FCS overall efficiency by using stored cathode oxygen during down-transients
AssigneeGM Global Technology Operations LLC
InventorsJoseph Mussro, Yanyan Zhang, Daniel C. Di Fiore
Life of this patent
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Abstract
A system and method for utilizing a pressurized volume of oxygen in a cathode plumbing of a fuel cell system. The system and method includes calculating an air/oxygen balance that is based on an air balance and an oxygen balance in the cathode plumbing. The system and method further include determining the number of moles of oxygen available for fuel cell chemical reactions using the calculated air/oxygen balance and drawing current from a fuel cell stack using the moles of oxygen available for fuel cell chemical reactions.
Claims19
A method for utilizing a pressurized volume of oxygen in a cathode plumbing of a fuel cell system including a fuel cell stack, said method comprising:
- calculating an air/oxygen balance that is based on an air balance and an oxygen balance in the cathode plumbing, wherein calculating the air/oxygen balance includes assuming that an oxygen mole fraction in an air stream exiting the fuel cell stack is equal to an oxygen mole fraction that is staying in the stack;
- determining the number of moles of oxygen available for fuel cell chemical reactions using the calculated air/oxygen balance;
- and
- drawing current from the fuel cell stack using the moles of oxygen available for fuel cell chemical reactions.
A method for utilizing a pressurized volume of oxygen in a cathode plumbing of a fuel cell system including a fuel cell stack, said method comprising:
- calculating an air/oxygen balance that is based on an air balance and an oxygen balance in the cathode plumbing at the beginning of a power down-transient of the fuel cell stack, wherein calculating the air/oxygen balance includes assuming that an oxygen mole fraction in an air stream exiting the fuel cell stack is equal to an oxygen mole fraction that is staving in the stack;
- determining a first number of moles of oxygen available for fuel cell chemical reactions using the calculated air/oxygen balance;
- drawing a first current from the fuel cell stack using the first number of moles of oxygen available for fuel cell chemical reactions;
- recalculating the air/oxygen balance that is based on an air balance and an oxygen balance in the cathode plumbing after the first draw of current is complete;
- determining a next number of moles of oxygen available for fuel cell chemical reactions using the calculated air/oxygen balance;
- and
- drawing a next current from the fuel cell stack using the next number of moles of oxygen available for fuel cell chemical reactions.
A system for utilizing a pressurized volume of oxygen in a cathode plumbing of a fuel cell system including a fuel cell stack, said system comprising:
- a controller that is programmed to perform the following:
- means for calculating an air/oxygen balance that is based on an air balance and an oxygen balance in the cathode plumbing, wherein calculating the air/oxygen balance includes assuming that an oxygen mole fraction in an air stream exiting the fuel cell stack is equal to an oxygen mole fraction that is staying in the stack;
- means for determining the number of moles of oxygen available for fuel cell chemical reactions using the calculated air/oxygen balance;
- and
- means for drawing current from the fuel cell stack using the moles of oxygen available for fuel cell chemical reactions to charge a battery.
Dependencies are inferred from the claim text.