Gas Sensor

1 - 14 . (canceled)

15 . A method for detecting the quantity of a measurement gas contained in a gas mixture with the aid of a gas sensor, comprising:

setting the partial pressure of a free gas component of a detection gas in a prechamber of the gas sensor to a predetermined value by a first pump device, the measurement gas being at least partly converted into the detection gas by reaction with the free gas component in the prechamber;

determining, by a detection device disposed in a measuring chamber of the gas sensor, the concentration of the detection gas by determining a measure of the quantity of a gas component that is liberated from the detection gas in the measuring chamber, the measuring chamber being separated from the prechamber by a first diffusion barrier;

setting the partial pressure of the free gas component of the detection gas in an inlet chamber of the gas sensor to a predetermined value below the value of the partial pressure prevailing in the prechamber by a second pump device, the inlet chamber being separated from the prechamber by a second diffusion barrier; and

setting the partial pressure of the free gas component in the measuring chamber to a predetermined value below the value of the partial pressure prevailing in the prechamber by a third pump device.

16 . The method as claimed in claim 15 , further comprising setting the partial pressure of the gas component in the inlet chamber to a predetermined value below the value of the partial pressure prevailing in the measuring chamber by the second pump device.

17 . The method as claimed in claim 15 , wherein the gas component is an oxidizing gas.

18 . The method as claimed in claim 18 , wherein the gas component is oxygen.

19 . The method as claimed in claim 15 , wherein the detection gas comprises gaseous oxides.

20 . The method as claimed in claim 19 , wherein the detection gas comprises nitrogen oxides.

21 . The method as claimed in claim 15 , wherein the measurement gas is a hydrogen-containing gas.

22 . The method as claimed in claim 21 , wherein the measurement gas is ammonia.

23 . The method as claimed in claim 15 , wherein the detection gas is reduced by the detection device using a catalyst.

24 . The method as claimed in claims 15 , wherein the detection device disposed in the measuring cell comprises a measuring electrode, a pump electrode, a current source, and an ammeter detecting the current intensity of the pump current flowing through the measuring cell as a measure of the concentration of detection gas in the measuring chamber.

25 . The method as claimed in claim 15 , wherein the first, second, and third pump devices each comprise a voltmeter for detecting the Nernst voltage between a reference electrode exposed to external air and a respective electrode assigned to the inlet, prechamber, and measuring chambers, and a current source for varying the current flowing through a respective pump cell to keep the Nernst voltage detected by the associated voltmeters at a predetermined value.

26 . The method as claimed in claim 25 , wherein the Nernst voltage assigned to the inlet chamber is kept at a value within the range of between 600 and 800 mV in the pump cell of the inlet chamber.

27 . The method as claimed in claim 25 , wherein the Nernst voltage assigned to the prechamber is kept at a value within the range of between 100 and 200 mV in the pump cell of the prechamber.

28 . The method as claimed in claim 25 , wherein the Nernst voltage assigned to the measuring chamber is kept at a value within the range of 350 and 450 mV in the pump cell of the measuring chamber.

29 . The method as claimed in claim 15 , wherein the detection gas passes from the prechamber into the measuring chamber through the first diffusion barrier separating the prechamber and the measuring chamber.

30 . The method as claimed in claim 15 , wherein the measurement gas passes from the inlet chamber into the prechamber through the second diffusion barrier separating the inlet chamber and the prechamber.

31 . A gas sensor for detecting the quantity of a measurement gas contained in a gas mixture, comprising:

a prechamber in which the measurement gas can be at least partly converted into a detection gas by reaction with a free gas component;

a first pump device configured to set the partial pressure of the free gas component of the detection gas in the prechamber to a predetermined value;

a measuring chamber separated from the prechamber by a first diffusion barrier, the measuring chamber comprising a detection device configured to determine the concentration of the detection gas by determining a measure of the quantity of the gas component that is liberated from the detection gas in the measuring chamber;

an inlet chamber separated from the prechamber by a second diffusion barrier;

a second pump device configured to set the partial pressure of the free gas component of the detection gas in the inlet chamber to a predetermined value below the value of the partial pressure prevailing in the prechamber; and

a third pump device configured to set the partial pressure of the free gas component in the measuring chamber to a predetermined value below the value of the partial pressure prevailing in the prechamber.

32 . The method as claimed in claim 31 , wherein the second pump device is further configured to set the partial pressure of the gas component in the inlet chamber to a predetermined value that is below the value of the partial pressure prevailing in the measuring chamber.

33 . The method as claimed in claim 31 , wherein the gas component is an oxidizing gas.

34 . The method as claimed in claim 33 , wherein the gas component is oxygen.

35 . The method as claimed in claim 31 , wherein the detection gas comprises gaseous oxides.

36 . The method as claimed in claim 35 , wherein the detection gas comprises nitrogen oxides.

37 . The gas sensor as claimed in claim 31 , wherein the measurement gas is a hydrogen-containing gas.

38 . The gas sensor as claimed in claim 37 , wherein the measurement gas is ammonia.

39 . The gas sensor as claimed in claim 31 , wherein the detection device comprises a catalyst for reducing the detection gas.

40 . The method as claimed in claim 31 , wherein the detection device comprises a measuring cell comprising a measuring electrode, a pump electrode, a current source, and an ammeter detecting the current intensity of the pump current flowing through the measuring cell as a measure of the concentration of detection gas in the measuring chamber.

41 . The gas sensor as claimed in claim 31 , wherein the first, second, and third pump devices each comprise a voltmeter for detecting the Nernst voltage between a reference electrode exposed to external air and a respective electrode assigned to the inlet, prechamber, and measuring chambers, and a current source which keeps the Nernst voltage detected by the associated voltmeters at a predetermined value by varying the current flowing through a respective pump cell.

42 . The method as claimed in claim 41 , wherein the pump cell of the inlet chamber keeps the Nernst voltage assigned to the inlet chamber at a value within the range of between 600 and 800 mV.

43 . The gas sensor as claimed in claim 41 , wherein the pump cell of the prechamber keeps the Nernst voltage assigned to the prechamber at a value within the range of between 100 and 200 mV.

44 . The gas sensor as claimed in claim 41 , wherein the pump cell of the measuring chamber keeps the Nernst voltage assigned to the measuring chamber at a value within the range of 350 and 450 mV.

45 . The gas sensor as claimed in claim 31 , wherein the measuring chamber is disposed downstream of the prechamber in the flow direction of the detection gas.

46 . The gas sensor as claimed in claim 31 , wherein the inlet chamber is disposed upstream of the prechamber in the flow direction of the free gas component.