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This study investigates the effect of traffic volume and speed data on the simulation of vehicle emissions and hotspot analysis. Data from a microwave radar and video cameras were first used directly for emission modelling. They were then used as input to a traffic simulation model whereby vehicle drive cycles were extracted to estimate emissions. To reach this objective, hourly traffic data were collected from three periods including morning peak (6–9 am), midday (11–2 pm), and afternoon peak (3–6 pm) on a weekday (June 23, 2016) along a high-volume corridor in Toronto, Canada. Traffic volumes were detected by a single radar and two video cameras operated by the Southern Ontario Centre for Atmospheric Aerosol Research. Traffic volume and composition derived from the radar had lower accuracy than the video camera data and the radar performance varied by lane exhibiting poorer performance in the remote lanes. Radar speeds collected at a single point on the corridor had higher variability than simulated traffic speeds, and average speeds were closer after model calibration. Traffic emissions of nitrogen oxides (NOx) and particulate matter (PM10 and PM2.5) were estimated using radar data as well as using simulated traffic based on various speed aggregation methods. Our results illustrate the range of emission estimates (NOx: 4.0–27.0 g; PM10: 0.3–4.8 g; PM2.5: 0.2–1.3 g) for the corridor. The estimates based on radar speeds were at least three times lower than emissions derived from simulated vehicle trajectories. Finally, the PM10 and PM2.5 near-road concentrations derived from emissions based on simulated speeds were two or three times higher than concentrations based on emissions derived using radar data. Our findings are relevant for project-level emission inventories and PM hot-spot analysis; caution must be exercised when using raw radar data for emission modeling purposes. 相似文献
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近年来,随着人们对环境保护的日趋重视,世界各国对内燃机废气排放的要求变得越来越严格,轻型柴油车开始实施国Iv标准。目前由于机内排放控制并不能完全起到净化效果,因此对已排出燃烧室但尚未排到大气中的废气进行处理,采取机外控制技术显得很有必要。PM和NOx是柴油机主要排放污染物,如何同时降低这两种尾气组成,达到国Ⅳ排放水平,是当今世界柴油机技术的难点和研究热点。本文介绍目前国内满足柴油机国IV排放标准的SCR和EGRDPF/DOC两种主流技术路线。通过对比分析两种系统的原理和优缺点得出适合国内发展的路线,并浅谈未来柴油机排放控制的发展方向。 相似文献
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H. -M. Kim S. -K. Park K. -S. Choi H. -M. Wang D. -H. Lee D. -K. Lee Y. -S. Cha J. -S. Lee J. Lee 《International Journal of Automotive Technology》2008,9(2):149-153
An important goal in diesel engine research is the development of a means to reduce the emissions of nitrogen oxides (NOx).
The use of a cooled exhaust gas recirculation (EGR) system is one of the most effective techniques currently available for
reducing nitrogen oxides. Since PM (Particulate Matter) fouling reduces the efficiency of an EGR cooler, a tradeoff exists
between the amount of NOx and PM emissions, especially at high engine loads. In the present study, we performed engine dynamometer
experiments and numerical analyses to investigate how the internal shape of an EGR cooler affects the heat exchanger efficiency.
Heat exchanger efficiencies were examined for plain and spiral EGR coolers. The temperature and pressure distributions inside
these EGR coolers were obtained in three dimensions using the numerical package program FLUENT. 相似文献
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通过调研国内外文献,介绍了柴油机颗粒物污染现状、颗粒物后处理技术、壁流式颗粒捕集器(DPF)的工作原理、材料和结构类型、捕集器再生技术和控制策略等。堇青石陶瓷壁流式DPF具有成本和性能方面的优势,占据主要市场份额,再生技术是DPF应用的关键。与主动再生技术相比,被动再生具有结构简单、节约油耗等优势,可通过涂敷催化剂、前置DOC和辅助主动再生等方法确保再生效果。 相似文献
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在总结柴油机微粒排放的生成机理的基础上,分析了影响柴油机微粒生成的各种因素。通过对柴油机微粒各种净化方式的比较,总结指出了柴油机微粒处理的发展趋势。 相似文献
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北京、上海、杭州3个城市的人口规模、城市功能、发展阶段不尽相同,交通结构和交通政策各有差异,但数据反映的交通对PM2.5的贡献度相当,背后原因值得探究。从PM2.5源解析结构和交通自身影响两个环节入手,对其内部机理和原因进行深入分析。就源解析结构而言,三城市在区域输送、本地源排放中的能源结构和产业结构等均有较大差异。就交通自身影响而言,北京、杭州过境道路交通影响较大,而上海的交通污染贡献还包括远洋船舶。因此,三城市机动车对PM2.5的贡献度存在差异,建议北京PM2.5的治理关注区域、燃煤和过境车辆要素,上海关注工业、船舶污染,杭州关注工业、燃煤、扬尘等影响。 相似文献