共查询到19条相似文献,搜索用时 234 毫秒
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摩托车空气滤清器性能检测方法探讨 总被引:1,自引:0,他引:1
空气滤清器(下简称空滤器)是摩托车发动机进气系统的重要部件,主要是滤去空气中的灰尘、杂物和水份,以减少发动机气缸、活塞、曲轴等运动部件的磨损及防止化油器孔道堵塞,部分空滤器还兼有进气消声作用。空滤器既是性能部件又是功能部件,尤其是滤清效率、通气阻力等性能参数直接影响发动机的动力性、燃油经济性、使用可靠性和耐久性等。很多整车厂和专业厂对空滤器各项检测试验数据不够重视, 相似文献
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针对某中型客车进气口辐射噪声和车内噪声较大的问题,首先根据车内声模态试验结果和对道路试验数据的偏相干与频谱分析结果,找到了主要噪声源为进气口,并确定了消声目标频段。接着研究了空滤器滤芯与穿孔管的声学特性,建立了进气系统有限元声学模型,并通过对比进气系统传递损失仿真曲线与怠速进气口噪声频谱,验证了模型的准确性。然后针对目标频段设计了进气消声器,使进气系统的传递损失在250~400Hz频段平均达24.7d B。最后进行了道路验证试验,结果表明设计的消声器有效降低了进气口辐射噪声和车内噪声。 相似文献
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正进气系统的阻力和声学是一对矛盾,顾此失彼都难以做到性能与成本的最优,是进气系统开发过程中的难点所在。本文详细阐述了在进气系统开发中,如何进行两者之间的合理平衡。针对不同的开发模式、开发阶段,提出了如何定义管道直径的方法,给出了流体设计的基本理念,以有效指导进气系统的初期开发工作。进气系统发动机进气系统主要包含进气引气管(脏管)、空气滤清器(以下简称"空滤器")、过滤后管路(干净管)、波纹管、消声器结构以及相应的固定连接小部件等。相较于自然吸气型发动机,增压发动机的进气系统通常设计有宽频消声器结构。跨入本世纪前,进气系统的开发主要关注其流动特性以及空滤器的过滤性能,以实现发动机优化 相似文献
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原HS125GY车所配化油器为柱塞式PZ26,与普通两气门125 mL发动机相当,采用四气门设计的目的是要提高进气填充效率,但PZ26化油器实际上却限制了发动机的进气效率.应匹配大口径化油器、进气管、空滤器来提高进气效率空间,按RX125进气口等效直径匹配化油器、进气管和低阻力系数空滤器. 相似文献
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汽车进出风口对汽车空气动力学特性有重要的影响。利用CATIA建立了三种不同进出风口的汽车模型,利用CFD方法研究不同进出风口对汽车流场的影响。采用三维不可压缩雷诺平均方程N~S方程采用RNG k-ε湍流模型,利用二阶迎风差分格式获得控制体积界面上的物理量,应用SIMPLEC算法进行迭代计算,对汽车流场进行模拟仿真,并将结果进行对比分析。研究结果表明:汽车前端只有一个进风口的情况下,发动机迎风面的高压区偏上,并且高压区的压力明显低于增加辅助进风口的情况。将三种情况下仿真得出的发动机舱内散热所需的冷却空气量与实际所需要的空气量对比,结果显示,汽车前端只有一个进风口的情况不能满足发动机舱内的散热需求,而其余两种情况能够满足散热需求。 相似文献
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The intake system in an automotive engine has a short duct compared with that of the exhaust system. The filtered-x LMS (FX-LMS)
algorithm has been applied to the active noise control (ANC) system in a short acoustic duct. This algorithm design is based
on the FIR (finite impulse response) filter; however, it has a slow convergence issue due to a large number of zero coefficients.
To improve the convergence performance, the step size of the LMS algorithm was modified from fixed to variable. However, this
algorithm is still not suitable for the ANC system of a short acoustic duct because the reference signal is affected by the
backward acoustic wave propagated from a secondary source. Therefore, the recursive filtered-u LMS algorithm (FU-LMS) based
on the infinite impulse response (IIR) is developed to consider backward acoustic propagation. Generally, this algorithm has
a stability problem. The stability issue was improved using an error-smoothing filter. In this paper, the recursive LMS algorithm
with a variable step size and smoothing error filter is designed. This recursive LMS algorithm, the FU-VSSLMS algorithm, uses
an IIR filter. With fast convergence and good stability, this algorithm is suitable for the ANC system in a short acoustic
duct, such as the intake system of an automotive engine. This algorithm is applied to the ANC system of a short acoustic duct.
The disturbance signals used as primary noise source are a sinusoidal signal embedded in white noise and the chirp signal,
which has a variable instantaneous frequency. The test results demonstrate that the FU-VSSLMS algorithm has a superior convergence
performance when compared with the FX-LMS and FX-LMS algorithms. The algorithm can be successfully applied to the ANC system
in a short duct, such as the intake duct. 相似文献
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颗粒捕集器喷油助燃再生燃烧器内的流场分布对气流组织及油气混合有重要影响,而供风形式是燃烧器内流场特性的主要影响因素之一.为了在燃烧室内形成稳定持续的回流,促进油气混合进程,分别采用双矩形口切向供风和直片式轴向旋流器供风两种供气形式,设计等入口截面面积的两种供风系统结构,并在相同发动机排气和补气条件下对燃烧器冷流场进行仿真分析.分析结果表明,两种供风形式均能形成可回流到油气混合室端面的中心回流区,轴向旋流器供风时的中心回流区的长度、最大回流速度、突扩位置的重附着区长度分别比双矩形口切向供风时大8.11%,5.63%和9.59%,且轴向旋流器供风时的湍动能大于双矩形口切向供风.对比结果显示,利用轴向旋流器供风更有利于促进混合过程的进行,对气流的组织更合理. 相似文献
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Linear acoustic theory is used for estimating the acoustical performance of the air cleaner box composed of the porous filter and encasing box in the engine intake system. The pleated filter structure is modeled as coupled multiple ducts having permeable micro-perforated walls and rectangular section, in which each duct area is assumed being homogeneous or inhomogeneous. Mathematical models describe the sound propagation within the narrow duct considering the visco-thermal effect at the filter pleats. For the validation, transmission loss (TL) is measured, and a change in TL spectrum is clearly observed by including the filter into the box. It is shown that the predicted TL counting the effect of visco-thermal loss agrees reasonably well with the experimental results. Noticeable effects of the filter on the TL are observed as highly smoothing effect at high frequencies and enhancing the TL magnitudes at troughs and lobes at low frequencies. Comparing homogeneous and inhomogeneous channel modelings, the latter is superior in precisely predicting the trough frequencies of TL curve, but the former is a bit better in predicting its magnitude. Parametric study on material and shape factors reveals that the number of pleats, length of the pleated filter, and distance between neighboring pleats are the key factors in determining the TL. It is concluded that an air filter element that has small number of long pleats with high flow resistance would bear the best acoustical performance among all designs. 相似文献
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本文基于Amesim软件建立完整的燃料电池系统模型,包含电堆、空气系统、氢气系统和冷却系统模型,研究系统操作条件变化对系统性能的影响,结果表明,该模型可对空气计量比、电堆空入压力、电堆氢入压力、电堆水入温度等参数进行敏感性分析,并选出了最优系统运行操作条件及其对应的系统功率和效率输出,支持系统开发和操作条件优化。 相似文献