Palaveev, S., Magar, M., Kubach, H., Schiessl, R. et al., "Premature Flame Initiation in a Turbocharged DISI Engine - Numerical and Experimental Investigations," SAE Int. J. Engines 6(1):54-66, 2013, doi:10.4271/2013-01-0252.
This paper presents the results of experimental and numerical investigations on pre-ignition in a series-production turbocharged DISI engine. Previous studies led to the conclusion that pre-ignition can be triggered by auto-ignition of oil droplets generated in the combustion chamber. Analysis of more recent experiments shows that a modification of the engine operation parameters that promotes spray/lubricant interaction also increases pre-ignition frequency, while modifications that enhance the speed of chemical reactions (thereby favoring auto-ignition) have little or no influence. The experimental and numerical findings can be explained if we assume the existence of a substance (originating from lubricant/fuel interaction) that displays extremely short ignition delay times.