Abstract: A system and method for waking up a vehicle controller during a hydrogen gas refueling process for a high pressure hydrogen storage tank on a fuel cell vehicle. The system includes a first temperature switch mounted to the high pressure tank and enclosed within an insulation housing for monitoring the temperature within the tank and a second temperature switch for monitoring the temperature of the hydrogen gas at the refuel receptacle, where the second temperature switch is also enclosed within an insulation housing. If the temperature within the tank increases above a predetermined temperature, the first switch will close, and if the temperature at the refueling receptacle falls below a predetermined temperature, then the second switch will close, which causes a wake up signal to be provided to the controller to allow the controller to monitor the temperature of the tank.

Abstract: A system and method for operating a fuel cell system in a stand-by mode. The method includes determining a power limit value based on fuel cell stack and battery power optimization, where if a system power request falls below the power limit value the system will enter the stand-by mode. The system first enters a dynamic stand-by mode where the fuel cell stack is turned off and a compressor providing cathode air to the cathode side of the stack is operated at an idle speed. The method accumulates a compressor power value identifying how much energy has been consumed by operating the compressor at the idle speed during the dynamic stand-by mode, and then switches to a static stand-by mode where the compressor is turned off when the accumulated compressor power value reaches a compressor restart energy value that identifies how much energy it takes to start the compressor.

Abstract: A valve for a pressure vessel system includes a housing having a cavity defined by an inner surface of the housing. The housing further includes a rod aperture and a pair of fluid flow ports. An actuator is disposed adjacent the housing. The valve also includes a piston having a rod coupled to a piston head. The piston head is disposed in the cavity of the housing, and the rod disposed through the rod aperture. The rod is also coupled to the actuator. A ring seal is disposed between the piston head and an inner surface of the housing. The ring seal biases the piston head toward one of the fluid flow ports and seals the one of the fluid flow ports to close the valve when the actuator is deactivated. The ring seal is elastically deformed and the fluid flow ports are opened when the actuator is activated.

Abstract: A valve for a pressure vessel system includes a housing including a cavity and a hollow fluid flow portion. A membrane actuator is disposed in the cavity of the housing. A piston is disposed in the cavity and in the hollow fluid flow portion of the housing. A spring is disposed in the hollow fluid flow portion of the housing. The spring biases a piston head toward a fluid flow port formed in the hollow fluid flow portion. The piston head seals the fluid flow port when the biasing of the piston head by the spring is not countered by an opposite deflection of the membrane actuator.

Abstract: A method a system and method for optimizing the power distribution between a fuel cell stack and a high voltage battery in a fuel cell vehicle. The method includes defining a virtual battery hydrogen power for the battery that is based on a relationship between a battery power request from the battery and an efficiency of the battery and defining a virtual stack hydrogen power for the fuel cell stack that is based on a relationship between a stack power request from the fuel cell stack and an efficiency of the fuel cell stack. The virtual battery hydrogen power and the virtual stack hydrogen power are converted into polynomial equations and added together to provide a combined power polynomial equation. The combined power polynomial equation is solved to determine a minimum of the fuel cell stack power request by setting a derivative of the virtual stack hydrogen power to zero.

Abstract: A communication interface for communication between a storage tank and a refueling station is described. One embodiment of the communication interface includes a control unit; an optical transmitter comprising an IR-LED, the optical transmitter directly integrated into the control unit or mounted on the control unit; and an optical frontend optically connected to the optical transmitter.

Abstract: High pressure gas vessels can have a sensitivity to temperature of the compressed gas. Over-temperature conditions in particular may cause decreased durability and/or vessel damage, including gas leakage to the environment. Articles of manufacture, methods, and systems are provided for over-temperature protection using a passive device. The passive closing device does not require electrical power and no controller, sensors, or wiring is needed. This affords cost savings in comparison to other systems. Pressure vessels using the passive closing device can protect themselves, independent of the compressed gas fueling station configuration.

Abstract: A technique for determining the relative humidity of the cathode input airflow to a fuel cell stack that eliminates the need for a dew-point sensor. The cathode input airflow is humidified by a water vapor transfer unit that uses water in the cathode exhaust gas. The technique employs an algorithm that determines the flow of water into the cathode inlet of the stack. In one embodiment, the algorithm determines the volume flow of water through the water vapor transfer unit using the Arrhenius equation, and then converts the water volume flow to a water mole flow. The algorithm then uses the water mole flow through the water vapor transfer unit and the water mole flow of ambient air to determine the water mole flow into the cathode inlet. The algorithm then uses the water mole flow into the cathode inlet to determine the relative humidity of the cathode airflow.

Abstract: A pressure retention valve with integrated valve is disclosed. The pressure retention valve with integrated valve includes a housing; an outer piston positioned in the housing; a main seal between the outer piston and the housing; an inner piston positioned in the outer piston, the inner piston having a bore containing a valve; a spring between the housing and a top of the outer piston; an ambient bore in the housing above the main seal; an outlet in the housing below the main seal; and a vessel connection in the housing adjacent to the bore of the inner piston. Methods of supplying fuel to a gas consuming system using the pressure retention valve are also described.

Abstract: A hydrogen sensor assembly is disclosed. A sensor is disposed within a slotted sleeve and a spiral shaped sensor housing surrounds the sensor within the sleeve. The spiral shape applies a centrifugal force to the fluid stream. This results in separation of liquid water from the fluid stream. The sleeve forms an internal inner perimeter of the spiral housing. The sensor housing includes a first opening to facilitate a fluid communication between the sensing element and a fluid stream through the slotted sleeve.

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 waking up a vehicle controller during a hydrogen gas refueling process for a high pressure hydrogen storage tank on a fuel cell vehicle. The system includes a first temperature switch mounted to the high pressure tank and enclosed within an insulation housing for monitoring the temperature within the tank and a second temperature switch for monitoring the temperature of the hydrogen gas at the refuel receptacle, where the second temperature switch is also enclosed within an insulation housing. If the temperature within the tank increases above a predetermined temperature, the first switch will close, and if the temperature at the refueling receptacle falls below a predetermined temperature, then the second switch will close, which causes a wake up signal to be provided to the controller to allow the controller to monitor the temperature of the tank.

Abstract: A system and method for determining whether a shut-off valve in a cabin heating by-pass line of a thermal sub-system associated with an engine has failed that uses the pump current for a pump that pumps the cooling fluid through the by-pass line. The method includes setting a predetermined constant speed of the pump and then providing a valve command that opens the by-pass valve. The method then determines if the pump current has increased or remained substantially the same when the by-pass valve is commanded open, and determines that the by-pass valve has not opened if the pump current remains substantially constant when the by-pass valve is commanded open.

Abstract: A system and method for regulating the pressure within a volume between a pressure regulator and an injector that injects hydrogen gas into the anode side of a fuel cell stack. The method includes delaying a copy of the a pulsed signal that controls the opening and closing of the injector a predetermined period of time and provides a bias signal from a look-up table that is determined by a desired average mass flow of the hydrogen gas flow to the fuel cell stack and the pressure at an upstream location of the hydrogen gas flow from the pressure regulator. The method selects the bias signal as a pressure regulator control signal that controls the pressure regulator when the delayed pulse injector signal is high and selects an arbitrary value at or near zero as the pressure regulator control signal when a delayed pulse injector is low.

Abstract: A method and system for controlling a pressure regulator in a gas storage system using a pressure switch as a pressure measurement device. A controller uses supply pressure data and gas flow demand data to compute a feed-forward control term, and uses data from a pressure sensor downstream of the pressure regulator to compute a feedback control term. During normal operation, with pressure downstream of the regulator oscillating about a set point pressure, on-time and off-time periods of a pressure switch are monitored, and an adaptive control term is computed which balances on-time and off-time. If the pressure sensor fails, excessive switch on-time or off-time will be detected; in response to this, the feedback control term is disregarded, and an adaptive control term is computed which aims to restore balanced on-time and off-time of the switch, thus indicating that the actual pressure is oscillating about the set point.

Abstract: Systems and methods to diagnose valve leakage in a vehicle storing gaseous fuel in two or more vessels. A valve regulating the flow of the gaseous fuel from one of the vessels is closed and reopened, while the other vessels are providing gaseous fuel during a full run. The pressure spike from reopening the valve is analyzed to determine the rate of pressure change. Pressure spikes having a rate of change lower than a threshold parameter are indicative of a leaking valve.

Abstract: A method for manufacturing a pressure vessel is provided. The method includes the steps of: providing the pressure vessel and a first temperature-pressure relief device, the temperature-pressure relief device having a housing; affixing the first temperature-pressure relief device to the pressure vessel; and forming a vent hole in the housing of the first temperature-pressure relief device after affixing the first temperature-pressure relieve device to the pressure vessel. The vent hole is selectively oriented in a desired direction via the method for manufacturing the pressure vessel. Temperature-pressure relief devices for vent hole alignment and selective orientation are also provided.

Abstract: A pressure retention valve with integrated valve is disclosed. The pressure retention valve with integrated valve includes a housing; an outer piston positioned in the housing; a main seal between the outer piston and the housing; an inner piston positioned in the outer piston, the inner piston having a bore containing a valve; a spring between the housing and a top of the outer piston; an ambient bore in the housing above the main seal; an outlet in the housing below the main seal; and a vessel connection in the housing adjacent to the bore of the inner piston. Methods of supplying fuel to a gas consuming system using the pressure retention valve are also described.

Abstract: A communication interface for communication between a storage tank and a refueling station is described. One embodiment of the communication interface includes a control unit; an optical transmitter comprising an IR-LED, the optical transmitter directly integrated into the control unit or mounted on the control unit; and an optical frontend optically connected to the optical transmitter.

Abstract: A system for detecting the absolute rotational angle of a shaft rotatable more than one revolution includes a drive wheel connected to the shaft to rotate therewith. The drive wheel includes measurement sectors adjacent to one another in a circumferential direction. First and second driven wheels are engaged to the drive wheel. First and second sensors monitor rotational positions of the driven wheels to thereby detect an absolute rotational angle of the shaft. A third sensor monitors a relative angular position of the shaft in relation to a detected one of the measurement sectors to thereby detect the relative angular position of the shaft within one revolution of the shaft. The detected absolute rotational angle of the shaft is refined with the detected relative angular position of the shaft to thereby generate the absolute rotational angle of the shaft with more precision.