正丁醇/生物柴油混合燃料的中低温着火特性

通过一台新开发的超高压快速压缩机,进行了不同比例的正丁醇/生物柴油混合燃料在当量比为0.3～1.0、压力为1～6 MPa以及温度为700～975 K条件下的自着火特性研究．结果表明：混合燃料的着火延迟时间随着温度、压力和当量比的升高而减小．此外,混合燃料的着火延迟时间随着正丁醇比例的增加而增大,但随着温度的升高,着火延迟时间对正丁醇的比例不敏感．采用已有的详细动力学模型进行了模拟研究并与试验结果进行了对比．通过对正丁醇/生物柴油自着火特性的化学动力学分析,研究了自着火过程中正丁醇和生物柴油之间的化学相互作用．结果表明：正丁醇的加入极大程度抢夺了生物柴油低温反应产生的自由基,削弱了生物柴油的低温反应路径．     

生物燃料丁醇的研究进展

将丁醇与汽油、其它生物燃料(如甲醇、乙醇)进行了性能对比,回顾了丁醇生产的发展过程并详细介绍了提高丁醇生产能力的各种方法.总结了丁醇作为一种生物燃料在利用燃烧反应器进行的基础燃烧试验和火花点火式发动机中的应用研究进展.对丁醇的燃烧特点进行了分析,结果表明:丁醇作为第二代生物燃料,是一种较好的汽油代用燃料;与乙醇相比,对丁醇的研究还不够广泛,可参考的文献较少.最后对目前丁醇在发动机性能和排放方面的研究成果进行了总结并指出了今后的研究方向.     

新型多碳醇-柴油燃料在发动机上的应用研究

本试验在一台S195柴油机上进行,试验结果表明,新型混合燃料的油耗率比纯柴油要高,但随负荷的增大,这种差距呈下降趋势。新型混合燃料在较大工况范围都保持较低的CO排放量。两种新型燃料的HC排放曲线呈相同的规律,绝大部分工况下,新型混合燃料的HC排放要高于纯柴油。新型混合燃料的NOx排放比纯柴油低,并且随燃料中碳原子数的增加,NOx排放进一步降低。新型混合燃料的碳烟排放比纯柴油低,BL20D80燃料对碳烟排放的改善要优于HL20D80燃料。     

CG125发动机燃用生物燃料(醇燃料)初探

生物燃料是清洁能源,目前,生物燃料主要指醇类燃料。首先简要介绍了醇类燃料的性质、国内外研究以及使用醇类燃料的现状;然后,选择目前国内生产量和保有量最大的小型发动机(排量125 mL)——CG125发动机为研究对象,探讨醇类燃料在该机中应用的技术方案,以及推广应用的途径。     

生物柴油燃料特性的研究

植物油及其衍生物被用作柴油的代用燃料,其中甲酯被定义为“生物柴油“.燃用生物柴油可降低汽车尾气中有害排放物HC,CO和颗粒物PM的浓度,降低CO2的净排放量.文章着重讨论了生物柴油的热值,CN,IV和低温流动性等参数,认为不饱和双键的数目和位置对燃油品质的影响极大.     

美国生物燃料计划推高世界粮价

全球大米和小麦等粮食价格的飞涨,已经导致了贫困国家的饥荒、骚乱和囤积居奇,人们往往将其归咎于中国这类快速发展的经济体粮食消耗量的增加以及恶劣气候导致的作物歉收。5月7日,世界银行行长罗伯特·佐利克在墨西哥访问期间表示,全球生物乙醇燃料生产的增加,亦推高了粮食价格。     

生物燃料在内燃机上应用的研究

随着全球气候变暖问题的日益突出,人类对矿物燃料的需求和依赖受到挑战,开发可再生能源正成为世界各国的重要课题之一。生物燃料的应用,特别在汽车发动机的广泛使用越来越受到青睐。对生物燃料的现状和前景作较广泛的阐述,对其中若干关键技术问题加以探讨。并对解决它们的一些途径作出评价。     

己酸甲酯和正丁醇混合燃料着火延迟试验和模拟

通过一台快速压缩机开展了己酸甲酯和正丁醇混合燃料着火延迟的试验.混合气初始温度为353,K,当量比为1.0,采用79%的Ar/N2混合气进行稀释,上止点压力分别为1.1、1.5和2.0,MPa,正丁醇在混合燃料中的比例分别为0、40%和60%,压缩上止点温度为660~830,K.利用CHEMKIN软件在较宽温度范围内对混合燃料着火延迟进行了模拟比较.结果表明:己酸甲酯/正丁醇的着火延迟随温度变化表现出3阶段燃烧特性,具有明显的负温度系数现象.混合燃料的着火延迟随压缩压力的增大而减小,随正丁醇预混比的增大而增加,正丁醇可减弱混合燃料燃烧爆震倾向.低温燃烧时,混合燃料中的己酸甲酯和正丁醇都呈现两阶段反应特征.高温燃烧时,混合燃料中的己酸甲酯和正丁醇都呈现出单阶段反应现象.正丁醇的加入对己酸甲酯的低温反应路径有较为明显的影响,对其高温反应路径影响不大.     

世界生物燃料研发应用的进展

新一代生物液体燃料在资源潜力、燃料性能和环境效益方面有明显优势,因此成为大型企业技术研发和试验示范的重心。美国Sandia国家实验室研究显示,     

Enhancing idle performance of an n-butanol rotary engine by hydrogen enrichment

Rotary engine generally sustains poor fuel economy and emissions performance at idle condition. Hydrogen has excellent physicochemical properties that can serve as an enhancer to improve the performance of the original engine. In this paper, a modified rotary engine equipped with dual fuel (hydrogen and n-butanol) port injection system and electronic ignition module was developed to explore the influence of hydrogen supplement on enhancing the idle performance of n-butanol rotary engine. In this study, the engine was run at the idle and stoichiometric with the original spark timing. Hydrogen volume percentage in the total intake was gradually increased from 0% to 7.9% by adjusting the fuel flow rate of n-butanol. The experimental results indicated that the engine instability and fuel energy flow rate were both reduced by enlarging the hydrogen supplying level. Combustion periods were shortened thanks to the enrichment of hydrogen. The peak chamber temperature was heightened as hydrogen fraction increased due to the improved combustion. HC and CO emissions were severally reduced by 50.4% and 85.8% when the hydrogen volume percentage was raised from 0% to 7.9%. However, NOx emissions were mildly increased because of the raised chamber temperature by increasing hydrogen fraction.     

Investigation on combustion and emissions characteristics of a hydrogen-blended n-butanol rotary engine

In this paper, a rotary engine equipped with an n-butanol and hydrogen port-injection system was developed to investigate the combustion and emissions characteristics of a hydrogen-blended n-butanol rotary engine at part load and stoichiometric conditions. A self-developed hybrid electronic control unit was adopted to adjust the injection durations of n-butanol and hydrogen. The rotary engine was run under the conditions of 4000 rpm, a manifold absolute pressure of 35 kPa and a fixed spark timing of 45 °CA before the top dead center during the whole testing operation. The hydrogen volumetric fraction in the total intake was varied from 0% to 6.30%. The test results manifested that the brake thermal efficiency and chamber temperature were simultaneously increased with hydrogen addition. The hydrogen supplement obviously shortened flame development and propagation periods. Both chamber pressure integral heat release fraction versus crank angle were increased when the hydrogen fraction was enhanced. HC emissions were reduced by 54.5% when hydrogen volume fraction was raised from 0% to 6.30%, CO and CO₂ emissions were also reduced after increasing hydrogen blending fraction. NOx emissions were mildly elevated due to the improved chamber temperature.     

Study on combustion and emission characteristics of a n-butanol engine with hydrogen direct injection under lean burn conditions

The n-butanol fuel, as a renewable and clean biofuel, could ease the energy crisis and decrease the harmful emissions. As another clean and renewable energy, hydrogen properly offset the high HC emissions and the insufficient of dynamic property of pure n-butanol fuel in SI engines, because of the high diffusion coefficient, high adiabatic flame velocity and low heat value. Hydrogen direct injection not only avoids backfire and lower intake efficiency but also promotes to form in-cylinder stratified mixture, which is helpful to enhance combustion and reduce emissions. This experimental study focused on the combustion and emissions characteristics of a hydrogen direct injection stratified n-butanol engine. Three different hydrogen addition fractions (0%, 2.5%, 5%) were used under five different spark timing (10° ,15° ,20° ,25° ,30° CA BTDC). Engine speed and excess air ratio stabled at 1500 rpm and 1.2 respectively. The direct injection timing of the hydrogen was optimized to form a beter stratified mixture. The obtained results demonstrated that brake power and brake thermal efficiency are increased by addition hydrogen directly injected. The BSFC is decreased with the addition of hydrogen. The peak cylinder pressure and the instantaneous heat release rate raises with the increase of the hydrogen addition fraction. In addition, the HC and CO emissions drop while the NOx emissions sharply rise with the addition of hydrogen. As a whole, with hydrogen direct injection, the power and fuel economy performance of n-butanol engine are markedly improved, harmful emissions are partly decreased.     

我国生物燃料乙醇产业新进展

燃料乙醇产业发展近20年来,为支持国家三农事业、改善大气环境、减少原油进口做出多重贡献。近年来,在国家政策推动下,我国生物燃料乙醇产业引起各界高度关注。产业链相关的生产企业、科研机构、石化和汽车行业等从不同视角做了大量实践和研究。本文从生物燃料乙醇技术进步、炼油产业的关联效应、对汽车行业的影响三方面进行概述,分析当前发展生物燃料乙醇产业呈现的新趋势。技术进步方面,从研究到生产实际,已更多地着眼于开发多种原料灵活加工的方式,构建新的产品结构,并采用技术手段降低过程能耗、发掘净能量提升空间、降低生产成本,开辟纤维素乙醇技术的新途径;此外,在产品转化率的科学评价方式、建立可持续综合效益评估模型以及设计新型对称双阴极结构解决乙醇燃料电池稳定性问题有更深入的研究。炼油产业关联效应方面,大量研究分析了油品升级、乙醇的加入对尾气污染物排放的影响;而燃料乙醇对炼油行业的影响涉及油库的改造、对组分油品质的要求、产品结构优化等诸多层面。汽车行业对新燃料系统的关注度也在不断提高,在乙醇汽油的燃烧效率、喷射策略和非常规污染物排放控制等方面有新的方案和比较。整体产业链的研发活力不断加强,正带动产业向着高质量方向发展。     

我国发展生物液体燃料的资源与技术潜力分析

发展生物质液体燃料有利于满足高品质能源的需求,改善生态环境,提高生物质能源综合利用水平和增加农民收入。清楚地认识和界定我国生物质的资源潜力和技术潜力,是科学、有序和有效地的发展生物液体燃料的关键问题。本文对我国生物质液体燃料资源潜力的分析结果表明,我国生物资源潜力大,但在现有技术和条件下,实际可利用潜力相对较小,缺乏技术经济优势。所以,应根据资源和技术条件,选择适当的技术路径,加强技术研发,并逐步完善产业管理。     

生物燃料在我国公路交通中替代潜力分析

首先从我国生物燃料开发的资源保障性、生产的技术经济性以及现代汽车技术利用的可能性等方面,对生物燃料的开发利用潜力进行了分析。之后重点论述了利用IPAC模型研究我国未来公路交通能源需求以及生物燃料替代的发展情景。研究表明:未来我国公路交通倍增的油品需求对我国石油供应造成巨大压力,推广新型汽车技术和发展替代燃料是降低公路交通油品消耗的战略措施,混合动力汽车技术与生物燃料结合是我国未来公路交通最佳的技术选择,并且生物燃料在我国未来公路交通中将展现出很强的燃料替代前景。     

甲醇在柴油机上应用的技术进展

在比较甲醇和柴油的物化特性的基础上,分析了甲醇作为柴油代用燃料的优劣势,详细综述了在柴油机上燃用甲醇的各种方式,指出甲醇用作柴油替代燃料的应用趋势,为甲醇用作柴油替代燃料的研究提供参考。     

HRD-76柴油生物燃料的模型燃料构建

HRD-76作为典型的第二代柴油生物燃料得到广泛关注.本文通过匹配核磁共振光谱分析的官能团信息,选用2,6,10-三甲基十二烷和正十六烷作为HRD-76燃料的模型燃料.构建了模型燃料的化学反应机理,并对该机理的可靠性进行了验证.最后,利用该模型燃料对HRD-76燃料在不同条件下的着火延迟时间进行了模拟.该模型燃料与实验...     

装载机载荷谱分析及应用

介绍装裁机载荷谱数据的分析方法,并用两种不同方法相互论证数据分析的准确性。通过两种不同发动机的数据比较,对装载机用发动机的性能开发具有一定的指导作用。