共查询到20条相似文献,搜索用时 62 毫秒
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《内燃机与动力装置》2016,(3)
以柴油机高压共轨燃油系统为研究对象,结合热力学分析,建立柴油机高压共轨燃油系统数学模型,利用Matlab/Simulink软件对其进行建模与仿真,获得了转速、轨压初始值和油门开度对燃油轨压力、单缸循环喷油量、喷嘴压力和燃油轨压力波动的影响规律。结果表明:喷射压力和单缸循环喷油量随油门开度的增大而增大;喷射压力和单缸循环喷油量随转速的增大而增大;喷射压力和单缸循环喷油量随轨压初始值的增大而增大;燃油轨压力波动量随轨压初始值的增大而减少。研究结果可为高压共轨燃油系统的设计提供参考。 相似文献
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为提升燃油系统电控化改造后4190ZLC-2船用中速柴油机的经济性能和排放性能,开展了燃油系统多参数优化试验;利用AVL FIRE软件对试验得到的经济性最优匹配参数下的柴油机高压工作过程进行了仿真计算;通过对燃烧室内三位流场的分析,提供进一步提高喷油压力和修改燃烧室形状的方案;再利用仿真计算得到喷油压力进一步提高后较优的燃烧室匹配方案。研究结果表明:喷油压力提高后,柴油机总体性能提高;为适应喷油压力的提高,燃烧室的深度和开口直径分别应该减小和增加,但燃烧室的深度太浅会造成燃烧不完全,导致油耗率上升。研究结果为该柴油机的燃烧系统改进提供了理论依据。 相似文献
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为了满足严格的排气排放法规,要求柴油机燃油喷射系统的喷油压力越来越高。在目前使用的几种主要的高速柴油机燃油喷射系统中,泵喷嘴能实现的喷油压力是最高的。本文介绍了泵喷嘴的工作特点,在柴油机上的应用和最新发展。 相似文献
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为了改善重型柴油机低速高负荷的燃油经济性,在一台两级可变截面涡轮增压重型柴油机上开展了空气系统与喷油参数优化策略研究。试验结果表明:对于缸内最高燃烧压力受限工况,获得最低有效燃油消耗率(BSFC)的可变截面涡轮增压器(VGT)关度应该使泵吸功基本为零;选取合适的喷油压力可提高机械效率,在改善燃油经济性的同时使NO_x排放有一定降低,而碳烟排放也能保持在较低水平。基于该优化策略,研究了缸内最高燃烧压力限值对不同工况点燃油经济性的影响,进而研究了提高缸内最高燃烧压力对改善燃油经济性的潜力。结果表明:随着转速与负荷的升高,提高最高燃烧压力限值对燃油经济性的改善作用更加明显;但缸内最高燃烧压力提高到一定程度以后,其对燃油经济性的改善作用逐渐减小。 相似文献
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为了满足严格的排气排放法规,要求柴油机燃油喷射系统的喷油压力越来越高。在目前使用的几种主要的高带柴油机燃油喷射系统中,泵喷嘴能实现的喷油压力是最高的。本文介绍了泵喷嘴的工作特点,在柴油机上的应用和最新发展。 相似文献
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Faried S.O. Billinton R. Aboreshaid S. Fotuhi-Firuzabad M. 《Energy Conversion, IEEE Transaction on》2000,15(3):305-311
This paper presents a Monte Carlo based approach to evaluate the maximum torsional torques induced in turbine-generator shafts during high-speed reclosing following system faults. In this context, investigations have been conducted on a large turbine-generator model taking into consideration the uncertainty of several factors associated with the practical operation of a power system. In the case of unsymmetrical faults, two switching schemes were considered in clearing and reclosing such faults, namely conventional (triple pole for line-to-line and double line-to-ground faults and single-pole for single line-to-ground faults) and selective-pole switching. In the latter case, the transmission system is balanced during the period between fault clearing and line reclosing using compensating capacitors. Moreover, an adaptive reclosing technique is used for reclosing the tripped phases. The effect of employing the adaptive short-time compensation and reclosing technique on the expected maximum torsional torques as well as their variances has been investigated. A risk index which reflects the likelihood that the torque induced in a turbine-generator shaft exceeds its design value is also presented 相似文献
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This paper mainly introduces the basic principles,the methods and the applications of infrared technique in the diagnosis and prediction of diesel engine exhaust faults. The test-bed for monitoring diesel engine exhaust faults by thermal infrared imager has been designed. In different running conditions, the exterior surface radiation temperatures of the exhaust pipe of the 6135G-1 diesel engine have been measured by infrared imaging system. According to the principle of infrared temperature measurement, the real temperatures of the exterior surface of the exhaust pipe have been calculated. Based on the principle of heat transfer, the method of calculating the exhaust temperatures according to the exterior surface radiation temperatures of exhaust pipe measured by thermal infrared imager is built. The relationship between diesel engine exhaust temperatures and faults has been analyzed. It is shown that the application of infrared inspection and diagnosis to the identifying of diesel engine exhaust faults is feasible and effective. 相似文献
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柴油机燃油系统故障诊断的研究 总被引:12,自引:0,他引:12
介绍了采用一种不解体柴油机燃油系统故障诊断的新方法,通过检测高压油管的弹性变形量,提取了反映燃油系统故障状态的特征向量,并利用模糊模式识别技术成功地诊断了燃油系统的各种典型故障。 相似文献
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在建立火电机组回热系统常见故障的故障集和征兆集基础上,利用模糊数学知识和相关理论,针对回热系统故障征兆参数的不同变化方向和程度,采用不同的变化等级和阈值,建立了回热系统典型故障样本模式知识库及实时故障模式集。同时利用基于MATLAB环境下的径向基函数网络,建立了回热系统故障诊断模型。并利用电站仿真机模似典型故障进行了神经网络模型的验证。实践表明,这种方法可有效地进行回热加热器故障样本模式的模糊量化处理,极大地改善了神经网络训练的收敛性。有利于回热系统的故障诊断。 相似文献
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柴油机喷油器故障直接影响到燃油的喷射质量,导致燃烧过程恶化,影响柴油机的性能指标。常规的模糊神经网络中,模糊运算往往采用静态的、局部优化运算方法,往往存在技术上的难点,为此提出了一种基于补偿模糊神经网络的智能诊断系统。该系统将神经网络和补偿模糊逻辑相结合,采用动态、全局优化的运算,充分利用了相互间的优点,使网络更适应、更优化,加快训练速度。运用到柴油机燃油喷射系统故障中,取得了较好的效果。 相似文献
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As a result of the increased wind power penetration, there are increased requirements for robustness of the wind farms during disturbances and faults. The wind farms are required to stay connected during short grid faults, and also, the disturbances as a result of internal faults should be minimized. In this paper, the fault ride‐through properties during external faults for a wind farm with an internal direct current (DC) grid are investigated. A safe detection of the fault is derived, as well as the reconnection procedure after the fault has been cleared. Also, the operation during internal faults has been investigated, focusing on the faults in the DC bus. It has been shown that the wind farm with an internal DC grid can operate through faults in the external grid and reconnect well within the requirements stated in the grid codes. Further, methods for detection of internal faults are derived, and it was shown that a faulted part can be disconnected and the non‐faulted parts can be back in operation within 100 ms using a DC breaker in each radial and within 300 ms without DC breakers. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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基于核主元分析的传感器故障检测 总被引:2,自引:0,他引:2
提出了一种新的火电机组传感器故障检测系统.传统的主元分析方法在非线性系统中不能很好的发挥作用.采用核主元分析方法提取系统的非线性冗余信息,建立核主元模型.并在输入空间对数据进行重构,通过最小化均方预测误差来选择合适的核函数和参数,对模型的建立过程进行指导.在线检测时,利用核主元模型,将实时数据投影到核主元空间,能够有效的去除系统的噪声.对重构残差采用序贯概率比检验方法进行检验,不仅能够诊断出传感器的漂移等明显故障,而且能够及时发现设备或者系统的早期故障.通过某电厂125MW机组真空系统的多传感器故障检测仿真实例,验证了该方法的有效性. 相似文献