Ceramic chip of NOx sensor

Abstract

The invention discloses a ceramic chip of a NOx sensor. An oxygen pump anode covered with a protective layer on the surface is arranged on a first-layer membrane, an acquisition cavity is formed on the oxygen pump anode and the first-layer membrane, second to fourth through holes are formed in a second-layer membrane, a first diffusion barrier is formed in the second through hole and divides the second through hole into a first measurement chamber and a buffer cavity, a main oxygen pump cathode is arranged in the first measurement chamber, a second diffusion barrier is arranged between the second through hole and a third through hole, the third through hole is a second measurement chamber, an auxiliary pump cathode is arranged in the second measurement chamber, a third diffusion barrier isarranged between the third through hole and the fourth through hole, the fourth through hole is a third measurement chamber, a measurement electrode covered with a protective layer on the surface isarranged in the third measurement chamber, a reference channel is formed in a third-layer membrane, a reference electrode covered with a protective layer on the surface is arranged in the reference channel, a heating electrode wrapped in a heating electrode insulating layer is arranged between the fourth-layer membrane and a fifth-layer membrane, an outer lead of the heating electrode penetrates through the fifth-layer membrane to be located on the lower surface of the fifth-layer membrane, and a stress release hole filled with heating electrode insulating layer slurry is formed in the fifth-layer membrane.

Description

technical field [0001] The invention belongs to the technical field of measurement or testing, and in particular relates to a nitrogen oxide sensor ceramic chip. Background technique [0002] In recent years, with the increasing number of automobiles in my country, automobile exhaust has become one of the main sources of air pollution. The harmful components in the exhaust gas are mainly carbon monoxide (CO), incompletely combusted hydrocarbons (HC), nitrogen oxides (NO X ) and particulate matter, etc. The discharge of these pollutants has caused serious threats to human health and the living environment. In response to this situation, the country has formulated increasingly strict regulations to control exhaust emissions. The National V emission standard was also implemented nationwide on July 1, 2017. Compared with the National IV standard, NO X The emission limit of the new model was changed from 3.5g / kwh to 2g / kwh, a drop of 42.9%. In order to achieve lower NO X For ...

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Problems solved by technology

The traditional nitrogen oxide sensor ceramic chip usually has a stress relief hole at the head of the heating electrode, which communicates with the reference channel. However, the Al on the heating electrode and its surface 2 o 3 During the high temperature and cooling process of the insulating layer, a small amount of gas or water vapor will be released and enter the reference channel through the stress relief hole, so that the composition of the reference gas will change. The two measurements characterized by the Nernst potential Room O 2 The concentration is not accurate

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