|Title:||Entwicklung und Vergleich von Kriterien zur Erkennung der klopfenden Verbrennung in Ottomotoren||Other Titles:||Development and Comparison of Criteria to Detect Knocking Combustion in Gasoline Engines||Authors:||Ohler, Sebastian||Language:||ger||Keywords:||Verbrennungsmotor;Glühzündung;Lichtwellenleiter;Optische Messtechnik;Self-Ignition-Center;Fibre optic;Combustion Chamber Resonance||Subject (DDC):||600 Technik||Issue Date:||2014||Publisher:||Universitätsbibliothek der HSU/UniBwH||Document Type:||Thesis||Publisher Place:||Hamburg||Abstract:||
Within the scope of downsizing and downspeeding concepts shifting the operating points in the engine map to higher load points of gasoline engines enhances the knocking endangered operating points in the vehicle used operation. In addition to the increased fuel consumption reduction of gasoline engines this denotes the important motivation for detecting, evaluating and avoiding the knocking combustion. As a starting point, this thesis presents a survey of both the overall schemes and the essential knowledge of the knocking combustion that has been gained in research over more than 100 years. The evaluation methods described in literature are presented and analysed with respect to their ability of being repeated. In the case of unequivocal repeatability these knock criteria are used for comparative investigations. These investigations yield the development of a new approach for the evaluation of the knocking combustion. The new approach is based on the detection of the self-ignition centers which is independent from the evaluation of the damaging potential of the knocking combustion. This proves to be a crucial benefit when compared with the established knock criteria. In order to detect the knocking combustion the slope of the net heat release curve of a high-resolution low-pass filtered cylinder pressure signal is analyzed. Simultaneously the point in time of the development of self-ignition centers and the prediction of occurrence of high frequency oscillations of knocking combustion are determined. The evaluation of the knocking combustion, however, requires the analysis of the high-frequency oscillations of the cylinder pressure signal. Hence, the approach developed here enables the evaluation of the knock intensity by analyzing the band-pass filtered net heat release rate of an unfiltered high resolution cylinder pressure signal. Using the fibre optic measurement equipment it is possible to detect both the knocking combustion and the development of the self-ignition centers by means of a measurement technology which is independent from the cylinder pressure signal. At the same time the differences in comparison with the established determination methods become apparent. The results based on the new approach suggest that even unfavourable conditions are not detrimental for the determination of the knocking combustion. This sets the new approach apart from the knocking criteria available in literature.
|Organization Units (connected with the publication):||Antriebssystemtechnik||DOI:||https://doi.org/10.24405/508||Advisor:||Thiemann, Wolfgang||Referee:||Bargende, Michael||Grantor:||HSU Hamburg||Type of thesis:||Doctoral Thesis||Exam date:||2014-05-16|
|Appears in Collections:||2 - Theses|
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