| 摘要 |
PURPOSE:To detect the concentration of oxygen in a gas to be measured with a low oxygen concentration at a high accuracy by measuring a voltage to be outputted corresponding to the concentration of oxygen in a gas to be measured with a fixed current flowing through a sensor element which is brought into contact with the gas being measured after it is formed on the surface of an element body made of an oxygen ion transmitting solid electrolyte. CONSTITUTION:A flange 16 is mounted to an exhaust tube of an internal combustion engine for an automobile and a voltage is applied from outside to generate heat from a heat generating body 10 so that an element S is heated to a operating temperature, for example, 700 deg.C. A gas to be measured flowing through an exhaust tube gets in contact with the elements S passing through a vent 14 of a protective cover 15. A fixed current flows through the element S through lead wires 12 and 12. A voltage change which takes place in the element S is introduced outside through the lead wires 12 and 12 and measured with a voltometer thereby enabling a highly accurate detection of oxygen concentration in the gas being measured. Applicable gas to be measured must be low in the oxygen concentration area, specially 5% or less and preferably below 3%. |
