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J. Graf, C. Martin:
"Evaluation of Gasoline Fuels with Standard and New Developed Test Methods to characterize the Knocking and Pre-Ignition Behaviour";
Report No. B14021, 2014; 14 pages.

The investigation of knocking, pre-ignition and/or self-ignition behaviour of gasoline fuel is a vital step for optimizing boosted downsized SI engines and their consumables.
Fuel specifications to describe knocking behaviour are the Research Octane Number (RON) and the Motor Octane Number (MON). These standard test methods are not able to characterize the increase of the knock resistance of fuels with high content of oxygenates. This cooling effect of alcohol blends is considered by the new test method "Direct injection Octane Number (DON)", developed by Prof. Geringer, Institute for Powertrains & Automotive Technology (IFA).
Furthermore the pre-ignition behaviour of gasoline fuels can also be detected with the modified CFR engine of the IFA. There are two major reaction mechanisms: A differentiation is made between inflammation triggered by a critical condition in the gas phase (e.g., high intake air temperature and/or high compression) and inflammation caused by a hot surface. The first characteristic number for compression ignition in the gas phase is called CPI (Compression Pre-Ignition), while HSPI (Hot Spot Pre-Ignition) means the second characteristic number for glow-ignition.