生物柴油溶LPG喷雾特性试验研究

在不改变喷油器结构参数、喷射压力和试验背压的前提下,采用马尔文激光粒度分析仪改变液化石油气（LPG）在生物柴油中的掺混比,研究不同的 LPG 掺混比对生物柴油雾化质量的影响。试验结果表明,LPG 的掺混比越大,生物柴油的雾化质量越好。     

生物柴油酯交换过程优化控制仿真平台的设计

生物柴油酯交换过程具有非线性、时变性和多变量耦合等复杂特性,采用常规控制方法很难获得较好的控制效果,为检验先进优化控制算法在实际生产过程中的应用效果,开发设计了生物柴油酯交换过程优化控制仿真平台.平台采用模块化设计,通过MATLAB和C++.net编程平台之间的数据交互,有效模拟了工艺过程的动态特性,实现了先进优化控制策略的仿真.实验结果表明系统交互性和扩展性优良,为先进优化控制算法的研究提供了良好的验证环境.     

基于酯交换反应的生物柴油中试控制系统

生物柴油是一种值得大力生产和推广的新型能源,本文介绍了酯交换反应制备生物柴油的工艺原理及控制系统的组成.针对此装置中存在的自控水平低及生物柴油产率低的问题,本控制系统利用串行通信和连锁实现了原料自动供给,提高了自控水平;利用连续PID占空比控制方式,改善了对反应釜液位的控制品质,极大地提高了生物柴油的产率.     

混沌粒子群优化算法在柴油排产中的应用

针对柴油生产过程中的加氢精制与调合优化问题,建立加工和库存成本优化模型,采用改进粒子群算法进行计算。通过对某炼油厂一个月的柴油生产数据进行测试,结果表明该算法有较好的应用效果,对柴油排产有一定的指导作用。     

柴油内燃机车辆动力与传动系统建模

研究车辆驾驶仿真系统,为达到真实地仿真车辆运动的特性.针对车辆优化运行速度、加速度等性能,需建立实车动力与传动性能的数学模型.在构造了虚拟车辆数学模型框架基础上,根据柴油内燃机车辆动力与传动系统原理,采用曲线重建、数据拟合方法建立了实车运动学、动力学数学模型.通过驾驶仿真器的操作信号,用建立的内燃机、传动系统数学模型求解虚拟车辆运动及动力参数.将采集的实车运行特性数据与求出的虚拟车辆的数据进行了对比分析,结果证明内燃机、传动系统的数学模型与实车系统运动与动力性能的相似程度较高,利用建立系统为实际研究提供参考.     

基于改进粒子群算法的柴油发电机自适应PID控制

对柴油发电机数字电子调速系统进行了研究;数字电子调速系统是运用闭环控制来实现柴油发电机的转速恒定,以确保供电频率的稳定;传统的柴油发电机组调速器中都是用经典PID控制算法,传统PID控制存在的主要问题其实就是PID参数的整定问题,因为一次性得到的PID参数很难保证其系统的控制效果始终处于最优化状态,因此在频率控制器中引入了基于改进粒子群算法的PID参数自整定方法,实时改变PID参数以保证通过控制取得优化控制效果;在执行器上采用了步进电机,使其调速性能有了很大的改进,成本降低;实验仿真表明,该调速系统动态特性较好,有较高的精度,不失为柴油机调速的一种新方法。     

脂肪酸甲酯添加比例和分子构型对混配柴油系统低温流动性影响的模拟研究

生物柴油是一种优质的清洁能源,与石化柴油混配能很好地改善柴油的低温流动性。为探讨其降凝作用机理,本文以硬脂酸甲酯、油酸甲酯,亚油酸甲酯、亚麻酸甲酯等4种常见的生物柴油组成分子作为添加剂,以石化柴油的组成分子正十六烷为柴油主体,构建不同混配比例的模拟柴油系统,利用Materials Studio软件,对系统的凝点以及降温凝固过程中系统微观结构变化进行了分子动力学模拟计算。采用热容、原子自扩散系数、链头尾距以及系统溶解度参数综合判断了系统的凝点,发现,系统的凝点随添加剂的添加比例以及含双键的数目的增加而呈下降趋势。利用对原子间径向分布函数的分析,根据降温过程中十六烷链微观结构的变化,探讨了添加剂中双键以及甲酯基对柴油系统低温流动性的影响。初步降凝机理为:双键的类块状结构以及甲酯基的类球状结构使得附近的十六烷分子在低温时仍能保持一定的弯曲度,从而影响了十六烷分子的有序排列,阻滞了蜡化作用。     

响应面法优化大豆油下脚料制备生物柴油工艺的研究

随着全球性能源的日益短缺与环境的逐渐恶化,生物柴油作为一种无毒、可生物降解和再生的替代燃料正受到越来越多的关注。研究了利用大豆油下脚料（油脚、皂脚混合物）制取生物柴油的工艺过程。先用乙醚室温下萃取下脚料,料液比1：2（g：mL）,萃取时间2h。离心后分为3层,上层有机相再经丙酮萃取分离出磷脂和中性油,磷脂作为高附加值副产品回收再利用以降低生物柴油的生产成本。分离出的皂相经酸化转化为混合脂肪酸,混合脂肪酸用于酸催化的酯化反应。利用响应面法对酯化反应工艺参数进行了优化,并得到回归方程。方差分析结果表明：在各影响因素中,醇酸摩尔比对转化率的影响最大,其次是反应温度和反应时间,醇酸摩尔比和反应温度的交互作用显著。酯化反应优化后的工艺条件为醇酸摩尔比为5：1,催化剂（H2SO4）添加量3％（wt．％）,反应温度为87℃,反应时间4．74h,在此条件下转化率达到92．5％。     

生物柴油分子系统凝固过程的分子动力学模拟

具有良好的低温流动性是生物柴油的重要特性之一,而这一性质与系统的凝点相关联.本文以硬脂酸甲酯、油酸甲酯等7种常见生物柴油组成分子为研究对象,通过建模构建了7种单组份生物柴油分子的模拟液态模型.利用分子动力学方法对7种液态模型系统的凝固过程进行了研究.采用PCFF力场,在一定的模拟条件下,对系统进行逐次降温分子动力学模拟.根据分子动力学轨迹,计算了不同温度下系统的热容、碳原子自扩散系数以及分子链的头尾距.模拟计算得到的液态热容合理.利用“热容法”和“扩散系数法”对不同系统的凝点进行判断,发现凝点区间基本一致,且与实际凝点基本相吻合.而采用2种区间交集的方法得到的凝点区间则与实际凝点十分相近.以油酸甲酯为例,模拟观察到,随着温度降低,分子链总体呈伸展趋势,符合热力学基本原理.在油酸甲酯的凝点前后,链长及链的微观结构存在明显差异.模拟结果表明,本实验方法对研究生物柴油分子系统确实有效.     

浅谈车用汽油机供油技术的发展及其对燃油性能的要求

1电子控制汽油喷射系统的发展及应用现代汽车上普遍使用的发动机是以汽油、柴油、气体燃料、煤气及液化石油气等为燃料的往复活塞式内燃机。其中以汽油或柴油为燃料的发动机技术较为成熟且应用广泛,简称为汽油机和柴油机。相对于柴油机而言,汽油机因具有体积较小,噪声低,技术成熟等优点而普遍应用于各类轿车及中、小型客、货车。汽油机的燃料是汽油,由原油中提炼出的轻质成分组成。汽车的运行性能与汽油燃烧状况息息相关。液态的汽油是无法燃烧的,所以进入气缸之前汽油必须先雾化和蒸发,然后与空气按一定的比例充分混合后,经进气门进入气缸并被火花塞点燃,产生压力推动活塞下行使发动机曲轴     

MODELING AND CONTROL OF INTERNAL COMBUSTION ENGINES USING INTELLIGENT TECHNIQUES

This article will compare two different fuzzy-derived techniques for controlling small internal combustion engine and modeling fuel spray penetration in the cylinder of a diesel internal combustion engine. The first case study is implemented using conventional fuzzy-based paradigm, where human expertise and operator knowledge were used to select the parameters for the system. The second case study used an adaptive neuro-fuzzy inference system (ANFIS), where automatic adjustment of the system parameters is affected by a neural networks based on prior knowledge. The ANFIS model was shown to achieve an improved accuracy compared to a pure fuzzy model, based on conveniently selected parameters. Future work is concentrating on the establishment of an improved neuro-fuzzy paradigm for adaptive, fast and accurate control of small internal combustion engines.     

Estimation of surface tension of methyl esters biodiesels using computational intelligence technique

Due to environmental benefits, methyl esters biodiesel got a considerable attention as a viable substitute to petroleum-based diesel. Surface tension plays significant role in atomization of this biodiesel since it controls the combustion process inside the engine through fuel–air mixing. Experimental determination of the surface tension of biodiesel is expensive and time consuming which limits its application as substitute for petroleum-based diesel. This is because proper choice of any methyl esters for diesel engine applications depend on the value of surface tension as high value of surface tension brings about difficulty in droplet formation. This work employs computational intelligence technique on the platform of sensitivity based linear learning method (SBLLM) to develop methyl esters surface tension estimator (MESTE) which estimates surface tension of methyl esters biodiesel with high degree of accuracy. Surface tensions of eight different classes of methyl esters were estimated at different temperatures by training and testing of neural network using SBLLM. The estimated surface tensions were compared with experimental results as well as surface tension obtained from Parachor model and Goldhammer model. The outstanding performance of the developed MESTE suggests its potential in estimating surface tension of methyl esters biodiesel for enhancing the atomization in biodiesels engine applications.     

Fuel blend fraction estimation for fuel-flexible combustion control: Uncertainty analysis

“Fuel-flexible combustion control” strategies require accurate fuel composition information. A physics-based fuel blend fraction estimator for lean-burn combustion is used to assess the impact of uncertain variables on the estimator accuracy. For biodiesel blends in a diesel engine, the strategy is shown to be minimally affected by biodiesel feedstock variations, and expected fuel flow and oxygen sensor errors. However, observed airflow estimate errors are expected to lead to large estimator errors. When applied to ethanol blends, the estimator error is lower due to a higher stoichiometric mixture fraction for ethanol, and inherent differences in typical lean-burn gasoline engine operating conditions.     

A FORTRAN program for calculating the thermodynamic and transport properties of diesel fuel

Advanced models of the thermodynamic processes in internal combustion engines require the exact estimation of the thermodynamic and transport properties of combustion reactants and products. Although many works have been reported on the properties of air, fuel vapour and combustion products, a study on the properties of the fuel liquid phase seems to be lacking in the open literature. These properties are very important for simulating the fuel droplet evaporation process, which plays an important role on diesel engine combustion and emitted pollutant modelling. In the present work the values of the thermodynamic and transport properties of liquid diesel fuel are computed, as a function of pressure and temperature, by polynomial fitting against available experimental data. This is accomplished in a fraction of a second when using a personal computer with a very small error. N-Dodecane is treated in the present study, which forms a representative fuel of the diesel fuel in most diesel engine cycle simulations. The relevant computer program subroutines are given in an educational form, in FORTRAN-77 language.     

Online calibration of combustion phase in a diesel engine

In this work, an online calibration mechanism is proposed for the combustion phase in a diesel engine. In particular, a simplified event-based engine model, of which the output predicts the optimum combustion phase, is used to aid the calibration, and the model is updated online along with the engine operation to keep the integrity high so as to improve the quality of optimum combustion phase prediction. It is found this mechanism can be applied to develop an online automated calibration process when the engine system shifts to a new operating point. Engine test results are included to demonstrate the effectiveness of the proposed mechanism.     

Numerical analysis of catalytic efficiency of diesel exhaust purification based on multimedia aided regression model

Automotive diesel has become an international trend, and more and more attention has been paid to the purification of diesel engine. In the face of the European emission standards, we need to develop emission control technologies applicable to high standards. Outside purification is the key to this technology. In this paper, the technology of diesel engine purification outside and outside of China is analyzed. The principle, characteristics, treatment effect and application prospect of various methods are analyzed. In this paper, the process and influence of the tail gas production in diesel engine fuel combustion are expounded. The chemical characteristics and chemical reaction equations of harmful tail gas, the emission hazard of diesel engine and the method and significance of exhaust gas treatment are listed. With the continuous development of multimedia technology, multimedia teaching plays a more and more important role in the field of modern teaching. At the same time, multimedia teaching is a breakthrough in the traditional backward teaching mode. Multimedia assisted instruction is widely used all over the world, and it also faces many problems caused by improper use while improving students’ academic achievements. Multimedia assisted and regression models are adopted in this paper.

     

四气门柴油机进气过程三维数值模拟

为减少柴油机的污染物排放、降低油耗和燃烧噪音,通过计算流体力学(Computational Fluid Dynamics,CFD)数值模拟,对车用电控四气门柴油机进气系统进行不同气门升程下气流稳态流动的数值研究,揭示四气门柴油机的进气流动特点以及气门开度对缸内涡流形成的影响和变化规律.仿真结果为电控四气门柴油机的气道设计、喷雾与燃烧的组织与优化提供理论依据.     

内燃机内甲烷喷射特性的研究

为了研究内燃机内部甲烷气体的喷射特性,采用纹影摄影技术和数字图像处理,研究了甲烷气体在不同喷射压力下的喷射贯穿距离、喷射角度,然后将获取的算法结果与实际测量和实际喷射情况进行对比.研究结果表明:在上升阶段,不同压力下的喷射距离与喷射角度均发生快速增加,而在平缓阶段,不同压力下喷射距离近似呈线性变化,而喷射角度随着压力的增大而减小,并且最终喷射角度趋于一个稳定度数.     

Homogeneous Charge Compression Ignition (HCCI) Engines: A Review

The homogeneous charge compression ignition (HCCI) combustion is considered to be the principally promising future IC engine concepts. HCCI is a concept of hybrid combustion, between the Otto engine and Diesel engine. HCCI is however not a modern finding. Already in the early twentieth century hot bulb engines operated with an HCCI-like combustion. They were superior in terms of brake efficiency compared with the contemporary gasoline engines and at the same level as the diesel engines. High engine efficiencies and ultra low NO emissions and low particulates are the benefits of HCCI engines. Volumetric auto ignited combustion of the compressed lean air–fuel mixture is attributed to these benefits. There are few drawbacks also were there in HCCI engines like, low specific output, narrow operating range, lack control over the ignition process, long start up time and high emissions like CO and UHC emissions. The CO and UHC emissions can be after treated using catalytic converters. In this study a literature review on HCCI engine has been performed and the parameters affecting the HCCI combustion phasing, performance and emissions were discussed. Strategies to widen the peak load bearing capacity of HCCI engine, reducing the emissions like NOx, CO and UHC, easy auto-ignition were discussed in the present study.     

基于声信号小波包分析的故障诊断

为了避免传统的基于振动信号的内燃机主轴承磨损故障诊断中安装传感器以及提取 故障特征频率的麻烦,提出了一种基于内燃机工作声信号小波包图像处理的方法.通过该方法, 可以得到含有内燃机主轴承间隙磨损状态的时频信息，定义出各个标准故障状态的时-频分布 图,建立了基于图像匹配技术的内燃机主轴承磨损故障诊断模型.通过比较待诊断时频分布图 与所有故障模式时频分布图的欧氏距离,可以判断出轴承的间隙磨损状态.结果表明此方法简 单有效、状态信息利用充分．