牵引车载荷对NOx排放和排温影响的试验研究

在五轴动力总成试验台架上对牵引车在不同载荷下进行同一路谱的排放试验,研究牵引车在不同载荷下NOx排放和排温的变化,得到载荷与排放物和选择性催化还原(selective catalytic reduction,SCR)上游排温的变化关系。结果表明:载荷为标定载荷的60%以下时,NOx比排放值与载荷基本呈线性相关;载荷超过标定载荷的75%时,NOx比排放值与载荷呈二次项相关;载荷在为标定载荷的23%以上时,NOx比排放值与SCR上游排温基本呈线性相关。利用该试验结论可以通过只进行单一载荷排放试验,判断车辆在其他载荷下的排放水平是否满足国家标准要求,并可通过载荷对排温的影响规律预判排放水平。

Experimental study on the influence of tractor load on NO_x emission and exhaust temperature

The emission test of the tractor under different load,the same path spectrum is carried out on the five-axis powertrain test bench,the changes of the NOx emission and exhaust temperature are studied,and the relationship between the load and emission and the upstream exhaust temperature of selective catalytic reduction(SCR)is obtained.It could be found that when load is less than 60%of the normal load,NOx emission show linear relationship with load;and when load is more than 75%of the normal load,NOx show a quadratic relationship with load.On the other hand,when load is above 23%of the normal load,NOx emission show linear relationship with the upstream temperature of the SCR system.Based on these conclusions,it is possible to evaluate the vehicle emission for different load by single testing,and the emission level can be predicted by the influence of load on exhaust temperature.