利用机外废气净化技术降低柴油机排放的试验研究

针对增压直喷柴油机开展全面净化的研究,设计了一套废气再循环(EGR)结合机外废气净化(EGC)系统,该系统能在柴油机较宽转速和负荷范围内有效净化废气排放。根据试验结果得出EGR结合EGC技术在降低柴油机的废气排放方面具有很大突破。     

EGR/EGC技术结合系统降低柴油机排放的研究

对柴油机的排放尾气NOx，CO，HC和PM等进行全面分析，探索设计了一套由EGR（废气再循环技术）和EGC（发动机机外废气净化技术）结合的系统，EGR技术可以有效降低NOx的排放，机外废气净化技术技术可以在有效除去PM的同时降低HC，CO的排放，该系统能在较宽的转速和负荷范围内有效降低废气排放，解决同时降低NOx与PM排放的矛盾，废气排放全面降低。     

EGR对增压柴油机排放特性的影响

废气再循环(EGR)是降低柴油机NOx的一条有效技术路径.对于轻型车用增压中冷柴油机,采用从涡轮前取气回流到压气机后的高压EGR系统.应用真空驱动的弹簧膜片式EGR阀,真空度由控制器根据输入的电压信号量决定,从而控制EGR阀的开度.在不同工况下,研究了EGR阀的流通特性,分析了柴油机的HC、CO、NOx排放,烟度和比油耗随EGR率的变化规律.     

具有自动控制功能的柴油机EGR系统的研制

研究了与柴油机匹配的电控废气再循环系统,进行了电控EGR系统中的部分硬件、硬件电路设计和软件的编写,EGR的实现方式和EGR系统与柴油机匹配的问题.试验用柴油机在使用了自行设计的电控EGR系统后,实现了整个转速、负荷范围内EGR率的自动控制.13工况排放测试结果表明:采用EGR系统,NOx排放降低26.7 %、微粒总量和HC排放几乎不变、CO排放上升15.5 %.     

WP3四缸柴油机实现国Ⅳ排放的技术研究

首先以某一国Ⅲ柴油机为样机,增加结构优化后的废气再循环(EGR)系统,在未装备后处理装置前提下进行欧洲稳态测试循环(ESC)和欧洲瞬态测试循环(ETC)测试;然后在实验台架上对加装柴油机氧化催化器(DOC)和微粒氧化催化转化器(POC)后处理装置前后的柴油机进行ESC测试。实验结果表明,EGR系统和DOC+POC后处理同时使用才能有效降低NOx和颗粒物(PM)的排放,达到柴油机国Ⅳ排放标准。     

增压柴油机废气再循环技术的应用研究

随着排放标准更加严格,为了降低增压柴油机NOx的排放,采用并联的文曲利管EGR系统,可克服在高负荷工况下排气压力低于进气压力的困难,能实现废气再循环,并分析了不同工况下EGR率对增压柴油机性能的影响.     

EGR+DPF系统降低柴油机的排放

柴油机具有良好的动力性和经济性,汽车柴油机已成为发展趋势,但柴油机NOx和颗粒(PM)的高排放成为制约柴油车发展的因素之一。随着机动车排放法规的日益严格,降低NOx和颗粒的排放成为现阶段柴油机汽车的主要研究课题。废气再循环(EGR)技术是现今降低柴油机NOx排放的有效方法之一,应用颗粒捕集器(DPF)可以有效的降低尾气中颗粒的排放。本文介绍了EGR技术和DPF技术的原理、特点,对不同工况下EGR对NOx排放进行了分析,同时对不同工况下颗粒捕集器的再生效率进行了研究,结果表明适宜的EGR率和颗粒再生效率才能同时降低柴油机NOx和PM的排放。     

柴油机实现高EGR率方法的计算分析

废气再循环是简单有效地减少NOx排放的方法。本文讨论了在柴油机中实现EGR的方法，并以一台4缸柴油机为例计算了不同工况条件下高、低压EGR系统的柴油机性能参数变化情况。结果表明：低压EGR系统在NOx排放上优于高压EGR系统；在高压EGR系统中，背压阀的位置对柴油机性能有一定影响；带有稳压箱的低压EGR系统在相同EGR率下油耗增加和功率损失最小。     

柴油机废气再循环电控系统的设计及应用

针对增压直喷柴油机开展废气再循环(EGR)技术的研究与应用,依据柴油机EGR控制系统的工作特点和功能要求,进行了控制系统的硬件电路设计和控制软件编写,实际控制效果良好,有效降低了氮氧化物的排放。     

某柴油机进气歧管EGR分布的CFD模拟与优化

废气再循环(EGR)可以有效降低NOx排放。对于采用EGR技术的多缸柴油机,若各缸废气分配不均会影响其燃烧稳定性,导致各缸工作不一致。本文采用1D-3D耦合计算方法,对柴油机部分负荷工况点进行CFD分析。通过对比EGR管出口处速度流场及各缸EGR率,找到优化方向,解决产品实际问题。     

Strategies for high-performance supercapacitors for HEV

Our paper highlights the role of supercapacitors in hybrid electric vehicles (HEVs), the current response to the worldwide demand for a clean and low fuel-consuming transport. The main strategies for increasing the specific energy of supercapacitors, which are electrochemical energy storage/conversion systems of high-specific power, are discussed, with the focus on electrode material, electrolyte and electrode/electrolyte interface properties. Particular emphasis is given to the use of ionic liquids (IL), which are attracting much attention as green and solvent-free electrolytes, and to the development of high-voltage, IL-based hybrid supercapacitor with high surface area carbon negative electrode and poly(3-methylthiophene) positive. Based on the results of laboratory cells featuring N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide and 1-ethyl-3-methyl-imidazolium bis(trifluoromethanesulfonylimide) ILs, the specific energies of hybrid supercapacitor modules are evaluated and compared to those expected for double-layer carbon supercapacitors displaying the same ILs.     

面向2050年的中国电力发展展望

电力转型是我国能源转型的重要环节。本文基于自主开发的适合我国中长期电力发展的源网荷储协调规划模型,将各类电源、骨干电网、需求侧资源与储能等统筹考虑,在计及相关发展目标与约束条件的情况下进行系统整体优化,求解了我国当前至2050年电力系统发展优化方案,可为研判我国电力系统发展路径、制定合理转型政策提供量化参考。     

Rules for paths construction for HENs debottlenecking

This paper is based on the heat exchanger network retrofit techniques, developed by Tjoe and Linnhoff and extended by Asante and Zhu. It considers, under the Network Pinch framework, two important cases — the Retrofit Initialisation and Topology Modification when the direct application of the classic Network Pinch concept and rules is not possible. With the help of a system of simple heuristics, these limitations are overcome which extends the application range of the Network Pinch framework.     

固定床反应器催化剂装填方案的优化

脱砷反应器压降升高会严重影响压缩机的安全运行,同时也制约了装置的加工量。分析认为,压降升高的主要原因是床层空隙率减小,而空隙率减小的主要原因是床层杂质增多,堵塞了颗粒间的空隙。阐述了级配剂和除垢篮在抑制压降升高方面的作用,提出级配剂加除垢篮的组合装填方案,有效解决了固定床反应器的压降问题,使撇头周期达到9个月,并对装填方案的进一步优化提出建议。     

Energy use for subsistence and prospects for development

This paper focuses on the present use of energy in the developing countries in order to estimate the energy required for subsistence-level activities and to see how much surplus is available for economically productive activities, taking into account both commercial and non-commercial (firewood, farmwaste) sources of energy. The energy required for subsistence is estimated to be in the range of 0.3 to 0.4 tce per capita. The consumption of most low income groups countries is below this level if only commercial energy is considered. Relations are derived to explain the uses of each of these energy forms in terms of economic and demographic variables from a sample of 82 countries. These relations are then employed to show that the dependence on non-commercial energy is likely to continue beyond 2000 AD and that, inspite of the annual rise of commercial energy consumption by 6%, the improvements in per capita consumption are small because of an increase in population and a decrease in per capita non-commercial energy.     

汽轮机低压叶片材料的选择

汽轮机低压叶片的材料选择对于保证整个汽轮发电机组的安全运行至关重要。从几个方面分析讨论了汽轮机低压叶片材料选择时需要注意的问题，并提出了解决办法。     

Strategy for selection of elements for heat transfer enhancement

The present paper points out that the selection of elements for heat transfer enhancement in heat exchangers requires a methodology to make a direct comparison of the performances of heat exchanger surfaces with different elements. Methods of comparison used in the past are, in many respects, approximate and hence fail to predict accurately the relative performance of conventional heat exchanger surfaces operated with different heat exchanger elements. Owing to the direct use of the Colburn factor for performance assessment, these methods over-predict the relative performance of heat exchangers. In the present paper, a more consistent comparison method is presented and is demonstrated to work by comparison of the performance of an experimentally investigated pin fin heat exchanger with that of a smooth pipe heat exchanger. The method yields results that belong to the volume goodness factors group. It represents a practical approach, as it is applicable to all kinds of heat exchanger surfaces and does not require the conversion of the experimental data in terms of Nusselt number and friction factor for comparison purposes. The present work demonstrates that the suggested method can also be used for performance comparison of existing heat exchanger surfaces with available heat transfer and pressure loss data.     

轧辊退火热处理炉自动控制系统

介绍了轧辊退火生产中自动控制系统的组成和各部分设备功能,通过此集散控制系统实现温度精确控制、数据记录监视以及仪表、电气设备的控制联锁。