Patent application number | Description | Published |
20080226956 | COLD START COMPRESSOR CONTROL AND MECHANIZATION IN A FUEL CELL SYSTEM - A fuel cell system is disclosed, wherein the fuel cell system is heated by a fluid during a starting operation to mitigate against vapor condensation and ice formation in a fuel cell assembly and to decrease a warm up time of the fuel cell system. | 09-18-2008 |
20090017340 | CONTROL METHOD FOR COLD FUEL CELL SYSTEM OPERATION - A method of operating a fuel cell system comprising a fuel cell and a compressor that provides air to the fuel cell. The method comprises sensing a temperature indicative of the temperature of a fuel cell, providing a restriction in an air flow path to the fuel cell when the sensed temperature is below a threshold, and increasing the speed of the compressor to provide a desired air flow to the fuel cell. In at least some implementations, increasing the speed of the compressor increases the power drawn from the fuel cell to power the compressor and helps to increase the heat of the fuel cell. The increased speed of the compressor can also result in warmer air flow from the compressor that can further increase the temperature of the system components. | 01-15-2009 |
20100028728 | HUMIDIFICATION CONTROL DURING SHUTDOWN OF A FUEL CELL SYSTEM - 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. | 02-04-2010 |
20100112383 | DIAGNOSTIC TO DETERMINE A VALVE/LINE FREEZE-UP OR FAILURE IN A FUEL CELL BLEED MANIFOLD UNIT - A system and method for determining whether valves in a fuel cell system bleed manifold unit (BMU) are blocked with ice or have otherwise failed. The system opens a first bleed valve, closes a second bleed valve and opens an exhaust valve, and then reads a pressure signal to determine whether there is flow through a flow restriction to determine whether the first bleed valve or the exhaust valve is blocked. The system then closes the exhaust valve, leaves the first bleed valve open, and again reads the pressure signal to determine the pressure drop across the flow restriction, which will indicate whether the flow restriction the pressure sensor lines are blocked. The system then closes the first bleed valve and opens the second bleed valve to determine whether the pressure signal indicates a flow through the second bleed valve. | 05-06-2010 |
20100112384 | REMEDIAL ACTION TO OPERATE A FUEL CELL SYSTEM WITH A FAILED BLEED MANIFOLD UNIT - A system and method for providing an anode exhaust gas bleed in a fuel cell system. The system provides a normal anode side bleed using first and second bleed valves if the first and second bleed valves are not blocked and the temperature of first and second split sub-stacks is greater than a predetermined temperature, provides a continuous anode side bleed using the bleed valves if the bleed valves are not blocked and the temperature of the sub-stacks is less than the predetermined temperature, provides a normal center anode bleed through the drain valve if the first or second bleed valve is blocked and the temperature of the sub-stacks is above the predetermined temperature and provides a continuous center anode side bleed through the drain valve if the first or second bleed valve is blocked and the temperature of the sub-stacks is below the predetermined temperature. | 05-06-2010 |
20100112410 | FREEZE TOLERANT INTRODUCTION OF H2 TO CATHODE EXHAUST IN A FUEL CELL SYSTEM - A technique for reducing the amount of water that accumulates in an anode exhaust gas bleed line in a fuel cell system. The system includes a fuel cell stack, a cathode exhaust line and an anode exhaust line. The anode exhaust gas line is coupled to an anode bleed valve. An anode bleed line is coupled to the bleed valve and the cathode exhaust gas line so the hydrogen in the bled anode exhaust gas is diluted by the cathode exhaust gas. The anode bleed line is coupled to the cathode exhaust gas line so that a stand-off portion of the bleed line extends through a wall of the cathode exhaust gas line and into the cathode exhaust flow therein so as to prevent water and water vapor clinging to the inside surface of the cathode exhaust gas line from draining into the anode bleed line. | 05-06-2010 |
20100151284 | METHODS AND CONTROLS FOR HYDROGEN TO CATHODE INLET OF A FUEL CELL SYSTEM - 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. | 06-17-2010 |
20100190079 | METHOD AND ALGORITHM TO DETECT FROZEN ANODE PRESSURE SENSOR - A method for performing a plausibility check of a fuel cell stack anode side pressure sensor to determine whether the pressure sensor is providing an accurate measurement. Prior to system start-up when a cathode side compressor is not providing cathode air to a fuel cell stack, and the cathode side of the stack is at ambient pressure, a pressure measurement from a differential pressure sensor between the anode side and the cathode side of the fuel cell stack is provided. The differential pressure sensor reading is added to a pressure measurement from an ambient pressure sensor, where the sum should be about the same as the pressure measurement from the anode side pressure sensor if the anode side pressure sensor is operating properly. | 07-29-2010 |
20110076582 | METHOD TO IMPROVE FUEL CELL SYSTEM PERFORMANCE USING CELL VOLTAGE PREDICTION OF FUEL CELL STACK - A system and method for determining the maximum allowed stack current limit rate for a fuel cell stack that considers cell voltage. The method includes estimating a fuel cell stack voltage based on a fuel cell resistance value, stack variables and a current request signal. The fuel cell resistance value can be modeled based on stack temperature and stack relative humidity. The stack variables can include exchange current density and mass transfer coefficient. The method then uses the estimated fuel cell voltage and a look-up table based on estimated voltage to determine a current rate limit value for changing the current of the stack. The method then adds the current rate limit value and the current request signal to obtain the current set-point. | 03-31-2011 |