Gm Global Technolgoy Operations, Inc.

Stanley Gutowski

Mark A Meltser

Kirk Weisbrod

Rodney Lynn Borup

Stephen Andreas Grot

Jay Kevin Neutzler

Yang-Tse Cheng

Daniel John Lisi

Yang Li

Andrea A Poli

A method of operating a H,&mdash;O,fuel cell fueled by hydrogen-rich fuel stream containing CO. The CO content is reduced to acceptable levels by injecting oxygen into the fuel gas stream. The amount of oxygen injected is controlled in relation to the CO content of the fuel gas, by a control strategy that involves (a) determining the CO content of the fuel stream at a first injection rate, (b) increasing the O,injection rate, (c) determining the CO content of the stream at the higher injection rate, (d) further increasing the O,injection rate if the second measured CO content is lower than the first measured CO content or reducing the O,injection rate if the second measured CO content is greater than the first measured CO content, and (e) repeating steps a-d as needed to optimize CO consumption and minimize H,consumption.

Method of controlling injection of oxygen into hydrogen-rich fuel cell feed stream

The CO concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and/or voltage behavior patterns from a PEM-probe communicating with the reformate feed stream. Pattern recognition software may be used to compare the current and voltage patterns from the PEM-probe to current and voltage telltale outputs determined from a reference cell similar to the PEM-probe and operated under controlled conditions over a wide range of CO concentrations in the H.sub.2 fuel stream. The PEM-probe is intermittently purged of any CO build-up on the anode catalyst (e.g., by (1) flushing the anode with air, (2) short circuiting the PEM-probe, or (3) reverse biasing the PEM-probe) to keep the PEM-probe at peak performance levels.

Method of monitoring CO concentrations in hydrogen feed to a PEM fuel

The CO concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and/or voltage behavior patterns from a PEM-probe communicating with the reformate feed stream. Pattern recognition software may be used to compare the current and voltage patterns from the PEM-probe to current and voltage telltale outputs determined from a reference cell similar to the PEM-probe and operated under controlled conditions over a wide range of CO concentrations in the H.sub.2 fuel stream. A CO sensor includes the PEM-probe, an electrical discharge circuit for discharging the PEM-probe to monitor the CO concentration, and an electrical purging circuit to intermittently raise the anode potential of the PEM-probe's anode to at least about 0.8 V (RHE) to electrochemically oxidize any CO adsorbed on the probe's anode catalyst.

Fuel cell CO sensor

A sensor for hydrogen is disclosed comprising an electrically insulating substrate carrying a thin amorphous film of co-deposited nickel and zirconium and an overlying film of palladium wherein during the operation of the sensor, hydrogen in a sample gas is dissociated on the palladium film and diffuses into the nickel-zirconium film to change its electrical resistance in proportion to the amount of hydrogen in the sample to be analyzed.

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Pittsford, NY, United States of America

Stanley Gutowski