基于单缸柴油机台架试验和虚拟样机仿真分析，研究了缸盖表面振动加速度信号的主要激励源及其耦合关系，讨论了带通滤波技术和经验模态分解提取的燃烧激励响应信号完整性与有效性。结果表明：缸盖表面振动加速度信号主要激励源为缸内压力和往复惯性力；二者的振动响应在时频域重叠，重叠部分的能量取决于缸内工作过程及发动机转速；基于相干性分析的带通滤波技术提取的燃烧激励响应曲线上，用于识别燃烧过程特征参数的特征点位置受发动机机型及缸内燃烧状态影响；经验模态分解得到的燃烧激励响应与非燃烧激励响应间存在模态混叠问题，基于往复惯性力激励响应信号描述模型可对分解得到的燃烧激励响应信号进行修正，降低燃烧激励响应曲线上与燃烧过程相关的特征点的离散度。
Abstract
Here, based on bench tests of single-cylinder diesel engine and simulation analysis of virtual prototype, main excitation sources and their coupling relationship of vibration acceleration signal on cylinder head surface were studied. The integrity and effectiveness of combustion excitation response signal extracted with the band-pass filtering technique and empirical mode decomposition (EMD) were discussed. The results showed that the main excitation sources of vibration acceleration signal of cylinder head surface are cylinder inner pressure and reciprocating inertia force; vibration responses of the two are overlapped in time domain and frequency one, and energy of the overlapped parts depends on working process in cylinder and engine speed; on combustion excitation response curve obtained using the band-pass filtering technique based on coherence analysis, position of feature points used to identify feature parameters of combustion process is affected by engine type and combustion state in cylinder; there is mode-mixing problem between combustion excitation response and non-combustion excitation one both obtained using EMD; the combustion excitation response signal obtained with EMD can be modified based on reciprocating inertia force excitation response signal description model to reduce the dispersion of feature points related to combustion process on combustion excitation response curve.
关键词
内燃机 /
振动分析 /
相干性 /
经验模态分解(EMD)
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Key words
internal combustion engine /
vibration analysis /
coherence /
empirical mode decomposition (EMD)
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参考文献
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