Department of Chemical Engineering and Applied Chemistry, University of Toronto , Toronto, Ontario M5S3E5 Canada.
Department of Mechanical and Industrial Engineering, University of Toronto , Toronto, Ontario M5S3G8 Canada.
Environ Sci Technol. 2016 Aug 2;50(15):8385-92. doi: 10.1021/acs.est.6b01800. Epub 2016 Jul 13.
Compared to port fuel injection (PFI) engine exhaust, gasoline direct injection (GDI) engine exhaust has higher emissions of black carbon (BC), a climate-warming pollutant. However, the relative increase in BC emissions and climate trade-offs of replacing PFI vehicles with more fuel efficient GDI vehicles remain uncertain. In this study, BC emissions from GDI and PFI vehicles were compiled and BC emissions scenarios were developed to evaluate the climate impact of GDI vehicles using global warming potential (GWP) and global temperature potential (GTP) metrics. From a 20 year time horizon GWP analysis, average fuel economy improvements ranging from 0.14 to 14% with GDI vehicles are required to offset BC-induced warming. For all but the lowest BC scenario, installing a gasoline particulate filter with an 80% BC removal efficiency and <1% fuel penalty is climate beneficial. From the GTP-based analysis, it was also determined that GDI vehicles are climate beneficial within <1-20 years; longer time horizons were associated with higher BC scenarios. The GDI BC emissions spanned 2 orders of magnitude and varied by ambient temperature, engine operation, and fuel composition. More work is needed to understand BC formation mechanisms in GDI engines to ensure that the climate impacts of this engine technology are minimal.
与进气道燃油喷射（PFI）发动机废气相比，汽油直喷（GDI）发动机废气中的黑碳（BC）排放量更高，而 BC 是一种加剧气候变暖的污染物。然而，用更省油的 GDI 车辆替代 PFI 车辆所带来的 BC 排放量增加和气候权衡仍不确定。在这项研究中，我们编译了 GDI 和 PFI 车辆的 BC 排放量，并制定了 BC 排放情景，以使用全球变暖潜势（GWP）和全球温度潜势（GTP）指标来评估 GDI 车辆的气候影响。从 20 年的时间范围来看，GWP 分析表明，需要 GDI 车辆的平均燃油经济性提高 0.14%至 14%，才能抵消因 BC 引起的变暖。对于除了 BC 最低情景之外的所有情景，安装汽油颗粒过滤器，其 BC 去除效率为 80%且燃料消耗降低<1%，都是有利于气候的。基于 GTP 的分析还表明，在 1-20 年内，GDI 车辆对气候是有利的；随着时间的推移，BC 情景越高，GDI 车辆的气候效益越低。GDI 的 BC 排放量跨越了两个数量级，并且随环境温度、发动机运行和燃料成分而变化。需要进一步研究以了解 GDI 发动机中 BC 的形成机制，以确保该发动机技术对气候的影响最小化。
