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 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 for validating a pressure sensor between a source of a gas and a pressure regulator that regulates a gas flow. The method includes providing a valve command signal and selecting a bias signal from a bias table. The method also includes comparing the selected bias signal to the valve command signal and determining there is a pressure sensor error if the difference between the selected bias signal and the valve command signal is above a predetermined threshold.

Abstract: A method for producing a spiral link fabric with a plurality of spirals joined to one another in an overlapping manner, with a plurality of seam wires stitched into overlapping regions of adjacent spirals and connecting the spirals to one another to form a flat structure, and with a plurality of packing elements introduced into free cross sections of the spirals, wherein the flat structure runs through a thermofixing operation before or after the introduction of the packing elements. The spirals are joined together to form the flat structure such that, before the thermofixing operation, the result is a clear width, as viewed in the plane of the flat structure, for the free cross sections of the spirals connected to one another to form the flat structure, which clear width is larger than a clear height of the free cross section of each spiral.

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 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: Method for producing an extrusion die having a functional surface for metal extrusion material, comprising the following steps: providing a die support body, depositing a weldable substance containing cobalt and/or nickel onto a subsection of the die support body by means of an effective bonding application process to produce an inseparable deposition layer, machining the deposition layer in a chipping and/or material removal process to form the functional surface of the extrusion die, and carrying out a CVD coating process with a reaction gas at least on the functional surface.

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 thermal sub-system for a fuel cell system that employs an algorithm using feed-forward control. The algorithm calculates a Reynolds number based on the velocity of the cooling fluid, a diameter of a coolant loop pipe and a kinematic viscosity (temperature) of a cooling fluid. The algorithm also uses a pressure loss number based on the Reynolds number and a position of a by-pass valve. The algorithm also defines a pressure loss value based on the pressure loss number, the density of the cooling fluid and the velocity of the cooling fluid. The algorithm then calculates a delivery head value based on the pressure loss value, the fluid density and a gravitational acceleration. The algorithm then uses the delivery head value and a predetermined set-point value of the volume flow to determine a desired pump speed based on the current operating parameters of the system.

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 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 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: A diagnostic system for determining whether a rotor shaft of a compressor is unbalanced. The compressor includes a displacement sensor that measures the displacement of the rotor shaft as it is rotating. The sensor dynamic frequency signal is sent to a bandpass filter that filters out an eigen-frequency frequency that is a function of shaft elasticity and rotor dynamics. The filtered frequency signal is then rectified by a rectifier to make the filtered frequency signal positive. The rectified signal is then passed through a low pass filter that converts the rectified signal to a DC signal. The DC signal is then sent to a controller that determines if the amplitude of the signal is above a predetermined threshold, which indicates a problem with the balance of the compressor.

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: 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 method for validating a pressure sensor between a source of a gas and a pressure regulator that regulates a gas flow. The method includes providing a valve command signal and selecting a bias signal from a bias table. The method also includes comparing the selected bias signal to the valve command signal and determining there is a pressure sensor error if the difference between the selected bias signal and the valve command signal is above a predetermined threshold.

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 diagnostic system for determining whether a rotor shaft of a compressor is unbalanced. The compressor includes a displacement sensor that measures the displacement of the rotor shaft as it is rotating. The sensor dynamic frequency signal is sent to a bandpass filter that filters out an eigen-frequency frequency that is a function of shaft elasticity and rotor dynamics. The filtered frequency signal is then rectified by a rectifier to make the filtered frequency signal positive. The rectified signal is then passed through a low pass filter that converts the rectified signal to a DC signal. The DC signal is then sent to a controller that determines if the amplitude of the signal is above a predetermined threshold, which indicates a problem with the balance of the compressor.

Abstract: A method for producing a coating of one or more layers on an extrusion die as a substrate body of a heat-resistant and/or long-term heat-resistant steel material by means of chemical vapour deposition (CVD), comprising the steps of: providing the substrate body from hot-work tool steel, which is intended for interacting with ductile extrusion metal, introducing a first reaction gas, comprising a metal, in particular titanium, into a reactor receiving the substrate body, to provide a coating metal, introducing a second reaction gas, comprising a carbon compound, into the reactor, to provide carbon for the coating, wherein the first and/or the second reaction gas or a further reaction gas provide(s) nitrogen for the coating, and carrying out a CVD coating process with the reaction gases.

Abstract: A method for producing a spiral link fabric with a plurality of spirals joined to one another in an overlapping manner, with a plurality of seam wires stitched into overlapping regions of adjacent spirals and connecting the spirals to one another to form a flat structure, and with a plurality of packing elements introduced into free cross sections of the spirals, wherein the flat structure runs through a thermofixing operation before or after the introduction of the packing elements. The spirals are joined together to form the flat structure such that, before the thermofixing operation, the result is a clear width, as viewed in the plane of the flat structure, for the free cross sections of the spirals connected to one another to form the flat structure, which clear width is larger than a clear height of the free cross section of each spiral.