Research On Relativity Of Knock Sensor Signal And HCCI Engine Combustion Parameters

Homogeneous Charge Compression Ignition (HCCI) is considered as the new generation combustion and received a lot of attention from the world-wide automotive field due to ultra-low NOx emissions and high thermal efficiency.HCCI combustion is a complicated chemical reaction dynamic process, so the conditions of self-ignition of fuel are sensitive to many factors such as thermodynamic and chemical state. And it is also sensitive to the history of the combustion. It is a vital task for HCCI engine control to monitor the combustion parameter due to the HCCI engine control mode-the control based on Cycle.At present, the main measure to get the combustion parameters is to monitor cylinder pressure with the cylinder pressure sensor which is not feasible used in mass production of HCCI engine. It is a good substitute to get the combustion parameter with the knock sensor which is equipped on engine on a large scale.The purpose of this paper is to find the relationship between the combustion parameters and the knock sensor signal. In this paper, character signal was extracted from the knock sensor signal with Fast Fourier Transform and Wigner-Ville Distribution and comparisons are made between pertinences of different couple parameter standing for combustion parameters and knock signal parameter respectively.It's shown in the analysis that there are strong relativity between knock sensor signal and combustion parameters. The correlation coefficient is high to 0.97842 between CA10 and the start phase of the knock signal. It is a feasible and cost effective way to get combustion parameters of HCCI engine from knock sensor signal for the HCCI control.