中文摘要：

为了使非道路用柴油机达到GB 20891 -2014《非道路移动机械用柴油机排气污染物排放限值及测量方 法（中国第三、四阶段）》中第四阶段排放限值的要求,按照稳态循环（ NRSC）和瞬态循环（ NRTC）规定的工况, 对一台非道路用自然吸气柴油机进行测试研究.引入分担率的概念,分析NRSC试验时柴油机各工况下CO、 NOx、 HC排放对整机排放的影响;研究NRTC试验时冷启动循环和热启动循环排放特性的差异和CO、 NOx、 HC的瞬时排放曲线.结果表明： NRSC试验下,污染物在2 400 r/min下1 0 0 %负荷时排放分担率均超过 18%,是控制污染物的关键工况;NRTC试验下,相对于NRTC试验热启动循环,冷启动循环的颗粒物（ PM）、 CO 比排放量分别为 0.25 g/（kW·h）和 3.36 g/（kW· h ）,高于热启动循环的 0.23 g/（kW· h ）和 2.28 g/（kW·h ）, 而 NOx＋HC的比排放量为6.67 g/（kW· h ）,略低于热启动循环的6.88 g/（kW· h ）.CO瞬时排放峰值基本对 应转矩峰值、转矩谷值及转速峰值;NOx瞬时排放峰值基本对应转矩峰值;H C的瞬时排放相对CO、 NOx变化 更平稳.该研究可为降低非道路用柴油机稳态和瞬态排放提供参考.

英文摘要：

To meet the requirements of the fourth stage emission regulations of G B 20891 - 2 0 1 4 Limits and Measurement Methods for Exhaust Pollutants from Non-road Diesel Engines of Mobile Machinery （ CHINA Ⅲ,Ⅳ ）,an experimental research was carried out to explore a non-road naturally aspirated diesel engine by Non-Road Steady Cycle（ N R S C ） and Non-Road Transient Cycle （ NRTC ）. The concept of contribution ration was introduced to analyze the effects of C O 、 N O % and HC emissions at each condition of total emissions under the N R S C test. T he differences of the emission characteristics of the NRTC tests between the cold start cycle and the warm start cycle were studied. At the same time, the instantaneous emission curves of CO 、 N O x and H C under the N R T C tests were analyzed. Under the N R S C test, it is found that the key factor to reduce gaseous pollutants is to control the emissions under full load at 2 400 r/ m i n because contribution ration are all over 18% . The test results under the N R T C tests showed that, N O x ＋ HC , particulate matter （PM ） and CO brake specific emissions of the cold start cycle were 6.67 g / （kW ·h ） , 0.25 g / （k W ·h ） ,3.36 g/（ kW · h ） respectively, NOx ＋ HC , PM and C O brake specific emissions of the warm start cycle were 6.88 g/（ kW ·h ）,0.23 g/（ kW ·h ）,2.28 g/ （ kW -h ） respectively. Compared with the warm start cycle, the PM and CO brake specific emissions of the cold start cycle were higher,while the N 〇x ＋HC brake specific emissions were lower. The instantaneous emissions peak of C O mainly occurred in torque trough,torque peak and speed peak. T he instantaneous emissions peak of N O X was corresponding to the torque peak. T he instantaneous emissions of H C were more stable than that of CO and NOx . The study is useful for reducing steady-state and transient emission levels of n on-road diesel engines.