碳酸二甲酯对柴油机排放特性的影响

为了研究碳酸二甲酯(DMC)和柴油的混合燃料对柴油机排放特性的影响,在一台TY1100直喷式柴油发动机上进行了不同碳酸二甲酯添加体积比的混合燃料的台架试验。试验结果表明:随着柴油中DMC添加比例提高,发动机功率有所下降,热效率有所提高,NOx的排放无明显变化;HC和CO2的排放略有增加;CO的排放略有降低;碳烟的排放大幅降低,当添加体积比为15%时,碳烟排放的降幅约为50%,此后随着DMC添加体积比的提高,碳烟减排效果逐渐减弱。     

汽车柴油机排气颗粒泡沫陶瓷过滤器的研制

着重论述了汽车柴油机排气颗粒泡沫陶瓷过滤器滤芯的性能要求，确定了泡沫陶瓷过滤器的配方、工艺和结构。所制得泡沫陶瓷的性能：抗弯强度为1．5MPa；膨胀系数为2．89×10－6／K－1；耐温性为1300℃．用此泡沫陶瓷做成的滤芯碳颗粒过滤效率为50％左右。根据台架试验与性能检测结果数据，集中讨论了工艺、添加剂和滤芯结构的影响。     

乙醇与柴油互溶性研究及混合燃料对柴油机排放性能的影响

乙醇可由生物质能源转化得到,可作为含氧清洁燃料与柴油混合用作柴油机燃料。以正丁醇为助溶剂促进乙醇在柴油中的溶解,形成稳定的混合燃料;同时以该混合燃料作为柴油机燃料,参照GB 20891-2014《非道路移动机械用柴油机排气污染物排放限值及测量方法(中国第三、四阶段)》测试柴油机的常规排放、非常规排放规律,探究其对柴油机排放性能的影响。结果表明,正丁醇作为助溶剂,可促进乙醇与柴油互溶,在乙醇与正丁醇的体积比接近1∶1时可形成稳定的混合燃料,静置10个月以上不分层,在-5℃左右不分层,可用作柴油机燃料;正丁醇的添加方式对其助溶效果影响较小;负荷特性下,与燃用纯柴油相比,柴油机燃用混合燃料时,CO和NO_x排放量分别减少13.96%～46.73%和1.35%～16.92%,VOCs排放量增加1.94%～32.43%,PM_(2.5)排放量减少5.81%～44.37%。柴油与醇类燃料混合燃烧可以实现在减少NO_x排放量的同时减少PM_(2.5)排放量。     

谈车用柴油机尾气排放的陶瓷滤材

陶瓷滤材具有的优良性能,使得其在空气净化、高温烟气过滤、金属液过滤、尤其柴油机尾气微粒捕集等方面得到了广泛的应用。针对车用柴油机的尾气排放治理已是当务之急,分析了柴油机排放颗粒的控制技术和柴油机尾气微粒捕集的净化技术受到关注,论述了柴油机排气微粒捕集过滤和扩散的机理,介绍了多孔陶瓷过滤元件的结构、性能特点及柴油机微粒过滤器的滤材性能特点,指出了柴油机微粒过滤器的发展趋势。     

生物柴油对车用柴油机NO_X排放影响的研究综述

生物柴油是内燃机用石化柴油的替代燃料之一。本文从4个方面梳理了生物柴油对车用柴油机NOX排放影响研究的现状,探讨了NOX排放增加、减少的原因,从改进生物柴油和柴油发动机两大方面细致分析了降低NOX排放的措施,给出了进一步研究影响NOX排放的方向。     

泡沫陶瓷研制过程中影响因素的试验研究

采用有机泡沫浸渍法制备泡沫陶瓷,研究了各种工艺因素对泡沫陶瓷制备的影响.研究表明,泡沫体的挂浆量在经过50%的酸处理或2mol/L的碱处理之后效果较好.在普通陶瓷的浆料中加入质量分数为0.05～O.25%的三聚磷酸钠作分散剂和少量表面活性剂获得的浆料性能优良.加入7～8%硅灰石为烧成助剂烧成温度降低为1260℃.最后得到了性能参数为:气孔率为80%以上,体积密度0.3g/cm3～0.7g/cm3,加工简单,过滤能力强的泡沫陶瓷.     

泡沫载体的表面处理对泡沫陶瓷性能的影响

本文研究了对软质聚氨酯泡沫塑料表面进行处理,从而改善泡沫陶瓷的性能。用浓度为2.4%的聚乙烯亚胺(PEI)溶液加以活化,可以使聚氨酯泡沫载体更好的和陶瓷浆料结合。聚乙烯亚胺既可以活化聚氨酯表面使聚氨酯表面具有亲水性,同时又因是有机物,燃烧时产生气体而影响坯体的抗压强度性能,试验证明,用浓度为2.4%的聚乙烯亚胺活化处理泡沫载体可以得到抗压强度最高的泡沫陶瓷产品。     

泡沫载体的表面处理对泡沫陶瓷性能的影响

本研究通过对软质聚氨酯泡沫塑料的表面进行处理,改善了泡沫陶瓷的性能。用浓度为2.4%的聚乙烯亚胺(PEI)溶液加以活化,可以使聚氨酯泡沫载体更好地和陶瓷浆料结合。聚乙烯亚胺既可以活化聚氨酯表面使其具有亲水性,同时又因其为有机物,燃烧时产生气体从而对坯体的抗压强度性能产生影响。试验证明,用浓度为2.4%的聚乙烯亚胺活化处理泡沫载体可以得到抗压强度最高的泡沫陶瓷产品。     

Evidences of the Cerium Oxide-Catalysed DPF Regeneration in a Real Diesel Engine Exhaust

The active phase Ce_0.5Pr_0.5O₂ has been loaded on commercial substrates (SiC DPF and cordierite honeycomb monolith) to perform DPF regeneration experiments in the exhaust of a diesel engine. Also, a powder sample has been prepared to carry out soot combustion experiments at laboratory. Experiments performed in the real diesel exhaust demonstrated the catalytic activity of the Ce–Pr mixed oxide for the combustion of soot, lowering the DPF regeneration temperature with regard to a counterpart catalyst-free DPF. The temperature for active regeneration of the Ce_0.5Pr_0.5O₂-containing DPF when the soot content is low is in the range of 500–550 °C. When the Ce_0.5Pr_0.5O₂-containing DPF is saturated with a high amount of soot, pressure drop and soot load at the filter reach equilibrium at around 360 °C under steady state engine operation due to passive regeneration. The uncoated DPF reached this equilibrium at around 440 °C. Comparing results at real exhaust with those at laboratory allow concluding that the Ce_0.5Pr_0.5O₂-catalysed soot combustion in the real exhaust is not based on the NO₂-assisted mechanism but is most likely occurring by the active oxygen-based mechanism.     

柴油性能对车用发动机的影响

柴油是柴油机的主要燃料,其使用性能和技术指标的控制对发动机正常工作有着深远的影响。文章简要介绍了发动机的工作原理,综述了柴油的物理化学性质对发动机的影响。     

Effect of Secondary Mixing on Starting Characteristics of a Cold Diesel Engine

Results of experiments performed in a constant-volume bomb are presented. The conditions in the bomb were typical of starting regimes of diesel engines. Cooled (down to 286 K) or noncooled inserts were placed in the bomb volume on the way of the fuel–air jet. These inserts were plates simulating a sector of the combustor wall. Leaf deflectors of the jet were mounted on the plates to obtain the effect of secondary mixing. In the case of an elevated pressure in the medium (2.5 MPa and higher), the presence of the inserts, including those equipped by deflectors, independent of their thermal state, affects ignition only at extremely low temperatures of the medium, at which the primary ignition of fuel vapors and products of its thermal decomposition occurs in an immediate vicinity of the insert. If the initial pressure in the medium is rather low (0.9 MPa), the influence of the insert is significant: a noncooled surface reduces both the induction period (by a factor of 1.5 as compared to injection into a free volume) and the limiting temperature of ignition. If the insert surface is cooled, however, the ignition delay increases by 20%, and the limiting temperature of ignition increases by 100 K. Under these conditions, a leaf deflector of the jet mounted on the wall-simulator surface significantly improves the ignition characteristics of the mixture: the ignition delay and the limiting temperature decrease down to values that do not exceed those upon injection into a free volume. It is assumed that the secondary injection of the mixture from the edge of the leaf deflector into the free space of the working volume leads to the formation of a closed circular vortex containing both the liquid phase (atomized fuel drops) and the gaseous phase (fuel vapors, products of its partial thermal decomposition, and air). Key words: diesel engine, mixing.     

排放影响的研究综述

生物柴油是内燃机用石化柴油的替代燃料之一。本文从4个方面梳理了生物柴油对车用柴油机NO_X排放影响研究的现状,探讨了NO_X排放增加、减少的原因,从改进生物柴油和柴油发动机两大方面细致分析了降低NO_X排放的措施,给出了进一步研究影响NO_X排放的方向。     

New Design of a Ceramic Filter for Diesel Emission Control Applications

Diesel particulate filters (DPF) made from an advanced ceramic material (ACM) based on mullite have demonstrated high filtration efficiency, low-pressure drop, high-temperature handling capability, and excellent mechanical integrity at a porosity of 60% or higher. Due to the ability to control microstructure, total porosity, and particle size distribution, Dow's acicular mullite can be tailored to meet requirements for deep bed filtration and fine particles emission control. In addition, the ACM DPF is suitable for catalyzed applications and it can retain its performance with a broad range of catalysts and over a wide range of catalyst loadings. This study describes a material selected for a DPF design that meets current diesel particulate emission control requirements as well as a four-way NO _x control system.     

Effect of Metal-Based SiO2 Nanoparticles Blended Concentration on Performance,Combustion and Emission Characteristics of CRDI Diesel Engine Running on Mahua Methyl Ester Biodiesel

Silicon - Biodiesel has been renowned as potential and alternative fuel for years. In order to improve the quality of the conventional fossil fuels, biodiesel, and air pollution from combustion,...     

6105机氮化硅陶瓷气门材料及部件制备的研究

本研究采用近净尺寸等静压成型，无压烧结Ｓｉ３Ｎ４工艺成功地制备了同了６１０５紫油机Ｓｉ３Ｎ４对陶瓷气门材料及制备工艺进行了详细讨论。     

泡沫陶瓷的研究进展

本文介绍了泡沫陶瓷的特性和制造工艺，并列举了泡沫陶瓷在的主要应用领域，指出了当前陶瓷材料的研究热点和今后要解决的问题。