A New Method of Diesel Engine Fuel System Fault Diagnosis

A method of diesel engine fuel system fault diagnosis based on wavelet transform and fuzzy C-means clustering is presented. Five characteristic parameters of reflecting fault state are distilled with wavelet transform of pressure wave of high-pressure oil pipe of diesel. The theory and generic approach of fuzzy C-means clustering algorithm (FCM) is given, and the validity of evaluating fuzzy clustering making use of partition coefficient, partition entropy and parting coefficient is pointed out. Identification of fault mode can be completed utilizing standard fault character modes established by FCM algorithm, and calculating and comparing the similarity degree between this standard mode and sample. The arithmetic is applied to all kinds of typical faults diagnose in the diesel engine fuel system. Measuring results indicate that the precision of fault diagnosis is increased with the analysis of wavelet and FCM.     

PAHs formation mechanism during Combustion Process of Diesel Engines

Based on the diesel surrogate fuel (n-heptane and toluene), we develop a new kinetic mechanism of diesel surrogate fuel included polycyclic aromatic hydrocarbon (PAHs) formation and growth of up to five aromatic rings. The new mechanism included 153 species and 697 reactions. We compare it with various experimental data available in the literature including shock tube, n-heptane premixed flames and homogeneous charge compression ignition(HCCI) engine, and the results show the good performance for HCCI combustion prediction by this new mechanism. The presented mechanism can be used as the basis for further reductions and applied the combustion and emission simulation by coupling chemical reaction kinetics model with computational fluid dynamics model in internal combustion engines.     

Research of the Ignition Timing System for Compressed Natural Gas Vehicle

Compared to bi-fuel engine,it uses completely CNG(Compressed nature gas) to replace diesel which can save more oil fuel than bi-fuel engine that reffited diesel engine into CNG engine. A 4102 diesel engine is refitted into CNG engine and a mechanical ignition timing system is designed by the method of gear and belt. The principles and the construction of the system is introduced and the characteristics of the design is analyzed. The system performed well and had good liability when run in a platform. Compared with the previous one, it kept higher dynamic character and emitted lower. It is a cheap one and can be use to reform the diesel engines.     

Multi dimensional numerical simulation of the combustion process on methanol fueled engine

The paper concludes the characters of methanol as a fuel in engines. Based on the kiva 3v program, it conducts the multi dimensional numerical simulation of the operation process in cylinder of a methanol fueled engine to obtain the detail information and performance graphic charts, as well as the real time data of pressure, temperature and so on. It is helpful for the research on methanol fueled engines. The results indicate that the methanol is a green alternative fuel and the methanol fueled engines have steady operations and lower emissions by comparing the numerical results with the data of gasoline engine.     

基于台架试验的渔船柴油机履行新排放标准探讨

环保部2016年发布了GB 15097—2016《船舶发动机排气污染物排放限值及测量方法（中国第一、二阶段）》,该标准相较于《渔业船舶法定检验技术规则（船长大于或等于12 m国内海洋渔业船舶2017）》的要求增加了一氧化碳、碳氢化合物、颗粒物3个控制项目,氮氧化物的排放限值也明显提高。为获知当前中国主流渔船柴油机排放的技术现状、了解履行新标准的差距,对2种典型的渔船柴油机进行了排放污染物测试试验和劣化试验验证。试验结果显示：典型渔船柴油机可满足新标准一阶段的要求,但距离二阶段要求有较大差距。其中颗粒物的排放超出二阶段限值25%~53%。通过两型柴油机试验数据的对比分析发现,燃油喷射方式是改善颗粒物排放和有效降低柴油机劣化程度的关键因素。针对渔船柴油机如何更好的履行二阶段排放要求给出建议：推迟新标准二阶段生效;鼓励研发新产品,促进先进技术引进;控制实船使用燃油质量,提高渔民的环保意识;加强实船监管力度。     

Analysis of Elevated Structure Radiated Noise with BEM-FEM Method

Urban rail transit is becoming an important means of transportation and elevated structure is one important part of urban rail transit. So the radiation noise induced by elevated structure attracts more and more attention. Based on the theory of Helmholtz integral equation of BEM and fluid-structure coupling system of FEM, the sound pressure transmission vector reflecting the relation between structural vibration acceleration and radiation of sound pressure is derived and solved by the element radiation superposition method. The calculated results are in good agreement with the experimental data from a viaduct section of the Beijing airport rapid rail transit.     

Calculation Method of Hydraulic Characteristics for Direct-Return Chilled Water System

In order to optimize design and operation, it is necessary to calculate accurately hydraulic characteristics large central air-conditioning systems. Simplified Model can not be applied to hydraulic calculation of large pipe network topological structure for its large calculation error. Taking into account the regulating characteristics of terminal branch temperature regulating valve, a direct-return chilled water system is studied, an accurate mathematical model of pipe network hydraulic characteristics has been established and a computer logic algorithm with virtual flow has been given. A direct-return pipe network with ten AHU branches is used as simulation calculation object, the pipe network supply-return water pressure difference is calculated, and also the temperature regulating valve opening and actual flow of each branch are calculated in the condition of different supply-return water pressure difference. The calculated results accord with the natural characteristics of high pressure difference unbalanced for direct-return pipe network. The calculation method can ensure calculation convergence.     

Kinetic characteristics of ignition process of diesel surrogate fuel

The purpose of this paper is to identify the effects of toluene and the toluene content which is at different initial temperatures on the ignition delay time of diesel surrogate fuel under homogeneous charge compression ignition (HCCI) engine condition. The CHEMKIN4.1 module (closed homogeneous batch reactor) is used with the constructed diesel surrogate fuel chemical kinetics model to simulate the constant volume. The results show that the ignition property is mainly characterized by n-heptane. The presence of the slowly oxidizing toluene in the surrogate fuel does not affect the auto-ignition time considerably. In addition,the influence of toluene content on the ignition delay time is significant only at low initial temperature. More ignition delayed combustion processes have been found when toluene content is increasing.     

Key technology of detecting hot heavy rail steel surface faults based on machine vision

Aiming at the low efficiency and precision of hot rail steel surface faults detecting at present,a suit of surface defect detection system of hot heavy rail based on the machine vision is put forward. Multi-CCD cameras are used to collect pictures. According to the geometric characteristics of the heavy rail and its defect characteristics of high-frequency region,six angle shot is used for heavy rail,and then various image processing technology are adopted in workstation. The system adopts improved Hough transform to get surface faults and Kohonen network to make a classification for the characteristics of low SVM training algorithm. The above key machine vision technology for detection of hot heavy rail surface defects greatly improves the speed and accuracy of testing and the detecting correct rate arrives over 85%.     

微波膨胀梗制丝关键工艺参数的优化

为研究微波膨胀烟梗制丝关键工艺参数的优化,以某品牌卷烟的烟梗配方模块（上部烟梗配方模块U、中部烟梗配方模块M和下部烟梗配方模块L）为研究对象,对微波膨胀梗制丝工艺的7 个关键工艺进行均匀实验设计,建立了微波膨胀烟梗工艺参数的BP神经网络模型,利用所建立的模型对3个部位模块的工艺参数进行仿真、优化;从仿真结果中分别筛选出上、中、下3个部位烟梗模块的高、中、低3个档次的感官评吸总分及其对应的工艺组合,然后根据筛选的工艺参数组合进行微波膨胀梗丝的中试生产和感官评吸验证;选取按照中试生产的微波膨胀梗丝,并根据混料试验设计方案进行组配,把微波膨胀梗丝样品混合均匀,以某3类烤烟型卷烟叶组为背景,等比例替换叶组中的常规梗丝,并以正常生产的某品牌卷烟为对照进行感官评吸,挑选出不同部位烟梗的最佳工艺参数组合及不同部位烟梗的混配比例。     

甲醇/柴油混合燃料的应用研究

本实验主要采取新的乳化工艺,将柴油、甲醇和水混合,按选定的配比方案研制混合燃料,在X195柴油机上进行试验,获得了较好的负荷特性,热效率有所提高,中、高负荷时耗油率显著下降,平均节油率达9.5%,烟度降低率25.6%以上,具有良好的经济效益和社会效益。     

Carbonyl Emission Influenced by Combustion Process of Diesel Engine

The bench test of diesel engine is conducted fueled with biodiesel, diesel and blending fuel, the changes of cylinder pressure with crank angle is also measured, combined with the measurement results of carbonyl emissions, the theoretical relationship between combustion process and carbonyl formation is analyzed. The results show that, combustion intermediates such as C7, C5, CO and C2H2 are produced in the fuel oxidation process during the premixed combustion phase. The diffusion combustion period extend with the increase of load, and it is the main stage of re-oxidation and decomposition for the intermediate products, the cylinder temperature and pressure increase with the increase of load, while the ignition delay period is shortened, the probability of oxidation and conversion for carbonyl pollutants improve because of the extended residence time in the high-temperature and high pressure region, the high exhaust temperature in high load is conducive to the re-oxidation of carbonyl emissions.     

基于RBF的安徽省资源环境压力动态预警

基于1996—2011年安徽省资源环境的相关数据,从资源压力、环境压力2方面构建安徽省资源环境压力预警指标体系。运用熵权法测算资源环境压力指数,进而运用RBF模型对1996—2011年安徽省资源环境压力演变趋势进行模拟预测,并结合预警指数和警度标准对1996—2011年安徽省资源环境压力预警状况进行分析,旨在为安徽省社会经济与资源环境和谐发展提供参考,使社会经济健康、快速、可持续的发展。结果表明：RBF模型有较高的模拟仿真精度,能够较好地拟合1996—2011年安徽省资源压力、环境压力和资源环境压力指数的发展趋势。安徽省资源压力预警指数总体呈现波动上升趋势,警度由“中警”上升到“巨警”。环境压力指数在1996—2011年一直呈现上升趋势,其预警指数在2004年以前基本处于“中警”格局,但2004年以来,这一指数明显增大,警度由“中警”逐步转变为“重警”和“巨警”状态。可得出结论,影响安徽省资源环境压力的主要因素包括人均用电量、人均用水量、自然灾害受灾面积比重、能源消费标煤总量、工业废气排放量、固体废弃物排放量等,是今后调控的重点。     

Design Approach to the Total Automation Systems of City Light Rail Transit

The design approach to the total automation systems of city light rail transit (LRT) is discussed, according to the specialty of city transport systems. Based on the operation modes and basic functions of LRT, the scheme of automation systems by using of the networked PLC systems is introduced. The general analysis for each sub automation systems is given, and the redundancy and fault tolerant function are emphasized.     

One Auto-optimized Fuzzy Control of Car-engines Based on GA

One new auto-optimized fuzzy control model of car-engines based on genetic arithmetic was introduced aiming at the problem that the parameters of car-engine are of the discreteness, the nonlinear and the uncertain characteristics, with which it is difficult to control accurately the excess air coefficient and the spark advance angle in dynamic procedure when using a conventional control model. The rule of the design scheme of the controller achieving the model based on embedded operating system is discussed. Further more, it is probed that the fuzzy control parameters are optimized automatically using GA based on on-line real-time simulation. The results of experiments show that the dynamic indexes and the fuel economy indexes are all improved greatly and the advantage of the model on reducing fuel consumption is obvious.     

Simulation of High Pressure Startu Poil Pum Pof Turbine

Dynamic mathematical model, which is based on the character of the 200 MW tubine lbricating oil system, is established by means of modularization. On the basis of dynamic mathematical models, simulation model of the startu Pprocess of hign pressure startu Poil pum Pis created with the Visual Fortran language. The validity of this model has been verified by the simulation experiments and analysis. The simulation helps to forecast the dynamic characteristic to high pressure startu Poil pum Pand have some directive significance to design method of lubricating oil system.     

Optimization of Helix Intake Port Based on Numerical Simulation

With numerical simulation, an analysis is done on the three-dimension air flow in the helix intake port of a diesel engine. The anthors acquire the distribution of characteristic parameters of air in the port, such as velocity, pressure, turbulence kinetic energy, as well as the flow coefficient and rotate moment around the erect axes at the outlet. The results of simulation indicate that the negotiability of the port is very good while the ability of forming eddy can be enhanced, so several improve measures have been put forward. Comparing with simulation results of these measures, it finds out that the method of combining increase the distance between the definition curve of volute cavity and central line of valve protruding support as well as increase the eddy shell angle can obviously enhance the ability of forming eddy, which is an efficient and rational method.     

Simulation on crack growth of drill pipe with XFEM

Crack growth of drill pipe is a typical discontinuous problem. It is difficult to simulate with conventional finite element method and extended finite element method (XFEM) is developed in recent years for the problem. With the introduction of XFEM, the XFEM model of 5 inch drill pipe was proposed with different depth initial cracks under combined action between torque and tension. Based on the simulation, It is found that the smaller cracks is not easy to grow, whilst the crack of depth more than 2mm could grow under relatively lower external load and larger growth surface, eventually leads to pipe fracture failure. Through this simulation on crack growth of drill pipe, it is showed that the XFEM is appropriate in analysis of fracture failure.     

MATLAB和VB在温室环境模型构建中的混合编程研究

旨在找到一种MATLAB和VB混合编程的方法,实现日光温室热环境模拟模型软件的可视化编写。采用基于组件对象模型COM（component object module）的方法,研究了MATLAB和VB在模型构建中的混合编程。采用MATLAB软件编写M.源函数文件,实现理论模型中的工程计算和图像图形处理功能,M.源函数文件编译成功后,通过COM方法转换为可被独立调用的组件;采用VB软件编写主程序文件,实现良好的人机交互功能。在主程序中完成模型各项参数的赋值后,再调用COM组件进行理论模型的计算与绘图。COM组件方法可以实现MATLAB和VB的混合编程。以此构建的日光温室热环境模拟模型软件,可在主程序输入各项参数：室外气象条件,温室结构、热性能等,模拟室内热环境的变化。     

Strengthening of Emission Controlling for Small and Medium Sized Motorcycle Engine

It is very difficult for small and medium sized motorcycle engine to use the combination of closed-loop control electronic fuel injection system and three-way catalytic converter for emission controlling due to the high cost. In order to strengthen emission controlling of the carburetor motorcycle engines, the metering characteristics of carburetor are adjusted, combustion chamber as well as intake and exhaust ducts are further optimized, and secondary air injection system and oxidation type catalytic converter are developed, and moreover a simplified positive crankcase ventilator is employed to eliminate the gas blowby from crankcase. It is verified by test cycle testing that pollutant emissions of the carburetor motorcycle engines can be effectively controlled within the emissions limits by taking the above technical approaches.