Development Of Multi-Channel Detection System Of The NO_x Sensor Ceramic Chip

As a core component of the vehicle selective catalytic reduction system,NOx sensor is used to detect the concentration of NOx on diesel vehicle exhaust gas between the different operating conditions,and detected NOx concentration signal feedback to the vehicle selective catalytic reduction system,it's used to control the urea sprayed on the exhaust gas and reduce air pollution.The NOx sensor ceramic chip as the core component of the NOx sensor.Due to its chip design on structure,the chip manufacturing process is relatively complex.And the NOx sensor need working in the high temperature,as the different of ceramic chips production batches,unable to control the rate of qualified products,on the other hand because of its ceramic chip for mass production,before leave the factory the ceramic chip need accurately and quickly detection to keep its qualified rate and sensitivity,and ensure that the NOx sensor is stability and reliability.In this paper,we design a detection system which can accurately,quickly and simultaneously to detect the large quantities of ceramic chips.First of all,this paper through its principle of operation and measurement to introduce the structure and material characteristics of NOx sensor ceramic chip,it can provide theoretical support for the development of the detection system and the analysis and induction of the chip data.Secondly described the multi-channel NOx sensor ceramic chip in detail,including the system testing process planning,the role of testing equipment components in the system and the upper computer needs to complete the function in the system testing process,and design of the ceramic chip detection equipment,summed up the problems in the design process.Then design the hardware and software of the system,completed the design of NOx sensor hardware circuit such as the signal acquisition circuit,the heating control circuit and the pump oxygen control circuit,and the bus design of the detection system.in software design such as set up the communication protocol of the system,completed the upper computer program design,including verification of the send instruction and receive data,the underlying hardware and interface programming were completed.Finally,the statistical data of the qualified chips in the air atmosphere and the unqualified chip data was analyzed in detail.Multi-channel NOx sensor ceramic chip detection system developed successfully,realized a ceramic chip accurate,quickly and massive detection.The integrated design of the detection system simplifies the operation of the detection chip.During the testing process,the experimental data were judged second by second to improve the eligibility criteria of the chip,and the strict quality control was carried out before the NOx sensor was put into the market.