【作者】 孙龙；

【导师】 徐达； 李孟良；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2011， 硕士

【摘要】 随着汽车工业的快速发展,汽车的生产量和保有量急剧增加,燃油汽车的有害气体排放严重的危害着人类健康。截至2010年,重型汽车保有量仅占机动车保有量的5%,但排放的氮氧化物排放量占到总排放量的70%。重型发动机进行型式核准时,其测试循环与车辆实际运行工况差异较大,车辆在实际运行过程中排放远远高于认证时排放水平。应尽快开发和制定基于整车的重型车辆排放试验方法,以加强重型车实际道路运行排放的监控和管理,提高重型车辆排放监管的科学性和有效性,有效地控制城市的重型车排放量。本文借鉴国外重型汽车道路排放测试手段,结合我国便携式排放测试系统的应用现状,提出采用便携式排放测试系统对重型汽车进行排放测试,并设计了重型汽车整车排放测试方案。对8辆运行在北京地区的国IV在用公交车进行排放测试,收集车辆在实际道路运行条件下的排放数据和发动机负荷信息。分析了测试车辆的基本排放特征和基本工况特征,对比了车辆实际运行工况和ETC循环工况的差异。利用美国NTE法和功基窗口法对车辆排放水平进行了评估。结合我国重型车辆运行工况特征,修正了美国NTE法,并重新对重型车辆的排放进行了评估。本文意义在于为加强重型车实际道路运行下排放的监控和管理提供了依据。弥补了重型发动机认证试验测试工况不能完全反映车辆在实际运行过程中的工况的不足,更全面、更真实地反映了车辆排放水平。对提升重型车辆污染排放评价能力,提高重型车辆排放监管的科学性和有效性,有效控制城市重型车排放量,有着非常重要的意义。本文的研究成果表明：采用便携式排放测试系统对重型车辆进行排放测试,是一种获取重型车辆在实际道路运行条件下排放的有效测试手段,可以作为我国重型发动机在用符合性检查手段的一种补充。不同车辆在同一条公交路线上日常运营时,其运行工况的基本特征相似。车辆在怠速和低速工况运行时间较多,比例占到20%-35%；加速度主要分布在-1.5m/s2～1m/s2之间,加速度在-0.25m/s2～0.5m/s2的比例占到65%以上。发动机进行型式核准时所运行的台架ETC循环工况,其发动机运行区域主要集中在中等转速的整个扭矩范围内；而实际运行工况下,发动机运行区域分布在中、低转速下的整个扭矩范围内。ETC测试工况并不能完全反映车辆实际工况下的发动机运行区域。对两种评估方法的分析表明：我国重型车辆运行工况下的发动机负荷较低,落入NTE区域的工况点较少。美国NTE法不适合直接用于评估我国重型车辆的排放水平。对美国NTE法修正后,增加了监控的工况点,可以对我国重型车辆的排放进行有效评估。选择限值为6.0g/kWh时,采用修正后NTE法计算,有2辆车能够满足要求。采用功基法对重型车辆进行评估时,选择限值为2倍ETC限值为7.0g/kWh时,有3辆车可以满足要求。更多还原

【Abstract】 With the rapid development of automobile industry, car production and ownership increase sharply, and emissions from vehicles do seriously harm to human health. By 2010, heavy-duty vehicle population accounted for only 5% of vehicle population, but the emissions of nitrogen oxide accounted for 70% of total emissions. Heavy-duty engine type approval test cycle is quite different from the actual vehicle operating conditions, and the vehicle emissions from the actual operation are much higher than the certification emission levels. It is priority to develop and to establish heavy duty vehicle emission testing methods, so as to strengthen monitoring and management of heavy duty vehicle emissions when operated in real world, and to improve scientific and effective supervision of heavy duty vehicle emissions, finally to effectively control the emissions of the city’s heavy duty vehicles.Reference to foreign means of heavy duty vehicle emissions road testing, Portable Emission Measurement System is chosen to test heavy duty vehicle emissions, combined with application of Portable Emission Measurement System in our country, and heavy duty vehicle emissions testing program is designed.8 in-use buses, which comply with State IV emission standard, run and were tested in Beijing, and emission data and engine load information data from vehicles operated in the real world were collected. The vehicle emission characteristics and driving cycle conditions were analyzed, and the actual vehicle operating conditions and ETC cycle were compared. U.S. NTE method and Work-Based Window method were used to assess vehicle emission. Based on driving characteristics of heavy-duty vehicles in our country, U.S. NTE method was amended, and was used to evaluate heavy duty vehicles emission.The significance lies in providing the basis for the monitoring and management of heavy duty vehicles emissions operated in real world. And it makes up heavy-duty engine certification testing cycle that the cycle cannot fully reflect the actual operation of the vehicle in real world, and it can more comprehensive and truly reflects the level of vehicle emissions. It has great meaning for enhancing evaluation capacity, improving scientific and effective supervision, and effectively controlling the emissions of heavy duty vehicles in the city.The major conclusions of this research are summarized that Portable Emission Measurement System is an effective emission testing means to collect heavy duty vehicle emission data which is operated in real world, and it can be used as additional way to conduct In-Use Compliance of heavy-duty engine in China. As long as operated on the same bus route, different vehicles have similar basic cycle features. Vehicles mainly run at idle and low speed conditions, with the proportion accounts for from 20-35 percent; acceleration mainly between -1.5 m/s2 and 1 m/s2, where the proportion of acceleration between-0.25 m/s2 and 0.5 m/s2 accounts for 65 percent or more. In the ETC cycle, the engine is running mainly in the middle region of the speed range and whole torque range; while in the actual operating conditions, the engine is running in middle of and low speed range and whole torque range. ETC cycle does not reflect the engine operating area of the vehicle operated in real world.The two assessment methods showed that:heavy-duty vehicles in China get low engine load operating conditions, and little load points fall into the NTE region. U.S. NTE method is not suitable for being used to directly assess heavy duty vehicles emissions. U.S. NTE method is amended to increase the operating points, and it can be used to assess heavy duty vehicles emission effectively. When select 6.0g/kWh as the NTE limit value,2 cars comply with the requirements calculated by the amended NTE method. Work-Based Window method is used to assess heavy duty vehicle,, and 3 cars comply with the requirements when select the limit value as 7.0g/kWh, which is2 times the limit of ETC.更多还原