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A Coordinating Research Council, Inc. (CRC) cooperative program was conducted to determine the difference in octane requirements between technical raters and “customers.” The trained raters used the CRC E-15 procedure to determine the octane requirement of the vehicles while the customers' perception and objection to knock were determined through the use of a questionnaire. The results showed that the customers' objections and perceptions were overwhelmingly based on knock, rather than acceleration performance or after-run. The difference between the technical and customer octane requirement at the midpoint satisfaction level was 3.8 (R+M)/2 octane numbers using the population comparison and 4.1 (R+M)/2 octane numbers using the distribution of delta analysis. The statistical analysis of the database also showed that the differences between customer objection and perception levels were generally small (less than or equal to 1 (R+M)/2 octane number).

The potential effect of fuel composition on total particulates and particulate character were measured on a variety of production vehicles, which are representative of different combustion system types, using commercial and laboratory fuel blends. Tests were made with a CVS dilution tunnel, primarily using the EPA CVS-CH test procedure. Particulate emissions were found to be a function of both fuel and vehicle parameters. Both the particle bound organic and the carbonaceous fractions of diesel particulates showed linear relationships with the fuel’s aromatic content and backend volatility (as measured by the fraction of the fuel boiling above 640°F). Emission rates were strongly affected by vehicle type. The regression models for each car indicated that the back-end volatility contributed primarily to the particle bound organic fraction, while the aromatic content of the fuel influenced the carbonaceous fraction.

The effects of API SE engine oils on the activity of a 1975 prototype monolithic, noble metal oxidation catalyst have been studied in long-term multicylinder laboratory engine tests. Results of this work showed that oil consumption rates, up to 1 qt/1000 miles, and lube ash up to 1.6%, do not significantly affect catalyst activity in 500 hour tests, equivalent to 20,000 miles (32,180 km). A commercial type 1% ash SE oil showed only a small effect on catalyst activity in an extended 1250 hour test, equivalent to 50,000 miles (80,450 km). At the end of the test, the catalyst met the original 1975 emissions standards of 3.4 g/mile CO and 0.41 g/mile HC. A higher-than-normal phosphorus-containing oil (0.32% P) caused significant loss in catalyst activity after testing for 30,000 miles (48,270 km). This suggests that any need for increased phosphorus-containing additives in future oils could cause catalyst poisoning before 50,000 miles.