天然气发动机EGR率计算方法研究

Research on EGR Rate Calculation Methods of NG Engine

废气再循环技术(EGR)是天然气(NG)发动机控制爆震的主要措施,EGR率的大小会影响天然气发动机对爆震的控制,EGR率的精确控制依赖于EGR率的精准标定和计算。天然气发动机电控系统通过测量空气、天然气和EGR流量计算EGR率;发动机台架试验中,通过测量进排气CO_(2)体积分数来计算EGR率。进行天然气发动机开发时,需要以台架EGR率为基准,对电控系统计算的EGR率进行精确标定。为了让2种计算方法准确匹配,进行了公式推导,并计算了相关的常用参数。

EGR is key method to control knock on the natural gas engine,accurate knock control is influenced by accurate EGR rate control,and EGR rate must be calculated and calibrated accurately to control accurate EGR rate.EGR rate is calculated based on flow rate of air,flow rate of NG and flow rate of EGR on the natural gas engine.For calibrate EGR rate of the engine,CO_(2) concentration is measured on the bench to calculate EGR rate as a standard of engine calibration.EGR rate calculation methods is derivation to match two calculation methods,and relevant constants of EGR rate were calculated.