Separated heating wide-range oxygen sensor

Abstract

The invention discloses a separated heating wide-range oxygen sensor. The separated heating wide-range oxygen sensor comprises a sensor chip core; a heater surrounds the outer part of one end of the oxygen sensor chip core; the relative position between the heater and the sensor chip core is not changed and the heater and the sensor chip core are not in contact with each other; the sensor chip core comprises a Nernst battery, a pump battery and a detection cavity which are respectively arranged on different stacked zirconium oxide substrates. The pump battery, a closed detection cavity and theNernst battery are combined, oxygen in the cavity cannot escape or diffuse through a closed cavity, the Nernst voltage detection precision is higher, and the threshold value is wide. Due to the design of the external heater, the difficulty of a manufacturing process is reduced, leakage current is completely eradicated, the measurement precision is improved, heating is uniform, consistency of allpositions is high, generation of thermal stress is reduced, and reliability is enhanced. A diffusion barrier is not needed, and the process is simple; no diffusion barrier material is needed, the material types are few, co-firing matching is good, and the yield is high. The structure is simple, the number of laminated layers is small, weight is reduced, vibration resistance is enhanced, and overall reliability is enhanced.

Description

technical field [0001] The invention relates to a separated heating high-precision wide-area sensor. Background technique [0002] The wide-area oxygen sensor has been widely used in the automotive industry. It is an important part of the automotive engine fuel feedback control system and plays a very important role in the air-fuel ratio control. There are two representative wide-area oxygen sensors. One is BOSCH's LSU4.2 / LSU4.9 oxygen sensor, which consists of a heater, a pump battery, a Nernst battery, a diffusion barrier, and a reference gas channel. Composition; the other is the limiting current oxygen sensor of DENSO, which is composed of a heater, a pump battery, a diffusion barrier and a reference airway. These two wide-area oxygen sensors both adopt the open diffusion barrier current-limiting design and the reference gas channel design that are in direct contact with the gas to be measured. Measure gas oxygen concentration. [0003] But these two wide-area oxygen ...

AI Technical Summary

Problems solved by technology

In practical applications, the reference gas or current is easily polluted or disturbed, resulting in large measurement errors and insufficient accuracy;

[0005] 2. They all integrate a heater in the zirconia substrate. Although the insulation treatment is carried out, there is still a small amount of leakage current, which interferes with the output oxygen sensor signal, resulting in complicated process, low yield, and affecting oxygen measurement. precision

[0006] 3. Due to the low thermal conductivity of zirconia and the heater is on one side, there are certain differences in temperature everywhere, which also affects the accuracy of oxygen measurement and affects the reliability.

The consistency and quality of all these factors will lead to changes in the magnitude of the limit current, resulting in poor consistency and large errors

However, the control system of the sensor calibrates the oxygen concentration of the gas to be measured according to the magnitude of the limiting current, so the poor consistency of the limiting current leads to large errors and low accuracy in the calibrated oxygen concentration results.

In addition, it is difficult to control the sintering shrinkage consistency between the porous ceramic filler used in the small diffusion cavity and the zirconia substrate ceramic, resulting in many cracks between the small diffusion cavity and the ceramic, and a high failure rate

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