System and method to avoid the influence of ozone for a gas sensor

Patent metadata

Field	Value
Publication number	US-11674940-B2
Application number	US-202017122761-A
Country	US
Kind code	B2
Filing date	Dec 15, 2020
Priority date	Dec 23, 2019
Publication date	Jun 13, 2023
Grant date	Jun 13, 2023

Abstract

In some embodiments, a method of operating a gas sensor includes setting power to a heater in contact with a MOx sensor to provide a temperature that is below a threshold temperature; holding the temperature below the threshold temperature for a period of time to reduce ozone concentration in a gas sample in contact with the MOx sensor; increasing power to the heater to increase the temperature of the MOx sensor to an operating temperature; acquiring resistance data from the MOx sensor at the operating temperature; and processing the resistance data to provide a result related the gas sample.

First claim

What is claimed is:

1. A method of operating a gas sensor, comprising:
setting power to a heater in contact with a MOx sensor to provide a temperature that is at a low temperature below a threshold temperature below which an ozone concentration is reduced;
holding the temperature at the low temperature below the threshold temperature for a period of time to reduce ozone concentration in a gas sample in contact with the MOx sensor;
increasing power to the heater to increase the temperature of the MOx sensor to an operating temperature;
acquiring resistance data from the MOx sensor at the operating temperature; and
processing the resistance data to provide a result related the gas sample.

2. The method of claim 1 , wherein the threshold temperature is between 15 C and 50 C.

3. The method of claim 1 , wherein the period of time is between 0.1 and 100 sec.

4. The method of claim 1 , wherein the operating temperature is a single temperature between 100 C and 500 C and acquiring resistance data includes measuring one or more data points at the single temperature.

5. The method of claim 1 , wherein the operating temperature is a range of temperatures between a low operating temperature and a high operating temperature and acquiring resistance data includes measuring one or more data points while the operating temperature is in the range.

6. The method of claim 5 , wherein acquiring resistance data includes measuring the one or more data points while the temperature is increasing and while the temperature is decreasing.

7. The method of claim 1 , wherein the result is one or more of concentration of a volatile organic compound (VOC), concentration of total VOCs (TVOC), concentration of carbon dioxide (eCO2), and indoor air quality (IAQ).

8. The method of claim 7 , wherein processing the resistance includes processing the result through a neural network to provide an adjusted result.

9. The method of claim 8 , further including providing the adjusted result to an external device.

10. The method of claim 1 , wherein the effect of ozone on the result is reduced.

11. A gas sensor, comprising:
a MOx sensor;
a heater in contact with the MOx sensor;
a heater driver configured to control the heater; and
a processor configured to receive resistance data from the MOx sensor, control the heater driver to control a temperature of the MOx sensor, and further configured to execute instructions to
set power to the heater in contact with the MOx sensor to provide a temperature that is at a low temperature below a threshold temperature below which an ozone concentration is reduced;
hold the temperature at the low temperature below the threshold temperature for a period of time sufficient to reduce ozone concentration in a gas sample to below a threshold concentration;
increase power to the heater to increase the temperature to an operating temperature;
acquire resistance data from the MOx sensor with the temperature at the operating temperature;
reduce power to the heater to reduce the temperature to the low temperature below the threshold temperature; and
process the resistance data to provide a result related the gas sample.

12. The gas sensor of claim 11 , wherein the threshold temperature is between 15 C and 150 C.

13. The gas sensor of claim 11 , wherein the period of time is between 0.1 to 100 sec.

14. The gas sensor of claim 11 , wherein the operating temperature is a single temperature between 100 C and 500 C and acquiring resistance data includes measuring one or more data points at the single temperature.

15. The gas sensor of claim 11 , wherein the operating temperature is a range of temperatures between a low operating temperature and a high operating temperature and acquiring resistance data includes measuring one or more data points while the operating temperature is in the range.

16. The gas sensor of claim 15 , wherein acquiring resistance data includes measuring the one or more data points while the temperature is increasing and while the temperature is decreasing.

17. The gas sensor of claim 11 , wherein the result is one or more of concentration of a volatile organic compound (VOC), concentration of total VOCs (TVOC), concentration of carbon dioxide (eCO2), and indoor air quality (IAQ).

18. The gas sensor of claim 17 , wherein processing the resistance includes processing the result through a neural network to provide an adjusted result.

19. The gas sensor of claim 18 , further including providing the adjusted result to an external device.

20. The gas sensor of claim 11 , wherein the effect of ozone on the result is reduced.

Assignees

• Renesas Electronics America Inc

Inventors

• Meyer Christian
• Deininger Debra
• Kostelecky Clayton
• Schreiber Ronald
• Saalbach Holger
• Chilumula Ravi Kanth Reddy

Classifications

• G01N27/123

  for controlling the temperature (temperature control per se G05D23/00) · CPC title

• G01N27/416

  Systems (G01N27/27 takes precedence) · CPC title

• G01N33/0039 Primary

  O3 · CPC title

• G01N27/12 Primary

  of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid {, for detecting components in the fluid} · CPC title

• G01N33/0016 Primary

  by regulating a physical variable, e.g. pressure or temperature · CPC title