Combination NOx and Oxygen sensor with common gas chamber

Patent metadata

Field	Value
Publication number	US-10634641-B2
Application number	US-201715447977-A
Country	US
Kind code	B2
Filing date	Mar 2, 2017
Priority date	Mar 2, 2017
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

A sensor system includes a common gas chamber and a reference gas chamber respectively configured to receive an exhaust gas and a reference gas. A Nernst cell is exposed to the common gas chamber and the reference air chamber. The Nernst cell provides a reference signal indicative of an oxygen difference between the common gas chamber and the reference air chamber. An oxygen electrochemical pump cell is exposed to the common gas chamber and exhaust gas and provides an oxygen signal indicative of an oxygen only concentration. A NOx electrochemical cell is exposed to the common gas chamber and provides a NOx signal indicative of a NOx concentration. A processor is in communication with the Nernst cell, the oxygen-only electrochemical pump cell and NOx electrochemical cells. The processor outputs oxygen and NOx signals and provide a NOx concentration and oxygen concentration of the exhaust.

First claim

What is claimed is:

1. A sensor system comprising:
multiple layers that include a common gas chamber and a reference gas chamber respectively configured to receive an exhaust gas and a reference gas;
a Nernst cell exposed to the common gas chamber and the reference gas chamber, the Nernst cell configured to provide a reference signal indicative of an oxygen difference between the common gas chamber and the reference gas chamber;
an oxygen electrochemical pump cell exposed to the common gas chamber and the exhaust gas, and configured to provide an oxygen signal indicative of an oxygen only concentration;
a NOx electrochemical cell exposed to the common gas chamber and configured to provide a NOx signal indicative of a NOx concentration;
a processor in communication with the Nernst cell, the oxygen electrochemical pump cell and NOx electrochemical cells, the processor configured to output oxygen and NOx signals and provide a NOx concentration and oxygen concentration of the exhaust gas;
a heater arranged in the multiple layers adjacent to the Nernst cell; and
a wire pigtail with only six wires electrically connected to the Nernst cell, the oxygen electrochemical pump cell, the NOx electrochemical cell and the heater;
wherein a first wire of the only six wires is electrically connected to a reference electrode located in the reference gas chamber;
wherein a second wire of the only six wires is electrically connected to a counter-oxygen electrode pump electrode which is exposed to the exhaust gas and which is not in either of the reference gas chamber or the common gas chamber;
wherein a third wire of the only six wires is electrically connected to an oxygen-only pump electrode of the oxygen electrochemical pump cell such that the oxygen pump electrode is located in the common gas chamber, the third wire is also electrically connected to an EMF electrode which is located in the common gas chamber;
wherein a fourth wire of the only six wires is electrically connected to a NOx sensing electrode which is located within the common gas chamber; and
wherein a fifth wire and a sixth wire of the only six wires are electrically connected to the heater.

2. The sensor system of claim 1 , wherein the oxygen electrochemical pump cell includes the oxygen-only pump electrode in the common gas chamber, supported on one side of a first doped zirconia layer of the multiple layers, and the counter-oxygen pump electrode supported on an opposite side of the one side of the first doped zirconia layer which exposed to exhaust gas.

3. The sensor system of claim 2 , wherein the Nernst cell includes the EMF electrode and the reference electrode arranged on opposing sides of a second doped zirconia layer of the multiple layers, the EMF electrode arranged in the common gas chamber, and the reference electrode arranged in the reference gas chamber, wherein the NOx electrochemical cell includes the NOx sensing electrode arranged in the common gas chamber and shares the same side of a second doped zirconia layer as that of EMF electrode.

4. The sensor system of claim 3 , wherein the oxygen-only pump electrode and the EMF electrode share a ground.

5. The sensor system of claim 3 , wherein the processor is configured to provide a fixed frequency excitation voltage feed into the Nernst cell to obtain the electrolyte impedance between the EMF and reference electrodes and provide a feedback control signal to modulate electrical power to the heater.

6. The sensor system of claim 3 , wherein the processor is configured to control a voltage to the oxygen electrochemical pump cell based upon an EMF signal from the Nernst cell.

7. The sensor system of claim 1 , comprising a gas diffusion-limiting aperture provided in at least one of the multiple layers and in fluid communication with the common gas chamber, the gas diffusion-limiting aperture configured to regulate an amount of exhaust gas into the common gas chamber.

8. The sensor system of claim 7 , wherein the common gas chamber is configured to have a constant ratio of nitrogen monoxide and nitrogen dioxide.

9. The sensor system of claim 7 , wherein the common gas chamber is configured to be free from hydrocarbons and carbon monoxide.

10. The sensor system of claim 9 , wherein the gas diffusion-limiting aperture includes a precious metal catalyst.

11. The sensor system of claim 1 , wherein the oxygen electrochemical pump cell and the Nernst cell are configured to have a constant oxygen concentration in the common gas chamber.

12. The sensor system of claim 1 , wherein the sensor system includes an ammonia sensing cell and a nitrogen dioxide sensing cell arranged in the multiple doped zirconia layers and respectively configured to provide NH3 and NO2 signals.

13. The sensor system of claim 12 , comprising a wire pigtail with only eight wires electrically connected to the Nernst cell, the oxygen electrochemical pump cell, the NOx electrochemical cell, the heater, the ammonia sensing cell, and the nitrogen dioxide sensing cell.

14. The sensor system of claim 12 , wherein the processor is configured to output a difference between the NO2 and NOx signals and provide a nitrogen monoxide concentration.

15. The sensor system of claim 12 , comprising a controller in communication with the processor and configured to command at least one of a fuel system, an emissions system, and an engine control device in response to the NOx concentration.

16. An exhaust gas sensor comprising:
multiple layers that include a common gas chamber and a reference gas chamber respectively configured to receive an exhaust gas and a reference gas;
a Nernst cell exposed to the common gas chamber and the reference gas chamber, the Nernst cell configured to provide a reference signal indicative of an oxygen difference between the common gas chamber and the reference gas chamber;
an oxygen-only electrochemical pump cell exposed to the common gas chamber and the exhaust gas, and configured to provide an oxygen signal indicative of an oxygen concentration;
a NOx electrochemical cell exposed to the common gas chamber and configured to provide a NOx signal indicative of a NOx concentration;
a heater arranged in the multiple layers; and
a wire pigtail with only six wires electrically connected to the Nernst cell, the oxygen electrochemical pump cell, the NOx electrochemical cell, and the heater;
wherein a first wire of the only six wires is electrically connected to a reference electrode located in the reference gas chamber;
wherein a second wire of the only six wires is electrically connected to a counter-oxygen electrode pump electrode which is exposed to the exhaust gas and which is not in either of the reference gas chamber or the common gas chamber;
wherein a third wire of the only six wires is electrically connected to an oxygen-only pump electrode of the oxygen electrochemical pump cell such that the oxygen pump electrode is located in the common gas chamber, the third wire is also electrically connected to an EMF electrode which is located in the common gas chamber;
wherein a fourth wire of the only six wires is electrically connected to a NOx sensing electrode which is located within the common gas chamber; and
wherein a fifth wire and a sixth wire of the only six wires are electrically connected to the heater.

17. The sensor of claim 16 , comprising an ammonia sensing cell and a nitrogen dioxide sensing cell arranged in the multiple layers and respectively configured to provide NH3 and NO2 signals, and comprising a wire pigtail with only eight wires electrically connected to the N

Assignees

• Delphi Tech Ip Ltd

Inventors

• Wang Da Yu
• Racine David M
• Yao Sheng

Classifications

• G01N27/4073

  Composition or fabrication of the solid electrolyte · CPC title

• G01N27/4075

  Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts · CPC title

• G01N27/41 Primary

  Oxygen pumping cells · CPC title

• G01N27/4067

  Means for heating or controlling the temperature of the solid electrolyte · CPC title

• G01N27/417

  using cells {, i.e. more than one cell} and probes with solid electrolytes · CPC title