柴油机排气微粒中有机可溶成分的分离与定性分析

本文采用索式萃取法及柱层析法，分离了柴油机排气微粒中的有机可溶成分（ＳＯＦ），并利用色谱－质谱联用技术对柴油及有机可溶成分中的饱和链烃和多环芳香烃（ＰＡＨ）进行了定性分析。此外，还讨论了排气微粒中有机成分的来源。     

车用直喷柴油机排气微粒的排放规律

在直喷式车用柴油机的各种稳态工况下测量了排气微粒、微粒的不可溶组份和微粒的可溶组份的排放规律。试验结果表明，微粒的可溶组份主要产生于中、小负荷。微粒的不可溶组份峰值在大负荷，随空燃比减小而增加。     

进气涡流对车用直喷式柴油机瞬态工况下微粒排放的影响

用自行设计的喷气式可变涡流进气系统（ＡＩＶＳＩＳ）调节气缸内的涡流水平,试验研究了进气涡流对车用直喷式柴油机恒转速增转矩瞬态工况下微粒排放的影响,结果表明,对于一定涡流比的瞬态工况,随着转矩变化率的增大,柴油机的微粒排放量逐渐增加,涡流比越小,瞬态工况微粒的排放随转矩变化率增大的速率越高。相同转矩增长率的瞬态工况,随着涡流比的增大,柴油机微粒的排放量逐渐降低。提高恒转速增转矩瞬态工况缸内的涡流强度     

柴油机排气微粒物理特性及生成机理研究

设计了柴油机排气微粒测量装置,对Ｓ１９５非直喷式柴油机的排气微粒数量浓度、表面积浓度、体积浓度进行了测量,发现了非直喷式柴油机排气微粒数量浓度呈双峰分布的特性。通过研究柴油机排气微粒在不同转速和负荷下的物理分布特性,对微粒的生成机理进行了探讨。     

利用燃烧室内直接采样研究直喷式柴油机微粒的形成

本文叙述了直喷式柴油机微粒（ＰＭ）的形成。并利用一种电磁驱动的采样阀系统在燃烧室内直接进行燃气采样。 对应于不同的曲轴转角和燃烧室内不同位置,分别测量了总微粒及两种组分,可溶性有机成分和不可溶性有机成分的浓度。测量发现,沿着油束喷射轴线方向采样位置上ＳＯＦ的浓度较高,靠近燃烧室壁面附近的采样位置上ＳＯＦ和ＩＳＦ的浓度比远离壁面位置的高。 实验结果显示,ＳＯＦ的形成明显受到油束壁面激冷的影响,燃烧室中微粒的浓度也比排气中的高得多。     

柴油机排气颗粒浓度和粒径分布特征试验研究

研究了6114柴油机不同工况下排气颗粒的数浓度、体积浓度和粒径分布特征，测试工况下柴油机排气颗粒数浓度均呈包括核模态（峰值粒径为10nm-20nm）和积聚模态（峰值粒径为50nm～80nm）的双峰对数正态分布。高转速下排气颗粒数浓度和体积浓度大于中间转速时的数浓度和体积浓度。相同转速下，颗粒体积浓度随负荷增加而增大，而数浓度高转速下随负荷增大而增加，中间转速下随负荷增加没有规律性变化。相同转速下，积聚模态数浓度随负荷增加而增大，核模态数浓度高转速下随负荷增大而增加，但在中间转速下随负荷增加无规律性变化。相同转速下，随负荷增加，核模态峰值粒径有减小趋势。中间转速下积聚模态峰值粒径随负荷增大先增大后减小，高转速下积聚模态峰值随负荷变化无明显变化。中间转速下排气颗粒的核模态峰值粒径小于高转速下核模态的峰值粒径，积聚模态峰值粒径大于高转速下积聚模态的峰值粒径。排气颗粒中核模态粒子占有较大的数量百分比，积聚模态粒子占有较大的体积百分比。     

柴油机排气微粒中SOF成分的试验研究

在柴油机排气管状态下，采用自行设计的微粒采样装置对十三工况下的排气微粒进行了采样，利用气相色谱一质谱联用技术对微粒中可溶性有机组分(SOF)的成分进行了测定、分析；还测定了排气温度对微粒排放质量流量及SOF组分的影响。结果表明：在排气管采样状态下，微粒SOF组分中80％左右为正烷烃和支链烷烃，碳数从C9～C26，余下组分为多环芳香烃(茚、芴、菲、萘等的同系物)以及少量其它有机物；同一工况下，随采样温度升高，微粒排放质量流量、SOF组分种类均呈现减少的趋势。     

进气涡流对车用直喷式柴油机微粒排放的影响

用自行设计的喷气式可变涡流进气系统（ＡＩＶＳＩＳ）调节气缸内的涡流水平,试验研究了进气涡流对连用直喷式柴油机微粒排放的影响。结果表明,中速工况为较低的微粒比排放工况,螺旋进气道形成的涡流水平基本可以满足燃料燃烧的要求,改变涡流水平对改善柴油机微粒排放贡献不大。而低速高负荷工况是柴油机较高的微粒比排放区,适度提高气缸内的涡流水平,可以有效降低柴油机微粒的排放量,使微粒降低的主要因素是不可溶组分排放的降低。高速工况螺旋进气道形成的涡流水平较高。降低气缸内的涡流水平可以降低柴油机微粒的排放量,使微粒排放降低的主要因素是可溶性有机组分排放的降低。     

车用直喷柴油机递增负荷工况下的微粒排放特性

采用自行设计的柴油机微粒袋式取样系统对车用柴油机恒转速、增转矩工况下的微粒排放进行了研究。试验结果表明:在恒转速增转矩瞬态工况下,随着转矩增加率的增大,微粒及其不可溶成分和可溶性有机成分排放量均增加;高转速时转矩增加率对微粒排放的影响稍大。不可溶成分的增加是微粒排放量增大的主要原因,但转速较低时可溶性有机成分的增加也不容忽视。冷却介质温度较低时微粒排放量增大。     

柴油机排气中可溶性有机物排放的特性

通过柴油机台架试验,在一款柴油机上加装氧化型催化转化器(DOC)装置,研究了DOC前/后排气颗粒物中可溶性有机物(SOF)和固相多环芳烃(PAHs)的变化趋势,分析了不同转速和负荷对SOF及PAHs排放的影响以及排气中SOF及PAHs排放在排气过程中的变化规律.结果表明:DOC能明显降低排气中SOF及PAHs排放,SOF最高减排为50.69%,PAHs最高减排为83.28%,同时PAHs的毒性当量最高降低为49.31%.随着柴油机转速增加,燃烧过程后燃增加,排气中SOF及PAHs有增加的趋势,而随负荷的增加,缸内燃烧温度升高,各成分氧化速率加快使得SOF及PAHs排量逐渐降低.随排气输运距离增加,排气组分冷凝现象加重致使SOF及PAHs排量明显升高.     

Evaluation of toxic potential of particulates emitted from Jatropha biodiesel fuelled engine

This study involved a comparative experimental characterization of trace metals and relative toxicity evaluation of particulates emitted by a medium-duty transportation diesel engine using diesel and 20% (v/v) Jatropha biodiesel blend (B20). The engine was operated at 1800 rpm and particulate samples were collected on a filter paper at five loads (0%, 25%, 50%, 75% and 100% rated load) at steady state using a partial flow dilution tunnel, for both diesel and B20. Samples were then analyzed for trace metals, particulate morphology, total organic carbon and benzene soluble organic fraction (BSOF), which is a marker of toxicity. Concentrations of crust elements (Al, Ca, Fe and Mg) in the particulates were relatively higher than that of anthropogenic elements (Cd, Cr, Cu, and Zn) for both test fuels. B20 emitted relatively lower trace metal concentrations in particulates compared to baseline mineral diesel and these concentrations decreased with increasing engine load. Concentrations of gaseous emissions namely CO and THC in biodiesel exhaust were relatively lower than mineral diesel however NOx was relatively higher. Scanning electron microscopy of the particulate samples collected on the filter papers was done along with EDAX analysis for comparison.     

喷油策略耦合EGR对柴油机燃烧过程与CDPF再生性能的影响

以匹配了可变截面几何增压系统(VGT)的D19高压共轨柴油机为研究机型,采用GT-Power和AVL FIRE构建了一维热力学整机模型和催化型微粒捕集器(CDPF)三维仿真模型,针对3 000r/min、50%负荷工况,研究了喷油策略耦合废气再循环(EGR)对燃烧过程和CDPF再生性能的影响。研究表明:随主喷定时提前,有效燃油消耗率(BSFC)先降后升,排气温度降低,排气流量与氧浓度变化则较小,排气中一氧化氮(NO)增加,CDPF再生速率逐渐降低,颗粒物残余量、压降与CDPF出口端二氧化氮(NO_2)同时增加;随EGR率增大,BSFC和排气温度升高,排气流量、排气氧浓度、排气中NO浓度则同时降低。在主喷定时较晚时,随EGR率增大,CDPF再生速率先升后降,颗粒物残余量先降低后略升高;而在主喷定时较早时,随EGR率的增大,CDPF再生速率降低,颗粒物残余量增多。在主喷定时较晚时,提高喷油压力使BSFC和排气温度明显降低;而在主喷定时较早时,提高喷油压力导致BSFC反而快速增加。此外,随喷油压力提高,排气流量与氧浓度变化较小,排气中NO浓度增加,CDPF再生速率逐渐减小,颗粒物残余量、压降和CDPF出口端NO_2排放同时升高。总体上,相比喷油压力,主喷定时对CDPF再生过程影响更大。     

稀土催化反应器净化柴油机排气微粒的实验研究

癌旁粘膜无论在形态和组织化学上都常与正常粘膜有差异。曾有人认为癌旁粘膜处于癌前病变状态。我们用聚合酶链式反应－－限制性片段长度多态性（ＰＣＲ－ＲＦＬＰ）分析方法检测了１３例结直肠癌及其相邻粘膜中ｋｉ－ｒａｓ基因的空变情况。结果发现癌组织和癌旁粘膜都有ｋｉ－ｒａｓ突变２例，仅癌组织有突变的２例，仅癌旁粘膜有突变有１例。该结果说明部分癌旁粘膜已经发生了ｋｉ－ｒａｓ基因的突变，并进一步证实ｋｉ－ｒａｓ     

增压6缸柴油机排气压力波变化规律的试验研究

针对某增压6缸柴油机进行了不同负荷特性下的排气压力波测量,分析了不同负荷特性下排气压力波的变化规律.试验结果表明:对于增压6缸柴油机,当配气相位相同时,在不同的负荷特性下,排气压力波平均值的变化规律是相同的,排气压力波平均值随着扭矩的增加而增大;不同转速下相同扭矩测试点的排气压力波平均值进行横向对比时以及在外特性上,排气压力波平均值随着转速的增加而增高.在不同的负荷特性下,排气压力波强度的变化规律是相同的,排气压力波强度随着扭矩的增加而增高;不同转速下相同扭矩测试点的排气压力渡强度进行横向对比时,排气压力波强度随着转速的增加而增高,但是在外特性上,随着转速的增加,排气压力波强度先增加后减小.     

扩缸与增压——提高现有柴油机功率的两种途径分析

本对比分析了现有机型上采用扩缸和增压方法对柴油机燃烧组织、工作过程，机械负荷与热负荷以及整机性能的影响。扩缸在工作过程组织上与原机无本质上的区别，在提高功率的同时，机械负荷加大，强度下降。     

Theoretical and experimental study on the performance of a diesel engine fueled with diesel–biodiesel blends

This study reports the effects of engine load and biodiesel percentage on the performance of a diesel engine fueled with diesel–biodiesel blends by experiments and a new theoretical model based on the finite-time thermodynamics (FTT). In recent years, biodiesel utilization in diesel engines has been popular due to depletion of petroleum-based diesel fuel. In this study, performance of a single cylinder, four-stroke, direct injection (DI) diesel engine fueled with diesel–biodiesel mixtures has been experimentally and theoretically investigated. The simulation results agree with the experimental data. After model validation, the effects of engine load and biodiesel percentage on engine performance have been parametrically investigated. The results showed that, effective power increases constantly, effective efficiency increases to a specified value and then starts to decrease with increasing engine load at constant biodiesel percentage and compression ratio. However, effective efficiency increases, effective power decreases to a certain value and then begins to increase with increasing biodiesel percentage at constant equivalence ratio and compression ratio.     

燃油中硫含量对颗粒物排放和气体排放的影响

着重阐述了燃油中硫含量与排放颗粒物直径和浓度的关系。通过在船用燃油(MDO)中混入二硫化物((CH3 )3CS-)2(DBDS)调整燃油中的硫含量,对柴油发动机排气进行测量和分析,对可溶性有机物质SOF(Sol-uble Organic Fraction)的浓度,非可溶性物质DS(Dray Soot)的浓度以及排放颗粒物PM的质量浓度以及颗粒物直径的分布进行了分析研究。试验结果表明:随着硫含量的增加,PM直径变小,但是质量浓度增加;SOF质量浓度和DS质量浓度增加,因此PM的质量浓度也增加;发动机的着火迟延期变短,最高燃烧压力降低,同时CO排放浓度增加,N O排放浓度降低。     

6BTA 5.9 G2-1 Cummins engine performance and emission tests using methyl ester mahua (Madhuca indica) oil/diesel blends

Neat mahua oil poses some problems when subjected to prolonged usage in CI engine. The transesterification of mahua oil can reduce these problems. The use of biodiesel fuel as substitute for conventional petroleum fuel in heavy-duty diesel engine is receiving an increasing amount of attention. This interest is based on the properties of bio-diesel including the fact that it is produced from a renewable resource, its biodegradability and potential to exhaust emissions. A Cummins 6BTA 5.9 G2- 1, 158 HP rated power, turbocharged, DI, water cooled diesel engine was run on diesel, methyl ester of mahua oil and its blends at constant speed of 1500 rpm under variable load conditions. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 20, 40, 60, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured to evaluate and compute the behavior of the diesel engine running on biodiesel. The results indicate that with the increase of biodiesel in the blends CO, HC reduces significantly, fuel consumption and NOx emission of biodiesel increases slightly compared with diesel. Brake specific energy consumption decreases and thermal efficiency of engine slightly increases when operating on 20% biodiesel than that operating on diesel.