Design Of The Performance Detecting System Of Universal Exhaust Gas Oxygen Sensor

With the increasing emphasis on environmental protection,people put forward stricter requirements on vehicle exhaust emissions,promoting the rapid development of lean-burn technology in the field of automobile engines.Traditional oxygen sensor due to its structural characteristics,can not meet the request of high emission standards in lean-burn engine,replaced by Universal Exhaust Gas Oxygen(UEGO)sensor,which can offer a higher control precision and a wider test range and has made up the shortcomings of traditional oxygen sensor,so that the oxygen sensor can provide accurate air-fuel ratio feedback signals under different concentrations of the mixture to ECU.Due to the pump circuit and the temperature of UEGO sensor must be controlled,an appropriate electronic controller is needed for UEGO.The thesis is to design a detecting system with a good match and temperature stability,integrating control and test,which can be used for batch testing the quality of UEGO sensors for sensor manufacturers.The performance detecting system basing on Bosch LSU4.9 sensor designed in this paper,including hardware circuit,software and PC display section.The hardware circuit is made up of an interface control module,power supply module,microcontroller module,heating control module and communication module.And based on the hardware circuit,the main program of control system and PC display program with C language as well as LabVIEW has completed,realizing the control and detect function of the system.In this paper,the value of the detecting system is brought by the summary of the related research on UEGO sensor performance test system at home and abroad firstly.And then,making a deep study about Bosch LSU4.9 sensor's structure,working principle,microcontroller and the integrated interface circuit module CJ125.On the basis of the above work,designed the hardware circuit of the system,given a detailed analysis of the circuit functions of each module,verified the correctness of the circuit through detecting the PCB board,then designed the system software program,achieving acquisition and display of the sensor signal.Finally,the detecting system has been used for products check on engine test bench.The test results show that the system can collect and display the signals from UEGO in real-time,the performance of the tested sensor can be presented correctly at the same time,thereby indicating that the detecting system is feasible.