| Abstract:Based on the engine test bench， the load characteristics and full load speed characteristics tests were performed to study the effects of the integrated aftertreatment diesel oxidation catalyst（DOC）+catalyzed diesel particulate filter（CDPF）+selective catalytic reduction（SCR） system on the performance and emissions of agricultural diesel engine. The results show that the integrated aftertreatment system has no obvious effect on the engine economy and power performance under the test conditions. DOC plays a key role in hydrocarbon（HC） and carbon monoxide（CO） emissions， and the average reduction is more than 80%. The conversion efficiency increases with the increase of load. The upstream DOC+CDPF has little influence on NOx emission while the NO2/NOx ratio is changed， which is conducive to passive regeneration and SCR NOx conversion. DOC+CDPF reduces particulate matter（PM） and particulate number（PN） emissions by more than 95%， and changes the particle size distribution， resulting in the percentage increase of nuclear particles and the decrease of accumulation particles. SCR reduces NOx emissions by 90%， and the ammonia leakage keeps below 20×10-6. Compared with the original engine， after equipping with DOC+CDPF+SCR， the CO、HC、NOx、PN and PM emissions of the engine are significantly reduced. Under all test conditions， the emissions are below the limits of non-road China—Ⅳ regulation except 10% load. |