Nucleation Mode Particles with a Nonvolatile Core in the Exhaust of a Heavy Duty Diesel Vehicle

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• 作者：Topi RÖ ; nkkÖ ; Annele Virtanen ; Jonna Kannosto ; Jorma Keskinen ; Maija Lappi ; Liisa Pirjola
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：September 15, 2007
• 年：2007
• 卷：41
• 期：18
• 页码：6384 - 6389
• 全文大小：218K
• 年卷期：v.41,no.18(September 15, 2007)
• ISSN：1520-5851

文摘

The characteristics of the nucleation mode particles of aEuro IV heavy-duty diesel vehicle exhaust were studied. TheNO_x and PM emissions of the vehicle were controlledthrough the use of cooled EGR and high-pressure fuelinjection techniques; no exhaust gas after-treatment wasused. Particle measurements were performed in vehiclelaboratory and on road. Nucleation mode dominated theparticle number size distribution in all the tested drivingconditions. According to the on-road measurements,the nucleation mode was already formed after 0.7 s residencetime in the atmosphere and no significant changes wereobserved for longer residence times. The nucleation modewas insensitive to the fuel sulfur content, dilution airtemperature, and relative humidity. An increase in thedilution ratio decreased the size of the nucleation modeparticles. This behavior was observed to be linked to the totalhydrocarbon concentration in the diluted sample. Involatility measurements, the nucleation mode particleswere observed to have a nonvolatile core with volatilespecies condensed on it. The results indicate thatthe nucleation mode particles have a nonvolatile coreformed before the dilution process. The core particles havegrown because of the condensation of semivolatilematerial, mainly hydrocarbons, during the dilution.