共查询到17条相似文献,搜索用时 93 毫秒
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根据火花塞点火放电过程中三个阶段等离子流能量的变化,通过改变火花塞电极结构,增大带电粒子的动量进而提高火花塞点火性能。设计了双点火间隙电极结构的等离子流火花塞,该火花塞工作时两个间隙同时点火形成双火核,等离子流能量增大,火焰传播速度快,点火能量及起动性增强。放电测量结果为,当特征长度L+=10mm,电极间隙h=1.0mm时,点火电压为19000V,最大峰值电流为200A,点火能量为103mJ。 相似文献
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基于平面火焰燃烧器设计并搭建了层流甲烷/空气预混燃气激光等离子体点火系统,研究了甲烷/空气预混燃气激光等离子体点火火焰传播与发展过程,发现将激光聚焦在层流火焰与扩散火焰交界面时点火成功率更高。通过大量重复性实验,获得了不同点火位置、当量比、入射激光能量下激光等离子体点火的成功率,发现贫燃、高激光能量更利于稳定燃烧火焰的形成。利用高速摄影技术获得了不同点火条件下火焰前沿位置随时间的变化规律,对火焰吹熄现象进行了研究,发现提高预混燃气当量比、增大入射激光能量能够降低火焰吹熄概率。 相似文献
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《机械工程与自动化》2016,(3)
发动机点火系统一般由点火装置、接触装置、半导体电嘴组成。现行军用飞机由于功能不同,发动机的结构及运行方式亦不同,所以发动机配置的点火系统点火频率及火花能量都不同。基于某型航空发动机的点火系统,研究其在不同储能下点火频率的稳定性,为其他型号航空发动机点火系统设计研发提供依据。 相似文献
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张本举 《机械工程与自动化》2008,(4)
煤气电除尘器与煤气发生炉一起用DCS集中控制,从限制煤气中氧气含量和点火所需能量两个方面避免爆炸的发生.在线连续检测电除尘器入口煤气中氧含量,当过氧时立即跳停电除尘器;使用恒流高压直流电源,并采用逐级缓慢调整电流的方式,以控制电流的点火能量,保证电除尘器的安全运行. 相似文献
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中心管是弹药点火系统的关键零件。在点火系统中起支撑药柱、会聚点火能量的作用。老式弹药的中心管采用纸管,容易吸潮变形,强度也不够,不能满足高密度点火装药的需求。新式弹药广泛采用金属管代替纸管。某军工单位生产的为新型火炮弹药配套的中心管尺寸见图1。材料为15钢,选用毛坯为φ30mm的冷拔钢棒。 相似文献
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为了满足电容充电式无触点(CDI)磁电机定子出厂性能检测的需求,提高检测精度、效率以及自动化水平,研究开发了一种磁电机定子自动检测系统。基于LabVIEW测控平台,设计并开发了检测台人机界面,实现了手动和自动控制两种模式的转换运行;对磁电机电压信号进行了采集、滤波、时频和峰值处理,同步测试出了开路峰值电压和点火提前角等指标;采用三针放电模拟火花塞点火,通过对火花电压和电流同步积分运算得出了点火能量值。该系统通过实际检测台的开发验证,能够自动同时测试出两个定子的各项性能指标,效率提高80%,测试误差不超过1%。研究结果表明,该系统具有较高的测量精度和柔性,能显著降低测试成本和工人劳动强度。 相似文献
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A constant volume combustion chamber is used to investigate the flame kernel development of gasoline air mixtures under various
ignition systems, ignition energies and spark plugs. Three kinds of ignition systems are designed and assembled, and the ignition
energy is controlled by the variation of the dwell time. Several kinds of spark plugs are also tested. The velocity of flame
propagation is measured by a laser deflection method, and the combustion pressure is analyzed by the heat release rate and
the mass fraction burnt. The results represent that as the ignition energy is increased by enlarging either dwell time or
spark plug gap, the heat release rate and the mass fraction burnt are increased. The electrodes materials and shapes influence
the flame kernel development by changing he transfer efficiency of electrical energy to chemical energy. The diameter of electrodes
also influences the heat release rate and the burnt mass fraction. 相似文献
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Hassan Mohamed Young -Sung Ko Keum -Joong Yoon Suk -Ho Chung 《Journal of Mechanical Science and Technology》1999,13(1):82-89
The combustion characteristics and minimum ignition energies using laser-induced spark ignition were demonstrated for quiescent
methane-air mixtures in an optically-accessible, constant volume combustion chamber. Initial pressure and equivalence ratio
as well as spark energy were varied in order to explore the flame behavior with laser-induced spark ignition. Shadowgraphs
for the early stages of combustion process showed that the flame kernel becomes separated into two, one of which grows back
towards the laser source. Eventually after a short period, the two flame kernels developed into two flame fronts propagating
individually, which is unique in laser-induced spark ignition. For a given mixture, lower initial mixture pressure and higher
spark energy resulted in shorter flame initiation period and faster flame propagation. The results of minimum ignition energies
for laser ignition shows higher values than electric discharge results, however, the difference decreases toward lean and
rich flammability limits. 相似文献
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随着石油能源的消耗量愈来愈大,而蕴藏量愈来愈少的国际能源状况,寻找发动机替代能源的要求越来越迫切。在此背景下,笔者以沼气作为小型汽油机的替代燃料,在165F汽油机上进行燃用沼气的改装实验,将原来汽油机磁电机式点火系统改成蓄电池式点火系统,通过试验得出以沼气作为小型汽油机燃料是初步可行的。 相似文献
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近年来,乘用车辆采用了越来越多的电子设备,需要系统考虑车辆上所有电器件的电磁兼容性能;同时发动机技术的提升也对电磁兼容性能提出了更高的要求。火花塞作为发动机点火系列中的点火执行器,其单体不具备辐射电磁波的能力。但火花塞点火时,释放点火线圈储存的能量,在间隙击穿的瞬间,其周围的电场会发生急剧变化,从而产生电磁波。可以通过减小间隙、使用贵金属尖端中心电极等手段,降低点火电压,从而降低电磁波的频率和能量;同时采用合适的包边口尺寸和合适的接线端子位置,采用屏蔽型等手段,来减短和缩小电磁波传播的路径,达到良好的火花塞电磁兼容性能。采用电阻型、电感型、磁阻型的火花塞结构是抑制电磁波常用和主要的手段,通过不同的组合可以实现更好的火花塞电磁兼容性能。 相似文献
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Minimum ignition energies of hydrogen/air and methane/air mixtures have been investigated numerically by solving unsteady
one-dimensional conservation equations with detailed chemical kinetic mechanisms. Initial kernel size needed for numerical
calculation is a sensitive function of initial pressure of a mixture and should be estimated properly to obtain quantitative
agreement with experimental results. A simple macroscopic model to determine minimum ignition energy has been proposed, where
the initial kernel size is correlated with the quenching distance of a mixture and evaluated from the quenching distance determined
from experiment. The simulation predicts minimum ignition energies of two sample mixtures successfully which are in a good
agreement with the experimental data for the ranges of pressure and equivalence ratio. 相似文献