Method and apparatus for analyzing mixtures of gases

• US 20060171847A1
• Filed: 01/12/2005
• Published: 08/03/2006
• Est. Priority Date: 10/16/2000
• Status: Active Grant

• Current Assignee: Patricia A. Morris
• Original Assignee: Patricia A. Morris
• Inventors: Morris, Patricia A.
• Granted Patent: US 8,043,566 B2
• Time in Patent Office: Days
• US Class Current: 422/83
• 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 emitted by the engine to an array of at least two 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, the electrical response characteristic of at least one material being quantifiable as a value, wherein the value of the response of that material is constant or varies by no more than about twenty percent during exposure of the material to the gas mixture at the selected temperature for a period of at least about one minute;

(c) a heater that heats the array to a temperature above 500°

C.;

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

(e) 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 (i) the electrical responses of the chemo/electro-active materials inputted thereto, but not from a baseline response value, comparison response value or reference gas value inputted thereto;

or (ii) only the electrical responses of the chemo/electro-active materials inputted thereto.

2. An apparatus according to claim 1 wherein the component gases in the gas mixture are not separated.

3. An apparatus according to claim 1 comprising means for calculating the concentration within the gas mixture of at least one individual gas component.

4. An apparatus 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.

5. An apparatus 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.

6. A vehicle for transportation, or a piece of equipment for construction, maintenance or industrial operation, comprising the emissions system of claim 1.

7. 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 first and second 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 chemo/electro-active materials are selected from the pairings in the group consisting of

(i) the first material is M¹O_x, and the second material is M¹_aM²_bO_x;

(ii) the first material is M¹O_x, and the second material is M¹_aM²_bM³_cO_x;

(iii) the first material is M¹_aM²_bO_x, and the second material is M¹_aM²_bM³_cO_x;

(iv) the first material is a first M¹O_x, and the second material is a second M¹O_x;

(v) the first material is a first M¹_aM²_bO_x , and the second material is a second M¹_aM²_bO_x ; and

(vi) the first material is a first M¹_aM²_bM³_cO_x, and the second material is a second M¹_aM²_bM³_cO_x;

wherein M¹ is selected from the group consisting of Ce, Co, Cu, Fe, Ga, Nb, Ni, Pr, Ru, Sn, Ti, Tm, W, Yb, Zn, and Zr;

M² and M³ are each independently selected from the group consisting of Al, Ba, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, Ga, Ge, In, K, La, Mg, Mn, Mo, Na, Nb, Ni, Pb, Pr, Rb, Ru, Sb, Sc, Si, Sn, Sr, Ta, Ti, Tm, V, W, Y, Yb, Zn, and Zr, but M² and M³ are not the same in M¹_aM²_bM³_cO_x;

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) a heater that heats the array to a temperature above 500°

C.;

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

(e) 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 (i) the electrical responses of the chemo/electro-active materials inputted thereto, but not from a baseline response value, comparison response value or reference gas value inputted thereto;

or (ii) only the electrical responses of the chemo/electro-active materials inputted thereto.

8. An apparatus according to claim 7 wherein the component gases in the gas mixture are not separated.

9. An apparatus according to claim 7 comprising means for calculating the concentration within the gas mixture of at least one individual gas component.

10. An apparatus according to claim 7 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.

11. An apparatus according to claim 7 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.

12. A vehicle for transportation, or a piece of equipment for construction, maintenance or industrial operation, comprising the emissions system of claim 7.

13. 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 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 at least one chemo/electro-active materials is selected from the group consisting of M¹O_x, M¹_aM²_bO_xand M¹_aM²_bM³_cO_x;

wherein M¹ is selected from the group consisting of Ce, Co, Cu, Fe, Ga, Nb, Ni, Pr, Ru, Sn, Ti, Tm, W, Yb, Zn, and Zr;

M² and M³ are each independently selected from the group consisting of Al, Ba, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, Ga, Ge, In, K, La, Mg, Mn, Mo, Na, Nb, Ni, Pb, Pr, Rb, Ru, Sb, Sc, Si, Sn, Sr, Ta, Ti, Tm, V, W, Y, Yb, Zn, and Zr, but M² and M³ are not the same in M¹_aM²_bM³_cO_x;

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) a heater that heats the array to a temperature above 500°

C.;

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

(e) 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 (i) the electrical responses of the chemo/electro-active materials inputted thereto, but not from a baseline response value, comparison response value or reference gas value inputted thereto;

or (ii) only the electrical responses of the chemo/electro-active materials inputted thereto.

14. An apparatus according to claim 13 wherein

M¹O_x is selected from the group consisting of Ce_aO_x, CoO_x, CuO_x, FeO_x, GaO_x, NbO_x, NiO_x, PrO_x, RuO_x, SnO_x, Ta_aO_x, TiO_x, TmO_x, WO_x, YbO_x, ZnO_x, ZrO_x , SnO_x with Ag additive, ZnO_x with Ag additive, TiO_x with Pt additive, ZnO_x with frit additive, NiO_x with frit additive, SnO_x with frit additive, or WO_x with frit additive;

and/or

M¹_aM²_bO_x is selected from the group consisting of Al_aCr_bO_x, Al_aFe_bO_x Al_aMg_bO_x, Al_aNi_bO_x, Al_aTi_bO_x, Al_aV_bO_x, Ba_aCu_bO_x, Ba_aSn_bO_x, Ba_aZn_bO_x, Bi_aRu_bO_x, Bi_aSn_bO_x, Bi_aZn_bO_x, Ca_aSn_bO_x, Ca_aZn_bO_x, Cd_aSn_bO_x, Cd_aZn_bO_x, Ce_aFe_bO_x, Ce_aNb_bO_x, Ce_aTi_bO_x, Ce_aV_bO_x, Co_aCu_bO_x, Co_aGe_bO_x, Co_aLa_bO_x, Co_aMg_bO_x, Co_aNb_bO_x, Co_aPb_bO_x, Co_aSn_bO_x, Co_aV_bO_x, Co_aW_bO_x, Co_aZn_bO_x, Cr_aCu_bO_x, Cr_aLa_bO_x, Cr_aMn_bO_x, Cr_aNi_bO_x, Cr_aSi_bO_x, Cr_aTi_bO_x, Cr_aY_bO_x, Cr_aZn_bO_x, Cu_aFe_bO_x, Cu_aGa_bO_x, Cu_aLa_bO_x, Cu_aNa_bO_x, Cu_aNi_bO_x, Cu_aPb_bO_x, Cu_aSn_bO_x, Cu_aSr_bO_x, Cu_aTi_bO_x, Cu_aZn_bO_x, Cu_aZr_bO_x, Fe_aGa_bO_x, Fe_aLa_bO_x, Fe_aMo_bO_x, Fe_aNb_bO_x, Fe_aNi_bO_x, Fe_aSn_bO_x, Fe_aTi_bO_x, Fe_aW_bO_x, Fe_aZn_bO_x, Fe_aZr_bO_x, Ga_aLa_bO_x, Ga_aSn_bO_x, Ge_aNb_bO_x, Ge_aTi_bO_x, In_aSn_bO_x, K_aNb_bO_x, Mn_aNb_bO_x, Mn_aSn_bO_x, Mn_aTi_bO_x, Mn_aY_bO_x, Mn_aZn_bO_x, Mo_aPb_bO_x, Mo_aRb_bO_x, Mo_aSn_bO_x, Mo_aTi_bO_x, Mo_aZn_bO_x, Nb_aNi_bO_x, Nb_aNi_bO_x, Nb_aSr_bO_x, Nb_aTi_bO_x, Nb_aW_bO_x, Nb_aZr_bO_x, Ni_aSi_bO_x, Ni_aSn_bO_x, Ni_aY_bO_x, Ni_aZn_bO_x, Ni_aZr_bO_x, Pb_aSn_bO_x, Pb_aZn_bO_x, Rb_aW_bO_x, Ru_aSn_bO_x, Ru_aW_bO_x, Ru_aZn_bO_x, Sb_aSn_bO_x, Sb_aZn_bO_x, Sc_aZr_bO_x, Si_aSn_bO_x, Si_aTi_bO_x, Si_aW_bO_x, Si_aZn_bO_xSn_aTa_bO_x, Sn_aTi_bO_x, Sn_aW_bO_x, Sn_aZn_bO_x, Sn_aZr_bO_x, Sr_aTi_bO_x, Ta_aTi_bO_x, Ta_aZn_bO_x, Ta_aZr_bO_x, Ti_aV_bO_x, Ti_aW_bO_x, Ti_aZn_bO_x, Ti_aZr_bO_x, V_aZn_bO_x, V_aZr_bO_x, W_aZn_bO_x, W_aZr_bO_x, Y_aZr_bO_x, Zn_aZr_bO_x, Al_aNi_bO_x with frit additive, Cr_aTi_bO_x with frit additive, Fe_aLa_bO_x with frit additive, Fe_aNi_bO_x with frit additive, Fe_aTi_bO_x with frit additive, Nb_aTi_bO_x with frit additive, Nb_aW_bO_x with frit additive, Ni_aZn_bO_x with frit additive, Ni_aZr_bO_x with frit additive, Sb_aSn_bO_x with frit additive, Ta_aTi_bO_x with frit additive, or Ti_aZn_bO_x with frit additive; and

/or

M¹_aM²_bM³_cO_x is selected from the group consisting of Al_aMg_bZn_cO_x, Al_aSi_bV_cO_x, Ba_aCu_bTi_cO_x, Ca_aCe_bZr_cO_x, Co_aNi_bTi_cO_x, Co_aNi_bZr_cO_x, Co_aPb_bSn_cO_x, Co_aPb_bZn_cO_x, Cr_aSr_bTi_cO_x, Cu_aFe_bMn_cO_x, Cu_aLa_bSr_cO_x, Fe_aPb_bZn_cO_x, Fe_aPb_bZn_cO_x, Fe_aSr_bTi_cO_x, Fe_aTa_bTi_cO_x, Fe_aW_bZr_cO_x, Ga_aTi_bZn_cO_x, La_aMn_bNa_cO_x, La_aMn_bSr_cO_x, Mn_aSr_bTi_cO_x, Mo_aPb_bZn_cO_x, Nb_aSr_bTi_cO_x, Nb_aSr_bW_cO_x, Nb_aTi_bZn_cO_x, Ni_aSr_bTi_cO_x, Sn_aW_bZn_cO_x, Sr_aTi_bV_cO_x, Sr_aTi_bZn_cO_x, or Ti_aW_bZr_cO_x;

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.

15. An apparatus according to claim 13 wherein the component gases in the gas mixture are not separated.

16. An apparatus according to claim 13 comprising means for calculating the concentration within the gas mixture of at least one individual gas component.

17. An apparatus according to claim 13 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.

18. An apparatus according to claim 13 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.

19. A vehicle for transportation, or a piece of equipment for construction, maintenance or industrial operation, comprising the emissions system of claim 13.

20. 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 three chemo/electro-active materials, each chemo/electro-active material exhibiting a change in electrical resistance upon exposure to a multi-component gas mixture, wherein at least one chemo/electro-active material, when at a temperature of about 400°

C. or more, (i) has an electrical resistivity in the range of about 1 ohm-cm to about 10⁶ ohm-cm, and (ii) exhibits a change in electrical resistance of at least about 0.1 percent upon exposure of the material to the gas mixture, as compared to the resistance before exposure;

(c) a heater that heats the array to a temperature above 500°

C.;

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

(e) 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 (i) the electrical responses of the chemo/electro-active materials inputted thereto, but not from a baseline response value, comparison response value or reference gas value inputted thereto;

or (ii) only the electrical responses of the chemo/electro-active materials inputted thereto.

21. An apparatus according to claim 20 wherein the component gases in the gas mixture are not separated.

22. An apparatus according to claim 20 comprising means for calculating the concentration within the gas mixture of at least one individual gas component.

23. An apparatus according to claim 20 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.

24. An apparatus according to claim 20 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.

25. A vehicle for transportation, or a piece of equipment for construction, maintenance or industrial operation, comprising the emissions system of claim 24.