Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California , Riverside, California 92521, United States.
Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT) , Riverside, California 92507, United States.
Environ Sci Technol. 2017 Feb 7;51(3):1580-1586. doi: 10.1021/acs.est.6b03908. Epub 2017 Jan 24.
The use of biodiesel and renewable diesel fuels in compression ignition engines and aftertreatment technologies may affect vehicle exhaust emissions. In this study two 2012 light-duty vehicles equipped with direct injection diesel engines, diesel oxidation catalyst (DOC), diesel particulate filter (DPF), and selective catalytic reduction (SCR) were tested on a chassis dynamometer. One vehicle was tested over the Federal Test Procedure (FTP) cycle on seven biodiesel and renewable diesel fuel blends. Both vehicles were exercised over double Environmental Protection Agency (EPA) Highway fuel economy test (HWFET) cycles on ultralow sulfur diesel (ULSD) and a soy-based biodiesel blend to investigate the aerosol hygroscopicity during the regeneration of the DPF. Overall, the apparent hygroscopicity of emissions during nonregeneration events is consistently low (κ < 0.1) for all fuels over the FTP cycle. Aerosol emitted during filter regeneration is significantly more CCN active and hygroscopic; average κ values range from 0.242 to 0.439 and are as high as 0.843. Regardless of fuel, the current classification of "fresh" tailpipe emissions as nonhygroscopic remains true during nonregeneration operation. However, aftertreatment technologies such as DPF, will produce significantly more hygroscopic particles during regeneration. To our knowledge, this is the first study to show a significant enhancement of hygroscopic materials emitted during DPF regeneration of on-road diesel vehicles. As such, the contribution of regeneration emissions from a growing fleet of diesel vehicles will be important.
在压燃式发动机和后处理技术中使用生物柴油和可再生柴油燃料可能会影响车辆废气排放。在这项研究中，两辆配备直喷式柴油发动机、柴油氧化催化剂（DOC）、柴油颗粒过滤器（DPF）和选择性催化还原（SCR）的 2012 轻型车辆在底盘测功机上进行了测试。一辆车辆在联邦测试程序（FTP）循环上使用七种生物柴油和可再生柴油燃料混合物进行了测试。两辆车辆均在超低硫柴油（ULSD）和大豆基生物柴油混合物上进行了两次环境保护署（EPA）高速公路燃油经济性测试（HWFET）循环，以研究 DPF 再生过程中气溶胶的吸湿性。总体而言，在 FTP 循环期间，所有燃料在非再生事件期间排放的表观吸湿性始终较低（κ<0.1）。在过滤器再生期间排放的气溶胶明显更具 CCN 活性和吸湿性；平均κ值范围从 0.242 到 0.439，高达 0.843。无论使用哪种燃料，作为“新鲜”排气管排放的非吸湿性物质在非再生操作期间仍然是正确的。然而，像 DPF 这样的后处理技术，在再生过程中会产生明显更多的吸湿性颗粒。据我们所知，这是第一项表明在道路柴油车辆的 DPF 再生过程中排放的吸湿性物质显著增强的研究。因此，越来越多的柴油车辆的再生排放的贡献将是重要的。
