基于广域氧传感器的λ分析仪设计

摘要

A design work for λ analyzer is carried out,which uses STM32f407 as core processor and universal exhaust gas oxygen( UEGO)sensor as sensitive component,measuring theory of UEGO sensor is described,and theoretical formular of limiting current and air-fuel ratio is deduced. Hardware circuits such as signal detecting and processing circuit working temperature control of sensor,and LCD are designed,hardware circuit of λ analyzer is designed. Combined deduced formula with hardware circuit,software driving program is compiled. In order to optimize the performance of the temperature control,and air to fuel ratio more accurate,PlD control algorithm is introduced into the process of sensor operating temperature control.%以广域氧( UEGO)传感器为敏感元件,STM32f407为核心处理器,开展了一种λ分析仪的设计.详细介绍了UEGO传感器测量原理,推导了UEGO传感器的极限电流对空燃比的理论公式.设计了传感器信号检测与处理、工作温度控制、LCD显示等硬件电路,完成了λ分析仪的硬件设计.结合推导公式和硬件电路编写相应的软件驱动程序,传感器工作温度控制过程中引入PlD控制算法,使得温度控制性能得到了优化,空燃比值更加精确.