柴油机排气微粒捕捉器燃气再生技术的研究

提出了一种新的柴油机排气微粒捕捉器的加热再生技术 ,即利用燃气与排气中的氧气燃烧清除微粒捕捉器中沉积的微粒 ;根据液化石油气的物化特性和排气中的含氧量 ,对这种方法的可行性进行了理论分析和试验验证 ;研制了一种以液化石油气为再生燃料的柴油机排气微粒捕捉器 ,并对燃气流量、过滤体内的微粒沉积量以及再生时间等影响因素进行了台架试验研究。     

柴油机微粒捕捉器主动再生特性的计算与分析

对柴油机排气微粒捕捉器（DPF）的主动再生特性进行了研究,建立了DPF主动再生数学模型,具体分析了柴油机转速、排气中的氧气浓度、DPF的微粒沉积量、微粒的活化能以及柴油机排气温度等参数对DPF主动再生特性的影响。结果表明,通过适当推迟柴油机喷油提前角以提高其排气温度,并辅以燃油加剂或利用催化剂降低微粒的活化能,在适当的条件下,进行DPF的主动再生是可行的。     

柴油机微粒捕捉器逆向喷气再生的关键技术

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。     

柴油车微粒捕捉器再生控制策略

对柴油车微粒捕捉器的各种再生控制方法进行了比较分析 ,并对背压控制方法进行了试验研究。利用背压模拟装置替代微粒捕捉器 ,研究了排气背压对 YC6 10 8柴油机的动力性、燃油经济性、排放和排温等参数的影响 ,在此基础上讨论了微粒捕捉器定背压再生控制方法的可行性及控制限值。首次提出利用排气温度对背压控制方法进行修正 ,以保证捕捉器在正确的时机进行再生     

柴油车微粒捕捉器逆向喷气再生的关键技术

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未很好解决的问题。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。     

柴油机DPF流场压降及微粒沉积特性数值模拟

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.     

柴油机微粒捕捉器的研究现状及发展趋势

随着排收法规的日益严格,柴油机排气后处理技术越来越受到重视,分析柴油机微粒排放控制技术所面临的挑战,综述微粒捕捉器在过滤材料和再重现从大关键技术的研究现状和存在的问题,并浅析微粒捕捉器技术的发展趋势。     

柴油机微粒捕集器流通性与微粒加载特性数值模拟

使用AVL-Fire软件建立柴油机微粒捕集器(DPF)三维计算模型,模拟DPF内的压降损失、深层微粒沉积、滤饼层微粒沉积和总微粒沉积特性.研究不同的排气流量、排气温度、初始灰分、灰分分布和微粒分布对DPF流通性与微粒加载特性的影响.结果表明:在微粒加载过程中(考虑微粒再生的影响),DPF压降主要由壁面压降损失、微粒深层...     

一种柴油机排气微粒喷油助燃再生装置设计与试验研究

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.     

车用柴油机微粒捕捉器的系统模拟

提出了一个车用柴油机微粒捕捉器（DPF）的系统模拟数学模型。利用数学模型可以对DPF在汽车实际运行过程中的性能,包括DPF再生的时间间隔,排气阻力特性以及DPF的使用对汽车附加能量的消耗等随汽车实际运行工况的变化进行分析研究,为汽车DPF的优化设计提供参考数据,并可以对DPF实际使用中的一些性能进行预测。     

NO2-Assisted Soot Regeneration Behavior in a Diesel Particulate Filter with Heavy-Duty Diesel Exhaust Gases

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.     

柴油机微粒捕集器再生技术的分析和研究

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。     

Effect of fuel on the soot nanostructure and consequences on loading and regeneration of diesel particulate filters

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.     

Thermogravimetric analysis of soot emitted by a modern diesel engine run on catalyst-doped fuel

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.     

柴油机新型排气微粒捕集技术的研究

研究了一种新型的柴油机排气微粒捕集器——燃媒剂再生微粒捕集器。通过大量的柴油机台架试验．分析了该微粒捕集器对CA6DL1-28柴油机的动力性、燃油经济性以及排放性能的影响,并结合大量的实验数据分析了微粒捕集器的强制再生过程。实验结果表明,该微粒捕集器具有同类其他产品无法比拟的良好特性,同时也为该方法对国产发动机的适应性提供了依据。     

Microstructure and particle-laden flow in diesel particulate filter

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.     

DPF主动再生过程颗粒排放特性试验

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.     

不同海拔下柴油机颗粒过滤器碳烟加载及再生特性研究

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。