Effects of Magnetic Nanofluid Fuel Combustion on the Performance and Emission Characteristics

Although the compression ignition engines are a significant source of power, their detrimental emissions create considerable problems to the environment as well as to humans. The objective of the present experimental investigation is to examine the effects of the magnetic nanofluid fuels on combustion performance characteristics and exhaust emissions. In this regard, the Fe₃O₄ nanoparticles dispersed in the diesel fuel with the nanoparticle concentrations of 0.4 and 0.8 vol% were employed for combustion in a single-cylinder, direct-injection diesel engine. After a series of experiments, it was demonstrated that the nanoparticle additives, even at very low concentrations, have considerable influence in diesel engine characteristics. Furthermore, the results indicated that the nanofluid fuel with nanoparticle concentration of 0.4 vol% shows better combustion characteristics in comparison with that of 0.8 vol%. Based on the experimental results, NO _x and SO₂ emissions dramatically reduce, while CO emissions and smoke opacity noticeably increase with increasing the dosing level of nanoparticles.     

乙醇/柴油混合燃料的相溶性及对发动机性能影响的研究

利用助溶剂解决乙醇/柴油的相溶性问题，讨论了混合燃料中乙醇和助溶剂添加量对相溶性的影响，并使用助溶剂体积分数为1.5%、乙醇体积分数分别为5%、10%、15%的混合燃料及 20号纯柴油（分别表示为E5、E10、E15和 E0）在发动机台架上进行了性能和排放试验。研究结果表明，柴油的烃组成是决定相分离温度的决定性因素；对全部测试油品，乙醇体积分数在10%、助溶剂添加体积分数为1.5%时，混合燃料相溶性较好。台架试验显示，随着混合燃料中乙醇掺烧比例的增加，发动机的燃油消耗率逐渐增加，而发动机的额定功率和最大扭矩逐渐降低，但最大扭矩降低的幅度较小；此外，随着乙醇掺烧比例的增加，CO比排放量减少，HC、NOx和PM的比排放量逐渐增加，但NOx和PM的比排放量增加幅度不大。10%体积分数的乙醇添加量是乙醇/柴油的最佳掺烧比。     

F-T柴油对电控高压共轨柴油机性能及排放影响的研究

在满足国Ⅲ排放的现代高压共轨柴油机上,研究了掺烧不同比例F-T柴油混合燃料对发动机性能和排放的影响。结果表明,随着掺烧比例的加大,发动机的动力性略有下降,在外特性上,与燃烧国Ⅲ柴油相比,燃用F-T柴油时,扭矩最大下降2.2%,而燃油消耗率最高下降7.1%,有效热效率提高了4.5%。在十三工况的排放上,碳氢化合物（HC）、氮氧化物（NO_{x）、一氧化碳（CO）和颗粒（PM）的比排放量较国Ⅲ柴油均有明星下降,其中尤以燃用F-T柴油下降的幅度最大,PM降低了25.5%、NOx降低了11.7%、HC降低了39.3%、CO降低了33.9%。F-T柴油是柴油机的优良替代燃料。}     

Phase Behavior of Bicontinuous and Water/Diesel Fuel Microemulsions Using Nonionic Surfactants Combined with Hydrophilic Alcohol Ethoxylates

Bicontinuous and water-in-diesel microemulsions were formulated using single nonionic alkyl poly glycol ethers combined with hydrophilic alcohol ethoxylates. The phase behavior at temperatures ranging from 0°C to 50°C was investigated. Visual inspection as well as cross-polarizers were used to detect anisotropy. The fish phase diagrams were determined. The presence of the hydrophilic alcohol ethoxylates was necessary to initiate both types of microemulsions. Increasing the hydrophobic chain length of the surfactant led to a wider range of temperature stability at lower surfactant concentration. Meanwhile, increasing the ethylene oxide units in the headgroup by two units led to a phase diagram that is dominated by lyotropic liquid crystal. The formulated water in diesel microemulsions were tested experimentally in a 4-cylinder diesel engine. From this it is observed that the emissions of NO_x, soot, and CO₂ were reduced substantially compared to neat diesel, while for the CO the reduction occurs just at low load.      

燃料特性对车用柴油机有害排放的影响

研究了车用柴油机燃用不同品质燃油时,其排气烟度、颗粒PM、氮氧化物NO_x、碳氢HC和一氧化碳的排放特性,采用了五种不同硫含量、芳烃含量和十六烷值的柴油,进行了发动机台架实验和模拟整车NEDC循环实验。结果表明,随着燃油硫含量的减少,柴油机排气烟度、HC、CO、SO₂排放有所下降;模拟整车NEDC循环的PM排放显著降低;NO_x排放的变化幅度很小。随着燃油芳烃含量的降低,柴油机排气烟度、PM、NO_x、HC、CO排放的降幅显著。随着燃油十六烷值的升高,柴油机的排气烟度大都呈持续下降趋势;PM、HC排放显著降低;NO_x、CO排放的变化幅度较小。     

Analyzing the Stability of the Water-in-Diesel Fuel Emulsion

The diesel engine exhaust gas consists of many hazardous components that need to be reduced. Incorporation of water in fuel restricts the emission of such toxic gases and helps to reduce pollution. The aim of this research work is to develop a water-in-diesel fuel emulsion having maximum stability. Initially, the most suitable surfactant/blend of surfactants has been investigated, which gives the maximum stability to the Water-in-Diesel (W/D) emulsion. It is found that a blend of Span 80 and Tween 80 gives an effective result. The W/D emulsion was prepared by using a high-speed mixing homogenizer and adding a small amount of water into the diesel containing blend of Span 80 and Tween 80. The results show that 10% W/D emulsion having 5% surfactant concentration gives the most desirable emulsion stability. Beyond 10% water concentration, the properties of the W/D emulsion get lowered.     

Trace and minor element characterization of diesel soot

Summary Concentrations of 20 trace and minor components, such as metals, nitrogen and sulphur, were determined in representative diesel soot samples corresponding to various driving patterns of an old and a new type of Mercedes-Benz diesel engine for passenger cars. The samples were analysed by instrumental neutron activation analysis, and after decomposition, by flame and graphite furnace atomic absorption spectrometry. The content of sulphur was determined by a method based on the formation of hydrogen sulphide and precipitation micro-titrimetry. The concentrations of the elements Au, La, Sb, Sc, and V were at the sub-g/g level; As, Ba, Cd, Co, Cr, Mn, Ni, and Se were at the lower g/g level; and Ca, Cu, Fe, N, Na, Pb, S, and Zn ranged from the upper g/g to lower percent levels. The emission of several elements was likely the result of different factors such as utilization of organometallic additives (Ca, Na, Zn) in diesel fuel or lubrication oil, contamination of diesel fuel by alkyllead compounds, wear and corrosion of the engine and exhaust system parts. The concentration of elemental components in diesel soot, generally, varied with operating conditions, which affected fuel and oil consumption, combustion efficiency (soot production), and mechanical strain. Permanent address: Czechoslovak Academy of Science, Institute of Analytical Chemistry, Vevei 96, CS-61142 Brno, SFR     

Microencapsulation of Calcium Using Water-in-Oil-in-Water Double Emulsion Method

Calcium in the form of tricalcium phosphate was encapsulated in the inner water phase of water-in-oil-in-water emulsion. Efficiency and payload of microcapsules were optimized using a D-optimal mixture design with four components (gelatin, agar, primary water-in-oil emulsion, and water in outer phase). Release profiles of calcium from microcapsules were determined at 4°C over 12 days. It was found that microencapsulation efficiency increased by increasing of water-in-oil emulsion to 45% and then decreased at higher contents of this portion. However, payload increased continuously with increase of water-in-oil fraction. Less calcium was released when both biopolymers and water-in-oil emulsion contents were increased.     

Impact of Various Parameters Over the Stability of Water-in-Vegetable Oil Emulsion

Theory regarding emulsification, its coalescence and impact of emulsifier over its stability has been updated. For the verification of the proposed theory, water-in-oil emulsion was prepared by mixing water and soybean oil in the presence and absence of emulsifier, monoglyceride. The effect of different parameters like emulsification time, contents of water, and concentration of emulsifier has been investigated on the emulsification and coalescence process of the emulsion. It was noted that the emulsion quality was highest if the mixture was homogenized for about 15 minutes and the water contents were 40% v/v. The addition of monoglyceride up to 0.5% w/v gave the most stable emulsion having higher quality than other composition. The results obtained were compared with the proposed theory and found to have good compositions.      

Demulsification of Gas Oil/Water Emulsion via High-Intensity Ultrasonic Standing Wave

High-intensity ultrasonic standing wave field was established in a horizontal direction and its effect on “gas oil” in “water” emulsion separation rate was studied. Also, effects of four parameters on emulsion instability behavior were investigated: ultrasound irradiation time (5–30 min), emulsion position in ultrasound field (17–37 cm), ultrasound input intensity (20, 45, and 75%) and dispersed phase concentration (0.5, 2, and 10%). Emulsion light absorbance, droplet diameter and distribution were measured to analyze separation efficiency. The optimum states were 10% oil in water emulsion treated at 17 cm distance from ultrasound source under 30 minutes irradiation time and 20% sound intensity.     

The relation between dioxin concentration from exhaust gas of diesel engine and chlorine content

In this paper, an experiment has been used to study the effect of pyrolysis stage (from injection to combustion) to dioxin exhaust from diesel engine. The characteristics of diesel fuel pyrolysis have been applied in order to calculate the mean molecular weight in varied temperatures and measure the concentration of inorganic chlorine (HCl). On the other hand, measuring the chlorine content of these particles after diesel pyrolysis enables researchers to find out the pyrolysis temperature that has the lowest possibility to produce dioxin. Additionally, the post-pyrolysis carbon particle diameter has been observed through electronic microscope so as to evaluate the combustion condition of the combustion stage. Result from this study would be helpful for researchers to understand the probability of dioxin formation.     

Tween-80–n-Butanol–Diesel–Water Microemulsion System—A Class of Alternative Diesel Fuel

Tween-80–n–butanol–diesel–water microemulsion systems with various surfactant:cosurfactant (S:C) ratio have been reported as a class of alternative diesel fuel from their phase behavior, clouding phenomena, conductivity, turbidity, and inflammation studies. Temperature induced clouding of microemulsion containing 2% brine at an S:C ratio of 1:1 from a suitable turbid zone has been examined to see the stability of the diesel–water microemulsion systems. Regression models have been proposed to understand the impact of various components of the microemulsion on their cloud point (CP) values. Conductivity of the microemulsions at various S:C ratio increases with the volume of brine having two cut points depicting the presence of three microheterogenous phases within the system, whereas turbidity shows a linear increase. Dye-probed investigation of water-rich and oil-rich zones of the microemulsions indicates the involvement of a dynamic mass transfer process within the various zones. The intensities of flames produced during burning of the microemulsions with various O:E:W weight percentages selected from the isotropic regions of the phase diagrams have been estimated using MATLAB image processing method and the impacts of various components on the fuel use of the microemulsions have been analyzed.     

Application of Plasma Fuel Reformer to an On-Board Diesel Burner

A conventional diesel burner has arisen several shortcomings, such a large supply of air for a stoichiometric combustion, and a long heat-up time to reach the light-off temperature of catalyst in a diesel after-treatment system. This study shows a promising potential of using a plasma reformer for staged diesel combustion with minimized air and fuel consumption, and increased the flame stability with low NOx emission. A working principle of a plasma fuel reformer for staged combustion is explained in detail by both visualizing the plasma-assisted flame and analyzing the gas products. The concentrations of H₂, CO, NOx and the unburned total hydrocarbons were measured by gas chromatography and a commercial gas analyzer. Considering the operating condition of diesel exhaust gas is too harsh to maintain a stable diesel flame with a conventional diesel burner, plasma fuel reformer has distinctive advantages in stable flame anchoring under the condition of low oxygen concentration and fast flow speed. The re-ignition and stable flame anchoring by entrapment of oxygen in exhaust gas is mainly attributed to the low ignition energy and high diffusion velocity of hydrogen molecule. From an economic point of view, plasma reformer is also the only technology which can use only 1/3–1/8 of the air required for the stoichiometric burning of a conventional diesel burner. A conventional burner was simulated and analyzed to consume up to 30 % more fuel compared to the plasma reformer with the staged combustion to get the same level of temperature elevation in a real diesel engine scale.     

Experimental Design Approach to Investigate the Effects of Operating Factors on the Surface Tension,Viscosity, and Stability of Heavy Crude Oil-in-Water Emulsions

In this article, the effects of various operating factors on the surface tension, viscosity, and stability of two heavy oil types in water emulsions for pipeline transportation are studied using the Taguchi experimental design approach. The surface tension of heavy crude oil-in-water emulsion is decreased by increasing the emulsifier concentration while the stability of emulsions is increased. The viscosity and stability are increased by an increase in oil content. An increase in the salinity and mixing speed leads to an increase in the stability of emulsion.     

Development and characterization of a mobile photoacoustic sensor for on-line soot emission monitoring in diesel exhaust gas

Upcoming regulations for vehicle exhaust emission demand substantial reduction of particle emission in diesel exhaust. To achieve these emission levels, the car manufacturing industry is developing new combustion concepts and exhaust after-treatment techniques such as the use of catalysts and particle filters. Many of the state-of-the-art analytical instruments do not meet the required detection limits, in combination with a high temporal resolution necessary for engine optimization. This paper reports a new detection system and the first results of its application to on-line diesel exhaust soot measurements on a engine test bench (MAN diesel engine facility Nürnberg, Germany). The instrument is based on differential photoacoustic (PA) spectroscopy of black carbon aerosol. It contains two identical PA cells, one for the measurement of the aerosol particles and one which analyses the particle-free gas. Thus, a potential cross-sensitivity to gaseous absorbers in the exhaust gas can be excluded. The PA cells were characterized in a laboratory set-up, with water vapor as reference gas and artificial soot generated by a spark discharge generator. The detection limit was found to be 2 microg m(-3) BC (for diesel soot) with a sampling rate of 3 Hz. The temporal response of the system was found to be in the order of 1 s. After full characterization of the cells, the system was transferred into a mobile 19"-rack. Characterization of the mobile sensor system under real-world conditions was performed during several measurement campaigns at an engine test bench for heavy-duty diesel engines. Results for the limit of detection, the time resolution, accuracy, repeatability, and robustness of the sensor system are very promising with regards to a routine application of the system in engine development.     

Extraction of Priority Pollutant 4-Nitrophenol from Water by Emulsion Liquid Membrane: Emulsion Stability,Effect of Operational Conditions and Membrane Reuse

This work aims to the extraction of the priority pollutant 4-nitrophenol (4-NP) from water by emulsion liquid membrane (ELM). Liquid membrane consists of a diluent (hexane) and a surfactant (Span 80). Sodium carbonate solution was used as internal aqueous phase. Effects of important experimental conditions governing the stability of the W/O emulsion were investigated. Influence of operating parameters that affects the permeation of 4-NP such as surfactant concentration, emulsification time, sulfuric acid concentration in external phase, acid type in external phase, internal phase concentration, type of internal phase, stirring speed, volume ratio of internal phase to membrane phase, treatment ratio, 4-NP initial concentration, and diluent type was examined. This study also evaluated the effect of Na₂CO₃ concentration in the internal aqueous phase on the stripping of 4-NP. Additionally, the reuse of the recovered membrane was studied. Under most favorable conditions, practically all the 4-NP and aniline (AN) molecules present in the feed phase were extracted. The recovery of the membrane phase was total and the extraction of 4-NP was not decreased. The ELM treatment process represents a very interesting advanced separation process for the removal of 4-NP and AN from aqueous solutions.     

界面膜引发的乳化燃油燃烧中的振荡反应

有关小分子醇、H。和CO等易燃气体在铂催化下的高温燃烧的温度振荡及以表面活性剂为关键组分的液膜扩散振荡已有报道"－'－．但由界面膜作用而产生的乳化燃油燃烧中的振荡反应尚无其它可操作的原始研究文献,只是在前文［'j中提及过出现该现象．为了解乳化燃油燃烧过程中界面变化及其对燃烧的作用,通过静态燃烧实验配方的调节及变换以改变燃烧界面的情况．实验发现,在乳化燃油中加入一般的食用豆油,并使之水解出长链竣酸盐,则富集在燃烧界面上的长链竣酸盐所形成的界面膜对燃烧的自阻抑作用便会产生明显的振荡反应,形成火焰温度与高…