Engines and exhaust after treatment systems for future automotive applications
Engines and exhaust after treatment systems for future automotive applications
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DOI：
10.1016/j.ssi.2006.05.051
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发表时间：
2006-10-31
影响因子：
3.2
通讯作者：
Schumann, Bemd
中科院分区：
文献类型：
--
作者：
Alkemade, Ulrich G.;Schumann, Bemd
未来汽车应用的发动机概念：安全、清洁和高效的发动机在现代社会中将变得更加重要，因为我们一方面将看到更高水平的机动性，另一方面也将看到有限的资源。用于乘用汽车的汽油发动机已经被开发以产生更多的功率并同时减少排放。由于柴油发动机的可靠性和效率，柴油发动机通常用于重型车辆，但近年来，由于其与涡轮增压器一起使用时的高扭矩，柴油发动机在乘用车汽车甚至运动车辆中变得越来越受欢迎。柴油发动机的发展，特别是直喷和共轨高压喷射的发展，带来了动力、效率和排放的进一步改善。未来将开发排气后处理系统，以符合与汽油发动机相似的排放标准。具有化学和物理传感器的排放控制系统：为了满足越来越严格的排放法规，汽油和柴油发动机将需要不断改进的排气后处理系统。各种应用的选择如下所述。今天，汽油发动机的废气通常用“三效催化剂”（TWC）处理。催化剂通过化学反应将污染物CO、NO（X）和碳氢化合物转化为无害的化合物，如CO（2）、H（2）O和N（2）。λ传感器控制发动机的空燃比和催化剂性能，以获得最佳的污染物转化率。现代稀燃发动机还有其他选择。在这里，废气中的污染物仅部分地通过TWC功能转化，即CO和烃。对于剩余的NO（X），采用所谓的NO（X）存储催化剂（NSC），其在稀燃阶段化学地存储NO和NO（2）。为了转化储存的NO（X），发动机周期性地转换到富燃料运行。这个更复杂的系统通过催化剂数学模型以及λ传感器、温度传感器和可选的NO（X）传感器进行控制。重型车辆的柴油发动机排气将通过选择性催化还原（SCR）用氨处理，以减少NO（X），同时催化氧化CO和碳氢化合物。氨在车辆上使用无害的前体（例如尿素）产生。为了控制该系统，采用了λ-、温度- NO（X）-和任选的NH（3）-传感器。除气体污染物外，柴油发动机排放的颗粒物将通过柴油颗粒过滤器（DPF）去除。氧化催化器和DPF系统由温度、压力和微粒传感器控制，这些亮点表明，汽油机和柴油机结合现代排气后处理系统可以满足安全、清洁和高效的三个目标。(c)2006 Elsevier B. V.保留所有权利。
Engine concepts for future automotive applications: Safe, clean and efficient engines will become more important in modem societies where we will see higher levels of mobility on one hand and limited resources on the other hand. Gasoline engines for passenger cars have been developed to generate more power and reduce emissions at the same time. Therefore the engine systems have become complex with a number of subsystems.Because of its reliability and efficiency the diesel engine is classically operated in heavy duty vehicles, however in recent years because of its high torque when used with a turbocharger it has become more popular for passenger cars and even sport vehicles as well. The development of the diesel engine especially the direct injection as well as the common rail high pressure injection brought further improvement regarding power, efficiency and emissions. In the future exhaust after treatment systems will be developed in order to comply with emission standards similar to those of gasoline engines. Emission control systems with chemical and physical sensors: In order to meet the more and more stringent emission regulations gasoline as well as diesel engines will need continuously improved exhaust after treatment systems. The options for the various applications are highlighted in the following.Today exhaust gas of gasoline engines is typically treated with "Three Way Catalysts" (TWC). The catalyst converts the pollutants CO, NO(X) and Hydrocarbons into harmless compounds like CO(2), H(2)O and N(2) by chemical reactions. Lambda-Sensors control the air fuel ratio of the engine and catalyst performance in order to get the best possible conversion of the pollutants.Modern lean burn engines have other options. Here the pollutants in the exhaust gases are only partially converted by a TWC function i.e. CO and Hydrocarbons. For the remaining NO(X) a so called NO(X) Storage Catalyst (NSC) is employed, which chemically stores NO and NO(2) during lean burn phase. For the conversion of stored NO(X) the engine is periodically shifted to fuel rich operation. This more complex system is controlled with the help of mathematical catalyst models and by Lambda-, Temperature- and optionally NO(X)-Sensors as well.Diesel engine exhaust of heavy duty vehicles will be treated with ammonia by Selective Catalytic Reduction (SCR) to reduce NO(X) additionally to the catalytic oxidation of CO and Hydrocarbons. The ammonia is generated on board of the vehicle using harmless precursors like for example urea. For the control of this system Lambda-, Temperature- NO(X)- and optionally NH(3)-Sensors are employed. In addition to gaseous pollutants the particulate emissions from diesel engines will be removed by Diesel Particulate Filters (DPF). The system of oxidation catalyst and DPF is controlled by Temperature-, Pressure- and Particulate-Sensors.The mentioned highlights show that all three goals safe, clean and efficient can be met in the future by both gasoline and diesel engines combined with modem exhaust after treatment systems. (c) 2006 Elsevier B.V. All rights reserved.