Accession Number : ADA136423

Title :   Octane Requirement Increase of 1981 Model Cars.


PDF Url : ADA136423

Report Date : Nov 1983

Pagination or Media Count : 42

Abstract : The need to study octane requirement increase (ORI) with unleaded fuel became evident in 1970 when manufacturers announced that cars would require catalytic converters and use unleaded gasoline of at least 91 RON quality to meet future emission standards. Since that time, manufacturers have made many engine modifications to meet both exhaust emission and fuel economy standards. Because of these engine design changes and the increasing use of unleaded gasoline, the Coordinating Research Council, Inc. (CRC) initiated a series of ORI programs in 1971. This report will summarize ORI data for 1981 model cars. Findings include: Octane requirement increase (ORI) was determined for eighty-six 1981 model cars operated on unleaded gasoline. At 15,000 miles, the mean ORI for all cars with full-boiling range unleaded (FBRU) fuels was 5.1 Research octane numbers, 3.3 Motor octane numbers, and 4.2 (R+M)/2 numbers; At 15,000 miles, the mean ORI for seventy-four cars with full-boiling high sensitivity unleaded (FBRSU) fuels was 5.2 Research octane numbers, 3.6 Motor octane numbers, and 4.4 (R+M)/2 numbers; At 15,000 miles, the mean ORI for seventy-four cars with primary reference fuels (PRF) was 4.1 octane numbers; Compared with 1980 models (120 cars), the mean ORI for all cars in the 1981 program with FBRU fuels was the same on a RON basis, and 0.1 MON higher; In general, the mean ORI with FBRU fuels has not changed appreciably for the 1975 through 1981 model cars; and ORI decreases about 0.2 to 0.3 octane number per octane number increase of initial octane requirements.

Descriptors :   *Passenger vehicles, *Fuel additives, *Gasoline, Requirements, Automotive fuels, Road tests, Test methods, Comparison, Specifications

Subject Categories : Surface Transportation and Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE