Abstract: A system for controlling purge operation of a fuel cell assembly includes a controller and one or more sensors configured to obtain respective sensor data. The fuel cell stack is configured to receive a stack coolant. The controller is configured to execute a first purge mode when at least one of a first enabling condition and a second enabling condition is met. The first purge mode defines a first group of setpoints, including a relatively low cathode stoichiometric ratio. The controller is configured to switch to a second purge mode when the coolant temperature is above a minimum warm-up temperature and a third mode when a relative humidity value of a stack cathode output falls below a threshold humidity. The second purge mode defines a second group of setpoints, including a relatively high cathode stoichiometric ratio.

Abstract: A system for controlling purge operation of a fuel cell assembly includes a controller and one or more sensors configured to obtain respective sensor data. The fuel cell stack is configured to receive a stack coolant. The controller is configured to execute a first purge mode when at least one of a first enabling condition and a second enabling condition is met. The first purge mode defines a first group of setpoints, including a relatively low cathode stoichiometric ratio. The controller is configured to switch to a second purge mode when the coolant temperature is above a minimum warm-up temperature and a third mode when a relative humidity value of a stack cathode output falls below a threshold humidity. The second purge mode defines a second group of setpoints, including a relatively high cathode stoichiometric ratio.

Abstract: Disclosed are fuel cell architectures, thermal sub-systems, and control logic for regulating fuel cell stack temperature. A method is disclosed for regulating the temperature of a fuel cell stack. The method includes determining a pre-start temperature of the fuel cell stack, and determining, for this pre-start temperature, a target heating rate to heat the stack to a calibrated minimum operating temperature. The method then determines a hydrogen bleed percentage for the target heating rate, and executes a stack heating operation including activating the fuel cell stack and commanding a fluid control device to direct hydrogen to the cathode side at the hydrogen bleed percentage to generate waste heat. After a calibrated period of time, the method determines if an operating temperature of the stack exceeds the calibrated minimum stack operating temperature. Responsive to the operating temperature being at or above the minimum operating temperature, the stack heating operation is terminated.

Abstract: Disclosed are fuel cell architectures, thermal sub-systems, and control logic for regulating fuel cell stack temperature. A method is disclosed for regulating the temperature of a fuel cell stack. The method includes determining a pre-start temperature of the fuel cell stack, and determining, for this pre-start temperature, a target heating rate to heat the stack to a calibrated minimum operating temperature. The method then determines a hydrogen bleed percentage for the target heating rate, and executes a stack heating operation including activating the fuel cell stack and commanding a fluid control device to direct hydrogen to the cathode side at the hydrogen bleed percentage to generate waste heat. After a calibrated period of time, the method determines if an operating temperature of the stack exceeds the calibrated minimum stack operating temperature. Responsive to the operating temperature being at or above the minimum operating temperature, the stack heating operation is terminated.