基于Hilbert—数学形态变换的柴油机燃烧始点辨识

Identification of Combustion Timing of Diesel Engine Based on Hilbert—Mathematical Morphology Transform

为了识别燃烧始点,本文对比了基于油压、缸压以及振动信号识别方法的优缺点,最后采用振动信号识别。在燃烧始点气缸压力急剧升高,缸盖振动响应也更为强烈。通过对信号进行一系列的Hilbert变换、形态滤波、差分运算、最后设置阈值即可提取燃烧始点。实验分析得出康明斯K38发动机燃烧始点约在上止点前20°CA,结果表明该方法具有稳定性、准确性和可行性。

Cylinder head vibration signals are adopted in this article in order to identify the timing of combustion after comparing the signals of oil pressure, cylinder pressure and cylinder vibration. Along with the sharp increasing of cylinder pressure, the cylinder head vibration response becomes intensive at the beginning of combustion. By a series of Hilbert transform, Mathematical Morphology filter, differential operation and threshold setting, the combustion timing is recognized. It can be calculated that the timing of combustion is 20 CA before TDC. The result of the experiment shows that this method is steady, precise and effective.