Knock acoustic signal estimation using parametric inversion

Knock in spark ignition engines goes against car manufacturers´ efforts to reduce fuel consumption as well as exhaust gas emissions. This paper develops a signal-processing method to quantify knock. After discussing some classical techniques of knock energy estimation, an acoustical measurement technique is presented. An original signal-processing method based on a parametric compartmental model for both knock and apparatus is used. A special inversion technique is also proposed to obtain actual knock parameters. The knock-related parameters are computed through a two-step process. First, a deconvolution algorithm is used to obtain a sparse spike train signal. Then, an efficient inversion method follows. The whole process is applied to real data from a one-cylinder engine. Results are compared to those obtained from an existing technique. They demonstrate the usefulness of such a procedure in a common industrial application