| US 7,597,975 B2 | ||
| Fuel cell operation to minimize RH cycles to improve durability | ||
| William H. Pettit, Rochester, N.Y. (US); John C. Fagley, Victor, N.Y. (US); John P. Salvador, Penfield, N.Y. (US); and Steven G. Goebel, Victor, N.Y. (US) | ||
| Assigned to GM Global Technology Operations, Inc., Detroit, Mich. (US) | ||
| Filed on May 15, 2006, as Appl. No. 11/434,385. | ||
| Prior Publication US 2007/0265802 A1, Nov. 15, 2007 | ||
| Int. Cl. H01M 8/00 (2006.01); H01M 8/04 (2006.01); G05D 22/00 (2006.01) | ||
| U.S. Cl. 429—13 [429/22; 429/23; 429/24; 429/25; 700/286; 236/44 R] | 19 Claims |
| 1. A method for controlling a relative humidity of a cathode exhaust gas from a fuel cell stack in a fuel cell system, said
method comprising:
providing sensor signals indicative of operating parameters of the fuel cell system;
calculating a maximum sustainable relative humidity of the cathode exhaust gas based on the sensor signals;
determining if the calculated maximum sustainable relative humidity is greater than a predetermined percentage;
providing a relative humidity set-point above 100% if the calculated maximum sustainable relative humidity is greater than
the predetermined percentage;
providing a relative humidity set-point below 100% if the calculated maximum sustainable relative humidity is less than the
predetermined percentage; and
controlling fuel cell system components based on the relative humidity set-point to attempt to maintain the relative humidity
of the cathode exhaust gas at the set-point.
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