喷油参数对重型柴油机喷油器喷油规律的影响

柴油机各孔喷油规律对燃油在燃烧室的分布、雾化、可燃混合气形成、燃烧有重要影响,从而影响柴油机排放性、经济性、动力性。基于自行搭建的动量法各孔喷油规律测试系统,以某大功率柴油机喷油器为研究对象,探讨了不同喷油压力、喷油脉宽和喷孔直径对喷油器各孔喷油规律的影响。结果表明:随着喷油脉宽的增加,相同压力下喷孔喷油速率和流量系数发展趋势保持一致,喷油持续期增加。随着喷油压力的增加,喷油速率和流量系数随之增加,喷孔有效流通面积增大,空化效应更弱。但相比于喷油速率,流量系数变化较小。随着喷孔的直径增大时,喷油速率及其波动增大,喷油速率最大值对应时刻延迟,喷油持续期减小,喷孔的流量系数增大。     

降低493柴油机排气污染物的研究

为满足国家新颁布排放法规的要求,对493柴油机的燃烧系统进行了改进设计,燃烧室由原来的四角ω型改为缩口凸台型,同时减小喷油提前角、提高喷油压力、增加喷孔数目、减小喷孔直径。大量的性能试验、排放试验和燃烧分析的结果表明,改进后的燃烧系统良好地兼顾了柴油机的动力性、经济性和排放特性。     

高压共轨柴油机燃烧室匹配设计

在柴油机引入高压共轨喷油系统后,进行了柴油机燃烧室参数设计匹配研究.提出了高压共轨喷油系统对燃烧室的结构要求.分析了高压喷射用燃烧室的结构设计因素,给出贯穿距离、压缩比、口径比以及径深比合理取值范围,提出了燃烧室匹配设计流程,设计493柴油机的不同结构缩口燃烧室.进行了不同方案燃烧室的匹配实验,实验数据表明,6喷孔及缩口大口径浅坑燃烧室是该柴油机燃烧系统较合理的方案.     

直喷式柴油机高强化燃烧新技术研究

抓住影响柴油机燃烧过程的主要因素，提高混合气形成质量，组织稀薄均质预混合燃烧方式，控制上止点着火，获得理想放热规律，在4气门1135型直喷式试验机上取得了经济性和排放性全面改善的效果。模拟的增压试验对不同增压比、气门重叠角、喷油定时及喷孔尺寸进行了实验研究。结果表明：适当提高增压比和加大气门重叠角，是柴油机强化燃烧的重要措施。     

小议船舶柴油机增压系统使用方法

增压就是提高气缸进气压力的方法,使进入气缸的空气密度增加,进而可以提高喷入气缸的燃油量,以提高柴油机的平均指示压力和平均有效压力Pe。采用废气涡轮增压,由于利用了废气能量,柴油机的经济性同时也得到提高。柴油机功率随增压压力的增大而成比例增加,所以增压是提高柴油机功率的最有效途径。该文通过预防性维护保养可有效解决增压系统出现的故障,提高了船舶运营的经济性和可靠性。     

可调靴形喷油规律的燃烧排放性能仿真研究

以改善大功率柴油机的燃烧与排放性能为目标,提出一种柔性可调的靴形喷油规律。利用Amesim软件建立包括共轨腔、增压泵和喷油器的超高压共轨系统仿真模型,研究可调靴形喷油规律曲线的实现方法。分析靴形喷油规律对柴油机燃烧排放性能的影响。研究结果表明:通过改变超高压共轨系统中增压泵的电磁阀开闭时刻可以实现靴形喷油规律的柔性可调;靴形喷油规律在燃烧排放性能比传统矩形喷油规律表现出更大的潜力和优越性;适当增大靴形喷油规律的喷油提前角有助于改善燃烧;靴形喷油规律匹配较大的预喷油量和预喷提前角可以提高燃油与缸内空气的混合程度,具有较好的排放效果。     

直喷式柴油机微粒排放特性研究

使用柴油机微粒排放单级部分稀释采样系统．对一台单缸车用直喷式柴油机的不 同类型燃烧室和不同油品及喷油提前角的变化作了微粒排放研究。探索了实现直喷式柴油机净化微粒排放的途径．试验表明缩口型燃烧室．适当加大喷油提前角可以明显 改善微粒的排放；燃油品质对微粒排放影响较大．     

柴油机电控蓄压式喷油系统的开发与应用

开发和应用电控蓄压式喷油系统。采用蓄压式泵－喷嘴系统及高速电磁阀来实现燃油增压过程和燃油喷射过程;采用电液比例溢流阀实现共轨燃油压力的调节过程;确定喷油量、喷油压力和喷油定时的电控实现途径;开发实验监控系统以满足喷油系统与柴油机匹配的需要。实现了喷油量、喷油压力和喷油始点的柔性（电子）控制,而且最高喷油压力已达１１３．５ＭＰａ,初步进行了喷油系统与１１５０Ｇ柴油机的匹配实验。在喷油压力与柔性控制方     

双卷流燃烧系统的双燃料发动机燃烧排放特性

为解决因生物柴油粘度过大,以及低温燃烧导致的燃油雾化、燃烧性能和排放恶化等问题,利用AMESim软件和AVL_FIRE软件对发动机燃烧室进行双卷流（DS）改造,对喷油提前角、喷孔直径进行优化匹配。结果表明:双卷流（DS）燃烧室燃油分布更加均匀,在运行范围内燃烧速率和功率比浅盆型燃烧室具有更大的优势;同时在加快燃油扩散速率和提高空气利用率方面具有显著的作用;在提高发动机动力性和经济性方面具有明显的优势。采用DS燃烧室、喷油提前角20.6°、喷孔直径0.28 mm组合结构形式的柴油机,其NO排放比原机降低81.83%,指示功率比原机降低7.73%。研究结果可为船用柴油机双燃料低温燃烧性能优化提供一定的指导依据。     

船用中速机中压共轨电控燃油喷射系统

为提高船用中速机燃油喷射系统性能,减少有害物排放,研制开发一种柴油机中压共轨液力增压式电控燃油喷射系统.以润滑油作为工作介质对燃油进行增压和喷射,无需增加其他增压机构和更换喷油器,结构简单.设计了系统的硬件和软件,并在油泵试验台架上对该系统进行性能试验.结果表明:系统的响应速度快,控制精度高;喷油量、喷油压力和喷油正时控制灵活,调节范围大.系统的工作性能和技术指标可满足船用中速柴油机对电控系统的要求.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that