The octane requirement increase (ORI) of 80 1990 and 43 1991 model-year vehicles operated on commercial fuels in customer-like service has been determined. These ORI values were established from the octane number requirements regardless of whether they were determined at maximum- or part-throttle. At 15,000 miles, the mean ORI of the 1990 vehicles with full-boiling range fuels (FBRU) was 4.4 (R+M)/2 octane numbers, 5.2 Research octane numbers (RON), and 3.5 Motor octane numbers (MON). The ORI of individual vehicles ranged from no increase to 1 1. 1 (R + M)/2 numbers. At 15,000 miles, the mean ORI of the 1991 vehicles with full-boiling range fuels (FBRU) was 3.3 (R+M)/2 numbers, 4.1 RON, and 2.6 MON. Individual vehicle ORI ranged from no increase to 9.2 (R + M)/2 numbers. As opposed to a number of 1989 models submitted which showed a somewhat unusual variation with mileage, the 1990 and 1991 models behaved in the more traditional manner.
Octane Requirement Increase of 1990 and 1991 Model Vehicles
1992
30 pages
Report
No indication
English