Method and apparatus for analyzing mixtures of gases

• US 8,043,566 B2
• Filed: 01/12/2005
• Issued: 10/25/2011
• Est. Priority Date: 10/16/2000
• Status: Expired due to Fees

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Morris, Patricia A.
• Primary Examiner(s): Alexander; Lyle
• Assistant Examiner(s): WHITE, DENNIS MICHAEL
• Application Number:
  US11/034,529
• Publication Number:
  US 20060171847A1
• Time in Patent Office: 2,477 Days
• Field of Search: 422/88, 422/90, 422/94, 422/98, 73/233.1, 73/310.6, 204/424
• US Class Current: 422/94
• CPC Class Codes: G01N 33/0031 comprising two or more sensors, e.g. a sensor array electrochemical electrode arrays G01N27/27
• CPC Class Codes: Y10T 436/11 Automated chemical analysis

Abstract

Disclosed herein is a method and apparatus for analyzing, sensing and measuring information related to the concentrations of various gases, including NO_x, hydrocarbons, carbon monoxide and oxygen, in a multi-component gas system using chemical sensors and chemical sensor arrays. The sensors and sensor arrays use chemo/electro-active materials to analyze and detect the presence of gases.

Claims

1. An emissions system comprising:

(a) an internal combustion engine that emits as exhaust a multi-component gas mixture;

(b) gas transmission equipment to direct the gas mixture from the engine to an array of at least four chemo/electro-active materials, each chemo/electro-active material exhibiting a different electrical response characteristic, upon exposure at a selected temperature to the gas mixture, than each of the other chemo/electro-active materials;

wherein the array of chemo/electro-active materials comprises Ga_aTi_bZn_cO_x and at least one of the chemo/electro-active materials in the group consisting of Al_aNi_bO_x, Cr_aTi_bO_x, Mn_aY_bO_x, Nb_aTi_bO_x, Nb_aW_bO_x, Ni_aZn_bO_x, Sb_aSn_bO_x, Ta_aTi_bO_x, and Ti_aZn_bO_x;

wherein a, b and c are each independently about 0.0005 to about 1; and

x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound;

(c) means for determining the electrical response of each chemo/electro-active material upon exposure of the array to the gas mixture; and

(d) means for detecting the presence of, or calculating the actual concentration of, one or more individual component gases and/or subgroups within the gas mixture from the electrical responses of the chemo/electro-active materials inputted thereto.

2. A system according to claim 1 wherein the array of chemo/electro-active materials comprises at least two of the chemo/electro-active materials in the group consisting of Al_aNi_bO_x, Cr_aTi_bO_x, Mn_aY_bO_x, Nb_aTi_bO_x, Nb_aW_bO_x, Ni_aZn_bO_x, Sb_aSn_bO_x, Ta_aTi_bO_x, and Ti_aZn_bO_x.

3. A system according to claim 1 wherein the array of chemo/electro-active materials comprises at least three of the chemo/electro-active materials in the group consisting of Al_aNi_bO_x, Cr_aTi_bO_x, Mn_aY_bO_x, Nb_aTi_bO_x, Nb_aW_bO_x, Ni_aZn_bO_x, Sb_aSn_bO_x, Ta_aTi_bO_x, and Ti_aZn_bO_x.

4. A system according to claim 1 wherein the array of chemo/electro-active materials comprises at least one of the chemo/electro-active materials in the group consisting of Ce_aO_x, NbO_x, SnO_x, and ZnO_x, wherein a is about 0.0005 to about 1, and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound.

5. A system according to claim 1 wherein the array of chemo/electro-active materials comprises at least two of the chemo/electro-active materials in the group consisting of Ce_aO_x, NbO_x, SnO_x, and ZnO_x, wherein a is about 0.0005 to about 1, and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound.

6. A system according to claim 2 wherein the array of chemo/electro-active materials comprises at least one of the chemo/electro-active materials in the group consisting of Ce_aO_x, NbO_x, SnO_x, and ZnO_x, wherein a is about 0.0005 to about 1, and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound.

7. A system according to claim 1 wherein the array of chemo/electro-active materials comprises at least one of the chemo/electro-active materials in the group consisting of Nb_aSr_bTi_cO_x and Nb_aSr_bW_cO_x, wherein a, b and c are each independently about 0.0005 to about 1;

and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound.

8. A system according to claim 1 wherein the array of chemo/electro-active materials comprises both of the chemo/electro-active materials in the group consisting of Nb_aSr_bTi_cO_x and Nb_aSr_bW_cO_x, wherein a, b and c are each independently about 0.0005 to about 1;

and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound.

9. A system according to claim 2 wherein the array of chemo/electro-active materials comprises at least one of the chemo/electro-active materials in the group consisting of Nb_aSr_bTi_cO_x and Nb_aSr_bW_cO_x, wherein a, b and c are each independently about 0.0005 to about 1;

and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound.

10. A system according to claim 4 wherein the array of chemo/electro-active materials comprises at least one of the chemo/electro-active materials in the group consisting of Nb_aSr_bTi_cO_x and Nb_aSr_bW_cO_x, wherein a, b and c are each independently about 0.0005 to about 1;

and x is a number sufficient so that the oxygen present balances the charges of the other elements in the compound.

11. A system according to claim 1 wherein one or more chemo/electro-active materials further comprises a frit additive.

12. A system according to claim 1 wherein the component gases in the gas mixture are not separated.

13. A system according to claim 1 wherein an individual component gas as to which presence is detected or concentration is calculated is selected from the group consisting of oxygen, a nitrogen oxide, a hydrocarbon, and ammonia.

14. A system according to claim 1 wherein a subgroup of component gases as to which presence is detected or concentration is calculated is (i) oxygen and a hydrocarbon, or (ii) a nitrogen oxide and ammonia.

15. A system according to claim 1 comprising means for calculating the concentration within the gas mixture of at least one individual gas component.

16. A system according to claim 1 wherein the means for determining the response of each chemo/electro-active material comprises conductors, electrical input and output circuitry and data acquisition and manipulation devices.

17. A system according to claim 1 wherein the means for detecting the presence of, or calculating the actual concentration of, one or more individual component gases and/or subgroups within the gas mixture receives as an input (a) the electrical responses of the chemo/electro-active materials but not a baseline response value, comparison response value or reference gas value;

or (b) only the electrical responses of the chemo/electro-active materials.

18. A system according to claim 1 wherein the means for detecting the presence of, or calculating the actual concentration of, one or more individual component gases and/or subgroups within the gas mixture comprises a modeling algorithm.

19. A system according to claim 18 wherein the values upon which the output of the modeling algorithm is based include the temperature of a chemo/electro-active material.

20. A system according to claim 1 further comprising a decision making routine for controlling the internal combustion engine that receives as inputs the outputs of the means for detecting the presence of, or calculating the actual concentration of, one or more individual component gases and/or subgroups within the gas mixture.

21. A vehicle for transportation, or equipment for construction, maintenance or industrial operations, comprising the emissions system of claim 1.