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Advanced Intra-cycle Detection of Pre-Ignition Events Through Phase-Space Transforms of Cylinder Pressure Data
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 15, 2020 by SAE International in United States
The widespread adoption of boosted downsized SI engines has brought preignition phenomena into greater focus, as the knock events resulting from preignitions can cause significant hardware damage. Much attention has been given to understanding the causes of preignition and identify lubricant or fuel properties and engine design and calibration considerations that impact its frequency. This helps to shift the preignition limit to higher specific loads and allow further downsizing but does not fundamentally eliminate the problem. Real-time detection and mitigation of preignition would thus be desirable to allow safe engine operation in preignition-prone conditions. This study focuses on earlier detection of preignition in an engine cycle where it occurs. Phase space transforms through time-delay embedding of cylinder pressure and principal component analysis were applied to same-cycle detection of preignition and shown to enable detection on the order of a crank degree earlier than deviation in cylinder pressure can be identified through direct statistical observation of the pressure data. Additionally, it appears that the deviation of the trajectory in phase space may offer the opportunity to extend this method to further extend the detection window and allow more time for mitigation actions to occur.