Experimental Study on the Performance and Emission of Chinese Small Agricultural Diesel Engine Fuelled with Methanol/Biodiesel/DTBP

Diesel engine alternative fuels, such as methanol and biodiesel, are beneficial to reduce diesel engine emission. In order to study the influence of methanol and biodiesel on the performance, economy and emission of small agricultural diesel engine, the physical-chemical properties(cetane number, lower heat value(LHV), viscosity, etc.) of methanol and biodiesel were analyzed. The methanol and biodiesel showed good complementary property to some extent. When a large proportion of methanol was added into biodiesel, the cetane number of the methanol/biodiesel blend will be greatly reduced. Since the cetane number of the blend fuel has great influence on the combustion process of diesel engine, after testing for blending ratio of methanol/biodiesel, the blend was prepared with 5%(BM5), 10%(BM10) and 15%(BM15) methanol, respectively. Di-Tert-Butyl Peroxide(DTBP) was chosen as a cetane number improver to be added into methanol/biodiesel blend. 0.25%, 0.50% and 0.75% of DTBP was added into BM15. The bench test was carried out on a 186 FA diesel engine to study the effect of methanol and DTBP on the engine performance and emissions. The results show that, at rated condition, compared with biodiesel, the NO;concentration of BM5, BM10 and BM15 is reduced by 5.02%, 33.85% and 21.24%, and smoke is reduced by 5.56%, 22.22% and 55.56%. However, the engine power is also reduced by 5.77%, 14.23% and 25.41%, and the brake specific energy consumption is increased by 3.31%, 7.78% and 6.37%. The addition of DTBP in methanol/biodiesel could recover the engine power to the level of diesel. DTBP shows good effect on the reduction of the brake specific energy consumption and NO_(x), CO, HC concentration, but a little increase of exhaust smoke.

Performance, emission and combustion characteristics of DI diesel engine running on blends of honne oil/diesel fuel/kerosene/DMC

Honne oil(tamanu)(H),a non-edible vegetable oil is native for northwards of Northern Marianas islands and the Ryukyu Islands in southern Japan and westward throughout Polynesia.It has remained as an untapped new possible source of alternative fuel that can be used as diesel engine fuel.Literature pertaining to use of vegetable oil in diesel engine with kerosene and dimethyl carbonate(DMC)is scarce.The present research is aimed to investigate experimentally the performance,exhaust emission and combustion characteristics of a direct injection(DI)diesel engine,typically used in agricultural sector,over the entire load range,when fuelled with neat diesel(ND)and blends of diesel fuel(D)/DMC/H/kerosene(K).DMC/D/H/K blends have a potential to improve the performance and emissions and to be an alternative to ND.Experiments have been conducted when fuelled with H20(20%H+80%D),HK(20%H+40%K+40%D)and HKD5(20%H+40%K+35D+5%DMC)to HKD15 in steps of 5%DMC keeping H and K percentages constant.The emissions(CO,HC and smoke density(SD))of fuel blend HKD15 are found to be lowest,with SD dropping significantly.The NOx level is slightly higher with HKD5 to HKD15 as compared to ND.The brake thermal efficiency of HKD5 to HKD15 is same and it is higher than that of ND.There is a good trade off between NOx and SD.Peak cylinder pressure and premixed combustion phase increases as DMC content increase.

Performance, emission and combustion characteristics of direct injection diesel engine running on calophyllum inophyllum linn oil (honne oil)

The present work examines the use of a non-edible vegetable oil namely honne oil,a new possible source of alternative fuel for diesel engine.A Direct Injection(DI)diesel engine typically used in agricultural sector was operated on Neat Diesel(ND)and neat honne oil(H100).At maximum load,with H100,brake thermal efficiency and NOx emission decreased where as emissions like CO,HC,smoke opacity increased.With H100,peak cylinder pressure and maximum rate of pressure rise decreased compared to ND.With H100,occurrence of peak pressure is away from top dead center compared to ND.With H100,ignition delay and combustion duration increased compared to ND.

Assessment of performance,combustion and emissions characteristics of methanol-diesel dual-fuel compression ignition engine:A review

The energy security concern and rapidly diminishing fossil fuel resources demand the development of renewable and economically attractive fuel for reciprocating engines.Methanol is a promising renewable alternative fuel.Numerous studies have been carried out to explore the various aspects of the utilization of methanol in compression ignition(CI)engine.This review paper presents a detailed analysis of the effect of methanol on performance,combustion,and emission(NOx,CO,HC,and soot)characteristics of conventional CI-engine along with dual-fuel combustion mode.This study focuses on methanol utilization in dual-fuel mode,which is an advanced engine combustion mode.First,methanol production and solubility issues of methanol in diesel are briefly discussed.This study discusses the soot and nano-particle emission from the methanol fueled CI-engine,which is one of the main concerns in the current emission legislation.It was found that the utilization of methanol in CI-engine has the potential to improve the performance and simultaneously with a significant reduction in NOx,CO,soot,and nano-particle emissions in comparison to neat diesel operation.However,unburnt HC emission reduces for methanol-diesel blended fuel operation whereas HC emissions are higher for methanoldiesel dual-fuel operation.

Characteristics of Diesel/N-Butanol Blend on a Common Rail Diesel Engine with Exhaust Gas Recirculation

20%n-butanol is blended in diesel by volume(noted as D80B20)and experiment has been carried out to study the effect on the combustion and emission characteristics based on a common rail diesel engine with exhaust gas recirculation(EGR)system.The results reveal thatD80B20 has longer ignition delay,shorter combustion duration and higher maximumin-cylinder temperature than pure diesel(noted as D100).Further,the number concentration and volume concentration of ultrafine particles decrease significantly while NO_(X) emissions increase a little with the addition of n-butanol.When the exhaust gas is induced into cylinder,NO_(X) emissions significantly decrease and ultrafine particles emissions increase.The number geometric mean diameters and volume geometricmean diameters of ultrafine particles increase withEGR ratio.Compared toD100 without EGR,D80B20 with 20%EGR ratio can reduce both NO_(X) and ultrafine particles emissions at 0.14MPa BMEP and 0.56MPa BMEP.

Optical characterization of nano-sized organic carbon particles emitted from a small gasoline engine

The nano-sized organic carbon （NOC） particles emitted from a small gasoline engine were characterized using various ex situ optical techniques to assess their hazardous impact. The exhaust gas was sampled iso-kinetically by a quartz probe and passed through de-ionized water to gather the hydrophilic car- bonaceous particulates as hydrosol. The hydrodynamic diameter of the particles ranged between 1.7 and 3.6 nm at no load, with a mean diameter of 2.4 nm. The particle size in the engine exhaust was found to increase at higher loads, which is attributed to coagulation of the particles. The chemical structure of the particles was analyzed using UV-vis and infra-red spectroscopy. Both the band gap energy and oscillator strength data evaluated from the UV-vis absorbance showed that the NOC particles contained polyaromatic hydrocarbon structures with three to five aromatic rings. Infra-red spectroscopy analysis further confirmed the presence of aliphatic and carbonyl functionalities in the aromatic structures of the particles. The fine size of the particles, their high number concentration for the type of the engine under study and their structural features, make the particles extremely hazardous for environment and health.

Performance,emissions and exergy analyses of adding CNTs to various biodiesel feedstocks

Extraction of biodiesel from waste cooking oil,jatropha,and corn oils is done by transesterification.Diesel and biodiesel were blended at 20%volume ratio to make methyl ester.At doses of 25,50,and 100 mg/l,carbon nanotubes(CNTs)was mixed with biodiesel blend.The objective of the present research is to examine experimentally a diesel engine performance,combustion characteristics,exergy and emissions analyses with inclusion of nano additive to various methyl ester feedstocks.Methyl ester blend is enriched with CNTs as JB20C100,WB20C100 and CB20C100 where the improvements in thermal efficiency are raised about biodiesel mixture by 9%,13%and 15%,respectively.Addition of 100 ppm of CNTs to biodiesel blends achieves the greatest reductions in CO(14%,22%and 30%),HC(16%,20%and 25%),and smoke emissions(15%,19%and 23%)for JB20C100,WB20C100 and CB20C100,respectively.By comparing with B20,blending 100 ppm CNTs with JB20,CB20,and WB20 obtained the highest increases in cylinder pressure of 3%,5%,and 10%,as well as the highest increases in heat release of 4%,7%,and 11%,respectively.The downside of CNTs addition achieves a rise in NOx emissions by 10%,17%,and 22%for JB20C100,WB20C100,and CB20C100,respectively.Exergetic efficiency increases by 8%,19%,and 24%for B20T100,B20A100,and B20C100,respectively.Sustainability index improvements achieve 1.5%,5%and 6.5%,for B20T100,B20A100,and B20C100,respectively.WB20 with CNTs of 100 ppm is highly recommended for improving engine performance,combustion,and exergy characteristics with considerable emissions reduction.

低碳醇汽油发动机燃烧分析实验平台设计及教学应用

为探究低碳醇掺混汽油的醇基燃料在缸内具体的燃烧状态和燃烧过程,该文基于自然吸气式气道喷射汽油发动机搭建实验平台,并改进了燃烧分析功能。基于实验平台开展了3种燃料(92号汽油、甲醇比例85%的甲醇汽油、50%异丙醇掺混的92号汽油)的缸内燃烧实验,分析了醇基燃料燃烧状和在发动机中的燃烧性能。实验平台可完成动力性、经济性分析等测试项目,并可对缸压、放热率以及燃料自燃性质进行测量分析。

EGR技术对生物柴油混合燃料发动机性能的影响研究

为缓解柴油掺烧生物柴油导致的NO_(x)排放过高问题,将4190ZLC船用中速柴油机作为试验台架,通过AVL_FIRE软件建立燃烧室模型,并验证该模型准确性。设置生物柴油掺混比0~40%等4组变量,EGR率0~12.5%等4组变量,进行柴油机燃烧、性能和排放分析。结果表明,掺烧适量生物柴油能够降低柴油机缸内温度,降低Soot排放,但同时会导致NO_(x)排放明显升高;EGR的引入能够实现低温燃烧,显著降低NO_(x)排放,但EGR率过高会增加Soot排放。生物柴油掺混比B40、EGR率12.5%组合NO排放比原机降低47.7%,Soot排放质量分数比原机降低98.13%。本文结果将为柴油掺混生物柴油燃烧并结合EGR技术提供一定的研究方向。

防爆柴油机排气颗粒物的微观结构研究

为研究废气水洗箱和含氧燃料对防爆柴油机排气颗粒物微观结构随工况变化的影响,利用扫描电子显微镜(Scananing Elecron Microscope,SEM)对0#柴油(D100)和丁醇/柴油混合燃料(BD20)的排气颗粒物的微观形貌、分形特征和粒径分布进行研究。其中,丁醇的质量分数为20%。结果显示:经过废气水洗箱后,颗粒物内吸附质含量增多,密集程度升高,在多数工况下,颗粒物支链减少,且BD20有利于减少颗粒物碳烟粒子含量;颗粒物的计盒维数分布在1.70~1.85,且经过废气水洗箱的颗粒物结构更紧密,计盒维数更大,D100的计盒维数大于BD20的计盒维数;颗粒物基础碳粒子粒径分布在10~90 nm,废气水洗箱对颗粒物有沉降作用,使颗粒物平均粒径减小,BD20的平均粒径小于D100平均粒径。

海拔高度对车用柴油发动机性能的影响

基于高原模拟试验台架开展不同海拔高度下柴油发动机的性能排放试验。结果表明:随着海拔高度的增加,进气质量流量减少,空气中氧气含量减少,对高转速和低转速下的最大扭矩输出有较大影响,但在中间转速下其影响较小;随着海拔高度的增加,缸内燃烧效率下降,做功能力下降;随着海拔高度的增加,排气烟度增大,其中在低转速、大负荷下烟度对海拔高度更为敏感;海拔高度为1900m时NO_(x)排放体积分数与平原基本相当,当海拔高度增加到2400m时,NO_(x)排放体积分数显著高于平原下的情况。

不同引燃方式下氨掺氢燃烧对发动机的性能影响

氨被认为是最有前景的零碳燃料之一,但掺氨量过大时氨逃逸现象严重,故将氨中掺混一定比例氢气,促进缸内燃烧反应进行,并将引燃柴油替换成氢气实现零碳燃烧。本文使用CONVERGE软件进行仿真,模拟了柴油引燃与氢气引燃时,氨掺氢对发动机燃烧和排放性能的影响。研究发现在柴油引燃时,当掺氢比为30%时与0时相比,缸内爆压、功率升高,燃油消耗率下降,氨逃逸占比下降,NO_(x)排放升高,CO_(2)零增长,soot、HC等排放改善;在氢气引燃时,当掺氢比为30%时与0时相比,缸内爆压、功率升高,燃油消耗率下降,氨逃逸占比下降,NO_(x)排放升高4倍,燃烧前后CO_(2)零增长,掺氢燃烧后改善了发动机整体性能,柴油引燃模式缸内直喷氨气掺混30%氢是实现净零碳排放较优方案。研究结果为氨燃料的实用性提供了依据,并可用于指导试验研究。

掺烧不同比例的异戊醇对船舶柴油机性能的影响

为了研究不同比例的异戊醇/柴油混合燃料在4190Z L C-2型船用中速柴油机中的燃烧和排放特性,运用AVL_FIRE仿真软件建立柴油机燃烧室模型,并通过台架实验验证其仿真模型的准确性。在仿真软件中通过调整异戊醇在柴油中的掺混比来研究混合燃料对柴油机燃烧和排放性能的影响。结果表明:掺混异戊醇有助于改变NO的生成规律,使NO在速燃期的生成量上升,在缓燃期与后燃期的生成量减少,并且总体生成的NO质量分数降低;随着异戊醇掺混比的上升,CO最终生成质量分数下降,Soot最终生成质量分数上升,同时生成的Soot质量分数峰值降低,在缓燃期的氧化速率增快,并因为较快的耗氧量使得最终生成的Soot质量分数比纯柴油的高。

高原含氧柴油燃料研究现状

高原的低压条件造成柴油燃烧性能下降,导致柴油机出现动力性不足等问题。在柴油中加入醇类燃料、醚类燃料、酯类燃料等含氧燃料,可以在不改变柴油机结构的情况下改善柴油机在高原环境下的使用性能。对上述含氧柴油燃料在柴油发动机中的燃烧特性、动力性和经济性等方面进行对比,结果表明,在高原环境下,含醇柴油会导致发动机滞燃期延长,且脂肪醇的碳数越少影响越严重;含醚柴油缩短滞燃期,但热值较低;含酯柴油凝点较高,难以在高原的低温环境条件下应用;复合型含氧柴油燃料或许能够综合含氧燃料的优点。新型高原含氧柴油燃料应关注聚醚、短链酯以及少量长链醇复合组分。

水翼船动力装置技术特点及未来发展趋势研究

本文介绍了水翼船的技术特点及我国水翼船行业的发展,以船舶动力装置为论题切入点,阐明了蒸汽机、汽轮机、汽油机、柴油机、燃气轮机、核动力装置及联合动力装置的技术特点,重点对柴油机及燃气轮机两类动力装置在水翼船领域的应用及发展进行了研究。柴油机具有较高的经济性及技术成熟度,曾长期在水翼船动力领域占据重要地位,但考虑到当前水翼船动力性及轻量化等方面的特性要求,航空改型燃气轮机目前在水翼船上有着更好的应用前景。

基于IMPSO的双韦伯燃烧参数标定及预测

针对柴油机放热规律的拟合,提出了基于免疫粒子群优化(IMPSO)算法的双韦伯方程标定方法.对25%负荷和100%负荷的放热规律分别进行了标定,对双韦伯方程采用改进算法和免疫算法进行多解问题优化,优化结果表明:量纲为1的决定系数R2大于0.998,最优解稳定性可以达到0.700以上;对其他工况和机型放热规律进行标定,拟合和试验结果吻合,具有良好的泛化性,满足柴油机多工况的放热规律拟合要求;选择转速、循环喷油量、进气压力和进气温度作为输入,建立了多层前馈(BP)神经网络双韦伯方程预测模型,各参数R2均大于0.950,表明预测值与校准值吻合,验证了神经网络预测建模方法的可行性.

预混氢/氨对船用发动机燃烧和排放性能的影响

为了减少内燃机领域的碳排放,降低全球变暖的速度,从柴油机的功率、燃烧和排放性能等方面考察预混氢/氨燃料在高压共轨船用柴油机上应用的可行性。结果表明:随着预混氢/氨混合燃料中氨燃料比例的增加,柴油机的缸内压力峰值和缸内温度峰值升高,但柴油机的功率下降明显。氨燃料的燃烧特性较差,当氨的比例大于60%后,柴油机功率下降更为明显。使用预混氢/氨混合燃料燃烧模式后,柴油机CO_(2)排放大幅降低。当掺氨比例较小时,soot和NO_(x)排放波动较小,CO和N_(2)O排放逐渐升高;当掺氨比例大于50%时,CO、soot、N_(2)O和NO_(x)排放大幅降低。综合考虑柴油机的整体性能,H30/A70被选为最佳的氢/氨混合比例。研究结果可为内燃机减碳提供方向。

气垫船推进系统技术特点研究及未来前景展望

简要介绍了气垫船的技术特点、气垫船推进系统的总体组成,重点对高速柴油机及燃气轮机等推进主机及其技术特点进行了阐述,随后详细介绍了用于气垫船的各类推进器及其技术特点,并对气垫船推进系统未来的发展趋势进行了展望。未来,气垫船主机仍会以高速柴油机及燃气轮机等传统热力发动机为主流,并有望采用电力推进。核动力装置虽然能为船舶提供较强的动力性及续航力,但考虑到其高昂的成本、复杂的结构、庞大的尺寸及重量,以及核泄漏等安全性问题,一定程度上限制了其在气垫船等高性能船舶领域的应用。

某大缸径高速船用柴油机性能优化

通过优化缸内燃烧过程提高某20缸大缸径高速船用柴油机的经济性。基于现有台架试验数据,通过三维燃烧仿真计算提出喷油器和燃烧室型线优化方案,在单缸机台架上进行优选方案的试验验证和超负荷耐久试验验证。仿真和单缸机试验结果表明:喷油器锥角由150°增大至154°、燃油体积流量由100 mL/s减小至95 mL/s都可提高柴油机性能,且大锥角喷油器优势更明显;台阶型燃烧室型线可改善缸内油气混合和燃烧。100 h超负荷耐久试验结果表明,大锥角喷油器满足可靠性设计要求。

生物柴油在柴油机中的应用研究

本文简要介绍了生物柴油在国内外发展现状,并以正和生物柴油为燃料,以4102QBZ增压柴油机为研究对象,进行了纯生物柴油和生物柴油与柴油的混合燃料在柴油机中应用的试验研究。试验结果表明:在柴油机不进行任何调整的情况下,燃用生物柴油能保证柴油机的动力性不变,并明显降低柴油机微粒、烟度、HC和CO排放,是一种理想的替代燃料。