测量条件对柴油机排放PM尺寸分布的影响

研究了不同测量条件对柴油机PM尺寸与浓度分布测量的影响,在一台单缸柴油机上用SMPS测量装置测量了不同运转条件下柴油机PM排放,试验中采用不同的稀释比、稀释空气温度、取样点位置等,在大量的试验研究基础上,分析了柴油机PM排放的特征和主要影响因素。结果表明,随稀释比增加,PM尺寸趋向于累积模式分布或粗粒子模式分布,其浓度趋于降低;随着稀释空气温度的升高,PM质量和数量也相应降低,低负荷时PM峰值浓度移向细小颗粒的碳核模式区域;取样点位置远离排气出口,PM浓度逐渐减小,累积模式尺寸的PM数增多。

The Influence of Measurement Conditions on Exhaust Particle Size Distribution of Direct Injection Diesel Engine

The effects of different measurement conditions on the number and volume concentration distribution of diesel exhaust particle were studied in this paper.Diesel exhaust particle measured used SMPS under the different operating conditions were measured in a single-cylinder diesel engine for the different dilution ratios,dilution air temperature and the position of the sampling.The characteristics and effects of exhaust particle of diesel engine were analyzed based on a lot of experiment data.The results were shown that the size distribution of diesel aerosol tended to accumulation or coarse mode and the mass concentration of diesel aerosol decreased with the increasing of dilution ratios.Increasing the dilution air temperature resulted in significant decreases in mass and number concentrations.Measured the peak value of number weighted size distribution fit well to ultra-fine nuclei mode at lower load condition.The more far from tailpipe exit for the sampling pipe,the smaller the mass and number concentration of diesel particles and the higher number weighted size distribution in accumulation mode.