Patent ID: 7662495

Claim:
A fuel cell system including a fuel cell having at least one membrane electrode assembly in reactive interface to at least one reactant flow channel carrying a reactant comprising: said fuel cell comprising a passive restriction passageway in fluid connection between a liquid accumulation portion of one said channel and a liquid reception portion of one said channel, said liquid accumulation portion containing fluid at a first pressure, said liquid reception portion containing fluid at a second pressure lower than said first pressure; and a control means for intermittently adjusting said first pressure in relation to said second pressure, said adjusting providing a first pressure difference between said first pressure and said second pressure at a first setting of said control means, said adjusting providing a second pressure difference between said first pressure and said second pressure at a second setting of said control means, said second pressure difference being greater than said first pressure difference; wherein said passive restriction passageway provides a fluid passageway having a length and a cross sectional area sufficient to preclude flow of said liquid between said liquid accumulation portion and said liquid reception portion at said low pressure difference, and sufficient to enable flow of said liquid in said passageway between said liquid accumulation portion and said liquid reception portion at said second pressure difference.