微米木纤维发动机空气滤芯过滤机理与试验

介绍了微米木纤维过滤体材料及其过滤机理,分析了微米木纤维空气滤芯的特性.对微米木纤维空气滤清器在稳态和非稳态工况下的过滤效率和过滤阻力进行了数值模拟,并结合空气滤清器模拟试验台进行了试验研究.结果表明,数值模拟与试验结果吻合较好;微米木纤维发动机空气滤清器过滤效率高,过滤阻力小,可满足汽车行业和机械行业标准要求.     

不同工况下DPF对柴油车颗粒物过滤特性的研究EI北大核心CSCD

通过对比某轻型柴油车DPF前、后端颗粒物在NEDC测试循环的不同工况段上的数量浓度和质量浓度随粒径分布的差异,分析了DPF对不同粒径颗粒物在不同工况下的过滤效果。结果表明,在市郊高速急减速工况下,DPF对各粒径颗粒物(特别是粒径小于1μm的细颗粒)过滤效果较低,是该车辆运行NEDC循环时DPF综合过滤效率低下(只有52%)的原因。     

基于响应曲面法的DPF捕集性能多目标优化

以提高整体捕集性能为目的开展柴油机颗粒捕集器(DPF)结构参数多目标优化设计，利用GT-Power建立DPF捕集模型，通过发动机台架试验验证了仿真模型的可靠性。以最大压降和初始过滤效率为优化目标，以孔隙率、孔直径、壁厚、过滤体长度和直径5个结构参数为优化变量，基于Box-Behnken试验设计方法构建了DPF捕集性能二阶响应面模型，通过三维响应面图对结构参数显著性与交互作用进行仿真分析，采用满意度函数法进行多目标参数优化。结果表明，孔直径对最大压降的影响较小，较小的孔隙率与壁厚、较大的过滤体直径有利于降低DPF最大压降，而适当增大过滤体直径与壁厚可提升DPF初始捕集效率。协同优化后的DPF压降较优化前下降51.34%,优化后的DPF初始过滤效率趋近于100%。     

柴油车排气后处理装置性能试验研究

对氧化催化转化器(DOC)和柴油机颗粒过滤器(DPF)进行了性能试验研究.分析了DOC对柴油车排放的影响规律;对DPF的压降特性和过滤性能进行了试验.最后还讨论了DPF再生过程中的安全问题.     

温度对DPF过滤参数影响的试验研究

柴油机颗粒捕集器(DPF)过滤参数研究对其再生时机的判断具有重要意义。基于外加热源再生台架,研究了过滤参数(压降及其与常温数据的比值、渗透率及其与常温数据的比值)随过滤温度的变化规律,同时考虑了流量和孔隙结构参数变化时的影响。结果表明:过滤温度升高,DPF压降及其比值近似线性增长,渗透率及其比值近似线性减小;线性拟合了压降及其比值、渗透率及其比值随温度的变化曲线,比较发现流量和孔隙结构参数对DPF压降和渗透率都具有一定影响,但对比值的影响较小。     

车用柴油机微粒捕集器碳载量分布及影响因素研究

微粒捕集器(DPF)技术是满足未来车用柴油机严格排放法规的重要措施。文章首先介绍了DPF净化机理及其常用的过滤体材料,然后阐述了DPF压降和碳载量计算的数学模型,最后结合以往文献试验数据对模型参数修正,并对DPF碳烟捕集过程与影响因素进行了分析。为研究DPF的性能与管理提供有效的理论依据。     

DPF孔道结构参数优化设计

以降低流动阻力为目的开展DPF孔道结构参数优化设计,运用GT-Power建立DPF仿真模型,研究非对称孔道边长比、孔密度和过滤壁厚对颗粒物捕集过程中DPF压降和捕集效率的影响,并以非对称孔道边长比、孔密度和过滤壁厚为设计参数,二次序列规划算法为优化算法,DPF捕集效率为约束,优化DPF孔道结构参数。结果表明:DPF采用进口孔道边长大于出口孔道边长的非对称孔道结构可以降低颗粒物饼层捕集过程中DPF的压降,但同时降低了DPF的捕集效率;采用提高孔密度的方法可以在一定范围内降低DPF的压降,同时提高DPF的捕集效率;降低DPF过滤壁厚可以有效降低DPF压降,但也会降低DPF的捕集效率。综合优化结果,DPF进出口孔道边长比值为1.024 8、孔密度为62孔/cm~2、过滤壁厚为0.333 mm时,DPF压降降低26%以上,饼层捕集效率保持98%以上。     

DPF对柴油车颗粒物排放的影响研究

利用ELPI（电子低压冲击器）对加载DPF的柴油车分别在DPF前后和未安装DPF时进行取样,能有效研究颗粒物排放状况以及颗粒物数量浓度和质量浓度在粒径上的分布。研究发现,安装DPF后将增加车辆发动机排放的颗粒物数量和质量,但经过DPF过滤后,颗粒物质量和数量都会大幅减少,过滤效果良好。     

DPF对柴油车微粒物排放的影响研究

研究发现,安装DPF后将增加车辆发动机排放的微粒物数量和质量,但经过DPF过滤后,微粒物质量和数量都会大幅减少,过滤效果良好。     

基于Boost的柴油机微粒捕集器(DPF)性能分析

柴油机微粒排放控制技术已成为柴油机技术发展中的核心之一。文中探讨了微粒捕集器的捕集机理、过滤体材料特性以及再生技术。并利用AVL Boost软件建立模型,仿真分析了发动机的排气温度和柴油机微粒捕集器(Diesel Particulate Filter,DPF)的过滤孔密度对DPF的最高温度、排气背压和排气碳烟量的影响,提出了柴油机微粒捕集器设计优化的方法。     

Performance of radial-type metal foam diesel particulate filters

An analytical study of the performance of a radial-type, metal foam diesel particulate filter is reported. A mathematical model for the filtration and regeneration of soot in a metal foam filter was developed. Nickel foam was selected for the filter medium due to its large specific area, high porosity, and high thermal resistance. For various metal foams, the filtration efficiency and the pressure drop through the filter were calculated, as was the deposition of soot. The results from the analytical model were compared with experimental data. In comparison with a conventional wall flow filter, the metal foam diesel particulate filter (DPF) is effective in utilizing the volume of material, due to the porous structures. As the size of the metal foam pores in the DPF increases from 580 μm to 800 μm, the filtration efficiency decreases from 90% to 50%, and the pressure drop decreases from 380 mbar to 20 mbar. The metal foam DPF with a large pore size is effective in utilizing the volume of material with a small pressure drop. The regeneration is completed within four minutes by the flow of hot exhaust gases under full load conditions.     

Investigation of particle emission characteristics from a diesel engine with a diesel particulate filter for alternative fuels

Particle number measurement is a new approach to determine emission, which may be more accurate at very low emission levels than when using gravimetric measurements. An experimental study was performed to investigate the effect of fuel properties on the performance, combustion process, regulated gaseous emissions and particle number emissions of a diesel engine with an uncatalyzed diesel particulate filter (DPF). The effect of the filter on the particle size distribution was reported. The DPF number-based filtration efficiency in terms of number efficiency and fractional efficiency for petroleum diesel fuel and two alternative fuels, BTL and GTL, were analyzed. For nearly all test modes, the filter had a higher number efficiency for diesel than for BTL and GTL. The DPF fractional efficiency showed it was highly dependent on fuel type and varied widely at each size range. For diesel, the filter fractional efficiency was sufficiently high and behaved as predicted by filtration theory. For BTL and GTL, the fractional performance of the filter decreased when unexpectedly low efficiencies within the nuclei mode were exhibited. This research will be helpful in understanding DPF number-based filtration performance for alternative fuels and will provide information for the development of particulate emission control technology.     

面向控制的DPF再生效率建模和试验研究

对柴油机颗粒物捕集器(DPF)的再生效率进行实时和准确的在线预估,可为DPF热再生结束的控制提供判断依据,是实现DPF系统化和高效应用的重要功能。本文基于热再生过程中DPF内碳烟颗粒的氧化反应机理探讨并建立了DPF再生效率计算模型,通过发动机台架试验对模型的化学反应动力学参数进行了校核和辨识,从而得到DPF内碳烟颗粒热再生氧化反应的反应级数为α=1与活化能参数为E_a=107.5 kJ/mol。台架稳态工况和车辆在实际道路行驶工况的试验结果表明,再生效率模型最大计算误差为5.6%,较好满足实际应用需求,为DPF热再生中准确判断再生结束的时机提供了参考。     

影响柴油机微粒捕集器背压因素的试验研究

采用搭建的气道试验台和实车试验系统研究了影响发动机排气背压的因素,同时量化了部分发动机工况下流量、背压和温度随时间的变化关系,为再生时机的判断提供了有力的数据支持。     

Comparison of fuel efficiency and exhaust emissions between the aged and new DPF systems of Euro 5 diesel passenger car

This study was conducted to examine the impact of aged and new DPF systems of the Euro 5 diesel passenger car on fuel efficiency and exhaust emissions. Test diesel vehicle used in this study was equipped with diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) as aftertreatment systems, and satisfied the Euro-5 emissions standard. The displacement volume of engine was 1.6 L and the cumulative mileage was 167,068 km before the test. The FTP-75 test procedure was used, and the time resolved and weight based exhaust emissions of total hydrocarbon (THC), carbon monoxide (CO) and nitrogen oxides (NOx) were measured. The results show that the vehicle with the new DPF system has lower emissions of THC, CO and NOx than the aged one, and fuel efficiency also increased about 5 percent. The aged DPF system had higher backpressure due to the particulate matter (mostly in the form of ash) accumulated in the DPF. As was shown in the analysis using X-CT (X-ray computer tomography), the aged DPF system had particulate matter (PM) accumulated to a length of 46.6 mm. In addition, a component analysis of PM through XRF (X-ray fluorescence) analysis found that 50 % or more of the components consisted of the P, S, Ca, and Zn.     

一种基于神经网络的氧化催化器出口温度控制方法

氧化催化器(DOC)出口温度控制是实现颗粒捕集器(DPF)主动再生控制的关键。本文介绍一种基于神经网络的氧化催化器出口温度控制方法,首先结合DOC系统的实际特征以及DOC传热及化学反应特性建立了一阶延迟DOC出口温度模型,然后在温度模型基础上基于神经网络建立了DOC出口温度预测模型,最后将DOC出口温度预测值作为闭环反馈输入建立反馈控制器计算HC喷射量进而控制DOC出口温度。本方法采用整车试验中连续变化工况来验证,试验结果表明DOC出口温度在DPF再生过程中控制在600±20℃范围内,满足DPF精确再生控制要求。     

加载减速工况下带有DPF柴油车的颗粒物排放

基于加载减速工况,利用ELPI能够有效研究颗粒物排放状况以及其数目浓度和质量浓度在粒径上的分布,研究证实,这种测试技术具有很高的DPF性能鉴别能力。通过量化分析颗粒物在DPF前后粒径上的浓度分布以及图解DPF前后的浓度差值,可以非常清晰地发现该DPF对于不同粒径的过滤性能,为开发和匹配柴油车颗粒物过滤器提供一种有效的手段。     

柴油机颗粒物后处理技术综述

通过调研国内外文献,介绍了柴油机颗粒物污染现状、颗粒物后处理技术、壁流式颗粒捕集器(DPF)的工作原理、材料和结构类型、捕集器再生技术和控制策略等。堇青石陶瓷壁流式DPF具有成本和性能方面的优势,占据主要市场份额,再生技术是DPF应用的关键。与主动再生技术相比,被动再生具有结构简单、节约油耗等优势,可通过涂敷催化剂、前置DOC和辅助主动再生等方法确保再生效果。     

Effects of Residual Ash on Dpf Capture and Regeneration

To study the effects of residual ash on the capture and regeneration of a diesel particulate filter (DPF), repeated capture and complete regeneration experiments were conducted. An engine exhaust particulate sizer was used to measure the particle size distribution of diesel in the front and back of DPF. Discrepancies in the size distribution of the particulate matter in repeated trapping tests were analyzed. To achieve complete DPF regeneration, a DPF regeneration system using nonthermal plasma technology was established. The regeneration carbon removal mass and peak temperatures of DPF internal measuring points were monitored to evaluate the effect of regeneration. The mechanism explaining the influence of residual ash on DPF capture and regeneration was thoroughly investigated. Results indicate that the DPF trapping efficiencies of the nuclear-mode particles and ultrafine particles have significant improvements with the increase quantity of residual ash, from 90 % and 96.01 % to 94.17 % and 97.27 %, respectively. The exhaust backpressure of the DPF rises from 9.41 kPa to 11.24 kPa. Heat transfer in the DPF is improved with ash, and the peak temperatures of the measuring points accordingly increase. By comparing the regeneration trials, the elapsed time for complete regeneration and time difference for reaching the peak temperature between adjacent reaction interfaces are extended with increased quantity of ash. The carbon removal mass rises by 34.00 %.     

Carbon Deposit Incineration During Engine Flameout Using Non-Thermal Plasma Injection

In order to investigate the influence of initial regeneration temperatures on diesel particulate filter (DPF) regeneration, an experimental study of DPF regeneration was implemented using a dielectric barrier discharge (DBD) reactor, aided by exhaust waste heat after engine flameout. DPF trapping characteristics and carbon deposit mass were discussed to facilitate further data analysis and calculation. DPF regeneration was then investigated by comparison analysis of deposit removal mass, backpressure drop, and internal temperature change. The results revealed that a large amount of particulate matter (PM) was deposited in DPF with a high filtration efficiency of about 90 %. The deposit removal rate and percentage drop of the backpressure both maximized at the initial temperature of 100 °C. During DPF regeneration, the sharp rise of internal temperature indicated vigorous PM incineration and high CO₂ emission. The results successfully demonstrated DPF regeneration using non-thermal plasma injection during engine flameout, and prominent heat durability was achieved in this method.