High temperature total NOx sensor
AssigneeThe Ohio State University Research Foundation
InventorsPrabir K. Dutta, Jiun-Chan Yang
Life of this patent
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Abstract
A total NOx sensor with minimal interferences from CO and O2 includes a yttria-stabilized zirconia (YSZ) pellet and a Pt-loaded zeolite Y layer. Furthermore, three platinum wires are attached to the YSZ surface which operate as the working, counter and reference electrode. A potentiostat is connected to the electrodes to maintain a fixed potential between the reference and working electrode. The potentiostat then monitors the relationship between time and current through the counter electrode.
Claims22
An amperometric sensor for simultaneously measuring NO and NO2 contained in a gas flowing through a conduit comprising:
- a YSZ pellet having a first surface, to be contacted by the gas during operation of the sensor;
- a reference electrode electrically connected to and disposed on the first surface;
- a counter electrode electrically connected to and disposed on the first surface;
- a working electrode electrically connected to and disposed on the first surface;
- a catalytic filter disposed upstream of the first surface;
- and
- an electrical device operable to apply a constant positive or negative voltage between the reference electrode and the working electrode while the gas contacts the first surface, the electrical device operable to measure current flowing through the counter electrode while the gas contacts the first surface,
- wherein operation of the sensor does not require a temperature difference between the catalytic filter and the YSZ pellet.
An automobile comprising:
- a combustion engine having an exhaust conduit;
- an amperometric sensor for simultaneously measuring NO and NO2 contained in a gas flowing though the exhaust conduit comprising:
- a YSZ pellet having a first surface to be contacted by the gas during operation of the sensor;
- a reference electrode electrically connected to and disposed on the first surface;
- a counter electrode electrically connected to and disposed on the first surface;
- a working electrode electrically connected to and disposed on the first surface;
- a catalytic filter disposed upstream of the first surface;
- and
- an electrical device operable to apply a constant positive or negative voltage between the reference electrode and the working electrode while the gas contacts the first surface, the electrical device operable to measure current flowing through the counter electrode while the gas contacts the first surface,
- wherein operation of the sensor does not require a temperature difference between the catalytic filter and the YSZ pellet.
A method of simultaneously measuring NO and NO2 contained in a gas flowing through a conduit comprising the steps of:
- conducting the gas through an amperometric sensor, the sensor comprising:
- a YSZ pellet having a first surface to be contacted by the gas during operation of the sensor;
- a reference electrode electrically connected to and disposed on the first surface;
- a counter electrode electrically connected to and disposed on the first surface;
- a working electrode electrically connected to and disposed on the first surface;
- a Pt-loaded zeolite Y filter disposed upstream of the first surface;
- and
- an electrical device operable to apply a constant positive or negative voltage between the reference electrode and the working electrode while the gas contacts the first surface, the electrical device operable to measure current flowing through the counter electrode while the gas contacts the first surface, wherein operation of the sensor does not require a temperature difference between the catalytic filter and the YSZ pellet;
- measuring the current while the gas contacts the sensor;
- and
- multiplying the measured current by a calibration constant to measure the amount of NO and NO2.
Dependencies are inferred from the claim text.