Detecting Knock in Spark Ignited Engines

Authors:	Nilsson Ylva, Linköping University, Sweden Frisk Erik, Linköping University, Sweden
Topic:	7.1 Automotive Control
Session:	Automotive Diagnosis and Warning
Keywords:	knock, detection algorithms, engine, cylinder pressure, ion current, oscillations

Abstract

In this paper we consider signal processing algorithms for detectingknock, i.e. auto-ignition of unburned fuel, in spark-ignited engines.To operate an engine with optimal efficiency, there is a need tooperate close to the knock limit. This motivates the need forefficient knock detection algorithms that not only indicates knock,but also gives estimates on knock timing and size. The proposeddetection algorithms are based on either in-cylinder pressure or ioncurrent and both off-line and on-line methods are developed. Themethods are tested on measured data, analysed, and compared withrespect to detection performance, knock timing estimation accuracy,and robustness against model uncertainties.