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OwnerWerner Gruenwald, Bernd Schumann +1inventors
InventorsWerner Gruenwald, Bernd Schumann, Sabine Thiemann-Handler
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A method for operating a sensor element (10) for determining at least one gas component of a gas, in particular of an exhaust gas of a combustion engine, is proposed. A measured gas space (35) that is in communication with the gas located outside the sensor element (10) is introduced into the sensor element (10). A first electrode (31) and a second electrode (32) are provided in the measured gas space (35) on an oxygen-ion-conducting solid electrolyte (21), and a third electrode (33) is provided outside the measured gas space (35). The second electrode (32) is electrically connected by the solid electrolyte (21) to the third electrode (33), so that oxygen is pumpable by application of a voltage between the second electrode (32) and the third electrode (33). A lower voltage is present between the second and the third electrode (32, 33) in a first time interval than outside the first time interval, so that under constant external conditions, the oxygen partial pressure in the measured gas space (35) is greater, at least when averaged over the durations, during a first time interval than during a second time interval.
A method for operating a sensor element (10) for determining at least one gas component of a gas, in particular of an exhaust gas of a combustion engine, comprising a measured gas space (35), introduced into the sensor element (10), that is in communication with the gas located outside the sensor element (10), a first electrode (31) and a second electrode (32) being provided in the measured gas space (35) on an oxygen-ion-conducting solid electrolyte (21), and a third electrode (33) being provided outside the measured gas space (35), and oxygen being pumpable by application of a voltage between the second electrode (32) and the third electrode (33), wherein at least one predefined first time interval is provided;
The method as recited in at least one of the preceding claims, wherein during the first time interval, there exists at the first electrode (31) a potential at which the gas component to be analyzed is not decomposed or is only slight decomposed;
The method as recited in at least one of the preceding claims, wherein the voltage between the second (32) and the third electrode (33) is selected so that the gas component to be analyzed is not decomposed during the first time interval at the second electrode (32) and can arrive at the first electrode (31);
The method as recited in at least one of the preceding claims, wherein during the second time interval, the pump voltage between the second and the third electrode (32, 33) is selected so that limit current conditions exist.
The method as recited in at least one of the preceding claims, wherein the method steps occurring in the first and the second time interval are utilized in recurring time intervals.
The method as recited in at least one of the preceding claims, wherein the oxygen partial pressure during the second time interval is at least intermittently less than 10−14 bar.
The method as recited in at least one of the preceding claims, wherein in the first time interval a voltage in the range from 0.1 to 0.25 V, preferably 0.2 V, is present between the second and the third electrode (32, 33), and a voltage in the range from 0 to 0.1 V, preferably 0 V, is present between the first and the third electrode (31, 33).
The method as recited in at least one of the preceding claims, wherein in the second time interval, at least while limit current conditions exist, a voltage of 1.2 to 1.5 V, preferably 1.4 V, is present between the first and the third electrode (31, 33).
The method as recited in at least one of the preceding claims, wherein in the second time interval, at least intermittently and in particular in order to establish limit current conditions, a voltage of 0.8 to 1.5 V, preferably 1.4 V, is present between the second electrode (32) and the third electrode (33).
The method as recited in at least one of the preceding claims, wherein the partial pressure of the gas component to be analyzed is ascertained by integrating the pump current flowing through the first electrode (31) during the second time interval.
The method as recited in at least one of the preceding claims, wherein the first time interval lasts 0.2 to 20 seconds, preferably 2 seconds, and the second time interval lasts 0.1 to 2 seconds, preferably 0.5 second.
The method as recited in at least one of the preceding claims, wherein the second electrode (32) is in contact with a region (36) of the measured gas space (35) located between the diffusion resistance (34) and the first electrode (31).
The method as recited in at least one of the preceding claims, wherein the third electrode (33) is in contact with the exhaust gas located outside the sensor element (10), or is in contact with a reference gas.
The method as recited in at least one of the preceding claims, wherein a further electrode that is in contact with a reference gas is provided.
The method as recited in at least one of the preceding claims, wherein the first electrode (31) and the third electrode (33), and the solid electrolyte positioned between the first and third electrodes (31, 33), constitute a pump cell.
The method as recited in at least one of the preceding claims, wherein the gas component to be analyzed is an oxygen compound, for example NOx and/or CO2 and/or SO2.
The method as recited in at least one of the preceding claims, wherein the first electrode (31) contains an oxide of the fifth subgroup, in particular V2O5, or a mixture of oxides of the fifth subgroup;
The method as recited in at least one of the preceding claims, wherein the first electrode (31) contains barium and/or cerium and/or magnesium in the form of nitrates, oxides, or sulfates.
The method as recited in at least one of the preceding claims, wherein a means for temperature regulation is provided;
Dependencies are inferred from the claim text.