydrogen gas into the fuel cell stack has failed in a stuck open position. During normal operation, the control of the injector is determined based on the pressure of an anode sub-system and the position of the pressure regulator is determined based on a supply pressure between the pressure regulator and the injector. If it is determined that the injector is stuck in an open position, then the position of the pressure regulator is controlled to the anode pressure instead of the supply pressure. If the pressure regulator is an electrical pressure regulator, then it is pulsed to mimic normal system operation. Alternately, another valve, such as a shut-off valve, can be employed to provide the flow pulsing.

Abstract: A system and method for determining if an RH sensor that measures the relative humidity of cathode inlet air provided to a fuel cell stack or an HFR circuit that measures stack water content is operating properly. The method provides the cathode inlet air through a WVT unit that increases the water content of the cathode inlet air. The method uses a water buffer model for determining the water content of the fuel cell stack based on inputs from a plurality of system components and revises a water transfer model using the HFR humidification signal or the RH signal to correct for WVT unit degradation. The method determines whether the RH sensor or the HFR circuit is operating properly, such as by determining if the HFR humidification signal is increasing at a rate that is faster than what the stack water content is able to increase.

Abstract: A system and method for controlling hydrogen gas flow to an anode side of a fuel cell stack using a pressure regulator in the event that an injector that normally injects the hydrogen gas into the fuel cell stack has failed in a stuck open position. During normal operation, the control of the injector is determined based on the pressure of an anode sub-system and the position of the pressure regulator is determined based on a supply pressure between the pressure regulator and the injector. If it is determined that the injector is stuck in an open position, then the position of the pressure regulator is controlled to the anode pressure instead of the supply pressure. If the pressure regulator is an electrical pressure regulator, then it is pulsed to mimic normal system operation. Alternately, another valve, such as a shut-off valve, can be employed to provide the flow pulsing.

Abstract: A fuel cell system is provided which includes a mounting system for a manifold having a mounting plate. The fuel cell system also includes a fuel cell stack with a first end and a second end. The first end of the fuel cell stack includes at least one port in communication with the manifold. A clamping system is disposed on the second end of the fuel cell stack and is operable to engage the mounting plate of the manifold to couple the manifold to the fuel cell stack.

Abstract: A temperature control system and method for a fuel cell stack cooling system is disclosed. The temperature control system includes a coolant circulation line for circulating a coolant to and from a fuel cell stack. A coolant pump is provided in the coolant circulation line, and a pump ?P sensor is provided in fluid communication with the coolant circulation line on inlet and outlet sides of the coolant pump. The pump ?P sensor measures a change in pump pressure between the inlet and outlet sides of the coolant pump. A pump map is provided having correlated values of pump speed, change in pump pressure and coolant flow rate for correlating the coolant flow rate with the pump speed and the change in pump pressure to attain a desired coolant flow rate for optimum fuel stack cooling.

Abstract: A control system and method controls an output of a fuel cell. A fuel cell stack controller that receives an output request signal and that generates an oxidant request signal and a fuel request signal using a first inverse model. A fuel delivery controller receives the fuel request signal, generates a fuel command using a second inverse model and generates a delivered fuel signal using a first model. An oxidant delivery controller receives the oxidant request signal, generates an oxidant command using a third inverse model and generates a delivered oxidant signal using a second model. The fuel cell stack controller receives the delivered oxidant signal from the second model and the delivered fuel signal from the first model and calculates a power available signal using a third model.

Abstract: An airflow control system and method for a fuel cell includes a compressor that supplies air to a storage chamber for storing the air. Fuel cell subsystems are connected to the air storage chamber. Each of the fuel cell subsystems includes a flow controller and flow sensor. A sensor measures air pressure in the storage chamber. A controller polls the flow controllers of the fuel cell subsystems for a minimum required air pressure for the fuel cell subsystems. The controller selects a highest minimum required air pressure. The controller controls the compressor to provide the highest minimum required pressure in the air storage chamber. The air storage chamber includes tubing, a manifold or both.

Abstract: An airflow control system and method for a fuel cell includes a compressor that supplies air to a storage chamber for storing the air. Fuel cell subsystems are connected to the air storage chamber. Each of the fuel cell subsystems includes a flow controller and flow sensor. A sensor measures air pressure in the storage chamber. A controller polls the flow controllers of the fuel cell subsystems for a minimum required air pressure for the fuel cell subsystems. The controller selects a highest minimum required air pressure. The controller controls the compressor to provide the highest minimum required pressure in the air storage chamber. The air storage chamber includes tubing, a manifold or both.

Abstract: A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell. Other polarization curves may be generated and used for fuel cell stack monitoring based on different operating pressures, temperatures, hydrogen quantities.

Abstract: A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

Abstract: A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell. Other polarization curves may be generated and used for fuel cell stack monitoring based on different operating pressures, temperatures, hydrogen quantities.

Abstract: A diagnostic system and method identifies fuel injector failure in a fuel cell system including a fuel processor and a fuel source. A fuel injector supplies fuel from the fuel source to the fuel processor. A pressure sensor generates a pressure signal based on pressure between the fuel source and the fuel injector. A fuel injector diagnostic identifies fuel injector failure based on the pressure signal. The fuel injector diagnostic includes a moving window tracker that tracks the pressure signal over a moving window. The fuel injector diagnostic further includes a standard deviation or variance calculator that generates a standard deviation or variance based on the pressure signal in the moving window.

Abstract: A control system and method for operating a cooling fan in a coolant system of fuel cell power plant having a high temperature coolant loop and a low temperature coolant loop. The fan controller generates a fan control signal based on a first control signal from the high temperature coolant loop and a second control signal from the low temperature coolant loop. The first control signal is a function of the waste heat energy in the high temperature coolant loop, and the second control signal is a function of the temperature in the low temperature coolant loop. The fan control signal may also be generated based on a third control signal which is a function of a localized ambient temperature such as the under hood temperature of a vehicle.

Abstract: A control system controls steam in a fuel cell system including a fuel processor. A fuel cell has run, standby and shutdown operating modes. A fuel processor provides reformate to the fuel cell. A pressure sensor generates a pressure signal based on a pressure of steam supplied to the fuel processor. A valve directs steam to or vents steam away from the fuel processor. A controller communicates with the pressure sensor, the fuel cell and the valve and controls the valve based on the operating mode of the fuel cell and the pressure signal. The controller opens the valve during the shutdown mode. The controller closes the valve during the run operating mode. The controller initially closes the valve during the standby mode. The controller opens the valve if the pressure signal exceeds a first predetermined pressure value and closes the valve when the pressure falls.

Abstract: A control method for monitoring a fuel cell stack in a fuel cell system in which the actual voltage and actual current from the fuel cell stack are monitored. A preestablished relationship between voltage and current over the operating range of the fuel cell is established. A variance value between the actual measured voltage and the expected voltage magnitude for a given actual measured current is calculated and compared with a predetermined allowable variance. An output is generated if the calculated variance value exceeds the predetermined variance. The predetermined voltage-current for the fuel cell is symbolized as a polarization curve at given operating conditions of the fuel cell.