Evaluation of the Antiknock Quality of Gasoline by the “Energetic Criterion” 912391
The aim of the present work is to test and verify the possibility of developing a rational test method founded on the Energetic Criterion to rate the antiknock performance of unleaded gasolines through the measurement of the Energetic Index (IE) on current CFR engines. This index gives the specific power (W/m3) associated to the knocking combustion in an I.C. engine.
Two conventional CFR engines for ASTM RON and MON ratings were fitted with a suitable instrumental chain in replacement of the standard detonation meter and relative magnetostrictive sensor to process the combustion pressure signals.
A number of tests performed in “Research” and “Motor” operating conditions on Primary Reference Fuels, clear and CORC fuels show the existence of a simple relation between the IE and the compression ratio.
Moreover by means of the new method it is possible to evaluate better antiknock performance of unleaded gasolines of different compositions than by the ASTM octane rating. In particular, it evidences the high knock resistence of aromatic components as observed in road tests.