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B. Geringer, J. Spreitzer, C. Martin, M. Mayer:
""Meta-analysis for an E20/25 technical development study - Task 2: Meta-analysis of E20/25 trial reports and associated data";
Report No. B14003, 2014; 72 pages.

The main focus is done on a detailed consideration of the ethanol content between 15% and 25% (named E20/25 in this study). To get a comprehensive overview of the effects of ethanol as a blending
component, higher mixing rates were examined with a comprehensive meta-Analysis too (up to 100 % ethanol).
It should be noted, however, that the current study represents an actual state of currently available global literature and do not reflect specific directly done Research results on this field. The vehicles and engines investigated in the literature sources are
mostly production engines available on the market and were used for the combustion of ethanol, but were usually not optimized for E20/25. In summary there is a variety of different boundary conditions in the individual studies, therefore comparability is limited for some cases. Therefore, the literature was selected according to specific criteria, to create comparative conditions across all the studies.
Furthermore, it should be noted that in addition to the current E10 (10 % ethanol blend rate) vehicles and the specially adapted flexible fuel vehicles (FFV) which allow operation up to an ethanol concentration of 85%, neither vehicles specifically designed nor produced for the range of E20/25 are currently available. In addition to extensive modifications in the engine control software (motor electronics) further adjustments to mixture formation, ignition, fuel circuit and material adaptation need to be made to the engine corresponding to the higher ethanol content in the fuel.
With 1st September 2014 the EURO 6 emission standard for type approval for passenger car and light duty trucks comes into effect, registration and sale for new types of vehicles are following on 1st January 2015. During the study EURO 6 engines were only sporadically available on the market. For this engines however, there are no
scientific studies regarding E20/25. Therefore, no EURO 6 vehicles are considered in this study.