汽车排放物中NOx、HC和CO的预测模型研究

为更深入细致的研究汽车有害排放物的排放规律,提出了用以计算机仿真计算的柴油机排放物的数学模型。该预测模型是以现象学燃烧模型为基础的,NOx的数学模型用广义Zeldoich不平衡原理建立,HC和CO的数学模型采用化学平衡和反应动力学原理建立。用该模型计算了某型号柴油机的排放物,得到了这3种排放物在缸内的生成过程,并从它们的生成机理出发,分析了不同喷油定时对排放规律的影响,讨论了推迟喷油措施对降低排放物的效果。实机实验结果表明计算值与测量值吻合较好,并且都反映出相同的规律:NOx和CO的生成量随喷油提前角的增大而增大,而HC排放量随喷油提前角的增大而减少。

Study of Prediction Models of NOx , HC and CO in Vehicle Emissions

To improve study capability of the emission laws,prediction models of diesel engine emissions were presented to be used in computer simulation.The models were based on the phenomenological combustion model.The mathematical model of NOx was created using Zeldowich disequilibrium theory,and chemical equilibrium and kinetics of reactions were used in the models of HC and CO.Some type of diesel engine emissions were calculated with these new models to get the production process in cylinder,the affection of different ejecting time to the emission laws were analyzed based on the production mechanism,and the effects of fuel ejection delay were discussed.The testing result shows that the calculating data agree with the testing data except errors,and reports the same law: NOx and CO emission productions increase with earlier fuel ejection,while HC emission decreases with earlier fuel ejection.