Air/fuel-ratio detecting apparatus

摘要

An air/fuel-ratio detecting apparatus includes a compact layer arranged on the outer surface of a solid electrolyte layer to externally conceal a gas diffusion layer, solid electrolyte layer, outer measuring electrode, and reference electrode to restrain entry of exhaust gas. A gas introduction window is formed in the compact layer to have a predetermined width. The gas introduction window allows entry of exhaust gas toward the gas diffusion layer and the outer measuring electrode in the range of an opening width of the gas introduction window.