Abstract: A gas sensor includes a gas sensor element for detecting a specific gas concentration in measured gas. The gas sensor element includes a solid electrolyte, a measured gas side electrode into which measured gas is introduced through a porous diffusion resistance layer, a reference gas side electrode facing a reference gas chamber, and a diffusion space portion between the porous diffusion resistance layer and the measured gas side electrode. The porous diffusion resistance layer has a measured gas inlet opened to an element outer surface and a measured gas outlet opened to the diffusion space portion. A relationship between a distance between the inlet and the outlet and a distance between the outlet and the measured gas side electrode is expressed by 0<L1/(L1+L2)<0.4.

Abstract: An A/F sensor includes a solid electrolyte body and a heater. The A/F sensor is disposed downstream of a purification device in a flow of exhaust gas g. The purification device purifies the exhaust gas g. The solid electrolyte body is in a cup shape. The solid electrolyte body has an outer surface provided with a measurement electrode 4 contacting the exhaust gas g, and an inner surface provided with a reference electrode contacting reference gas. The solid electrolyte body is made of zirconia. The solid electrolyte body includes a detection part sandwiched between the measurement electrode and the reference electrode and conducted with oxygen ions. The detection part has a cubic phase ratio of 88 mol % or more.

Abstract: A gas sensor includes a gas sensor element for detecting a specific gas concentration in measured gas. The gas sensor element includes a solid electrolyte, a measured gas side electrode into which measured gas is introduced through a porous diffusion resistance layer, a reference gas side electrode facing a reference gas chamber, and a diffusion space portion between the porous diffusion resistance layer and the measured gas side electrode. The porous diffusion resistance layer has a measured gas inlet opened to an element outer surface and a measured gas outlet opened to the diffusion space portion. A relationship between a distance between the inlet and the outlet and a distance between the outlet and the measured gas side electrode is expressed by 0<L1/(L1+L2)<0.4.

Abstract: An A/F sensor includes a solid electrolyte body and a heater. The A/F sensor is disposed downstream of a purification device in a flow of exhaust gas g. The purification device purifies the exhaust gas g. The solid electrolyte body is in a cup shape. The solid electrolyte body has an outer surface provided with a measurement electrode 4 contacting the exhaust gas g, and an inner surface provided with a reference electrode contacting reference gas. The solid electrolyte body is made of zirconia. The solid electrolyte body includes a detection part sandwiched between the measurement electrode and the reference electrode and conducted with oxygen ions. The detection part has a cubic phase ratio of 88 mol % or more.