Aerosol Physics Laboratory, Department of Physics, Tampere University of Technology , P.O. Box 599, FIN-33720, Tampere, Finland.
Environ Sci Technol. 2013 Oct 15;47(20):11882-9. doi: 10.1021/es402354y. Epub 2013 Oct 2.
Diesel exhaust gaseous sulphuric acid (GSA) concentrations and particle size distributions, concentrations, and volatility were studied at four driving conditions with a heavy duty diesel engine equipped with oxidative exhaust after-treatment. Low sulfur fuel and lubricant oil were used in the study. The concentration of the exhaust GSA was observed to vary depending on the engine driving history and load. The GSA affected the volatile particle fraction at high engine loads; higher GSA mole fraction was followed by an increase in volatile nucleation particle concentration and size as well as increase of size of particles possessing nonvolatile core. The GSA did not affect the number of nonvolatile particles. At low and medium loads, the exhaust GSA concentration was low and any GSA driven changes in particle population were not observed. Results show that during the exhaust cooling and dilution processes, besides critical in volatile nucleation particle formation, GSA can change the characteristics of all nucleation mode particles. Results show the dual nature of the nucleation mode particles so that the nucleation mode can include simultaneously volatile and nonvolatile particles, and fulfill the previous results for the nucleation mode formation, especially related to the role of GSA in formation processes.
研究了装有氧化排气后处理的重型柴油机在四种驾驶条件下的柴油废气气态硫酸（GSA）浓度和粒径分布、浓度和挥发性。研究中使用了低硫燃料和润滑油。观察到废气 GSA 的浓度取决于发动机的驾驶历史和负荷。GSA 影响高发动机负荷下的挥发性颗粒分数；较高的 GSA 摩尔分数伴随着挥发性成核粒子浓度和尺寸的增加，以及具有非挥发性核的粒子尺寸的增加。GSA 不影响非挥发性颗粒的数量。在低负荷和中负荷下，废气 GSA 浓度较低，未观察到任何 GSA 驱动的颗粒群变化。结果表明，在排气冷却和稀释过程中，GSA 除了对挥发性成核粒子形成至关重要外，还可以改变所有成核模式粒子的特性。结果表明成核模式粒子的双重性质，使得成核模式可以同时包含挥发性和非挥发性粒子，并满足成核模式形成的先前结果，特别是与 GSA 在形成过程中的作用有关。
