非道路柴油机台架非循环排放(OCE)试验方法研究与实践

Research and Practice on Off-Cycle Emission(OCE)Bench Test Method of Non-Road Diesel Engine

按照UNECE Regulation No.49、UNECE Regulation No.96关于重型车用柴油机和非道路移动机械用柴油机排放型式核准的台架试验要求,除了分别进行标准循环试验之外,还需分别进行WNTE试验、控制区试验[又称为非循环排放(off-cycle emission)试验。介绍非道路柴油机控制区试验方法并将之与重型车用柴油机WNTE试验方法进行异同比较的基础上,选用两台排放分别达到非道路国三和国四阶段要求的柴油机,在标准循环试验以外,各自进行控制区试验。主要试验结果为:国三柴油机(NOx+HC)排放,控制区9个试验点中有3个点超过标准循环限值两倍,而国四柴油机控制区各点NOx排放在标准循环限值两倍以内;对于CO、PM等污染物,两台发动机控制区各点试验结果在标准循环限值以内。相比于直接在整个控制区随机选择3个点,参考WNTE试验网格选点的方法进行操作会在不影响效率的前提下使所选择的点更具有代表性。

In the light of bench test requirement of HDV（Heavy-duty vehicle） diesel engine and NRMM（Non-road mobile machinery） diesel engine emission type approval by UNECE Regulation No. 49 and UNECE Regulation No. 96, WNTE test and control area test is respectively necessary in addition to standard cycle test, which is also called OCE（Off-Cycle Emission） test. In this article, the first work is the introduction of NRMM control area test method and the comparison between it and HDV WNTE test method. Then, two diesel engines, the emission level of which respectively meets the standard of CN 3 and CN 4, are chosen to be subjected to standard cycle test and control area test. The main test result is as follows： For the（NOx＋HC） pollutant of CN 3 diesel engine, the emission results of 3 in all 9 test points in control area exceed twice of the emission limit of standard cycle. However, NOxemission of each point in control area of CN 4 diesel engine is inside twice of the emission limit of standard cycle. For PM, CO,etc., all the results of control area test are inside the emission limit of standard cycle. In comparison to selecting 3 points randomly and directly in the whole control area, the method of selecting points after generating grids by WNTE method can improve the representativeness of test points, which has little impact on the efficiency by contrast.