不同EGR闭环控制方式应用研究

姚旺，庞斌，张晨，杜飞飞，栾军山，牛鸿斌

潍柴动力股份有限公司，山东 潍坊  261001

摘要：基于不同废气再循环（exhaust gas recirculation，EGR）闭环控制方式的测量原理和控制策略，通过台架试验，对比稳态新鲜空气测量精度和瞬态排放，分析不同控制方式的控制精度及瞬态排放差异。结果表明：基于新鲜空气量和EGR率的2种闭环控制方式精度均较高，新鲜空气测量相对偏差分别小于±3%、±5%；基于废气氧浓度的闭环控制在低负荷区域的测量相对偏差最大达-10%；基于新鲜空气量的闭环控制在瞬态测试循环中EGR阀关闭速率快，NOx排放出现峰值；基于文丘里流量计的EGR率闭环控制可以有效兼顾新鲜空气和EGR废气流量，在满足柴油机动力性的同时有效控制排放污染物。

关键词：柴油机；EGR；EGR率；闭环控制

Study on the application of different EGR closed-loop control

YAO Wang, PANG Bin, ZHANG Chen, DU Feifei, LUAN Junshan, NIU Hongbin

Weichai Power Co., Ltd., Weifang 261001，China

Abstract：Based on the measurement principles and control strategies of different closed-loop control methods for exhaust gas recirculation (EGR), the steady-state fresh air measurement accuracy and transient emissions are compared by bench tests, and the control accuracy and transient emissions differences of different closed-loop control methods are analyzed. The results show that the two closed-loop control methods based on fresh air volume and EGR rate have high accuracy, and the relative deviation of fresh air measurement is less than ± 3% and ± 5%, respectively. The maximum relative deviation of measurement in low load based on closed-loop control of exhaust gas oxygen concentration is -10%. The closed-loop control based on fresh air volume had a fast closing rate of the EGR valve and a peak in NOx emissions during transient testing cycles. The closed-loop control of EGR rate based on Venturi flowmeter can effectively balance the flow of fresh air and EGR exhaust gas, which meets the power requirements of diesel engines and effectively controlls emission pollutants.

Keywords:diesel engine; EGR; EGR rate; closed-loop control