离子电流检测系统的抗干扰设计

Anti-interference Design of Ionization Current Detection System

发动机复杂的工作环境必然对利用离子电流检测技术实现发动机的燃烧状况进行实时监测造成干扰.为此对整个离子电流检测系统进行了抗干扰优化设计.在一台SI-HCCI(spark ignition-homogeneous charge compression ignition)发动机上进行试验研究,试验结果表明,高压隔离模块很好地保护了采集系统;电容点火隔离方法可以减少信号中的背景干扰;电容检测法无法准确反映发动机的爆震现象;采用软件消除零点漂移的方法取得了很好的效果;采用了优化后的离子电流检测系统,HCCI离子电流的信噪比显著提高.

The complex engine operation environment will result in interference while utilizing ion current detection technique to achieve real-timing monitoring of the combustion consequentially. Anti-interference design of the detection system was optimized. An experiment was done on a spark ignition-homogeneous charge compression ignition （SI-HCCI） engine. Results show that high-voltage isolation module can protect collection system well; using capacitance to isolate ignition can reduce the interference from background; capacitance detection method cannot reflect accurately when knock phenomenon happens. Eliminating zero drift with a software achieves good effect. With the optimized ion current detection system, the ratio of signal to noise of ion current increases significantly in HCCI combustion.