12机动车.pptVIP

第十一章 Emission control of Internal Combustion Engines 主要内容 1. 城市交通趋势及影响 2. Spark Ignition Engines 3. Compressed Ignition Engines 4.. Advanced technology 了解城市交通发展的趋势，机动车问题的由来 掌握汽油发动机、柴油发动机工作原理、污染物来源、控制技术 了解新型机动车的思路、发展状况和面临的问题 Section 1 城市交通趋势及影响 世界机动车增长趋势 城市机动车污染现状 随着经济的快速发展，我国汽车保有量连年高速增长 汽车单车排放因子高 机动车污染物排放总量大，城市机动车污染分担率高 严重影响城市大气环境质量 中国机动车保有量增长情况 近10年来，全国机动车保有量迅速增加，平均增长速度约14% 重点大城市保有量增长更快，北京市92年以来平均增长速度超过20% 机动车收入弹性系数研究表明：收入增长1%，机动车保有量增长1.02—1.94% 我国经济发展水平决定城市机动车保有量将会在一定时期内保持迅速增加 中国机动车保有量增长情况 中美机动车排放因子比较 北京市机动车排放污染分担率 汽车污染物产生来源 Section 2 Spark Ignition Engines 汽车动力系统 Theoretical Combustion EngineCylinder Actual Combustion Lead Hydrocarbons Carbon Monoxide Oxides of Nitrogen Carbon Dioxide Particulates Other pollutants Water Vapor Stoichiometry等当点 汽油车 Other Emissions 城市机动车污染控制 曲轴箱 HC 的 20% 排气管 所有的CO、NOX、Pb和 HC的 60% 油箱和化油器蒸发 HC的15% Fuel + Oxygen Carbon Dioxide Energy动力 Ignition点火 Water Vapor ηet 汽油车: 0.25~0.3 柴油车: 0.3~0.45 ε=6~10，而柴油机ε=16~24 ε= (Vc+Vd)/Vc Ambient Air Real Fuel Engine/Emission Technology 尾气管排放物 汽油(C8H18)理论空燃比: 约14.7 CO: 局部不均匀 残余HC HC: 不完全燃烧 壁面淬灭 油膜吸附 NOx: Thermal Prompt NO Fuel NO Evaporative Emissions diurnal, running losses, hot soak Crankcase Losses due to blow-by Refueling Losses displaced vapors Other Emissions brake linings, tire wear, fluid leaks This paper is designed to provide an overview of the commonly used strategies available to control mobile source air pollution. These strategies have been implemented in the United States and many other places in the world. Thus, there is a history of experience with these programs that can inform planners looking for ways to control air pollution from mobile sources. The focus here is on in-use control of highway mobile sources, rather than lawn and garden equipment, marine engines, locomotives, agricultural and construction equipment. While these latter categories are important, the focus for these vehicles, at least at this time in the United States, is on ne