Abstract: A multi-function fuel delivery system and method of providing fuel delivery is provided that addresses space-related and cost related challenges as well as other challenges by combining a noise attenuating function, a hydrogen heating function, and a fuel supply rail capable of supplying hydrogen to multiple injectors within a single volume where a heat-transfer core utilizes an existing available internal volume of an attenuating volume or a fuel rail of a hydrogen supply manifold. A hydrogen fuel manifold, a hydrogen heat exchanger, and a fuel rail are housed in a single chamber such that a hydrogen fuel heating/cooling function, a hydrogen fuel noise/vibration attenuating function, providing the heat to the heat-transfer core, and providing the noise-attenuated H2 are performed in the single chamber.

Abstract: A system and method for a cathode subsystem in a fuel cell system. The system includes a fuel cell stack, a cathode inlet line that provides cathode air to a fuel cell stack and a cathode exhaust line that exhausts a cathode exhaust gas out of the fuel cell stack. Also included is a backpressure valve in the cathode exhaust line that is located downstream of a drip rail of the cathode exhaust line, where the drip rail includes a protrusion that prevents condensed water from building up near the backpressure valve. The drip rail further includes a sump that collects drips of condensed water from the protrusion of the drip rail. The system also includes a drain below a water vapor transfer unit that includes an orifice that is in a portion of the drain that is within the cathode exhaust line.

Abstract: A method for starting a cold or frozen fuel cell stack as efficiently and quickly as possible in a vehicle application is based upon a state of charge of a first power source such as a high voltage battery. Power flow between the first power source and fuel cell system is coordinated in conjunction with a specific load schedule and parallel control algorithms to minimize the start time required and optimize system warm-up.

Abstract: System and methods for controlling and optimizing coolant system parameters in a fuel cell system to obtain a requested cabin temperature in a fuel cell vehicle are presented. A method for managing a temperature in a vehicle cabin may include receiving an indication relating to a desired vehicle cabin temperature and a plurality of measured operating parameters. Based on the measured operating parameters, a projected output temperature of a cabin heat exchanger may be estimated. A determination may be made that the projected output temperature of the cabin heat exchanger is less than the indication. Based on the determination a fuel cell coolant parameter may be adjusted.

Abstract: A method for shutting down a fuel cell system including operating a fuel cell stack. the method includes providing an increased cathode air flow so as to dry fuel cell membranes in the stack until a first desired level of high frequency resistance is achieved, rehydrating the cell membranes of the stack until a second desired level of high frequency resistance is achieved, and operating the stack with a decreased cathode input relative humidity until a third desired level of high frequency resistance is achieved.

Abstract: A system and method for a cathode subsystem in a fuel cell system. The system includes a fuel cell stack, a cathode inlet line that provides cathode air to a fuel cell stack and a cathode exhaust line that exhausts a cathode exhaust gas out of the fuel cell stack. Also included is a backpressure valve in the cathode exhaust line that is located downstream of a drip rail of the cathode exhaust line, where the drip rail includes a protrusion that prevents condensed water from building up near the backpressure valve. The drip rail further includes a sump that collects drips of condensed water from the protrusion of the drip rail. The system also includes a drain below a water vapor transfer unit that includes an orifice that is in a portion of the drain that is within the cathode exhaust line.

Abstract: A fuel cell system includes a water vapor transfer unit and a fluid flow distribution feature, the water vapor transfer unit including a first plate having a plurality of first flow channels for receiving a flow of a first fluid therein, and a second plate having a plurality of second flow channels for receiving a flow of a second fluid therein. The fluid flow distribution feature is configured to control at least one of a volume of flow of the first fluid through the first flow channels and a volume of flow of the second fluid through the second flow channels, wherein at least one of a flow distribution of the first fluid across the first plate and a flow distribution of the second fluid across the second plate is varied.

Abstract: System and methods for controlling and optimizing coolant system parameters in a fuel cell system to obtain a requested cabin temperature in a fuel cell vehicle are presented. A method for managing a temperature in a vehicle cabin may include receiving an indication relating to a desired vehicle cabin temperature and a plurality of measured operating parameters. Based on the measured operating parameters, a projected output temperature of a cabin heat exchanger may be estimated. A determination may be made that the projected output temperature of the cabin heat exchanger is less than the indication. Based on the determination a fuel cell coolant parameter may be adjusted.

Abstract: A method for starting a cold or frozen fuel cell stack as efficiently and quickly as possible in a vehicle application is based upon a state of charge of a first power source such as a high voltage battery. Power flow between the first power source and fuel cell system is coordinated in conjunction with a specific load schedule and parallel control algorithms to minimize the start time required and optimize system warm-up.

Abstract: A method for starting a cold or frozen fuel cell stack as efficiently and quickly as possible in a vehicle application is based upon a state of charge of a first power source such as a high voltage battery. Power flow between the first power source and fuel cell system is coordinated in conjunction with a specific load schedule and parallel control algorithms to minimize the start time required and optimize system warm-up.

Abstract: A device for minimizing a buoyancy driven convective flow inside a manifold of a fuel cell stack includes a plurality of spaced apart baffle walls. The spaced apart baffle walls are configured to be disposed inside the manifold of the fuel cell stack. The spaced apart baffle walls increase a viscous resistance to the buoyancy driven convective flow inside the manifold.

Abstract: A system and method for quickly heating a fuel cell stack at fuel cell system start-up. The fuel cell system includes a three-way valve positioned in the anode exhaust that selectively directs the anode exhaust gases to the cathode input of the fuel cell stack so that hydrogen in the anode exhaust gas can be used to heat the fuel cell stack. During normal operation when the fuel cell stack is at the desired temperature, the three-way valve in the anode exhaust can be used to bleed nitrogen to the cathode exhaust.

Abstract: A fuel cell system includes a water vapor transfer unit and a fluid flow distribution feature, the water vapor transfer unit including a first plate having a plurality of first flow channels for receiving a flow of a first fluid therein, and a second plate having a plurality of second flow channels for receiving a flow of a second fluid therein. The fluid flow distribution feature is configured to control at least one of a volume of flow of the first fluid through the first flow channels and a volume of flow of the second fluid through the second flow channels, wherein at least one of a flow distribution of the first fluid across the first plate and a flow distribution of the second fluid across the second plate is varied.

Abstract: A device for minimizing a buoyancy driven convective flow inside a manifold of a fuel cell stack includes a plurality of spaced apart baffle walls. The spaced apart baffle walls are configured to be disposed inside the manifold of the fuel cell stack. The spaced apart baffle walls increase a viscous resistance to the buoyancy driven convective flow inside the manifold.

Abstract: A process for controlling the length of a purge and the purge rate of a fuel cell stack at system shut-down so as to provide the desired amount of stack humidity. The membrane humidification is measured at system shut-down by a high frequency resistance sensor that detects membrane humidification and provides the measurement to a controller. The controller controls the compressor that provides cathode input air to the fuel cell stack so that the time of the purge and the flow rate of the purge provide a desired membrane humidity for the next start-up.

Abstract: A fuel cell system that employs a heat exchanger and a charge air cooler for reducing the temperature of the cathode inlet air to a fuel cell stack during certain system operating conditions so that the cathode inlet air is able to absorb more moisture in a water vapor transfer unit. The system can include a valve that selectively by-passes the heat exchanger if the cathode inlet air does not need to be cooled to meet the inlet humidity requirements. Alternately, the charge air cooler can be cooled by an ambient airflow.

Abstract: A method for shutting down a fuel cell system including operating a fuel cell stack. the method includes providing an increased cathode air flow so as to dry fuel cell membranes in the stack until a first desired level of high frequency resistance is achieved, rehydrating the cell membranes of the stack until a second desired level of high frequency resistance is achieved, and operating the stack with a decreased cathode input relative humidity until a third desired level of high frequency resistance is achieved.

Abstract: A method for quickly and efficiently heating a fuel cell stack at system start-up. The method uses and prioritizes various stack heat sources based on their efficiency to heat the stack. A thermal set-point for heating the stack to the desired temperature is determined based on the ambient temperature and, the stack cooling fluid temperature. The set-point is then compared-to the stack heating provided by the heat sources that are operating through normal system start-up operation. If more heat is necessary to reach the set-point, the method may first charge a system battery using stack power where the load causes the fuel cell stack to heat up. If additional heating is still required, the method may then turn on a cooling fluid heater, then flow a small amount of hydrogen into the cathode inlet stream to provide combustion, and then increase the compressor load as needed.

Abstract: A primary reactor for a fuel processor system that employs steam and air to convert a liquid hydrocarbon fuel into a hydrogen-rich gas stream. The liquid fuel and an air-steam mixture are mixed in a mixing region within the reactor. The fuel mixture is then directed through an electrically heated catalyst region that heats the mixture to the operation temperature of a light-off catalyst at system start-up. The heated fuel mixture is then directed through a light-off catalyst monolith where the hydrocarbon fuel is dissociated. Once the fuel mixture is heated to the operating temperature of the light-off catalyst, the electrically heated catalyst region is turned off because the exothermic reaction in the light-off catalyst monolith generates the heat necessary to sustain the catalytic reaction.

Abstract: A system and method for reducing RH cycling of the membranes in a fuel cell stack. A control algorithm damps a power request signal using a first order filter during low power transients so that the fuel cell stack continues generating power at a higher rate than is requested. The excess power generated by the stack is used to recharge a battery in the fuel cell system. The damped power signal is weighted so that more fuel cell stack power is provided for a low battery state of charge unless stack power is provided for a high battery state of charge.