Analysis and Detection Methodology of Knock Phenomenon in Gasoline Engines Based on Cylinder Pressure Sensors

摘要

In this paper, the analysis about the cylinder pressure signal was conducted. Furthermore, the optimized knock window was selected. And the frequency of knocking signal was determined. Besides, evaluation methodology of knock intensity was investigated and confirmed. The conclusions are as follows: 1. The selection of knock window is significant to the knock detection. The optimized pre-ignition and knock window should be selected and confirmed separately. The knock window of 20°CA after the knock occurrence is recommended based on the investigation results. 2. The value of knock frequency is significant in the knock sensor calibration. The frequency of knocking signal is estimated by Bessel function, EFT, and power spectrum density analysis 3. The methodology of the knock intensity evaluation should change in different engine operating conditions. Having eliminating the influence of background noise, the knocking intensity (KJ) is defined based on different sampling resolutions, operating conditions of various ignition timings, and Lambda values.