关键词: 重型柴油机；台架试验；颗粒物数量；细小颗粒物；稀释比

Abstract: Based on the methods of engine test bench, the emission of PN10 (particulate number above 10 nm) and PN23 (particulate number above 23 nm) for a heavy-duty diesel engine that meet the China VI emission standards in the steady state working conditions and the CHINA VI standard cycle tests were simultaneously measured, and the effect of dilution ratio on the measurement results was analyzed. The results show that the emission amount of particles is highly dependent on the carbon accumulation state of the pretreatment, and the change of the dilution ratio will change the distribution of the particle size. Within the initial of the cold start WHTC cycle, the proportion of 10 nm～23 nm fine particles was at the highest level at the beginning of the cycle, because the mixture of fuel and air combustion is insufficient, the emission of PN at first 150 s contributes more than 80% of the entire test. In the WHSC steady cycle test, PN10 and PN23 have basically the same trends under different cycle, and the emission of PN at the the full load corresponding the most economical operating region is small, and deviations from this speed will lead to an increase in PN.

Key words: Heavy-duty diesel engine; Engine test bench; Particulate number; Fine particles; Dilution ratio