基于宽域氧传感器的发动机空燃比测试系统设计

Design of engine air-fuel ratio test system based on universal exhaust gas oxygen sensor

为了实现发动机电子控制系统对空燃比的精确反馈控制和方便对发动机进行诊断等用途,在熟悉宽域氧传感器工作原理的基础上,设计了空燃比采集显示系统和PC监控系统。并对测试系统的输出电压和混合气的过量空气系数的对应关系进行了试验标定,最后在发动机试验台架上该测试系统进行了试验验证。结果表明该系统灵敏度高、响应时间短(100ms),采集数据显示直观,可用于发动机空燃比闭环控制和车载自动诊断系统(OBD)等的开发。

For realizing the accurate feedback control of engine electronic control system on air-fuel ratio and facilitating the diagnosis of engine an air-fuel ratio acquisition-display system and a PC monitor system were developed based on the working principle of universal exhaust gas oxygen（UEGO）sensor.The corresponding relationship between the output voltage and the air-fuel ratio in the system was calibrated.The test systems were also validated on the engine testing bench.The results showed that the systems had high sensitivity and fast response time（100 ms）.Meanwhile,the designed systems could show the testing data directly.Those two systems were proposed to be used in the development of engine closed loop air-fuel ratio control and on-board diagnostics（OBD）system.