摘要:
A fuel cell system that employs an algorithm for limiting the current output from a fuel cell stack using feedback during high stack temperature operation. The system includes a PID controller that receives an error signal that is the difference between the cooling fluid output temperature from the stack and a predetermined temperature value. The algorithm detects whether the cooling fluid output temperature goes above a predetermined temperature value, and if so, calculates a proportional gain component and an integral gain component that sets the proportional and integral gains of the PID controller. Based on the proportional gain component, the integral gain component and the error signal, the algorithm generates a total current allowed, and sets the maximum current draw from the stack accordingly. The rate of the rise or fall of the allowed current from the stack from the actual current is limited to provide a smooth transition.
摘要:
A fuel cell system is disclosed that employs a thermal sensor for measuring an amount of heat generated in the fuel cell system, wherein a sensor signal from the thermal sensor is used to adjust operation of the fuel cell system when the fuel cell system is operating outside of desired thermal operating conditions.
摘要:
A valve for a fuel cell system includes a valve housing having a valve seat formed therein. The valve seat includes an orifice formed therein to permit a fluid to flow through the valve housing. A movable member is disposed in the valve housing and is movable between an open position and a closed position. The movable member includes a first end having an elongate portion and a generally conical shaped base. At least a portion of the base is disposed in the orifice of the valve seat when the movable member is in the closed position to militate against a formation of ice across the orifice of the valve seat.
摘要:
A method for determining a flow of a gas through an injector and a flow of a gas through a valve in a fuel cell system. The method includes determining an injector flow estimation for the gas flowing through the injector and determining a valve flow estimation for the gas flowing through the valve. The method also includes calculating an error that is a difference between the injector flow estimation and the valve flow estimation and adjusting the flow of the gas through the valve based on the error.
摘要:
A detection method for enabling gas composition observation during fuel cell system start-up is described. In one embodiment, the method includes initiating a flow of hydrogen to the anode to pressurize the anode; opening an anode flow valve; determining if an anode pressure exceeds an anode pressure threshold; enabling anode flow set point detection after a first predetermined time if the anode pressure exceeds the anode pressure threshold; monitoring an anode flow set point using the anode flow set point detection; determining if the anode flow set point exceeds an anode flow set point threshold; and closing the anode flow valve after a second predetermined time if the anode flow set point exceeds the anode flow set point threshold.
摘要:
A system and method for correcting a large fuel cell voltage spread for a split sub-stack fuel cell system. The system includes a hydrogen source that provides hydrogen to each split sub-stack and bleed valves for bleeding the anode side of the sub-stacks. The system also includes a voltage measuring device for measuring the voltage of each cell in the split sub-stacks. The system provides two levels for correcting a large stack voltage spread problem. The first level includes sending fresh hydrogen to the weak sub-stack well before a normal reactive bleed would occur, and the second level includes sending fresh hydrogen to the weak sub-stack and opening the bleed valve of the other sub-stack when the cell voltage spread is close to stack failure.
摘要:
A system and method for improving fuel cell system start-up reliability. The method includes determining if the resistance of the membranes in a fuel cell stack is too high, where the reliability of system start-up will be reduced, and if so, providing one or more remedial actions to help ensure that the start-up is more reliable. In one embodiment, the system and method determine that the fuel cell membranes are to dry based on whether a high frequency measurement of the fuel cell stack exceeds a predetermined HFR threshold. If the HFR threshold has been exceeded, a special start-up procedure is used that increases the reliability that the start-up will be successful using the remedial actions, such as reducing cathode airflow and turning on stack end cell heaters.
摘要:
A method for providing a fast and reliable start-up of a fuel cell system. The method uses a stack voltage response to a load to assess if hydrogen and oxygen are being sufficiently distributed to all of the fuel cells by coupling an auxiliary load to the fuel cell stack until a predetermined minimum cell voltage has been reached or a first predetermined time period has elapsed. The method then determines whether a minimum cell voltage has dropped to a first predetermined voltage and, if so, reduces the maximum power allowed to be below the first predetermined voltage value, determines whether the minimum cell voltage in the stack is below a second predetermined voltage, or determines whether the minimum cell voltage drop rate is greater than a predetermined voltage drop rate. If none of these conditions are met, the method returns to loading the stack with system components.
摘要:
A method that employs a model based approach to determine a maximum anode pressure set-point based on existing airflow in the exhaust gas line. This approach maximizes anode flow channel velocity during bleed events while meeting the hydrogen emission constraint, which in turn increases the amount of water purged from the anode flow channels to increase stack stability.
摘要:
A remedial method for starting a fuel cell system is described. The method includes determining if the remedial method is required; providing air to an exhaust of a fuel cell stack; setting a hydrogen flow rate to an anode side of the fuel cell stack; providing a predetermined volume of hydrogen to the anode side of the fuel cell at the hydrogen flow rate; providing a predetermined volume of air to a cathode side of the fuel cell stack after the predetermined volume of hydrogen has been provided to the anode side while continuing to provide air to the exhaust of the fuel cell stack and hydrogen to the anode side of the fuel cell stack; determining if a stack voltage is stable after the predetermined volume of air has been provided to the cathode side; and closing the anode outlet valve after the stack voltage is stable.