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Influence of Exhaust Gas Recirculation on Low-Load Diesel Engine Performance

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Wuhan University Journal of Natural Sciences 2017年第5期22卷 443-448页

作者： cheng wenming LI Xianghu YI Xing School of Automotive Engineering Jiangxi University of Technology School of Mechanical and Electrical Engineering Nanchang University

In the condition of constant speed and light load, an experimental study of a turbocharged and intercooled diesel engine with exhaust gas recirculation （EGR） system focuses on the influence of different EGR rates on combustion process, dynamic performance, economic performance and emission performance of a diesel engine. With the increase of EGR rate, the oxygen concentration of the intake-side decreases, the fuel air equivalence ratio increases, and the maximum explosion pressure in the cylinder decreases. Meanwhile, the average temperature in the cylinder drops, the ignition delay is prolonged, the ignition timing delays, and the maximum heat release rate decreases. The increase of EGR rate makes NOx emissions decrease obviously and continue to decline. When EGR is low, the smoke rate enlarges slowly with the increase of EGR rate, and enlarges greatly at the rate higher than 43% and reaches the maximum at the rate of 57%. When EGR rate is higher than 61%, the smoke rate drops rapidly, and the content of CO and hydrocarbon （HC） increases rapidly with high EGR rate.

关键词： exhaust gas recirculation (EGR) diesel engine performance

The Effect of Ignition Parameters on the Combustion Characteristics of an Aviation Piston Engine

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World Journal of Engineering and Technology 2024年第2期12卷 245-257页

作者： Luda Zhu wenming cheng Eryang Liu Shupeng Wang School of Aircraft Engineering Nanchang Hangkong University Nanchang China

A cylinder combustion simulation model was established for a two-stroke aviation piston engine used in a small unmanned aerial vehicle. The influence of different ignition system parameters on the combustion process of aviation kerosene was studied using this model. The research results showed that under the working conditions of 5500 r/min and 50% throttle opening, as the ignition energy increased, the peak values of average cylinder pressure and average temperature increased, and the combustion duration shortened, The advance of the combustion center of gravity increases the tendency of the engine to knock. Under the same operating conditions, as the ignition timing advances, the peak values of average pressure and average temperature in the cylinder increase, gradually approaching the top dead center, and the tendency of engine detonation increases more significantly.

关键词： Aircraft Piston Engines Aviation Kerosene Ignition Combustion Characteristics Knock

Partial State Feedback Sliding Mode Control of Double-pendulum Crane Systems using Neural Networks

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Partial State Feedback Sliding Mode Control of Double-pendul...

Load's Swing Angle Equation and Structure Parameter for Container Crane Hydraulic Anti-sway System

第三十九届中国控制会议

作者： Qingrong Chen wenming cheng Run Du School of Mechanical Engineering Southwest Jiaotong University Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province

In this paper, a neural network-based partial state feedback incremental sliding mode control scheme is proposed for double-pendulum overhead crane systems. First of all, it is proved that if the hook stays at the equilibrium point, then the payload also stays at the equilibrium point. Based on this, we provide access to address the control issue of the double-pendulum crane without the need for prior knowledge and feedback signals of the payload. Secondly, two neural networks contained in the equivalent control law are used to approximate unknown nonlinear dynamic terms caused by the lack of information such as the mass, swing angle, swing angular velocity, and swing angular acceleration of the payload, as well as the length of the cable connecting the hook and payload. Thirdly, we designed a switching control law to compensate for the unmodeled dynamics such as the parameter uncertainties and unknown bounded external disturbances. Then, we theoretically proved the asymptotic stability of all the sliding surfaces and all state variables. Finally, some simulations are performed to validate the effectiveness of the proposed method.

关键词： Partial State Feedback Neural Network Control Crane Systems Sliding Mode Control Lyapunov Stability Theorem

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Load's Swing Angle Equation and Structure Parameter for Cont...

2010 3rd International Conference on Computer and Electrical Engineering(ICCEE 2010)

作者： Bin Zhong Yan Zhao wenming cheng Equipment Transportation Department Engineering College of Armed Force Research Institute of Mechanical Engineering Southwest Jiaotong University

The container crane may damp the container swing with hydraulic anti-sway system. The container may be accurately located and promptly placed. To obtain the load’s swing angle equation when the crane trolley is stationary after braking for the container crane’s hydraulic anti-sway system on the basis of structural characteristic of the anti-sway system and its trolley-load system’s moving characteristic and engineering practice. The system’s structure Parameter is one of influencing factors on the anti-sway system’s performances when the hydraulic cylinder system’s design is accomplished. Through analyzing anti-swing rope’s spatial arrangement characteristic and simulating, simulation results show that changing fixed blocks’ lateral distance may obviously change the system’s structure parameter when the fixed blocks’ lateral distance is less than 2.5 m. And changing anti-swing crown blocks’ longitudinal distance can not obviously improve the anti-sway system’s performances.

关键词： Container crane hydraulic anti-sway system dynamic analysis swing angle equation structure parameter

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粒子群算法在结构非概率可靠性优化中的应用

西南交通大学学报 2011年第5期46卷 847-852页

作者：郑严程文明程跃张则强西南交通大学机械工程研究所四川成都610031 成都大学工业制造学院四川成都610106

为了解决实际工程中不确定性结构的可靠性优化问题,建立了以结构非概率可靠性指标和横截面积为约束条件、最小化结构质量为目标的优化模型.利用非概率集合理论中的凸模型方法,求出可靠性指标,提出了基于粒子群算法的结构非概率可靠性优... 详细信息

为了解决实际工程中不确定性结构的可靠性优化问题,建立了以结构非概率可靠性指标和横截面积为约束条件、最小化结构质量为目标的优化模型.利用非概率集合理论中的凸模型方法,求出可靠性指标,提出了基于粒子群算法的结构非概率可靠性优化方法.算例分析结果表明:与参数取平均值时的结构确定性优化方法相比,容许非概率可靠性指标为零时的结构非确定性优化方法得到的结构质量误差仅为0.009%.随着容许非概率可靠性指标的增大,桁架结构横截面积及质量也相应增大;当容许非概率可靠性指标为1.5时,与梯度投影法优化结果相比,利用该方法优化后的结构质量减少了0.323%.

关键词：粒子群算法凸模型非概率可靠性优化可靠性指标

Research and practice on the construction of excellent resource sharing course for Crane Metallic Structure

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Research and practice on the construction of excellent resou...

2013年教育技术与管理科学国际会议

作者： Xiao Wu wenming cheng Lanfeng Yu School of Mechanical Engineering Southwest Jiaotong University

The excellent resource sharing course construction aims at promoting the transformation of the concept of education and teaching, leading the reform of teaching content and teaching methods, driving colleges and universities excellent resource through modern information technology to build and share, improving talents training quality and servicing to society. In this paper, the construction practice of excellent resource sharing course is illustrated on the base of National Great Courses, combined with the course of Metallic Structure which is the core professional courses of the Southwest Jiaotong University’s mechanical major. A number of issues in the construction and practice of excellent resource sharing course are analyzed and demonstrated in the aspect of the course characteristic, teaching staff, course content, course resources, etc. The construction of excellent resource sharing courses Metallic Structure is discussed according to the characteristics of course and the training requirements of mechanical talents.

关键词： higher engineering education excellent resource sharing course Metallic Structure construction of course practice

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多人共站第一类混流装配线平衡问题的优化

西南交通大学学报 2021年第5期56卷 981-988页

作者：杨武成程文明西南交通大学机械工程学院四川成都610031

针对使用传统模型和算法求解第一类多人共站混流装配线的平衡问题,兼顾工作站数、工人数和工作站负荷均衡,引入了新变量和不对称约束来构建新的数学模型.提出了一种改进的鸡群算法,使用基于优先权值的编码方式在解码过程中优先选择能最... 详细信息

针对使用传统模型和算法求解第一类多人共站混流装配线的平衡问题,兼顾工作站数、工人数和工作站负荷均衡,引入了新变量和不对称约束来构建新的数学模型.提出了一种改进的鸡群算法,使用基于优先权值的编码方式在解码过程中优先选择能最早开始作业的工人来减少序列相关空闲时间,设定工位分配接受准则来分配工人数量以减少工位平均空闲时间;根据适应值大小将种群分为3个不同的群体来实现系统的有效搜索,其中,公鸡群个体基于其适应值差异在不同大小的邻域范围内搜索,母鸡群个体基于适应值相关的参数分别向所归属的公鸡或者其他公鸡/母鸡方向搜索,小鸡群个体则向其归属的母鸡方向搜索;最后将新模型和改进的鸡群算法用于求解标杆算例.研究结果表明:在算例验证中,对比传统的模型,新模型多找出8个算例的最优解,且寻优速度更快;在算法平均收敛运算时间相似的情况下,本文所提算法求得的平均工人数、工位数以及平滑指标系数等评价指标分别提高了10.74%、16.05%和44.89%,验证了所提模型和算法的有效性和优越性.

关键词：多人共站装配线平衡问题混流装配线鸡群算法数学模型

求解具有恶化工件单机调度问题的改进遗传算法

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西南交通大学学报 2011年第3期46卷 506-511页

作者：郭鹏程文明张则强西南交通大学机械工程研究所四川成都610031

为克服现有算法求解工件数较多的单机调度问题计算量大的缺点,分析了加工时间为阶梯函数的工件排序规则,以极小化最大完工时间为目标,提出了基于局部搜索的改进遗传算法,对基于工序编码方式的染色体设计了线性顺序交叉算子和融合工件排... 详细信息

为克服现有算法求解工件数较多的单机调度问题计算量大的缺点,分析了加工时间为阶梯函数的工件排序规则,以极小化最大完工时间为目标,提出了基于局部搜索的改进遗传算法,对基于工序编码方式的染色体设计了线性顺序交叉算子和融合工件排序性质的局部变异算子,并引入局部搜索策略,提高了算法局部搜索能力和收敛速度.算例测试结果表明:工件数为40件时,与模拟退火算法相比,本文算法求得的最大完工时间平均减少了56.6%,显著缩短了制造周期,并有效地避免了局部最优解,收敛速度显著提高.

关键词：单机调度恶化工件遗传算法完工时间

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复杂生产过程的小故障检测与分类方法

西南交通大学学报 2014年第5期49卷 842-847页

作者：张敏程文明刘娟西南交通大学机械工程学院四川成都610031 西南石油大学电气信息学院四川成都610500

为监测复杂生产过程的状态,根据多元统计过程控制方法和支持向量机理论,将累积和控制图原理扩展为多变量的形式对过程数据进行预处理,并通过主元分析方法提取复杂生产过程的关键信息,得到有效的小故障数据,进而构建计算正常数据的统计... 详细信息

为监测复杂生产过程的状态,根据多元统计过程控制方法和支持向量机理论,将累积和控制图原理扩展为多变量的形式对过程数据进行预处理,并通过主元分析方法提取复杂生产过程的关键信息,得到有效的小故障数据,进而构建计算正常数据的统计量阀值及故障数据的Hotelling T平方统计值(T2)和平方预测误差值,实现了复杂生产过程的小故障模式检测,并采用支持向量机多分类方法将检测到的故障进行了分类.沥青混合料生产过程的仿真研究表明:在集料均值发生小波动、周期性上升和下降3种小故障模式下,故障检测识别率均达到95%,与主元分析方法相比平均提高了75%;分类准确率达到92.5%,与BP神经网络方法相比提高了19.3%.

关键词：故障检测与分类主元分析支持向量机多变量累积和