Results of Octane Number Requirement Survey 1959∼1968 Japanese Model Passenger Cars

Abstract

This is a summary report of a ten year survey results of the octane number requirements of Japanese passenger cars from 1959 models to 1968 models.Each year 10 to 12 new car models of high population were tested and 1, 063 cars were covered in the ten years. Primary reference fuels and one or two types of full-boiling range reference fuels selected from reformed type, cat-cracked type and mixed type were used.During 1959 to 1963, octane number requirements were determined based on CRC-E-1-748, and after 1964, according to JPI test methods (JPI-6R-3-64∼JPI-6R-3-68). These provide methods for manual transmission cars rating by full and part throttle acceleration. JPI-6R-4-68 was established based on Detent acceleration for rating passenger cars with automatic transmissions.Octane number requirements of each year models at 50% and 90% satisfaction levels increased up to 1964, 90.4 and 96.4 octane numbers respectively, and thereafter changed little until 1968. Octane number requirements of all cars at 50% and 90% satisfaction levels gradually increased. In 1963, these were 87.4 and 94.0 octane numbers respectively, but increased to 90.2 and 95.7 octane numbers in 1968. By inspecting the data for 1962 to 1968 models grouped by engine displacements, it was shown that the octane number requirements of the larger displacement cars were hinger than the smaller cars.