Both ultrafine particle and toxicity emissions originating from diesel engine gain an increasing concern. In this study, size distribution and toxicity of particles from a turbocharged common rail engine fueled with clean fuels-dimethyl ether (DME) and biodiesel blends-were investigated. Effects of different DME-biodiesel blends (B0, B5, B10, and B15) and different engine loads were considered. The results demonstrate that particles emitted from DME-biodiesel engine are mainly in form of nucleation mode. Engine running at intermediate load exhausts the maximum number of accumulation mode particles owing to local hypoxia and not high enough combustion temperature. The addition of biodiesel slightly increases the total particle number, peak of particle number concentration, and particle size corresponding to the peak. Effect of biodiesel proportion on particle size distribution gets weaker with the increase of engine load. Engine fueled with B5, B10, and B15 mainly exhausts low molecular weight polycyclic aromatic hydrocarbons (PAHs) (ring number ≤ 4) which are closely related to unburned fuel, and the total PAH emissions are linear versus the fuel consumption. Toxicity equivalent (TE) of particles at low load is lower than that at intermediate load. DME-biodiesel blends with biodiesel mass proportion ≤ 15% can release the DME engine from abrasion and leakage, but no obvious increase in both particle emissions and the risk of particle toxicity.

中文翻译：

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涡轮增压共轨二甲醚生物柴油发动机排放的颗粒物的成分和毒性。

源自柴油发动机的超细颗粒物和毒性排放物都受到越来越多的关注。在这项研究中，研究了用清洁燃料-二甲醚（DME）和生物柴油混合物为燃料的涡轮增压共轨发动机的颗粒尺寸分布和毒性。考虑了不同DME-生物柴油混合物（B0，B5，B10和B15）和不同发动机负荷的影响。结果表明，DME-生物柴油发动机排放的颗粒主要为成核模式。由于局部缺氧且燃烧温度不够高，在中等负载下运行的发动机会排放出最多数量的累积模式颗粒。添加生物柴油会略微增加总颗粒数，颗粒数浓度峰以及与该峰对应的粒径。随着发动机负荷的增加，生物柴油比例对粒度分布的影响变弱。使用B5，B10和B15燃料的发动机主要排放与未燃烧燃料密切相关的低分子量多环芳烃（PAH）（环数≤4），并且PAH的总排放与燃料消耗呈线性关系。低负荷下颗粒的毒性当量（TE）低于中负荷下的颗粒。生物柴油质量比例≤15％的DME-生物柴油混合物可将DME发动机从磨损和泄漏中释放出来，但颗粒排放和颗粒毒性风险均无明显增加。B15主要排放与未燃烧燃料密切相关的低分子量多环芳烃（PAHs）（环数≤4），并且PAH的总排放与燃料消耗呈线性关系。低负荷下颗粒的毒性当量（TE）低于中负荷下的颗粒。生物柴油质量比例≤15％的DME-生物柴油混合物可将DME发动机从磨损和泄漏中释放出来，但颗粒排放和颗粒毒性风险均无明显增加。B15主要排放与未燃燃料密切相关的低分子量多环芳烃（PAHs）（环数≤4），并且PAH的总排放与燃料消耗呈线性关系。低负荷下颗粒的毒性当量（TE）低于中负荷下的颗粒。生物柴油质量比例≤15％的DME-生物柴油混合物可将DME发动机从磨损和泄漏中释放出来，但颗粒排放和颗粒毒性风险均无明显增加。