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US 6,274,016 B1Granted
Nitrogen oxide gas sensor
AssigneeRiken
InventorsMasaharu Hasei, Yongtie Yan, Akira Kunimoto
Life of this patent
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Abstract
A nitrogen oxide gas sensor wherein an alloy electrode of platinum and rhodium or a cermet electrode of platinum, rhodium, and zirconia or of a rhodium alloy and zirconia is used as the gas sensing electrode. The electrode of the sensor is suitable for measuring nitrogen oxide such as NO and NO2 in an exhaust gas.
Claims10
A nitrogen oxide gas sensor comprising a sensor body;
- a chamber formed inside the sensor body;
- a zirconia solid electrolyte substrate which is an oxygen ion conductor forming a wall of said chamber;
- a sensing electrode provided in the chamber on the solid electrolyte substrate, said sensing electrode being an alloy electrode comprising platinum and 0.5-7 wt % rhodium or a cermet electrode electrode comprising zirconia and an alloy of platinum and 0.5-7 wt % rhodium;
- a platinum counter electrode paired to the sensing electrode, said platinum counter electrode provided in the chamber on the solid electrolyte substrate;
- and means for controlling the oxygen concentration at the sensing electrode.
2 more elements
A nitrogen oxide gas sensor comprising a sensor body;
- a chamber formed inside the sensor body;
- a zirconia solid electrolyte substrate which is an oxygen ion conductor forming a wall of said chamber;
- a gas sensing electrode provided in the chamber on the solid electrolyte substrate, wherein the gas sensing electrode of said sensor is an electrode formed by laminating a rhodium layer having a thickness of 10-50 Å on a platinum layer or a cermet electrode formed by dispersing zirconia in each of the rhodium layer and and the platinum layer of the laminated electrode with a rhodium layer of 10-50 Å thickness;
- a platinum counter electrode paired to the sensing electrode, said platinum counter electrode provided in the chamber on the solid electrolyte substrate;
- and a means for controlling the oxygen concentration at the sensing electrode in a range of from 0.05 to 21% by volume.
2 more elements
A nitrogen oxide gas sensor comprising a sensor body;
- a chamber formed inside the sensor body;
- a zirconia solid electrolyte substrate which is an oxigen ion conductor forming a wall of said chamber;
- a gas sensing electrode provided in the chamber on the solid electrolyte substrate, wherein the gas sensing electrode of said gas sensor is made up of an alloy comprising platinum, rhodium and a third metal element, said third metal element being at least one of Ru, Ir, Pd, Au, and Ag;
- a platinum counter electrode paired to the sensing electrode, said platinum counter electrode provided in the chamber on the solid electrolyte substrate;
- and a means for controlling the oxygen concentration at the sensing electrode in a range of from 0.05 to 21% by volume.
2 more elements
A nitrogen oxide gas sensor comprising a sensor body;
- a chamber formed inside the sensor body;
- a zirconia solid electrolyte substrate which is an oxygen ion conductor forming a wall of said chamber;
- a gas sensing electrode provided in the chamber on the solid electrolyte substrate, wherein the gas sensing electrode of said gas sensor is made up of a mixed phase of rhodium oxide and platinum or an electrode formed by adding at least one of an oxide of a third metal element to a mixture of rhodium oxide and platinum, said third metal element being one of Ru, Ir, Pd, Ag, Ni, and Cr;
- a platinum counter electrode paired to the sensing electrode, said platinum counter electrode provided in the chamber on the solid electrolyte substrate;
- and a means for controlling the oxygen concentration at the sensing electrode in a range of from 0.05 to 21% by volume.
2 more elements
A nitrogen oxide gas sensor comprising a sensor body;
- a chamber formed inside the sensor body;
- a zirconia solid electrolyte substrate which is an oxygen ion conductor forming a wall of said chamber;
- a gas sensing electrode provided in the chamber on the solid electrolyte substrate, wherein the gas sensing electrode of said sensor is an electrode comprising iridium, an electrode comprising an alloy or a mixed phase of iridium and rhodium, or a cermet electrode formed by adding zirconia to iridium or an alloy or a mixed phase of iridium and rhodium;
- a platinum counter electrode paired to the sensing electrode, said platinum counter electrode provided in the chamber on the solid electrolyte substrate;
- and a means for controlling the oxygen concentration at the sensing electrode in a range of from 0.05 to 21% by volume.
2 more elements
Dependencies are inferred from the claim text.