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Impact of oxygen enriched combustion on the performance of a single cylinder diesel engine

K. RAJKUMAR, P. GOVINDARAJAN

《能源前沿（英文）》 2011年第5卷第4期页码 398-403 doi: 10.1007/s11708-011-0157-7

摘要： In the present experiment, a computerized single cylinder diesel engine with a data acquisition system was used to study the effects of oxygen enriched combustion technology (OECT) on the performance characteristics. The use of different levels of oxygen-enriched air was compared with respect to percentage load. Increasing the oxygen content in the air leads to faster burn rates and increases the combustibility at the same stoichiometry (oxygen-to-fuel ratio). These effects have the potential to increase the thermal efficiency and specific power output of a diesel engine. The power increases considerably with oxygen enrichment. In addition, oxygen enrichment can also be considered as a way to reduce the sudden loss in power output when the engine operates in a high load condition. Assessed high combustion temperature from the oxygen enriched combustion leads to high combustion efficiency. OECT reduces the volume of flue gases and reduces the effects of greenhouse effects. Engine tests were conducted in the above said engine for different loads and the following performance characteristics like brake power (BP), specific fuel consumption (SFC), mean effective pressure, brake thermal efficiency, mechanical efficiency, and exhaust gas temperature were studied. The objective of this paper is to address, in a systematic way, the key technical issues associated with applying OECT to single cylinder diesel engines.

关键词： oxygen enriched combustion exhaust gas temperature brake power (BP) specific fuel consumption (SFC)

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Real-time monitoring of brake shoe keys in freight cars

Rong ZOU,Zhen-ying XU,Jin-yang LI,Fu-qiang ZHOU

《信息与电子工程前沿（英文）》 2015年第16卷第3期页码 191-204 doi: 10.1631/FITEE.1400305

摘要： Condition monitoring ensures the safety of freight railroad operations. With the development of machine vision technology, visual inspection has become a principal means of condition monitoring. The brake shoe key (BSK) is an important component in the brake system, and its absence will lead to serious accidents. This paper presents a novel method for automated visual inspection of the BSK condition in freight cars. BSK images are first acquired by hardware devices. The subsequent inspection process is divided into three stages: first, the region-of-interest (ROI) is segmented from the source image by an improved spatial pyramid matching scheme based on multi-scale census transform (MSCT). To localize the BSK in the ROI, census transform (CT) on gradient images is developed in the second stage. Then gradient encoding histogram (GEH) features and linear support vector machines (SVMs) are used to generate a BSK localization classifier. In the last stage, a condition classifier is trained by SVM, but the features are extracted from gray images. Finally, the ROI, BSK localization, and condition classifiers are cascaded to realize a completely automated inspection system. Experimental results show that the system achieves a correct inspection rate of 99.2% and a speed of 5 frames/s, which represents a good real-time performance and high recognition accuracy.

关键词： Condition monitoring Feature expression Brake shoe key Machine vision

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Wear mechanism of disc-brake block material for new type of drilling rig

WANG Xinhua, WANG Simin, ZHANG Siwei, WANG Deguo

《机械工程前沿（英文）》 2008年第3卷第1期页码 10-16 doi: 10.1007/s11465-008-0009-2

摘要： To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and elementary components of the brake block’s wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechanism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Fe-abundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Fe-abundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same time. During the high-temperature wear period, severely influenced by friction heat, obvious softening and plastic flow can be found on the friction surface of the brake block, its anti-shearing ability is weakened, and adhesive wear is intensified. Thermal decomposition of cohesive material in the brake block is simultaneously strengthened, so that constituents shed due to loss of adhesion. Organic fibre is in a flowing state and obviously generates drawing, shearing, carbonization and oxidization. In addition, thermal cracking, thermal oxidization, carbonization and cyclization of organic substances on the surface of brake block can make the friction surface produce pores or cracks, thus fatigue wear occurs.

关键词： asbestos-free frictional Fracture cyclization friction disc-brake

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基于GA－BP网络的人工湿地污水净化效果研究

黄娟,王世和,雒维国,钱卫一,鄢璐

《中国工程科学》 2007年第9卷第2期页码 79-83

摘要：基于大量可靠的试验数据，首次采用遗传神经网络方法模拟湿地除污系统，详细论述了网络拓扑结构优化和训练数据预处理等关键问题，建立了可靠的GA－BP模型，并采用该模型仿真湿地系统正交试验，依据正交试验结果对影响因素进行分级

关键词：人工湿地污水净化 GA-BP网络正交试验

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基于正交实验的BP神经网络预测研究

蔡安辉,刘永刚,孙国雄

《中国工程科学》 2003年第5卷第7期页码 67-71

摘要：

用不同的L₉（3⁴）正交实验方案结果作为训练学习样本集，对BP神经网络预测应用过程的策略进行了探讨，结果表明：完备的正交实验样本集是基本训练学习单元，在完备的正交实验样本集上添加或减少样本数量同一实验的条件下，完备的信息量大的正交实验样本集，能以很高的精度预测完备的信息量小的正交实验样本集；提出了一条新的实验设计思路——通过实验得出一个完备的正交实验样本集，通过计算机用BP

关键词： BP神经网络正交实验策略实验设计思路样本集

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一种改进BP算法在机械手逆运动学中的应用

吴爱国,郝润生

《中国工程科学》 2005年第7卷第7期页码 34-38

摘要：

通过对传统BP算法的分析，提出了一种改进激励函数的学习方法，并且在神经网络的每一层采用不同的学习速率，以提高训练速度；采用所提出的改进BP算法，训练多层前向神经网络，建立机械手逆运动学模型，仿真结果表明了该算法的有效性；与传统BP算法相比，大大提高了机械手逆运动学的精度。

关键词：神经网络 BP算法激励函数机械手逆运动学

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基于BP神经网络的工程图形数据远程安全快速传输法

秦威,秦书玉

《中国工程科学》 2007年第9卷第1期页码 49-52

摘要：根据图形的几何元素相关性的特征，建立参数结构，采用人工神经网络BP算法同时进行数据编码压缩和数据加密，实现复杂工程图形数据的远程高效安全传输。实例表明，此方法可用于实际工程。

关键词：神经网络 BP算法相关性加密快速传输图形数据

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Optimization of turbine cold-end system based on BP neural network and genetic algorithm

Chang CHEN,Danmei XIE,Yangheng XIONG,Hengliang ZHANG

《能源前沿（英文）》 2014年第8卷第4期页码 459-463 doi: 10.1007/s11708-014-0335-5

摘要： The operation condition of the cold-end system of a steam turbine has a direct impact on the economy and security of the unit as it is an indispensible auxiliary system of the thermal power unit. Many factors influence the cold-end operation of a steam turbine; therefore, the operation mode needs to be optimized. The optimization analysis of a 1000 MW ultra-supercritical (USC) unit, the turbine cold-end system, was performed utilizing the back propagation (BP) neural network method with genetic algorithm (GA) optimization analysis. The optimized condenser pressure under different conditions was obtained, and it turned out that the optimized parameters were of significance to the performance and economic operation of the system.

关键词： optimization turbine cold-end system BP neural network genetic algorithm

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基于BP-AGA的非线性组合预测方法研究

王硕,张有富,金菊良

《中国工程科学》 2005年第7卷第4期页码 83-87

摘要：

运用神经网络和加速遗传算法建立非线性组合预测模型，在BP算法训练网络出现收敛速度缓慢时启用加速遗传算法（AGA）来优化网络参数，把AGA的优化结果作为BP算法的初始值，再用BP算法训练网络，如此交替运行BP算法和AGA以加快网络的收敛速度，同时改善局部最小问题。

关键词：神经网络加速遗传算法非线性组合预测预测精度

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一种BP神经网络的改进方法及其应用

李宏刚,吕辉,李刚

《中国工程科学》 2005年第7卷第5期页码 63-65

摘要：

针对BP神经网络中学习因子取值小、收敛性好但训练时间长，学习因子取值大、权值变化剧烈但可能导致振荡的情况，提出了一种修正学习因子的方法，即给学习因子前加一比例因子，在网络权值调整过程中自动调整学习因子的大小

关键词：神经网络改进算法仿真

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基于神经网络的建筑工程造价预测研究

聂规划,刘平峰,何柳

《中国工程科学》 2005年第7卷第10期页码 56-59

摘要：

采用误差反向传播人工神经网络模型（BP网络模型），以建筑特征参数为输入变量，通过实际资料对网络进行训练和模拟，并用贡献分析法筛选输入变量，对网络结构进行优化，结果显示了该模型在建筑工程造价预测中的有效性

关键词： BP神经网络建筑造价预测

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Transient analysis of thermoelastic contact problem of disk brakes

Ali BELHOCINE, Mostefa BOUCHETARA

《机械工程前沿（英文）》 2013年第8卷第2期页码 150-159 doi: 10.1007/s11465-013-0266-6

摘要：

The main purpose of this study is to analyze the thermomechanical behavior of the dry contact between the brake disk and pads during the braking phase. The simulation strategy is based on computer code ANSYS11. The modeling of transient temperature in the disk is actually used to identify the factor of geometric design of the disk to install the ventilation system in vehicles. The thermal-structural analysis is then used with coupling to determine the deformation established and the Von Mises stresses in the disk, the contact pressure distribution in pads. The results are satisfactory compared to those found in the literature.

关键词： brake disks heat flux heat-transfer coefficient Von Mises stress contact pressure

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智能预报模式与水文中长期智能预报方法

陈守煜,郭瑜,王大刚

《中国工程科学》 2006年第8卷第7期页码 30-35

摘要：

建立了以模糊优选、BP神经网络及遗传算法有机结合的智能预报模式与方法。在应用该方法进行中长期水文智能预报时，首先选取训练样本的数量，根据预报因子与预报对象的相关关系得到相对隶属度矩阵;再将其作为BP神经网络输入值以训练连接权重；最后将得到的连接权重值用于预报检验。

关键词：模糊优选 BP神经网络遗传算法智能预报模式中长期水文智能预报

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Three-dimensional electromagnetic analysis and design of permanent magnet retarder

Lezhi YE, Desheng LI, Bingfeng JIAO

《机械工程前沿（英文）》 2010年第5卷第4期页码 438-441 doi: 10.1007/s11465-010-0111-0

摘要： An eddy current retarder for vehicles generates much heat when it works continuously, which leads to serious decline in braking torque. This paper proposes a novel permanent magnet retarder (PMR) for vehicles, whose cooling system connects with engine cooling-water. A three-dimensional finite element model is developed to model the electromagnetic behavior of a permanent magnet retarder under a constant speed. The magnetic field and eddy current field in PMR are numerically solved by a finite element method. By accounting for the nonlinear permeability of the rotor and the weakened effect in the magnetic field that is generated by the eddy current magnetic field, the calculation accuracy of air-gap magnetic field is enhanced. Experiment shows that the temperature of the retarder is less than 150°C, and the braking torque keeps the hard characteristics curve. The calculated air-gap magnetic flux density is fairly good agreement with the measured one.

关键词： auxiliary brake permanent magnet retarder water-cooling finite element method