Patent ID: 7858253

Claim:
A method of purging a fuel cell, comprising: determining for a first statistical measure of a current load on said fuel cell comprising a running average current load on said entire fuel cell, a second statistical measure of cell voltages of said fuel cell comprising a standard deviation of all cell voltages of said fuel cell, and a maximum change in each cell voltage of said fuel cell; establishing a first threshold related to the first statistical measure, a second threshold related to the second statistical measure and a maximum rate of change related to the cell voltage; and purging said fuel cell if at least one of the following conditions exists: said first statistical measure exceeds said first threshold related to the first statistical measure, said second statistical measure exceeds said second threshold value related to the second statistical measure, and said maximum change in cell output parameter exceeds said maximum rate of change related to the cell voltage; wherein a purge period is determined by a plurality of functions formulated based on said running average current load on said fuel cell, said standard deviation of cell voltage of said fuel cell and said maximum change in cell voltage of said fuel cell.