A New Method to Detect Knocking Zones

It is a well known fact that indicated efficiency of a SI engine at WOT is predominantly limited by knock occurrence. Therefore many investigations have been carried out to avoid knocking. Considering the further development of downsized engines knocking will also pose a greater challenge. Not only knocking but also irregular combustion in general will require further investigation in supercharged SI eingines. Premature ignition, for instance, hasn’t yet been completely understood and therefore limits the low end torque of supercharged SI engines.

The purpose of this paper is to introduce different analysis methods which allow to identify the knock onset and the knocking zones in the combustion chamber. In addition to established methods new techniques have been developed to account for the complex nature of pressure oscillation during knocking combustion.

Experimental data was acquired on a single cylinder research engine to validate the methodology using six pressure transducers.