Nitrogen-oxygen sensor ceramic core

Abstract

The invention provides a nitrogen-oxygen sensor ceramic core. The nitrogen-oxygen sensor ceramic core is characterized in that a heating electrode is arranged on an upper surface of a first substrate,and the heating electrode is wrapped in a heating electrode insulating layer; an upper surface of a second substrate is provided with a reference electrode and a pressure relief hole, a third substrate is provided with a reference gas channel, and an upper surface of the third substrate is sequentially provided with a lower pump electrode of a first-stage pump electrode, a lower pump electrode ofa second-stage pump electrode and a measuring electrode; five cavities are sequentially formed on a fourth substrate, barrier layers are arranged among the cavities, upper pump electrodes of the first-stage pump electrode and the second-stage pump electrode are sequentially arranged on a lower surface of a fifth substrate, and a common electrode is arranged on an upper surface of the fifth substrate; an upper pump electrode and a lower pump electrode of the first-stage pump electrode of a third cavity are connected through a semi-through hole of the fourth substrate to form the first-stage pump electrode; an upper pump electrode and a lower pump electrode of the second-stage pump electrode of a fourth cavity are connected through a semi-through hole of the fourth substrate to form the second-stage pump electrode. The nitrogen-oxygen sensor ceramic core is advantaged in that measurement electrode pollution caused by volatilization of precious metal gold in the second-stage pump electrode is avoided, measurement precision is high, and the sensitivity is good.

Description

technical field [0001] The invention relates to the technical field of automobile exhaust gas detection sensor cores, in particular to a ceramic core for nitrogen and oxygen sensors. Background technique [0002] The nitrogen and oxygen sensor is a very important sensor in automobiles, which is used to detect the concentration of NOx in automobile exhaust emissions. The standards and regulations introduced by countries around the world are becoming more and more stringent to address the environmental pollution caused by vehicle exhaust emissions. This sensor, based on a ceramic sensing element, measures the NOx concentration in vehicle exhaust and sends an input signal to the engine electronic control unit (ECU) for the most efficient control of the engine's combustion process and exhaust aftertreatment. In diesel locomotives, this is achieved by injecting ammonia into the Selective Catalytic Reduction (SCR) system; in gasoline engines, it is achieved by controlling the reg...

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Problems solved by technology

The secondary pump electrode and the measuring electrode are in the same chamber. Since the secondary pump electrode contains gold, a metal material that has almost no catalytic activity for nitrogen monoxide, the melting point of gold is 1064 ° C, and the solid electrolyte ZrO 2 When the material is used to make sensor chips, the sintering temperature is as high as 1400-1500°C. The volatilization of gold during the sintering process will pollute the measuring electrodes, greatly reducing the performance of the measuring electrodes and seriously affecting the performance of the NOx sensor.

In addition, a small amount of oxygen generated by the decomposition of NO by the measuring electrode will diffuse to the secondary pump electrode through the porous protective layer, thereby increasing the pump current of the secondary pump electrode, thereby affecting the measurement accuracy of NOx

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