基于离子电流的缸内异常燃烧诊断

In-cylinder Abnormal Combustion Detection Using Ion Current

在一台涡轮增压PFI发动机上安装火花塞式离子电流传感器,在不同燃烧状况下对比离子电流信号与缸压信号及燃烧特征值的关系。当发动机转速不变,随着负荷的增加,离子电流信号积分值和平均指示有效压力均呈现增加的趋势;通过分析离子电流波形,能分别识别由火花塞未发生点火或喷油器未喷油或混合气过稀造成的失火循环。进一步试验还发现离子电流信号能够提前识别早燃循环。

The ion current signal is collected and compared with the cylinder pressure signal and other combustion characteristics in different combustion conditions on a turbo charged PFI engine, integrated with a spark plug type ion current signal sensor. As the engine load increases with the same engine speed, both ion current signal integral value and IMEP increase. The ion current signal can detect the misfire cycles and distinguish from different misfire cycles caused by ignition-free of the spark plug and injection-free of the injector or over-lean air fuel mixture. Further test also identifies that ion current signal can detect the pre-ignition cycles in advance.