Patent ID: 11940406
Assignee: NGK INSULATORS, LTD.
Field: Measurement (Instruments)
Classification: CPC G  Y | IPC G

Claim 5:
6. A gas sensor for detecting an oxygen concentration as a concentration of a specific gas in a measurement-object gas, the gas sensor comprising:
an element body including an oxygen-ion-conductive solid electrolyte layer and having a measurement-object gas flow section provided therein, the measurement-object gas flow section introducing the measurement-object gas and causing the measurement-object gas to flow;
a first measurement pump cell that includes a first measurement electrode and a first outer measurement electrode and that pumps out oxygen in the measurement-object gas, the first measurement electrode being disposed in a first measurement chamber in the measurement-object gas flow section, the first outer measurement electrode being provided outside the element body so as to contact with the measurement-object gas; and
a second measurement pump cell that includes a second measurement electrode and a second outer measurement electrode and that pumps out oxygen in the measurement-object gas, the second measurement electrode being disposed in a second measurement chamber in the measurement-object gas flow section, the second outer measurement electrode being provided outside the element body so as to contact with the measurement-object gas, and
a specific gas concentration detection device having a low concentration measurement mode and a high concentration measurement mode, the low concentration measurement mode being a mode on which the first measurement pump cell is controlled such that a pump current that flows in the first measurement pump cell becomes a limiting current, and, based on a value of the pump current, the specific gas concentration in the measurement-object gas is detected, the high concentration measurement mode being a mode on which the second measurement pump cell is controlled such that a pump current that flows in the second measurement pump cell becomes a limiting current, and, based on a value of the pump current, the specific gas concentration in the measurement-object gas is detected,
wherein the measurement-object gas flow section is configured such that the measurement-object gas passes through a first measurement-electrode diffusion-rate-controlling section and reaches the first measurement chamber and that the measurement-object gas passes through the first measurement chamber and a second measurement-electrode diffusion-rate-controlling section in this order and reaches the second measurement chamber.