Gas sensor device

A gas sensor device comprising:

• a sensor cell which is made up of a first portion of an oxygen ion conductive solid electrolyte body and a pair of sensor electrodes disposed on the solid electrolyte body, the sensor cell working to measure a concentration of a given gas component in a measurement gas;
• a pump cell which is made up of a second portion of the solid electrolyte body and a pair of pump electrodes disposed on the solid electrolyte body, the pump cell working to regulate a concentration of oxygen in the measurement gas;
• an inner void space which faces one of the sensor electrodes and one of the pump electrodes and into which the measurement gas is introduced;
• and
• a diffusion resistor through which the measurement gas is introduced into said inner void space and which is shaped to provide a given diffusion resistance to the measurement gas introduced into said inner void space,
• wherein if a dimension of said diffusion resistor in a direction in which the measurement gas flows in said diffusion resistor is defined as L1, a sectional area of said diffusion resistor taken perpendicular to the direction of flow of the measurement gas in said diffusion resistor is defined as S1, a distance between said diffusion resistor and said sensor cell is defined as L2, and a sectional area of said inner void space taken perpendicular to a direction in which said pump cell and said sensor cell are aligned with each other is defined as S2, a relation of 1000≤(L1/S1)×(L2/S2)≤5000 is met, and the product of (L1/S1)×(L2/S2) has the unit of 1/length unit2,
• in that the above diffusion resistor is made of a porous body, and said sectional area S1 is a value derived by a product of a sectional area of the porous body taken perpendicular to the direction of flow of the measurement gas and a porosity of the porous body, and
• in that said inner void space is shaped to have a configuration uniform from a region where the inner void space faces the pump electrode to a region where the inner void space faces the sensor electrode;
• wherein a direction in which said sensor cell and a monitor cell are aligned with each other is perpendicular to a direction in which said pump cell and said sensor cell are aligned with each other.