CRC Customer Versus Rater Octane Number Requirement Program (1990)
COORDINATING RESEARCH COUNCIL INC ATLANTA GA
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A CRC cooperative program was conducted to determine the difference in octane requirements between technical raters and customers the general driving public. The tests were conducted in two phases, with the second being a repeat of the first to verify the results obtained. 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 customers responses perception and objection level were based upon audible knock, acceleration performance, and after-run on a series of full-boiling-range customerrater unleaded FBRCU reference-fuels. Data were analyzed from 168 1988-1991 model-year vehicles, with 126 of these tested in Phase II. The results showed that the customers, objections and perceptions were overwhelmingly based on knock, rather than acceleration performance or after- run. Two general methods, a population comparison and a delta analysis, were used to estimate the difference between customer and rater octane requirements. In the first method, the data were analyzed by comparing satisfaction curves for the technical and customer octane requirements population comparison.