Effects of Spark Energy on Spark Plug Fault Recognition in a Spark Ignition Engine

The increasing demands for fuel economy and emission reduction have led to the development of lean/diluted combustion strategies for modern Spark Ignition(SI)engines.The new generation of SI engines requires higher spark energy and a longer discharge duration to improve efficiency and reduce the backpressure.However,the increased spark energy gives negative impacts on the ignition system which results in deterioration of the spark plug.Therefore,a numerical model was used to estimate the spark energy of the ignition system based on the breakdown voltage.The trend of spark energy is then recognized by implementing the classification method.Significant features were identified from the Information Gain(IG)scoring of the statistical analysis.k-Nearest Neighbor(KNN),Artificial Neural Network(ANN),and SupportVector Machine(SVM)models were studied to identify the best classifier for the classification stage.For all classifiers,the entire featured dataset was randomly divided into standardized parameter values of training and testing data sets with the ratio of 70-30 for each class.It was shown in the study that the KNN classifier acquired the highest Classification Accuracy(CA)of 94.1%compared to ANN and SVM that score 77.3%and 87.9%on the test data,respectively.

Electrode Erosion of a High Energy Impulse Spark Gap Switch

Based on the principle of thermal conduction, three metal alloys （stainless steel, copper-tungsten and graphite） were chosen as the material of the high impulse current discharging switch. Experimental results indicate that the mass loss and surface erosion morphology of the electrode are related with the electrode material （conductivity σ, melting point Tin, density p and thermal capacity c） and the impulse transferred charge （or energy） per impulse for the same total impulse transferred charge. The experimental results indicate that the mass loss of stainless steel, copper-tungsten and graphite are 380.10 μg/C, 118.10 μg/C and 81.90 μg/C respectively under the condition of a total impulse transferred charge of 525 C and a transferred charge per impulse of 10.5 C. Under the same impulse transferred charge, the mass loss of copper-tungsten（118.10 μg/C） with the transferred charge per impulse at 10.5 C is far larger than the mass loss （38.61μg/C） at a 1.48 C transferred charge per impulse. The electrode erosion mechanism under high energy impulse arcs is analyzed briefly and it is suggested that by selecting high conductive metal or metal alloy as the electrode material of a high energy impulse spark gap switch and setting high erosion resistance material at the top of the electrode, the mass loss of the electrode can be reduced and the life of the switch prolonged.

Spark plasma sintering of a high-energy ball milled Mg-10 wt% Al alloy

The influence of spark plasma sintering(SPS)temperature on microstructure,hardness and corrosion behavior of a high-energy ball milled Mg-10wt%Al alloy was investigated in this work.The holding time and sintering pressure for SPS were kept constant while varying the sintering temperature from 200 to 350℃.The grain size and microstructure were studied using X-ray diffraction analysis,scanning electron microscopy,energy dispersive X-ray spectroscopy,and Archimedes'based density measurement.Corrosion behavior was investigated using potentiodynamic polarization tests.The nanocrystalline regime(grain size<100nm)was maintained even after SPS up to 350℃.The density of the alloy increased with increasing the SPS temperature.Vickers'hardness and corrosion performance improved up to 300℃ followed by a decrease after SPS at 350℃.Possible reasons for densification,strengthening,and corrosion behavior have been discussed in the light of reduced porosity and microstructural changes.

Repeated Sparks Produce Free Energy: A Rigorous Mathematical Explanation of the Authors, by the Hidden Ampere Force Law

This is the twinned paper of the increased mass paper, “Gravity is acting at superluminous infinite speed, thus collapsing special theory of relativity of Einstein, an explanation for almost everything (according to the authors’ rigorous mathematical proof and overwhelming experimental evidence)"?[1]. In the present paper, we describe the repeated spark or repeat current in terms of the hidden, Non-Relativistic Longitudinal Cardinal Ampere Force which is not found yet infallible for every case. The impressive finding is the fact that these repeated sparks as we shall see, have no back-emf, but forward-emf and forward-Ampere-motive-force. The only consumption is the resistive load with the very high currents needed. This means its total energy consumption is less than the released energy-output work plus heat, plus the energy recharging the batteries. All these are in excess of the consumed input energy. This means the Repeated sparking is “over-unity” efficiency and that, using super-conductive materials, we shall have constructed the first “perpetual mobile” plus producing extra electrical energy. Several previous journals that we did not mention here their names did not dare to publish our disliked papers of very important and revolutionary results but were not able to counter argue our arguments. They preferred the silence and have not answered us at all for many years now. Even some of them were involved previously with the repeated sparking which is the same topic of our present paper.

煤矿井下金属结构等效储能模型耦合电磁波能量安全性分析

煤矿井下无线通信设备发射的电磁波能量可以被周围金属结构耦合吸收,这种现象存在点燃矿井内爆炸性气体的危险。现有针对井下金属结构耦合电磁波安全性研究只是对金属结构等效阻性模型耦合电磁波能量进行分析,缺乏对金属结构耦合电磁波能量在时间上积累的储能过程研究。针对上述问题,提出一种适用于金属结构耦合−积累−释放电磁波能量研究的等效储能结构模型,即金属结构等效容性储能模型与金属结构等效感性储能模型。首先通过低衰减度传输线模型,推导出发射天线输出功率、发射天线与金属结构之间距离与接收端感应电压之间的关系。然后建立金属结构等效储能模型,推导出接收端参数与放电火花能量之间的数学关系式,分析了接收端参数对放电火花能量的影响。最后通过接收端感应电压与感应电压有效值的关系,推导出发射天线输出功率、发射天线与金属结构之间距离与放电火花能量之间的数学关系式,分析了发射天线输出功率、发射天线与金属结构之间距离对放电火花能量的影响,并给出在其他参数确定情况下2种金属结构等效储能模型各自的理论参考安全点。仿真结果表明:①对于金属结构等效容性储能模型,放电火花能量随着等效储能电容、接收端感应电压有效值增大而增大,安全点向左偏移,对等效储能电容、接收端感应电压有效值的安全要求变得严苛。②放电火花能量随着发射天线功率增大而增大,随着发射天线与金属结构之间距离增大而减小,得到金属结构等效容性储能模型理论参考安全点。③对于金属结构等效感性储能模型,放电火花能量随着等效储能电感、接收端感应电压有效值增大而增大,安全点向左偏移,对等效储能电感、接收端感应电压有效值的安全要求变得严苛。④放电火花能量随着发射天线功率增大而增大,随着发射天线与金属结构之间距离增大而减小,得到金属结构等效感性储能模型理论参考安全点。⑤对比2种金属结构储能模型理论参考安全点,得到金属结构等效容性储能模型的危险性远大于金属结构等效感性储能模型的结论。

Microstructure and fracture toughness of a TiAl-Nb composite consolidated by spark plasma sintering

A TiAl-Nb composite was prepared by spark plasma sintering （SPS） at 1250 °C and 50 MPa for 5 min from prealloyed TiAl powder and elemental Nb powder in a molar ratio of 9：1 for improving the fracture toughness of TiAl alloy at room temperature. The microstructure, phase constitute, fracture surface and fracture toughness were determined by X-ray diffractometry, electron probe micro-analysis, scanning and transmission electron microscopy and mechanical testing. The results show that the sintered samples mainly consist of γ phase, O phase, niobium solid solution （Nbss） phase and B2 phase. The fracture toughness is as high as 28.7 MPa？m1/2 at room temperature. The ductile Nbss phase plays an important role in absorbing the fracture energy in front of the cracks. Moreover, B2 phase can branch the propagation of the cracks. The microhardness of each phase of the composite was also tested.

正负极性伪火花开关初步研究

介绍一种正负极性工作、无需热丝供电配套的伪火花开关,其触发方式可以采用电触发、空间激光触发以及光纤传输激光能量触发。在电触发模式下开关技术指标达到工作电压±60 kV、脉冲电流16.2 kA以及抖动7 ns;空间光触发模式下,开关抖动3 ns(1 mJ/532 nm),最低触发激光能量0.15 mJ;光纤传输激光能量触发工况下(光纤入射端能量7 mJ/出射端5 mJ/532 nm),开关抖动技术指标达到3 ns。

基于Spark平台和多变量L_2-Boosting回归模型的分布式能源系统短期负荷预测

分布式能源系统负荷预测是系统规划与经济运行的可靠前提和依据,在当前海量高维数据的背景下,有效的在线数据处理平台与精确的负荷预测方法是当前的研究重点。基于分布式能源系统负荷数据特点,在缺失数据处理、坏数据分类以及特征选择的基础上,建立了基于Spark平台与多变量L_2-Boosting回归模型的分布式能源系统短期负荷预测方法。首先,利用Spark平台分割全部数据得到多个子数据模型,通过并行计算提高数据处理效率,采用特征提取方法得出模型需要的输入向量;其次,将得出的有效数据信息输入到多变量L_2-Boosting回归模型进行训练学习,得到训练后的多变量L_2-Boosting回归模型;最后,利用测试数据测试模型。算例结果验证了所提模型的有效性。

基于Spark的MapReduce相似度计算效率优化

随着互联网的用户及内容呈指数级增长,大规模数据场景下的相似度计算对算法的效率提出了更高的要求。为提高算法的执行效率,对MapReduce架构下的算法执行缺陷进行了分析,结合Spark适于迭代型及交互型任务的特点,基于二维划分算法将算法从MapReduce平台移植到Spark平台;同时,通过参数调整、内存优化等方法进一步提高算法的执行效率。通过2组数据集分别在3组不同规模的集群上的实验表明,与MapReduce相比,在Spark平台下算法的执行效率平均提高了4.715倍,平均能耗效率只有Hadoop能耗的24.86%,能耗效率提升了4倍左右。

Spark DAG优化MapReduce协同过滤算法

大数据的规模效应给数据存储、管理以及数据分析带来了极大的挑战,高效率低成本的大数据处理技术成为学术界及工业界的研究热点。为提高协同过滤算法的执行效率,对MapReduce架构下的算法执行步骤进行了分解,并对算法执行缺陷进行了分析。结合Spark适于迭代型及交互型任务的特点,提出将算法从MapReduce平台移植Spark平台的改进思路。设计了算法在Spark中的实现流程,并通过参数调整、内存优化等方法进一步提高算法效率。实验结果表明:与MapReduce平台中的算法相比,基于Spark DAG调度的算法能够减少65%以上的HDFS重复I/O操作,执行效率与能耗效率分别提升近200%及50%。

井下环状金属结构等效多圈小环天线接收电磁波能量安全性分析

在井下狭小的巷道空间内金属结构集中,如存在长导线、铁轨、绞车钢丝、支架、铁丝环等不同的金属结构形式。井下金属结构可能会通过磁耦合或接收辐射电磁波的方式接收发射天线的电磁波能量。若金属结构存在断点,则在断点处可产生感应电压;若金属结构断点处发生刮擦,则会在断点处以刮擦放电的形式以很低的电压产生刮擦放电火花,有点燃并引爆井下瓦斯气体的危险。金属结构的不同形式如环状金属结构、柱状金属结构等对耦合电磁波能量具有不同的特性。小型环状金属结构在井下广泛存在,具有体积小、摆放与安装自由度大的特点,井下小型环状金属结构等效为环状接收天线接收发射天线电磁波能量的安全性值得关注与研究。本文针对井下环状金属结构电磁波能量的安全性进行了研究,分析了将井下环状金属结构等效为多圈小环接收天线接收电磁波能量的安全性。建立了环状金属结构等效多圈小环接收天线的等效电路,求出了环状金属结构等效多圈小环接收天线负载上消耗的功率。当环状金属结构等效多圈小环接收天线谐振时,小环接收天线的输入阻抗恰好为阻性,可利用环状金属结构等效多圈小环接收天线等效电路求出负载上消耗的最大功率,以及环状金属结构等效多圈小环接收天线与发射天线之间应保持的安全距离。仿真分析了环状金属结构等效多圈小环接收天线的等效半径、导体直径、圈数以及环状金属结构等效多圈小环接收天线和发射天线之间的夹角对负载上消耗最大功率和安全距离的影响。仿真结果表明,安全距离随环状金属结构等效多圈小环接收天线等效半径的增大而增大,随环状金属结构等效多圈小环接收天线导体直径增大变化不明显,随表示发射天线和等效接收天线之间相对高度关系的夹角增大而减小。本文研究可为无线通信新技术在煤矿井下应用的电磁波能量安全性问题提供参考。

汽油机点火系统控制参数对缸内燃烧特性的影响

利用电力测功机和自然吸气汽油机组成的测试平台,通过设计的4种火花塞对发动机点火性能进行了实验研究,结果表明:发动机点火平均需求电压与发动机的负荷、火花塞间隙相关,间隙每增大0.1 mm,平均需求电压上升约1 kV。发动机点火需求能量与发动机的转速、负荷相关;点火可用能量相对于点火需求能量需要保持一定的余量;过渡工况点火电压和点火需求能量均低于稳态工况。点火线圈充磁时间与点火能量之间近似呈线性变化,只有当充磁时间减小到40%以下时,燃烧稳定性才会产生显著劣化。

基于Spark框架的能源互联网电力能源大数据清洗模型

对能源大数据清洗可提高能源大数据质量的正确性、完整性、一致性、可靠性。针对能源大数据清洗过程中的提取统一异常检测模式困难、异常数据修正连续性及准确性低下等问题,提出了一种基于Spark框架的能源能源大数据清洗模型。首先基于改进CURE聚类算法获取正常簇;其次,实现了正常簇的边界样本获取方法,并设计了基于边界样本的异常识别算法;最后通过指数加权移动平均数实现了异常数据修正。通过对某风电场风力发电监测数据进行了数据清洗实验分析,验证了清洗模型的高效性、准确性。

基于Spark Streaming的实时能耗分项计量系统

能耗分项计量能够准确、及时、有效地发现能源使用问题,形成和实现最有效的节能措施。能耗分项计量系统需要对各项能源使用量在不同粒度上进行统计,既有实时性的需求,又需要涉及到聚合、去重、连接等较为复杂的统计需求。由于数据产生快、实时性强、数据量大,所以很难统一采集并入库存储后再作处理,这便导致传统的数据处理架构不能满足需求。为此,提出基于Spark Streaming大数据流式技术构建一个实时能耗分项计量系统,对实时能耗分项计量的系统架构和内部结构进行了详细介绍,并通过实验数据分析了系统的实时数据处理能力。与传统架构不同,实时能耗分项计量系统在数据流动的过程中实时地进行捕捉和处理,一方面把捕捉到的异常信息及时报警到前端,同时把分类分项统计处理的结果保存到数据库,以便进行离线分析和数据挖掘,能有效地解决上述数据处理过程中遇到的问题。

High-temperature mechanical properties and deformation behavior of high Nb containing TiAl alloys fabricated by spark plasma sintering

A high Nb containing TiA1 alloy was prepared from the pre-alloyed powder of Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y （at%） by spark plasma sintering （SPS）. Its high-temperature mechanical properties and compressive deformation behavior were investigated in a temperature range of 700 to 1050℃ and a strain rate range of 0.002 to 0.2 s 1. The results show that the high-temperature mechanical properties of the high Nb containing TiA1 alloy are sensitive to deformation temperature and strain rate, and the sensitivity to strain rate tends to rise with the deformation temperature increasing. The hot workability of the alloy is good at temperatures higher than 900℃, while fracture occurs at lower temperatures. The flow curves of the samples compressed at or above 900℃ exhibit obvious flow softening after the peak stress. Un- der the deformation condition of 900-1050℃ and 0.002-0.2 s 1, the interrelations of peak flow stress, strain rate, and deformation tempera- ture follow the Arrhenius＇ equation modified by a hyperbolic sine function with a stress exponent of 5.99 and an apparent activation energy of 441.2 kJ.mol-1.

Electric ignition energy evaluation and the energy distribution structure of energy released in electrostatic discharge process

Ignition energy is one of tbe important parameters of flammable materials, and evaluating ignition energy precisely is essential to the safety of process industry and combustion science and technology. By using electric spark discharge test system, a series of electric spark discharge experiments were conducted with the capacitor-stored energy in the range of 10 J, 100 J, and 1000 J, respectively. The evaluation method for energy consumed by electric spark, wire, and switch during capacitor discharge process has been studied respectively. The resistance of wire, switch, and plasma between electrodes has been evaluated by different methods and an optimized evaluation method has been obtained. The electric energy consumed by wire, electric switch, and electric spark-induced plasma between electrodes were obtained and the energy structure of capacitor-released energy was analyzed. The dynamic process and the characteristic parameters （the maximum power, duration of discharge process） of electric spark discharge process have been analyzed. Experimental results showed that, electric spark-consumed energy only accounts for 8%-14% of the capacitor-released energy. With the increase of capacitor-released energy, the duration of discharge process becomes longer, and the energy of plasma accounts for more in the capacitor-released energy. The power of electric spark varies with time as a damped sinusoids function and the period and the maximum value increase with the capacitor-released energy.

Numerical Study of the Threshold Intensity Dependence on Wavelength in Laser Spark Ignition of Molecular Hydrogen Combustion

A numerical investigation of laser wavelength dependence on the threshold intensity of spark ignition in molecular hydrogen over a wide pressure range is presented. A modified electron cascade model (Gamal et al., 1993) is applied under the experimental conditions that carried out by Phuoc (2000) to determine the threshold intensity dependence on gas pressure for spark ignition in hydrogen combustion using two laser wavelengths namely;1064 nm and 532 nm. The model involves the solution of the time dependent Boltzmann equation for the electron energy distribution function (EEDF) and a set of rate equations that describe the change of the formed excited molecules population. The model takes into account most of the physical processes that expected to occur in the interaction region. The results showed good agreement between the calculated thresholds for spark ignition and those measured ones for both wavelengths, where the threshold intensities corresponding to the short wavelength (532 nm) are found to be higher than those calculated for the longer one (1064 nm). This result indicates the depletion of the high density of low energy electrons generated through multi-photon ionization at the short wavelength via electron diffusion and vibrational excitation. The study of the EEDF and its parameters (viz, the temporal evolution of: the electron density, ionization rate electron mean energy, …) revealed the important role played by each physical process to the spark ignition as a function of both laser wavelength and gas pressure. More over the study of the time variation of the EEDF explains the characteristics of the ignited spark at the two wavelengths for the tested pressure values.

Conductive Channel for Energy Transmission

Laser spark obtained by using a conical optics is much more appropriate to form conducting channels in atmosphere. Only two types of lasers are actively considered to be used in forming high-conductivity channels in atmosphere, controlled by laser spark： pulsed sub-microsecond gas and chemical lasers （CO2, DF （deuterium fluoride））, short pulse solid-state and UV （ultraviolet） lasers. Main advantage of short pulse lasers is their ability in forming of super long ionized channels with a characteristic diameter of- 100 mm in atmosphere along the beam propagation direction. At estimated electron densities below 1,016 cm3 in these filaments and laser wavelengths in the range of 0.5-1.0 mm, the plasma barely absorbs laser radiation. In this case, the length of the track composed of many filaments is determined by the laser intensity and may reach many kilometers at a femtosecond pulse energy of-100 mJ. However, these lasers could not be used to form high-conductivity long channels in atmosphere. The ohmic resistance of this type a conducting channels turned out to be very high, and the gas in the channels could not be strongly heated （〈 1 J）. An electric breakdown controlled by radiation of femtosecond solid-state laser was implemented in only at a length of 3 m with a voltage of 2 MV across the discharge gap （670 kV/m）. Not so long ago scientific group from P.N. Lebedev physical institute has improved that result, the discharge gap （-1m） had been broken under KrF laser irradiation when switching high-voltage （up to 390 kV/m） electric discharge by 100-ns UV pulses. Our previous result -16 m long conducting channel controlled by a laser spark at the voltage -3 MV was obtained more than 20 years ago in Russia and Japan by using pulsed CO2 laser with energy -0.5 kJ. An average electric field strength was 〈 190 kV/m. It is still too much for efficient applications.

Fabrication of ultrafine grain WC alloys by spark plasma sintering

Ultrafine grain WC alloys were prepared by high energy ball milling and subsequent spark plasma sintering from elemental mixed powders of nominal composition of WC-6Co-1.5Al(%, mass fraction). The influences of spark plasma sintering parameters on the density, hardness, bend strength and microstructure of sintered WC alloys were also investigated. The results show that there existed a proper time combination of pulse current and constant current employed for sintering.When the peak, base, frequency and occupational ratio of pulse current, constant current, total sintering time and sintering pressure were chosen as 3000 A, 360 A, 50 Hz, 50%, 1500 A, 6 min and 30 MPa, respectively, the optimal sintering was a combination application of 1min pulse-current and subsequent 5 min constant-current. The density, hardness and bend strength of the as sintered alloys could get up to 14.224 g/cm^3, HRA94 and 1660 MPa, respectively, and the average grain size of WC was only about 500 nm.

基于放电齿开关的自供电摩擦纳米发电机能量管理电路

基于摩擦起电和静电感应耦合的摩擦纳米发电机(TENG)是一种清洁、可持续的能源技术,但由于其输出具有高电压、低电流特点,限制了其的广泛应用。为提高TENG对传统电子设备的供电效率,提出一个基于气体放电开关与变压器的自供电电源管理电路。该实验利用印刷电路板(PCB)技术制造的放电齿克服了手工制作火花开关的缺点,能够精准控制放电间距,具有更稳定、体积更小等优点,使电源管理电路实现了高度集成化。实验结果表明,该电源管理电路具有优秀的输出性能,在0.6 Hz超低工作频率下,能在60 s内将220μF的电容充电至9.21 V,即存储了9.33 mJ能量,是直接方式的9.5倍。最后,将TENG与此电源管理电路相结合实现了为小型电子设备的高效供电,促进了TENG的实际应用。