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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).

During the Coordinating Research Council's (CRC) program to select an engine to replace the BMW 31 8i as the industry standard intake valve deposit test engine, an opportunity was identified to compare the driveability performance of the engines evaluated with and without deposits. This Coordinating Research Council project confirmed that intake valve deposits increase driveability demerits as measured by the BMW Driveability Test Procedure. This was true for the BMW 31 8i reference vehicles as well as the three candidate engines. The driveability demerits for the reference engine as well as the three candidate engines increased with decreasing fuel volatility of the engines considered. The BMW 31 8i was by far the most sensitive to intake valve deposits. A modification of the CRC Driveability Test Procedure did not produce the clear separation found with the BMW Driveability Test.

From 1995 to 1997, the Coordinating Research Council (CRC) conducted a cold-start driveability program to evaluate the behavior of lower volatility fuels at cold, intermediate, and warm ambient temperatures. The program used 135 vehicles to evaluate 87 hydrocarbon, MTBE blended, and ethanol blended fuels. Evaporative driveability index equations (EDIs) were developed using the test design fuel variables (E158°F, E200°F, E300°F), and three other variable sets: (E158°F, E250°F, E330°F), (T10, T50, T90), and (E70°C, E100°C, E140°C). The models that best fit the data contained oxygenate offsets. Overall, the best indices are the E70°C, E100°C, E140°C equation and the DI equation with offsets.

Port-fuel-injection (PFI) problems were first reported late in 1984. Deposits that formed on the tip of the pintle-type injectors of certain engines restricted fuel flow and caused driveability and emission problems. Responding to this problem, industry test programs were initiated to reproduce the deposits under controlled conditions. In 1986, a vehicle test procedure was identified and the automotive industry recommended a pass/fail performance level. Building upon available information, the Coordinating Research Council's (CRC) Port Fuel Injector Deposit Group developed a standard vehicle test procedure to evaluate various unleaded gasolines for port-fuel-injection fouling. The vehicle test procedure was adopted as an ASTM test method. The United States Environmental Protection Agency (EPA) and the State of California accepted the procedure as the standard for measuring a gasoline's propensity to form deposits in a pintle-type injector.