重型天然气发动机氧传感器控制系统研究

Research on Oxygen Sensor Control System for Heavy-duty Natural Gas Engine

为了提升重型天然气发动机空燃比控制精度,本文基于模型控制方法,从氧传感器的工作原理出发,构建了基于氧传感器的自适应空燃比测量及控制系统模型,通过自适应控制及瞬态补偿策略,实现全工况空燃比精确闭环控制,λ控制精度提升20%,实现更佳的排放控制水平,在WHTC循环排放测试中,主要排放污染物均实现明显降低,NO_(x)降低23%,CH_(4)排放降低40%。

In order to improve the accuracy of the air-fuel ratio of the heavy-duty natural gas engine,based on the model control method the principal of oxygen sensor,this paper is constructed a control system model and a measurement of an adaptive air-fuel ratio.Through adaptive control and transient compensation strategy,the engine can realize an accurate closed-loop control of air-fuel ratio in all working condition.In the WHTC cycle emission test,if the accuracy ofλincreased 20%,NO_(x) is reduced 23%,CH_(4) is reduced 40%.The main emission pollutants are significant reduced.The emission of the engine can achieve a higher level.