School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing, 100084, PR China.
School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing, 100084, PR China; Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA.
Environ Pollut. 2019 Oct;253:731-740. doi: 10.1016/j.envpol.2019.07.045. Epub 2019 Jul 12.
The government of China has announced an ambitious plan to expand the mandatory use of ethanol blended gasoline fuels by 2020. Given the dissimilarity in fuel properties between China and other countries with ethanol blending practices, it is necessary to assess the energy and environmental impacts of ethanol blending. In this study, we prepared two types of ethanol blended fuels (E10, with ethanol contents of approximately 10%) with lower contents of aromatics (ELA) and olefins (ELO), respectively, compared with the market China 5 gasoline. Nine in-use gasoline vehicles varying by manufacturer, engine technology, model year, and emission standard level were analyzed using a chassis dynamometer, which followed the Worldwide Harmonized Light Vehicles Test Cycle (WLTC). Two major positive effects from using E10 fuels could be observed in this study. First, tested turbocharged gasoline direct injection (GDI) vehicles could gain reductions in CO emission, fuel consumption and energy consumption by switching to the higher-octane-number ELO. This finding, along with the engine development trends in the automotive industry (e.g., downsizing and higher compression ratio), may have a synergistic effect to deliver greater energy efficiency in the future. Second, the two ethanol blended fuels could be more effective in reducing the particle mass (PM) and particle number (PN) emissions than the levels of using China 5 gasoline. Notably, the benefit of using ELO was more significant, with average emission reductions of 35% for the PM and of 44% for the PN. However, ELA and ELO possibly increased emissions of gaseous pollutants for certain vehicles in the study, but the intra-vehicle differences between the various fuel groups were not statistically significant (not significant, p > 0.05, t-test). We suggest that more measurements under various environmental conditions and comprehensive air quality simulations should be conducted to better understand the environmental impacts of ethanol blending in China.
中国政府宣布了一项雄心勃勃的计划，即在 2020 年前扩大乙醇混合汽油燃料的强制使用范围。考虑到中国与其他有乙醇混合实践的国家之间燃料特性的差异，有必要评估乙醇混合的能源和环境影响。在这项研究中，我们分别制备了两种类型的乙醇混合燃料（E10，乙醇含量约为 10%），与市场上的中国 5 号汽油相比，芳烃（ELA）和烯烃（ELO）的含量较低。使用底盘测功机分析了来自 9 家制造商、发动机技术、车型年份和排放标准的在用汽油车，底盘测功机遵循全球轻型车辆测试循环（WLTC）。本研究观察到使用 E10 燃料的两个主要积极影响。首先，测试的涡轮增压汽油直喷（GDI）车辆可以通过切换到更高辛烷值的 ELO 来减少 CO 排放、燃料消耗和能量消耗。这一发现，以及汽车行业的发动机发展趋势（例如，缩小尺寸和提高压缩比），可能会在未来产生协同效应，从而提高能源效率。其次，与使用中国 5 号汽油相比，两种乙醇混合燃料在减少颗粒质量（PM）和颗粒数量（PN）排放方面更为有效。值得注意的是，使用 ELO 的好处更为显著，PM 排放量平均减少 35%，PN 排放量平均减少 44%。然而，ELA 和 ELO 可能会增加研究中某些车辆的气态污染物排放，但各燃料组之间的车内差异在统计学上并不显著（不显著，p > 0.05，t 检验）。我们建议在各种环境条件下进行更多测量，并进行综合空气质量模拟，以更好地了解乙醇混合在中国的环境影响。
