共查询到18条相似文献,搜索用时 162 毫秒
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柴油机微粒排放控制是当前汽车排放污染控制领域中的研究热点。使用微粒捕捉器是净化柴油机排气微粒的有效方法,但微粒捕捉器的再生是一个世界上尚水很好解决的问题。逆向喷气再生适合中国的国情,有望解决微粒捕捉器的再生问题。本文分析了这一再生方法的关键技术,如压缩空气的消耗问题、逆向喷气再生过滤体的型式与选择、系统的优化和再生控制的改进等。 相似文献
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《内燃机学报》2017,(6)
运用AVL-FIRE软件建立柴油机微粒捕集器(DPF)三维模型,模拟柴油机微粒捕集器内部压降和微粒沉积特性.针对DPF不同排气流量、进口温度、微粒沉积量及分布类型,对DPF压降特性进行模拟,并着重研究非对称孔结构(ACT)和灰分沉积量及分布形式对DPF压降和微粒沉积特性的影响.结果表明:随着DPF排气流量、进口温度、微粒沉积量和灰分沉积量的增加,DPF的压降增大,且DPF压降变化与进口温度呈非线性关系;沿DPF轴线方向,微粒沉积量呈先减小后增大趋势;"逐渐减少"型微粒分布形式压降损失较小,且再生速率较快.灰分在壁面上的层状分布对DPF压降和微粒沉积影响较大;非对称孔结构有利于降低DPF压降和提高微粒沉积能力,从而延长DPF寿命. 相似文献
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设计了一种柴油机排气加热装置.该装置的创新点在于从柴油机涡轮增压器取出新鲜二次空气供给燃烧器燃烧,加热排气.以BJ493ZQ3增压发动机为试验用发动机,将该装置加装在柴油机排气管尾端,应用于微粒捕集器喷油助燃再生中,对该装置应用的可行性进行了论证,对其加热能力进行了试验研究.试验表明,该排气加热装置能在发动机较大工况范围内快速加热排气到500℃以上,有效燃烧微粒使捕集器可靠再生,同时易于车载,较好解决了微粒捕集器热再生存在的问题. 相似文献
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A major concern in operating a diesel engine is how to reduce the soot emission from the exhaust gases, as soot has a negative effect on both human health and the environment. More stringent emission regulations make the diesel particulate filter (DPF) an indispensable after-treatment component to reduce diesel soot from exhaust gases. The most important issue in developing an effective DPF, however, is regeneration technology to oxidize the diesel soot trapped in the filter, either periodically or continuously, during regular engine operations. Various methods exist for regenerating diesel soot captured by the filter. Of these, NO2 is widely used for continuous regeneration of diesel soot since it can oxidize diesel soot at lower temperatures than the conventional oxidizer O2 In this work, after introducing governing equations for trapping and regenerating diesel soot in the DPF, regeneration behavior is examined by changing such various parameters as exhaust gas temperature and O2 concentration. Numerical investigation is then performed in order to find the optimum NO2/soot ratio required for continuous regeneration of the soot deposited in the DPF. 相似文献
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柴油机微粒捕集器再生技术的分析和研究 总被引:2,自引:0,他引:2
柴油机微粒捕集器技术是柴油机微粒排放控制的有效手段,其关键技术是过滤材料和再生方法。详细介绍了几种过滤材料和不同的再生技术,指出了各种技术的特点和主要问题。 相似文献
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Magín Lapuerta Fermín Oliva John R. Agudelo André L. Boehman 《Combustion and Flame》2012,159(2):844-853
An automotive diesel engine was tested in three representative modes of soot accumulation, active regeneration and spontaneous regeneration of its catalyzed diesel particulate filter (DPF), among the typical driving operation modes. During the engine tests, pressure and temperature along the DPF were measured, and soot samples were taken from the exhaust manifold upstream of the DPF for their thermal, structural and morphological characterization. The collected soot samples were subjected to: Transmission Electron Microscopy (TEM) for morphological analysis, thermal heating under oxidant atmosphere for studying the oxidation kinetics, Raman spectroscopy for describing their nanostructure and X-ray diffraction spectroscopy (XRD) for studying their internal lattice parameters. When the engine was operated in a typical accumulation mode, the pressure drop across the DPF increased up to 80 hPa with diesel fuel, while pressure drop stopped increasing after 4000 s of engine testing with biodiesel. In the regeneration mode, the DPF regenerated more slowly in the biodiesel case as a consequence of lower post-injected fuel energy and thus lower exhaust temperature. In the self-regenerating mode, the DPF was charged more slowly with biodiesel than with diesel fuel and its break even temperature was 40 °C lower with biodiesel fuel. These results provide further evidence that biodiesel soot is more reactive to oxidation. Although thermogravimetric results confirmed this tendency based on the differences on the pre-exponential factor, Raman spectra showed that biodiesel soot reached more ordered graphite-like structures and lower amorphous carbon concentration and XRD analysis showed that biodiesel soot displayed a higher degree of graphitization. The TEM analysis of the agglomerates showed that soot primary particles obtained with biodiesel fuel were significantly smaller and had higher specific active surface than those of diesel soot. From these results, an interpretation of the differences in soot oxidation between both soot samples was made based on the different length scales, from the carbon fringes to the particulate filter. 相似文献
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《Combustion and Flame》2003,132(1-2):157-169
Understanding the mechanisms that affect catalytic activity in porous ceramic diesel particulate filters (DPF) at the temperature range 200 to 400°C is important for the successful modeling of the initiation and evolution of catalytic regeneration by use of fuel additives. This refers not only to the dry carbon particulate, but also to the volatile hydrocarbons adsorbed on it. In this paper, a detailed analysis of the hydrocarbon adsorption-desorption and oxidation behavior of diesel particulate emitted by a modern diesel engine and collected on a SiC diesel filter is performed by use of thermogravimetric and differential scanning calorimetry analysis (TGA-DSC). Non-isothermal tests were performed with samples collected directly from a ceramic filter connected to the exhaust system of the diesel engine running under low and medium speed and load operating conditions with and without fuel additive. Fuel additive concentration was varied to investigate its effect on the soot oxidation behavior. Based on the TGA data, the kinetic parameters of the soot oxidation reaction were calculated. The effect of volatile adsorbed hydrocarbons on the soot oxidation reaction was evaluated by comparing the calculated activation energies for samples collected from the center and the periphery of the filter at various exhaust temperatures prevailing at filter loading phase. In particular it was seen that the catalytic activity of the fuel additive is enhanced by the presence of the volatile organic components. 相似文献
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Kazuhiro Yamamoto Shingo Satake Hiroshi Yamashita 《International Journal of Thermal Sciences》2009,48(2):303-307
Due to the public awareness with regard to harmful diesel emissions, more strict diesel emissions standards such as Euro V in 2008 are being set in the world. As one of the key technologies, a diesel particulate filter (DPF) has been developed to reduce particulate matters (PM) in the after-treatment of exhaust gas. Since the structure of the filter is small and complex, it is impossible to examine the phenomena inside the filter experimentally. In this study, we conducted fluid simulation in DPF. We used the lattice Boltzmann method (LBM). The microstructure of DPF was taken into account. The complex flow pattern appears by using the non-slip boundary condition on the filter wall surface. The soot accumulation was simulated to consider the PM trap in the diesel filter. Results show that the flow is largely changed due to soot deposition. As the soot concentration inside the filter is increased, the filter backpressure is increased. 相似文献
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DPF主动再生过程颗粒排放特性试验 总被引:1,自引:0,他引:1
通过柴油发动机台架,采用后喷助燃的再生方式研究了主动再生过程中柴油机颗粒捕集器(DPF)出口的颗粒排放特性.结果表明:在主动再生期间,DPF出口颗粒浓度可增加2~3个数量级;在升温过程和再生过程,出口颗粒物数量浓度和粒径分布会因为碳载量和再生温度的共同作用而表现出差异;升温过程中,10 nm左右核模态颗粒物的排放主要由来流中颗粒物的穿透引起;再生过程中,10 nm左右核模态颗粒物的排放主要由碳烟颗粒层氧化反应生成的二次颗粒逃逸引起;整个再生期间,100 nm左右的积聚态颗粒物的排放主要由DPF载体内碳烟颗粒的逃逸引起. 相似文献
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为研究不同海拔下柴油机颗粒过滤器(diesel particulate filter,DPF)碳烟加载规律及再生特性,在一台高压共轨柴油机上分别在两种大气压力(80kPa和100kPa)下进行了试验研究。研究内容包括全球统一瞬态循环(world harmonized transient cycle,WHTC)排放测试、DPF碳烟加载及压降特性、DPF再生过程温度场及压降特性。结果表明:高原环境下DPF的排气温度和各项排放数据指标均高于平原环境。高原环境下压降损失随碳烟的累积呈现出先快速增加后缓慢增加的趋势。再生温度和海拔高度对DPF再生压降、载体再生峰值温度、载体再生径向和轴向温度梯度、再生时机均有影响;再生温度越高及海拔越低,DPF再生压降越高;再生温度及海拔越高,再生时载体的峰值温度越高且载体径向和轴向温度梯度越大。 相似文献