Testing device for detecting nitrogen oxide sensor performance and method

Abstract

The invention discloses a testing device for detecting nitrogen oxide sensor performance and method. The device comprises a voltage source 1, a voltage source 2, a temperature control unit, a data acquisition card, a solid state relay, a nitrogen oxide sensor, a digital ammeter, a serial port photoelectric Isolation module and an industrial computer. The real-time current signal of the entire heating circuit and the real-time voltage signal across two ends of a thermistor are collected, a real-time thermistor value is solved, and the real-time temperature value of the sensor is finally obtained. In view of the real-time current signal of the heating circuit and the real-time voltage signal across two ends of the thermistor, as a large amount of interference signals and noise signals are mixed in the signal, filtering is firstly carried out through an RC filter module, and then, through a comprehensive algorithm of median filter, dithering elimination filter, moving average filter and translation invariant wavelet denoising, noise elimination is carried out. The device and the method disclosed in the invention have the characteristics of convenient testing method, high measurement precision, strong anti-interference ability and long-term accurate and stable operation.

Description

technical field [0001] The invention belongs to the field of sensor performance testing, in particular to a testing device and method for testing the performance of a nitrogen oxide sensor. Background technique [0002] A gas sensor is a device that senses the type and concentration of an external gas through an internal active substance, and converts it into a physical quantity such as light and electricity that can be measured by instruments and computers through a converter. Gas sensors are mainly used to detect the concentration of various flammable, explosive, toxic, and harmful gases, so they are widely used in various fields such as fire protection, civil, and military industries. In recent years, with the continuous improvement and development of my country's road transportation network and the improvement of people's living standards, cars have gradually entered thousands of households. While bringing convenience to people, the environmental pollution caused by aut...

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Problems solved by technology

For the accuracy performance test of the NOx sensor, especially the test system that uses the step voltage method to measure the corresponding current at each voltage at a constant temperature of 750°C and finally obtains the sensor resistance to determine whether the sensor accuracy is qualified, there are almost no relevant patents involved

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