进气条件对不同柴油机NOx排放影响的试验

Experimental Study on the Effect of Intake Conditions on NOx Emissions of Different Diesel Engines

在发动机台架上,使用不同后处理系统的发动机进行了ESC、WHSC和WHTC等不同循环工况的排放试验,研究了进气温度和进气湿度等因素对发动机NOx排放的影响规律。研究结果表明,无论是WHSC还是热态WHTC循环工况,随着进气湿度的增加,催化剂前NOx排放略有降低,经过NOx修正系数的调整后,修正后的催化剂前NOx排放基本保持不变。国六柴油机催化剂后的NOx排放随着进气湿度和进气温度的增加而有逐渐降低的趋势,但是幅度很小。国六柴油机的后处理系统形成闭环控制,SCR对NOx的转化效率高,进气湿度对催化剂后NOx排放的影响较小。

The effects of intake temperature and humidity on NOx emission were studied in different cycle conditions,such as ESC,WHSC and WHTC,on the engine bench.The results show that the NOx emission before the catalyst decreases slightly with the increase of inlet humidity in both WHSC and hot WHTC cycles.Adjusting by the NOx correction coefficient,the NOx emission before the catalyst basically remains unchanged after the correction.With the increase of inlet humidity and inlet temperature,NOx emissions after the catalyst of ChinaⅥdiesel engine has a tendency to gradually reduce,but the amplitude is small.The aftertreatment system of ChinaⅥdiesel engine form a closed loop control,while the SCR system has a high efficiency conversion on NOx emission.Thus,the inlet humidity has a less effect on the NOx emission after the catalyst.