中文版 English
HOME >  technology > 

 

 

 

 

 

 

 

technology

At high temperatures > 650 oC, stabilized zirconium dioxide (ZrO2) exhibits two mechanisms: (a) ZrO2 partly dissociates producing mobile oxygen ions and therefore becomes a solid electrolyte for oxygen, and (b) ZrO2 behaves like an electrolyte. If two different oxygen pressures exist on either side of a piece of ZrO2, a voltage (Nernst voltage) is generated across it. Two different ion concentrations on either side of an electrolyte generate an electrical potential known as the Nernst Voltage. This voltage is proportional to the natural logarithm of the ratio of the two different ion concentrations. Today’s automobile oxygen sensor is based on the Nernst principle. As noted, all the sensors are heated over 650 oC during operation in order to improve the sensor sensitivity.

 

In the automobile applications, oxygen sensors are constructed so that a thin layer of the stabilized zirconium is exposed to exhaust gas on one side and air as a reference on the other side. The voltage generated across the zirconium layer is feed into the automobile electronic control system to regulate the air/fuel ratio.

 

There are two types of oxygen sensors on the market. The traditional one is called a conical type, and the new one is called planar type. The market is surely shifting to the planar sensors due to its shorter cold startup time, thus reducing the emission further, and being better suitable for mass productions.

 

A typical cross section of a planar oxygen sensor (sensor element only) is shown below:

 

CONTACT

    Nanao Tech Limited
    Bld 2, 600 21th Street
    HEDA, Hangzhou
    China 310018


    QQ:  2368018531
    Skype:  alice298
    Phone:  +86 571 8838 1236
    Email:  sales@nanaotech.net