A study on the usability of biodiesel fuel derived from rice bran oil as an alternative fuel for IDI diesel engine

The world is faced with a problem of air pollution due to the exhaust emissions from automobile. Recently, lots of researchers have been attracted to develope various alternative fuels and to use renewable fuels as a solution of these problems. There are many alternative fuels studied in place of diesel fuel made from petroleum. Biodiesel fuel (BDF) is a domestically produced, renewable fuel that can be manufactured from vegetable oils, used vegetable oils, or animal fats. In this study, the usability of BDF, one of the oxygenated fuels as an alternative fuel for diesel engines was investigated in an IDI diesel engine. Emissions were characterized with a neat BDF and with a blend of BDF and conventional diesel fuel. Since the BDF includes oxygen of about 11%, it could influence the combustion process strongly. Therefore, the use of BDF resulted in lower emissions of carbon monoxide and smoke emissions with some increase in emissions of oxides of nitrogen. It is concluded that BDF can be utilized effectively as a renewable fuel for IDI diesel engines.     

Effect of water induction on the performance and exhaust emissions in a diesel engine (II)

This study was to investigate the effects of water induction through the air intake system on the characteristics of combustion and exhaust emissions in an IDI diesel engine. The fuel injection timing was also controlled to investigate a method for the simultaneous reduction of smoke and NOx when water was injected into the combustion chamber. The formation of NOx was significantly suppressed by decreasing the gas peak temperature during the initial combustion process because the water played a role as a heat sink during evaporating in the combustion chamber, while the smoke was slightly increased with increased water amount. Also, NOx emission was significantly decreased with increase in water amount. A simultaneous reduction in smoke and NOx emissions was obtained when water was injected into the combustion chamber by retarding more 2°CA of the fuel injection timing than without water injection.     

EFFECTS OF COOLED EXTERNAL EXHAUST GAS RECIRCULATION ON DIESEL HOMOGENEOUS CHARGE COMPRESSION IGNITION ENGINE

The effects of cooled external exhaust gas recirculation (EGR) on the combustion and emission performance of diesel fuel homogeneous charge compression ignition (HCCI) are studied. Homogeneous mixture is formed by injecting fuel in-cylinder in the negative valve overlap (NVO) period. So, the HCCI combustion which has low NOx and smoke emission is achieved. Cooled external EGR can delay the start of combustion effectively, which is very useful for high cetane fuel (diesel) HCCI, because these fuels can easily self-ignition, which makes the start of combustion more early. External EGR can avoid the knock combustion of HCCI at high load which means that the EGR can expand the high load limit. HCCI maintains low smoke emission at various EGR rate and various load compared with conventional diesel engine because there is no fuel-rich area in cylinder..     

The experimental investigations of recirculated exhaust gas on exhaust emissions in a diesel engine

The effects of recirculated exhaust gas on the characteristics of NOx and soot emissions under a wide range of engine loads were experimentally investigated by using a four-cycle, four-cylinder, swirl chamber type, water-cooled diesel engine operating at three engine speeds. The purpose of this study was to develop the EGR-control system for reducing NOx and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal device with a cylinder-type scrubber for the experiment system was specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The experiments were performed at the fixed fuel injection timing of 4° ATDC regardless of experimental conditions. It was found that soot emissions in exhaust gases were reduced by 20 to 70% when the scrubber was applied in the range of the experimental conditions, and that NOx emissions decreased markedly, especially at higher loads, while soot emissions increased owing to the decrease in intake and exhaust oxygen concentrations, and the increase in equivalence ratio as the EGR rate is elevated.     

Investigation of the effects of steam injection on the emissions and performance of a diesel engine using waste chicken oil methyl ester

The use of biodiesel-blended fuels in diesel engines improves the engine performance parameters and the partial recovery of incomplete combustion products, while also increasing the level of NOx emissions. In this study; biodiesel obtained through the transesterification of waste chicken frying oil was mixed with diesel fuel (90% diesel + 10% biodiesel-B10), and was then used as fuel in a direct injection diesel engine. To reduce the increased NOx emissions caused by the use of B10 fuel, the steam injection method (which is one of the NOx reduction methods) was applied. Steam was injected into the intake manifold at different ratios (5%-S5, 10%-S10 and 15%-S15) and at the time of the induction stroke with the aid of an electronically controlled system. Based on the study results, it was observed that steam injection into the engine using B10 fuel improved both the engine performance and the exhaust emission parameters. It was determined that the S15 steam injection ratio resulted in the best engine performance and emissions parameters. In comparison to STD fuel; the highest increase observed at the S15 steam injection ratio in the effective engine power was 2.2%, while the highest decrease in the specific fuel consumption was 3.4%, the highest increase in the effective efficiency was 3.5%, and the highest decrease in NOx emissions was 13.7%.

     

An experimental study on heat exchange effectiveness in the diesel engine EGR coolers

Both reducing nitrogen oxides (NOx) and particulate matter (PM) emissions from diesel engine and improving fuel consumption are important in meeting government regulations and society needs. Use of the Cooled Exhaust Gas Recirculation (EGR) system is one of the most effective techniques currently available for reducing NOx and PM emissions. However, the EGR system has a trade-off between NOx and PM emissions at high loads. In the present study, engine dynamometer experiments have been performed to investigate the heat exchange effectiveness of EGR coolers with shell & tube-type and stack-type. The results show that the heat transfer effectiveness of the stack-type EGR cooler is 25–50 % higher than that of the shell & tube type due to an increased surface area and a better mixing of the exhaust gas flow.     

柴油机废气再循环系统冷却器的数值模拟

柴油机废气再循环(EGR)技术能有效降低NOx有害排放,而EGR冷却器的结构优化是提高冷却器效率,减少NOx排放的有效手段.应用FLUENT软件对柴油机废气再循环系统冷却器的数值模拟,为柴油机废气再循环系统冷却器的设计和优化提供理论依据.     

Multidimensional engine modeling: NO and soot emissions in a diesel engine with Exhaust Gas Recirculation

The effects of EGR (Exhaust Gas Recirculation) on heavy-duty diesel engine performance, NO and soot emissions were numerically investigated using the modified KIVA-3V code. For the fuel spray, the atomization model based on the linear stability analysis and spray wall impingement model were developed for the KIVA-3V code. The Zeldovich mechanism for the formation of nitric oxide and the soot model suggested by Hiroyasu et al. were used to predict the diesel emissions. In this paper, the computational results of fuel spray, cylinder pressure, and emissions were compared with experimental data, and the optimum EGR rates were sought from the NO and soot emissions trade-off. The results showed that the EGR is effective in suppressing NO but the soot emission was increased considerably by EGR. Using cooled EGR, soot emission could be enhanced without worsening of NO.     

Emission characteristics of exhaust gases and nanoparticles from a diesel engine with biodiesel-diesel blended fuel (BD20)

This experimental study sought to investigate the characteristics of the exhaust emissions, and nanoparticle size distribution of particulate matter (PM) emitted from diesel engines fueled with 20% biodiesel-diesel blended fuel (BD20). The study also investigated the conversion efficiency of the warm-up catalytic converter (WCC). The emission characteristics of HC, CO, NOx and nano-sized PM were also observed according to engine operating conditions with and without exhaust gas recirculation (EGR). The study revealed that the maximum torque achievable with the biodieseldiesel blended fuel was slightly lower than that achievable with neat diesel fuel at high-load conditions. Smoke was decreased by more than 20% in all 13 modes. While the CO and THC emissions of BD20 slightly decreased, the NOx emission of BD20 increased by 3.7%. Measured using the scanning mobility particle sizer (SMPS), the total number and total mass of the nanoparticles in the size range between 10.6nm and 385nm were reduced by about 10% and 25%, respectively, when going from D100 to BD20. The particle number and mass for both fuels were reduced by about 43% when going from with EGR to without EGR. When EGR was applied in the engine system, the particle number and mass were reduced by 24%, and 16%, respectively, when going from D100 to BD20.     

The effect of exhaust gas recirculation (EGR) on combustion stability, engine performance and exhaust emissions in a gasoline engine

The EGR system has been widely used to reduce nitrogen oxides (NOx) emission, to improve fuel economy and suppress knock by using the characteristics of charge dilution. However, as the EGR rate at a given engine operating condition increases, the combustion instability increases. The combustion instability increases cyclic variations resulting in the deterioration of engine performance and emissions. Therefore, the optimum EGR rate should be carefully determined in order to obtain the better engine performance and emissions. An experimental study has been performed to investigate the effects of EGR on combustion stability, engine performance, NOx and the other exhaust emissions from 1. 5 liter gasoline engine. Operating conditions are selected from the test result of the high speed and high acceleration region of SFTP mode which generates more NOx and needs higher engine speed compared to FTP-75 (Federal Test Procedure) mode. Engine power, fuel consumption and exhaust emissions are measured with various EGR rate. Combustion stability is analyzed by examining the variation of indicated mean effective pressure (COV_imep) and the timings of maximum pressure (P_max) location using pressure sensor. Engine performance is analyzed by investigating engine power and maximum cylinder pressure and brake specific fuel consumption (BSFC).     

柴油/乙醇混合燃料对发动机排放性能分析

介绍了在柴油中混合不同比例的乙醇对柴油机CH、NOx和碳烟排放的影响.采用柴油/乙醇制成不同比例乳化燃料在一台直喷、增压、中冷柴油机上进行试验.试验结果表明随着乙醇掺烧比例的增加,HC排放逐渐的增加,尤其在小负荷工况范围内,HC排放恶化严重;NOx排放在小负荷工况下有所改善;发动机碳烟排放逐渐的降低.     

甲醇裂解气-柴油混合燃料对柴油机排放的影响

为研究甲醇裂解气-柴油混合燃料对柴油机排放的影响,设计了一种集成式尾气裂解甲醇反应器和进气共轨系统,将YC6A220型柴油机改装成燃烧由甲醇裂解而成的氢富气与柴油混合燃料的柴油机。实验研究表明,改装后的柴油机在中、高负荷运行时可以使NOx、HC和碳烟大幅度降低,且随着甲醇裂解气掺烧量的增加,各排放物质的减少量增加。     

柴油引燃甲醇双燃料发动机排放性能试验分析

介绍了柴油引燃甲醇双燃料燃烧对柴油机CH、NOx和碳烟排放的影响。采用柴油引燃甲醇双燃料在一台单缸、直喷、中冷柴油机上进行。随着甲醇质量分数的增加,HC排放迅速增加,NOx排放减少,发动机碳烟排放大幅度降低。     

文丘里管废气再循环系统对涡轮增压柴油机性能影响的研究

加装文丘里管的高压废气再循环(Exhaust gas re-circulation,EGR)进气系统,在兼顾柴油机经济性、动力性的前提下,研究该进气系统对NO_x排放的影响。根据一款柴油机的基本结构建立柴油机一维仿真计算模型和燃烧室的三维仿真计算模型。在对模型进行标定和对柴油机原机性能仿真计算的基础上,为进气系统引入文丘里管装置并对其结构参数进行优化设计。应用所建立的一维和三维柴油机模型,对文丘里管EGR系统柴油机的经济性、NO_x和Soot排放特性进行仿真计算研究,并对计算结果进行试验验证。研究结果表明,优化设计的文丘里管EGR系统可使柴油机在欧洲稳态循环(European steady state cycle,ESC)各工况下实现较为理想的EGR率,并在不明显影响柴油机燃油经济性的前提下,使NO_x排放量下降了约28.4%。文丘里管进气系统可以实现较为理想的高压EGR循环,在柴油机ESC工况下(怠速除外)能够达到较为理想的EGR率。     

船舶柴油机冷EGR自控系统设计研究

设计了一套船舶柴油机冷EGR系统,并对其控制系统进行了软件和硬件的设计,控制部分通过单片机控制伺服水泵的转速来调节冷却水的循环量,保证不同工况下的最佳EGR冷却温度,在船舶柴油机YC4F90L-C20上进行了试验,结果表明,与无EGR系统相比,该自控冷EGR系统在CO和HC的排放基本不变的情况下,可以有效的降低NOx的排放和烟度,保护了海洋环境。     

Experimental verification of optimized NOX reduction strategies in a decrepit Euro-3 diesel engine retrofitted with a cooled EGR system

Vehicle-produced NOx is among emissions that deteriorate human health and the environment. To regulate the NOx emissions from transport, especially from diesel-powered vehicles, various standards have been established globally, and regulations are becoming more stringent across the world. Considerable NOx from diesel vehicles are due to the compression ignition characteristics of engines. Accordingly, to meet the national and global standards, manifold advanced aftertreatment technologies, such as EGR, SCR and LNT, have been developed and widely adopted since introduction of the Euro-4 standards in 2006. In Korea, current allowable NOx standards have been greatly reinforced to one fourth of the permissible level in 2004 and one sixth in 2000. However, the percentage of diesel vehicles in Korea more than 10 years old, manufactured prior to Euro-4, is still significant, accounting for 29% of passenger vehicles, 32% of buses, and 45% of trucks in total registration. Against this backdrop, tremendous efforts are required to improve air quality, especially in metropolitan areas. Of all technical options currently available, installing a cooler to typical EGR systems is considered as a more efficient way for superannuated diesel vehicles to meet the Euro-4 than installing a SCR or LNT in terms of technical acceptability and costeffectiveness. In this study, NOx characteristics of a decrepit Euro-3 diesel engine are thoroughly analyzed before and after the installation of the EGR coolers with different cooling capacities. By applying real time control of EGR rate and exhaust backpressure in calibration procedures, optimized NOx reduction strategies are established.

     

纳米WS2车用机油添加剂在柴油发动机中的应用效果研究

通过柴油发动机台架实验和行车实验,分析了不同工况下自制纳米WS2车用机油添加剂在柴油发动机中的应用效果。结果表明,在FC2000柴油发动机台架上应用时,纳米WS2车用机油添加剂在不同转速和不同负载下均能在一定程度上降低发动机油耗率,减少发动机尾气中NOx含量和颗粒物含量,并且当发动机转速为1 700r/min,负载为70N.m时,节油率最高为9.95%,颗粒物减排率最高为49.3%,而当发动机处于低速、高速、低载和高载等工况时,NOx减排率较高,最高达到36%;在柴油机大客车上应用时,纳米WS2车用机油添加剂使其耗油量下降约14.4%,并能在一定程度上降低发动机的运行噪声,使发动机的有害气体(NOx)排放减少34.8%～51%。综合表明纳米WS2车用机油添加剂具有良好的节能减排效果。     

A study of the fouling characteristics of EGR coolers in diesel engines

Diesel emission regulations have recently become more severe. An important goal in diesel engine research is the development of methods to reduce the emissions of NOx and PM (particulate matter). Cooled EGR (exhaust gas recirculation) system has been widely used to reduce the NOx and PM emissions of light-duty diesel engines. In this study, numerical analyses, rig tests and engine tests were performed to assess how changes in internal shape characteristics can improve the heat exchange efficiencies of EGR coolers. The heat exchange efficiencies of EGR coolers have been numerically and experimentally measured during a fouling process. The results show that the second type of oval EGR cooler tested (oval #2) exhibited better heat exchange efficiency than either the first type of oval EGR cooler was tested (oval #1) or the shell and tube cooler examined. The turbulence generated in exhaust gas flows by the wavy-finned design of the oval EGR coolers facilitated PM desorption that allows these coolers to self-purify. With respect to the two similar oval EGR coolers, the cooler with fin pitch 4 mm has better efficiency than the cooler with fin pitch 6 mm due to differences in the heat transfer areas of these coolers. Both CFD analyses involving extreme conditions of engine operation and engine fouling tests involving conditions experienced during vehicular operation indicate that the two oval coolers differed by less than 4% with respect to both initial heat transfer efficiency and heat transfer efficiency after a 78-hour fouling test.     

Performance and emission studies on an agriculture engine on neat Jatropha oil

Diesel engines have proven their utility in the transportation, agriculture, and power sectors in India. They are also potential sources of decentralized energy generation for rural electrification. Concerns on the long-term availability of petroleum diesel and the stringent environmental norms have mandated the search for a renewable alternative to diesel fuel to address these problems. Vegetable oils have been considered good alternatives to diesel in the past couple of years. However, there are many issues related to the use of vegetable oils in diesel engine. Jatropha curcas has been promoted in India as a sustainable substitute to diesel fuel. This study aims to develop a dual fuel engine test rig for evaluating the potential suitability of Jatropha oil as diesel fuel and for determining the performance and emission characteristics of an engine with Jatropha oil. The experimental results suggest that engine performance using Jatropha oil is slightly inferior to that of diesel fuel. The thermal efficiency of the engine was lower, while the brake-specific fuel consumption was higher with Jatropha oil compared with diesel fuel. The levels of nitrogen oxides (NOx) from Jatropha oil during the entire duration of the experiment were lower than those of diesel fuel. The reduction of NOx was found to be an important characteristic of Jatropha oil as NOx emission is the most harmful gaseous emission from engines; as such, its reduction is always the goal of engine researchers and makers. During the entire experiment, carbon monoxide (CO), hydrocarbon (HC), and carbon dioxide (CO₂) emissions in the case of using Jatropha oil were higher than when diesel fuel was used. The higher density and viscosity of Jatropha oil causes lower thermal efficiency and higher brakespecific fuel consumption. The performance and emission characteristics found in this study are significant for the study of replacing diesel fuel from fossils with Jatropha oil in rural India, where the availability of diesel has always been a problem.     

发动机燃用生物柴油的颗粒可溶有机组分及多环芳烃排放

以一台车用柴油机为样机,研究发动机燃用生物柴油的常规排放,重点探讨其颗粒(Particulate matter,PM)、可溶有机组分(Soluble organic fraction,SOF)及多环芳烃(Polycyclic aromatic hydrocarbons,PAHs)的排放特性。所用燃油分别为柴油、生物柴油掺混配比为10%的B10燃油。结果表明,与柴油相比,该车用柴油机燃用B10燃油后颗粒、SOF和PAHs的质量排放均有所降低;NOx排放略有增加,HC和CO排放有所下降。B10燃油燃烧的颗粒SOF中醇类、酮类、醚类质量分数下降;脂类、酸类、醛类质量分数上升。在检测到的12种PAHs中,B10燃油有10种质量排放减少,尤其是苯并(a)芘等高环数致癌性的PAHs降幅明显,这表明发动机燃用生物柴油后,排气颗粒的化学成分毒性有所降低。