RAPID RESPONSE SENSOR FOR CARBON MONOXIDE
First Claim
1. An electrochemical sensor for a chemical species, which chemical species is a contaminant in a fluid stream, comprising:
- an electrochemical device having an electrode, said electrode having a catalyst facilitating a chemical reaction in a component of a fluid stream, said catalyst being capable of being poisoned by a contaminant in said fluid stream;
a voltage source, said voltage source operable to provide an electrical stimulus to said electrode; and
a monitor, said monitor operable to detect and monitor a time-dependent response of said electrode to said electrical stimulus,said time-dependent response being correlatable with the presence and/or amount of said contaminant.
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Accused Products
Abstract
Species detection techniques are described based on measurement of a dynamic response to an external stimulus. One embodiment includes a voltage stimulus applied to a polymer electrolyte fuel cell (PEFC), with the response to said stimulus used to measure CO concentration on the anode catalyst. The principles of symbolic dynamics, finite state machines or a simplified peak response-to-asymptotic value measurement can be used to achieve a high degree of precision for measuring CO concentrations. Using the techniques of the present invention, CO poisoning of a fuel cell can be monitored and diagnosed before reaching a critical condition, thereby allowing early implementation of mitigation or graceful degradation strategies.
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Citations
15 Claims
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1. An electrochemical sensor for a chemical species, which chemical species is a contaminant in a fluid stream, comprising:
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an electrochemical device having an electrode, said electrode having a catalyst facilitating a chemical reaction in a component of a fluid stream, said catalyst being capable of being poisoned by a contaminant in said fluid stream; a voltage source, said voltage source operable to provide an electrical stimulus to said electrode; and a monitor, said monitor operable to detect and monitor a time-dependent response of said electrode to said electrical stimulus, said time-dependent response being correlatable with the presence and/or amount of said contaminant. - View Dependent Claims (2, 3, 4, 5)
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6. An electrochemical sensor for a chemical species, which chemical species is a contaminant in a fluid stream, said sensor comprising:
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a fuel cell, said fuel cell having an anode and an anode catalyst facilitating a chemical reaction in a component of a fluid stream, said anode catalyst being capable of being poisoned by a contaminant in said fluid stream; an electrical circuit, said circuit having a voltage source, a variable resistor and a monitor; said voltage source and variable resistor operable to provide an overvoltage to said anode of said fuel cell; and said monitor operable to detect and monitor a time-dependent response of said anode to said overvoltage, the time-dependent response being correlatable to a contaminant bound to said anode catalyst. - View Dependent Claims (7, 8, 9, 10)
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11. A method for detecting the presence and/or a concentration of a contaminant within a fluid stream, the method comprising:
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exposing a catalyst to a fluid stream, the fluid stream having a contaminant therein, the contaminant poisoning the catalyst; applying a stimulus to the catalyst; and monitoring the time-dependent catalyst performance to the stimulus, the time-dependent catalyst performance being correlatable to presence and/or concentration of the contaminant bound to the catalyst. - View Dependent Claims (12, 13, 14, 15)
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Specification