| Patent application number | Description | Published |
|---|
| 20080236930 | SOFT START FUEL CELL CONTROL STRATEGY - A method of operating an electrochemical conversion assembly is provided. According to the method, an assembly warm-up operation is executed by increasing the temperature T | 10-02-2008 |
| 20100178580 | BIPOLAR PLATE FOR A FUEL CELL STACK - A bipolar plate for a fuel cell is provided that includes a pair of unipolar plates having a separator plate disposed therebetween. One of the unipolar plates is produced from a porous material to minimize cathode transport resistance at high current density. A fuel cell stack including a fuel cell and the bipolar plate is also provided. | 07-15-2010 |
| 20100190076 | TWO STAGE, HFR-FREE FREEZE PREPARATION SHUTDOWN STRATEGY - A system and method for providing a fuel cell stack purge at fuel cell system shut-down. The method provides a two-stage purge process where the first stage purge uses humidified cathode air to get the fuel cell stack to a known stack hydration level from an unknown stack hydration level at system shut-down. As the stack is purged with the humidified air, the hydration level of the stack decreases asymptotically to the known stack hydration level where the duration of the first stage is set based on the asymptote as a safety margin. Once the known hydration level is achieved, then the second stage purge is performed with dry air to further reduce the stack hydration to a final desired hydration level. | 07-29-2010 |
| 20110087441 | ONLINE METHOD TO ESTIMATE HYDROGEN CONCENTRATION ESTIMATION IN FUEL CELL SYSTEMS AT SHUTDOWN AND STARTUP - A system and method for estimating the amount of hydrogen and/or nitrogen in a fuel cell stack and stack volumes at system start-up and shut-down. The method defines the fuel cell stack and stack volumes as discrete volumes including an anode flow-field and anode plumbing volume, a cathode flow-field volume and a cathode header and plumbing volume. The method estimates the amount of hydrogen and/or nitrogen in the anode flow-field and anode plumbing volume, the cathode flow-field volume and the cathode header and plumbing volume when the fuel cell system is shut down, during a first stage when the hydrogen partial pressure between the anode and cathode is not in equilibrium and during a second stage when the hydrogen partial pressure between the anode and cathode is in equilibrium by considering various flows into and out of the volumes. | 04-14-2011 |
| 20110189569 | AUTO-LEARNING OF BASE STACK RESISTANCE FOR HFR BASED RH CONTROL - A method for determining membrane humidification by determining the membrane protonic resistance of a fuel cell stack at humidified conditions, and normalizing the base resistance of the fuel cell stack against the base resistance of a reference fuel cell stack. | 08-04-2011 |
| 20110207010 | Relative Humidity Control For A Fuel Cell - A model uses various operating characteristics of a fuel cell to predict the relative humidity profile that is occurring within the fuel cell as a function of the reaction progress. The model is used to predict the relative humidity profile that will occur in response to changes to one or more of the operating characteristics of the fuel cell. A high frequency resistance of the fuel cell can also be used as a measure that is indicative of the humidity within the fuel cell. The model and/or the high frequency resistance can be used in a closed-loop feedback system to control the operation of the fuel cell to maintain the humidification of the MEA and fuel cells within a desired range to achieve a desired fuel cell performance. | 08-25-2011 |
| 20110239747 | USING AN EFFECTIVENESS APPROACH TO MODEL A FUEL CELL MEMBRANE HUMIDIFICATION DEVICE - A method for determining the water transfer in a water vapor transfer unit of a fuel cell system that employs a model based approach. The method includes determining a capacity ratio of wet streams and dry streams flowing through the water vapor transfer unit, determining the number of mass transfer units of the water vapor transfer unit, estimating a mass transfer effectiveness value given the capacity ratio and the number of mass transfer units for the water vapor transfer unit, and determining the amount of water transferred in the water vapor transfer unit using the mass transfer effectiveness value, the mass flow rates on a dry basis of the dry stream and the wet stream, and the mass flow rates of water of the dry inlet stream and the wet inlet stream. | 10-06-2011 |
