The current study investigates the influence of hot and cold start on the emissions of a non-road diesel engine with an after-treatment system. The emissions were studied by experimental measurements on an engine during non-road transient operating conditions. These results indicate that the emissions of cold start are much higher than that of the hot start. The conversion efficiency of particular matter (PM) is only 33%, which is 31% lower than that of the hot start. Besides, the conversion efficiency of PM is weak under the cold start, and high exhaust flow, and the phenomenon of blow-off is prone to happen. The conversion efficiencies of NOx, HC, and CO are 86%, 79% and 63%, respectively, which differs from the hot-start conversion efficiency by 10%–16%. And their differences are mainly reflected in the early stage (0–600 s). Overall, the exhaust temperature and flow are important factors that affect the conversion efficiency of the after-treatment system, and the specific process was discussed in this paper. These provide enlightenment/direction for the emission reduction of non-road diesel engines.

目前的研究调查了热启动和冷启动对带有后处理系统的非道路柴油发动机排放的影响。排放是通过在非道路瞬态运行条件下对发动机进行的实验测量来研究的。这些结果表明，冷启动的排放量远高于热启动的排放量。特殊物质（PM）的转化效率仅为33%，比热启动低31%。此外，冷启动下PM的转化效率较弱，排气流量大，容易出现吹脱现象。NOx、HC、CO的转化效率分别为86%、79%和63%，与热启动转化效率相差10%~16%。它们的差异主要体现在早期（0-600 s）。全面的，排气温度和流量是影响后处理系统转化效率的重要因素，本文讨论了具体过程。这些都为非道路柴油机的减排提供了启示/方向。