Road Octane Number Trends of Japanese Passenger Cars

To develop empirical road octane number (RdON) equations and to obtain the relationship between high speed RdON and fuel quality, RdON were determined by the Modified Uniontown Technique (MUT) and the Modified Borderline Technique (MBL) using 1974 and 1975 Japanese passenger cars.

The effects of RON and DON on RdON-MUT were more pronounced than that of MON. Aromatic and olefin hydrocarbon types had little influence on RdON-MUT. RdON-MBL measured at low speed was similar to RdON-MUT. As speed increased, however, it was influenced by MON.

Road octane number depreciation (ΔRdON) at high speed was increased with sensitivity or olefin content.