gas sensor

Abstract

To provide a gas sensor with which, while simplifying a structure, it is possible to detect short-circuiting with a power supply in a sensor cell.SOLUTION: In a gas sensor 1, a sensor cell 3 has: a solid-state electrolyte body 2 having oxygen ion conductivity; and a pair of electrodes 21, 22 provided on the solid-state electrolyte body 2. A reference cell 4 has: a solid-state electrolyte body 2 identical to the solid-state electrolyte body 2 constituting a part of the sensor cell 3; and a pair of electrodes provided on the solid-state electrolyte body 2. A sensor current detection unit 51 detects a sensor current Is. A reference current detection unit 52 detects a reference current. A determination unit 6 determines whether or not sizes of both of the sensor current Is and the reference current are greater than or equal to a predetermined threshold. The gas sensor 1 is constituted so as to measure, on the basis of the sensor current Is, the NOx concentration of a gas to be measured that is introduced into a measurement gas chamber 10.SELECTED DRAWING: Figure 3

Claims

1. A gas sensor (1) for measuring the NOx concentration of a gas to be measured, The above-mentioned gas to be measured is introduced into the gas chamber (10), A sensor cell (3) having a solid electrolyte (2) that conducts oxygen ions, and a pair of electrodes (21, 22) provided on the solid electrolyte, A reference cell (4) having the same solid electrolyte as the solid electrolyte that constitutes a part of the sensor cell, and a pair of electrodes provided on the solid electrolyte, A sensor current detection unit (51) detects the sensor current (Is), which is the current flowing through the sensor cell, A reference current detection unit (52) detects the reference current, which is the current flowing through the above-mentioned reference cell, The system includes a determination unit (6) that determines whether the magnitudes of both the sensor current and the reference current are greater than or equal to a predetermined threshold, Based on the sensor current described above, the system is configured to measure the NOx concentration of the gas to be measured introduced into the gas chamber to be measured. A gas sensor configured to determine that a short circuit has occurred between the sensor cell and the power supply (16) when the magnitudes of both the sensor current and the reference current are greater than or equal to the threshold.

2. The gas sensor according to claim 1, wherein it is configured to determine that a short circuit has occurred between the sensor cell and the power supply when the magnitudes of both the sensor current and the reference current continuously exceed the threshold for a predetermined period of time or longer.

3. The gas sensor according to claim 1, further comprising a pump cell (71) for adjusting the oxygen concentration of the gas to be measured introduced into the gas chamber to be measured, wherein the pump cell is the reference cell.

4. The gas sensor according to claim 1, comprising a pump cell (71) for adjusting the oxygen concentration of the gas to be measured introduced into the gas chamber to be measured, and a sub-pump cell (72) for further adjusting the oxygen concentration of the gas to be measured whose oxygen concentration has been adjusted by the pump cell, wherein at least one of the pump cell and the sub-pump cell is the reference cell.

5. A gas sensor according to any one of claims 1 to 4, comprising: a pump cell (71) for adjusting the oxygen concentration of the gas to be measured introduced into the gas chamber to be measured; and a monitor cell (73) for measuring the residual oxygen concentration of the gas to be measured after the oxygen concentration has been adjusted by the pump cell, wherein at least one of the pump cell and the monitor cell is the reference cell.

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