Development Of UEGO Sensor Controller

Automobiles are becoming more and more necessary for our daily life nowadays,and the rate of automobile ownership is rising year by year. At the same time,environmental pollution produced by automobiles is getting increasingly serious andfuel energy is decreasing gradually. Therefore, lean burn technology becomes moreand more widely used in automotive engines. Traditional EGO sensor cannot apply tolean burn engines, while UEGO sensor (Universal Exhaust Gas Oxygen Sensor),which can measure in wider range and more accurately, is becoming more and morepopular gradually. Because of its special working principle, UEGO sensor cannotoperate normally but equipped with particular controller.This project is a part of Hunan Science and Technology Planning Project“Development of UEGO Sensor for Automobiles”. In this thesis, a UEGO controller isdeveloped based on Bosch LSU4.2UEGO. Following is the main content of theresearch:1. The operating principles of UEGO sensor and its controller are introduced.Compared with traditional EGO and limiting current oxygen sensor, the advantages ofUEGO sensor is analyzed.2. The UEGO controller hardware is designed. MC9S12P128is used as masterchip and CJ125as core control module. MOSFET in heating circuit is controlled byPWM from MC9S128P128to control the temperature of UEGO. CAN is applied totransfer data between MC9S12P128and ECU. The+12V system voltage is convertedto voltage applied to UEGO controller by DC voltage regulator.3. The UEGO controller software is programmed with C language to control thetemperature of UEGO, caltulate lambda and data-transfer between MCU and ECU.Kalman filtering is applied to filter digital signals. Based on the typical feature ofUEGO temperature controlling, fuzzy PID control is applied to control thetemperature of UEGO.4. Static and dynamic calibration experiments of UEGO are conducted on theengine bench to correct and evaluate the working performance of UEGO controller.